Deep water Ophiuroidea (Echinodermata) of New ...

DEEP-WATER

OPHIUROIDS FROM

NEW CALEDONIA

Deep water Ophiuroidea (Echinodermata) of New Caledonia: Ophiacanthidae and Hemieuryalidae

Timothy D. O’HARA Museum Victoria, GPO Box 666E, Melbourne, 3001, Australia. [email protected]

Sabine STÖHR Swedish Museum of Natural History, Box 50007, SE-10405 Stockholm, Sweden. [email protected]

ABSTRACT Ophiuroids of the families Ophiacanthidae (46 species) and Hemieuryalidae (2 species) are monographed for the region around New Caledonia in the southwest Pacific Ocean. Ophiohamus nanus n. gen. n. sp. is described in the Ophioplinthacinae. New species are also described in the following genera: Ophiacantha (O. fuscina n. sp., O. richeri n. sp.), Ophioplinthaca (O. amezianeae n. sp.), Ophiomitrella (O. mensa n. sp., O. parviglobosa n. sp.), Ophiothamnus (O. biocal n. sp.) and Ophiurothamnus (O. eleaumei n. sp.). The genus Ophiocyclus is synonymised with Ophiurothamnus, Ophiomelina with Ophiacantha, Toporkovia with Ophiolimna, Ophiomytis with Ophioplinthaca, and Ophiogyptis with Ophiomoeris. Ophiomelina moniliformis (Koehler, 1904) thus becomes a junior homonym of Ophiacantha moniliformis Lütken & Mortensen, 1899 and the replacement name Ophiacantha renekoehleri n. nom. is proposed. In addition there are 37 new species-level synonymies and 19 other new genus-species combinations. A key is provided for all genera and all tropical Indo-West Pacific species of the Ophiacanthidae. The results show that the biogeographical relationship of the ophiacanthid fauna of New Caledonia is with the tropical Indo-Pacific. Less than ten percent of the fauna is shared with Southern Australia and fifteen percent with New Zealand. More broadly, there appears to be a single ophiacanthid fauna at upper to middle slope depths (200-2500 m) across the Indo-West Pacific from Africa to Hawaii, with limited east-west differentiation. This fauna grades into distinct temperate bathyal faunas near South Africa, China/Japan and Australia/New Zealand, until there is an almost complete changeover of species by 45° latitude in both hemispheres.

RÉSUMÉ Ophiuroidea (Echinodermata) de mer profonde de Nouvelle-Calédonie: Ophiacanthidae et Hemieuryalidae. Les Ophiures des familles Ophiacanthidae (46 espèces) et Hemieuryalidae (2 espèces) de Nouvelle-Calédonie, sud-ouest Pacifique, sont décrites. Ophiohamus nanus n. gen. n. sp. est décrit dans les Ophioplinthacinae. De nouvelles espèces appartenant aux genres Ophiacantha (O. fuscina n. sp., O. richeri n. sp.), Ophioplinthaca (O. amezianeae n. sp.), Ophiomitrella (O. mensa n. sp., O. parviglobosa n. sp.), Ophiothamnus (O. biocal n. sp.) et Ophiurothamnus (O. eleaumei n. sp.) sont décrites. Sont mis en synonymie les genres Ophiocyclus et

O’HARA T. D. & STÖHR S. 2006. ¢ Deep water Ophiuroidea (Echinodermata) of New Caledonia: Ophiacanthidae and Hemieuryalidae, in RICHER DE FORGES B. & JUSTINE J.-L. (eds), Tropical Deep-Sea Benthos, volume 24. Mémoires du Muséum national d’Histoire naturelle 193: 33-141. Paris ISBN: 2-85653-585-2.

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TIMOTHY D. O’HARA & SABINE STO¨HR

Ophiurothamnus ; Ophiomelina et Ophiacantha ; Toporkovia et Ophiolimna ; Ophiomytis et Ophioplinthaca ; Ophiogyptis et Ophiomoeris. Ophiomelina moniliformis (Koehler, 1904) devient donc un homonyme d’Ophiacantha moniliformis Lütken & Mortensen, 1899. Ophiacantha renekoehleri n. nom. est proposé en remplacement. De plus, 37 nouvelles synonymies d‘espèces et 19 nouvelles combinaisons de genres sont incluses. Une clé est donnée pour tous les genres et espèces d’Ophiacanthidae de l’Indo-Ouest Pacifique tropical. Les résultats montrent que la faune d’Ophiacanthidae de Nouvelle-Calédonie est en relation biogéographique avec l’Indo-Pacifique tropical. Moins de 10% de cette faune est partagée avec le sud de l’Australie, et 15% avec la Nouvelle-Zélande. D’une façon générale, il semble que la faune d’Ophiacanthidae de l’Indo-Ouest Pacifique, allant des côtes de l’Afrique jusqu’à Hawaii, et présentant une bathymétrie allant du sommet du talus continental (200 m) jusqu’à 2500 m, présente une différentiation est-ouest limitée. Cette faune fait progressivement place à une faune tempérée bathyale au large de l’Afrique du sud, de la Chine et du Japon, de l’Australie et de la Nouvelle-Zélande. Un changement presque complet de faune s’opère aux alentours de 45°de latitude dans les deux hémisphères.

INTRODUCTION The French Office de la Recherche Scientifique et Technique Outre-Mer (ORSTOM), and its successor l’Institut de Recherche pour le Développement (IRD), have investigated the deep sea benthos in the region around New Caledonia in the south-west Pacific since 1984 (Richer de Forges 1990, http://www.tropicaldeepseabenthos.org). The many expeditions of this program have generated an enormous collection of invertebrates that is now housed in the Muséum National d’Histoire Naturelle in Paris. This paper is the first of a series describing the deep-sea ophiuroid fauna from these collections and covers the species-rich family Ophiacanthidae Perrier, 1891 and the closely-related Hemieuryalidae Verrill, 1899a. The region covered by this material includes the continental slope around the island of New Caledonia (the expeditions BIOCAL, BIOGEOCAL, MUSORSTOM 4), the Loyalty Island Ridge and seamounts to the east (MUSORSTOM 6, BATHUS 3, VOLSMAR), the Norfolk Island Ridge to the south (CHALCAL 2, SMIB, BERYX 11, HALIPRO 2, BATHUS 3), and the plateau and seamounts around the Chesterfield Islands to the west (CHALCAL 1, MUSORSTOM 5). The deep-water tropical Indo-West Pacific ophiuroid fauna (defined here as extending from 30°N to 30°S, East Africa to Hawaii) is predominantly known from the great scientific voyages of the late nineteenth and early twentieth centuries, including the circumglobal HMS Challenger expedition (Lyman 1878a, 1879, 1882), the HMS Investigator dredgings around India (Koehler 1897, 1898, 1899, 1900), the Siboga expeditions to Indonesia (Koehler 1904, 1905), the Albatross expeditions to the Northern Pacific (H.L. Clark 1911), Philippines (Koehler 1922a), and Hawaii (A.H. Clark 1949), Mortensen’s Pacific Expedition (Koehler 1930) and the John Murray expedition to the eastern Indian Ocean (H.L. Clark 1939). More recent material has been described from northern South Africa (Mortensen 1933b, A.M. Clark 1974, 1977, A.M. Clark & Courtman-Stock 1976), south of Japan (Murakami 1944, Irimura et al. 1995, Irimura & Kubodera 1998), China (Liao & A.M. Clark 1995), the Philippines (Guille 1981), and the northern Tasman Sea (H.L. Clark 1946, Baker 1979, McKnight 1975, 1993). To date the only deep sea ophiuroids to have been described from the waters around New Caledonia are some paedomorphic species from the family Ophiuridae Müller & Troschel, 1842 (Vadon 1990, 1991). The taxonomic classification of the Ophiacanthidae and Hemieuryalidae originated with Verrill (1899a, 1899b) and Matsumoto (1915, 1917), complemented by Koehler (1922a). Paterson (1985) provisionally grouped ophiacanthid genera into four subfamilies, a scheme that has been largely followed in this report. Despite all this work however, there has never been a systematic revision of the Indo-Pacific fauna and many taxa are imperfectly understood, at all levels of the taxonomic hierarchy from species to family. This project began as a biogeographical analysis of the Tasman Sea ophiuroid fauna but the poor state of knowledge of deep-sea Indo-Pacific ophiacanthids has necessitated the re-examination of many type specimens collected from throughout the Indo-Pacific. Although, new information from these specimens has been incorporated into this report, which includes a key to all tropical Indo-Pacific species, this work essentially remains a description of the ophiacanthid and hemieuryalid fauna from waters around New Caledonia. The important task of preparing a phylogenetic classification, redefining problematic genera and subfamilies, requires a thorough cladistic and molecular analysis of the global fauna. The type species of many ophiacanthid genera are from the western Atlantic (Verrill 1899a, 1899b) and lie outside the scope of this work.

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The material is lodged in the following institutions: Australian Museum, Sydney (AM); Natural History Museum, London (BMNH); Bernice P. Bishop Museum, Honolulu, Hawaii (BPBM); Faculty of Science, University of Tokyo, Tokyo (CSTIU); Institute of Oceanography, Moscow (IOUSSR); Museum of Comparative Zoology, Harvard (MCZ); Muséum National d’Histoire Naturelle, Paris (MNHN); Musée Océanographique de Monaco, Monaco (MOM); Museum Victoria, Melbourne (MoV); National Museum of New Zealand, Wellington (NMNZ); Naturhistoriska Riksmuseet, Stockholm (SMNH); United States National Museum, Smithsonian Institution, Washington (USNM); Zoologisch Museum, Universiteit van Amsterdam (ZMA); Zoological Museum, University of Copenhagen (ZMUC); and the Zoological Survey of India, Kolkata (ZSI). The abbreviation ‘‘d.d.’’ is used for disc diameter. Specimens were photographed using scanning electron (SEM) and light microscopes. For SEM photos, all dry specimens were brushed with a small artist’s brush to remove dirt where necessary, mounted on aluminium stubs with spray glue and photographed using a Hitachi FE-SEM 4300. Holotypes and some other single specimens were then removed from the stub by dissolving the glue in butyl acetate, remounted with the opposite side facing up. Skeletal elements such as vertebrae were prepared by submerging an arm piece in household bleach (NaOCl) until all soft tissue was dissolved. The vertebrae were then washed in tap water, air-dried and mounted for SEM as described. Light photographs are a composite of a series of images taken with a Leica MZ16 microscope-camera and combined using Auto-Montage Pro v5.02 software. Measurements on all images were taken either based on instrument magnification, measured on contact copies of the photo negatives, or with a dissecting microscope fitted with an ocular micrometer.

SYSTEMATIC ACCOUNT Family OPHIACANTHIDAE Perrier, 1891 Subfamily OPHIACANTHINAE Paterson, 1985

Genus OPHIACANTHA Müller & Troschel, 1842 Ophiacantha Müller & Troschel, 1842: 106. Ophiacantha ¢ Verrill 1899a: 36, 41. Ophiomelina Koehler, 1922a: 129-130 [new synonymy].

Type species: Asterias bidentata Retzius, 1805 (designated by H.L. Clark,1915). REMARKS. — Ophiacantha is a ill-defined, heterogeneous taxon that contains several groups of species that probably deserve their own genus and many other species that are difficult to place taxonomically. For example, there is a group of similar species with a dense covering of disc stumps or granules and unusual short rectangular adoral shields restricted to the proximal edge of bell-shaped or elongate oral shields. This group includes the five-armed O. rosea Lyman, 1878a, O. pentactis Mortensen, 1936 and the six-seven armed O. vivipara Ljungman, 1872, O. anomala Sars, 1872 and O. nodosa Lyman, 1878a. Another group contains the large abyssal species with irregularly thorny disc stumps, adoral shields that frequently extend distally around the lateral angles of the oral shield, wide ventral arm plates and minute tentacle scales. This group includes O. bathybia H.L. Clark, 1911, O. cosmica Lyman, 1878a and O. sociabilis Koehler, 1897. Of the genera that have been distinguished from Ophiacantha, Ophiogema, Ophialcaea and Ophiotreta appear to be well-defined taxa. The characters of Ophiomelina, however, overlap with many Ophiacantha species. Koehler (1922a) compared Ophiomelina with Ophiomitrella and ‘‘Ophiophthalmus’’; however the presence of rib-like radial shields that

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are mostly concealed by thin overlapping disc plates indicates an affinity with the Ophiacanthinae as defined by Paterson (1985). Koehler (1922a) characterised Ophiomelina by the elongate adoral shields that separate the oral shield from the first lateral arm plate. While this character may be absent from Ophiomitrella and ‘‘Ophiophthalmus’’, there are many species within Ophiacantha with a similar arrangement. For example, O. dallasii Duncan, 1879, O. hospes Koehler, 1930 and O. vagans Koehler, 1898 have enlarged adorals that almost completely surround the diminutive oral shield. Moreover, the oral shield sits over the distal section of the adoral shields in the O. cosmica group of species as well as in some specimens of O. indica Ljungman, 1867. Koehler referred two species to Ophiomelina, O. placida Koehler, 1904 and O. moniliformis Koehler, 1922a. The generic type, O. placida, is unusual for an Ophiacantha - large specimens having supplementary oral papillae, grooved oral shields and spines on the ventral arm plates. However, O. moniliformis and juvenile O. placida do not have these characters, and, pending a generic-level revision, Ophiomelina is treated here as a synonym of Ophiacantha. Unfortunately, the new combination Ophiacantha moniliformis (Koehler, 1904) is a junior homonym of O. moniliformis Lütken & Mortensen, 1899 from the eastern Pacific Ocean, and a replacement name is required. Koehler’s species is in fact very similar to Lütken & Mortensen’s, the only difference appears to be between the arm spines, which have some thorns and number up to six on Koehler’s species, falling away to four after a few segments. Lütken & Mortensen’s figures show no thorns, and arm spines on a 5 mm d.d. specimen number five, reducing quickly to three. We propose the replacement name Ophiacantha renekoehleri for Koehler’s species, in recognition of the French naturalist’s outstanding contribution to echinoderm taxonomy.

Ophiacantha cornuta Lyman, 1878 Fig. 2A-D Ophiacantha cornuta Lyman, 1878a: 145, pl. 10 (266). Ophiacantha cornuta ¢ Lyman 1882: 193-194, pl. 40 (3-5). — Rowe 1989: 287.

TYPE MATERIAL. — Holotype: BMNH 1882.12.23.69. Paratype: BMNH 1882.12.23.321 (lost?). TYPE LOCALITY. — Off Kermadec Islands, 1116 m. MATERIAL EXAMINED. — New Caledonia. MUSORSTOM 5: stn DW 251, 25°6.36’S, 160°1.51’E, 1330 m, 07.10.1986: 2 (MNHN EcOs 22632).

New Zealand. Challenger: stn 171, Kermadec Islands, 28°33’S, 177°50’W, 1116 m, 15.07.1874, holotype: 1 (BMNH 1882. 12.23.69).

DESCRIPTION. — (New Caledonian material) Disc 5 and 6 mm d.d, all arms broken. Disc covered in thin overlapping plates, only the widely separated distal tips of the radial shields are visible; a few disc spines remaining near the radial margin, small (0.2-0.3 mm d.d.) and angular with a crown of short divergent thorns. Oral shields 2-3 times as wide as long, with a concave distal margin and an obtuse proximal angle; adoral shields small and thick, do not separate the oral shields from the lateral arm plate, jaw longer than wide with 1 long stout apical papilla and 3 spaced oral papillae on each side, the inner one is thin and pointed, the distal ones are smaller and more rounded. Dorsal arm plates are small, wider than long at the base, widely separate; ventral arm plates wide and quadrangular, 2-3 times as wide as long, with a slightly concave distal margin, widely separate; 8 arm spines basally, almost meeting across the dorsal midline, reduced to 5 by the third segment, upper spines broken off, lowest spine curved outward from the third segment, with a blunt round tip, other spines lanceolate, with a rough to thorny surface, bluntly pointed; 2-3 tentacle scales on basal pores, reducing to one leaf-shaped scale by the third segment, 1/2 to 2/3 as long as the ventral arm plate.

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DISTRIBUTION. — New Caledonia (1330 m), Kermadec Islands (967-1116 m), Norfolk Island (308 m). REMARKS. — Although the New Caledonian specimens are missing most disc spines and upper arm spines, the remaining characters are very similar to the holotype, and the thickened curved lower arm spines are a distinctive characteristic for this species. The holotype still has many disc spines attached. Some of these spines are more complex, with the thorns bifurcating near the tip. The upper and middle arm spines of the holotype are notably serrated. There is some discrepancy between the recorded type specimens and those that still exist in the BMNH. Lyman (1882) recorded two specimens of this species; the holotype (5.5 mm d.d.) from Challenger station 171 and a smaller specimen (3 mm d.d.) from station 170 (from the Kermadec Is, not Fiji as noted in the description). In addition to the holotype (which has at some point been dried) there is also a jar in the spirit collection from station 171 with two small animals (and the same registration number as the holotype). The specimen from station 170 (registered in the catalogue as BMNH 1882.12.23.321) could not be located. The two small animals from station 171 (2 & 3 mm d.d.) differ somewhat from the holotype. They have long narrow adoral shields that separate the oral shield from the lateral arm plate, and moniliform arms. The disc is slightly incised and the lowest arm spine, although curved, is not thickened. They bear some resemblance to O. renekoehleri (see below). It is unlikely that these specimens are conspecific with the type of O. cornuta, although more specimens of intermediate size are required before a definitive decision can be made. The disc spines, wide ventral arm plates, fan of arm spines, the curved lowermost arm spine are reminiscent of the holotype of O. granulifera Verrill, 1885 from off Cape Cod in the Western Atlantic as described and figured by Paterson (1985). This species appears to differ however, in having a narrow, arrow-shaped oral shield.

Ophiacantha funebris (Koehler, 1930) n. comb. Fig. 1H-J Ophiomitrella funebris Koehler, 1930: 74-76, pl. 7 (9-10).

TYPE MATERIAL. — Holotype: ZMUC. TYPE LOCALITY. — Indonesia, Kei Islands, 245 m. MATERIAL EXAMINED. — Indonesia. MPE Kei Is: stn 12, 5°30’S, 132°35’E, 325 m, 09.04.1922: 3 UC). — MPE Kei Is: stn 3, 5°32’S, 132°36’E, 245 m, 31.03.1922, holotype: 1 (ZMUC). New Caledonia. BIOCAL: stn DW 08, Bassin des Loyauté, 20°34.35’S, 166°53.9’E, 435 m, 12.08.1985: 1 (MNHN EcOs 22342). — BIOCAL: stn DW 36, Ride de Norfolk, 23°8.64’S, 167°10.99’E, 650 m, 29.08.1985: 1 (MNHN EcOs 22344). — BIOCAL: stn DW 51, Ride de Norfolk, 23°5.27’S, 167°44.95’E,

680-700 m, 31.08.1985: 5 (MNHN EcOs 22343). — BIOCAL: stn DW 83, Bassin des Loyauté, 20°35.07’S, 166°53.99’E, 460 m, 06.09.1985: 1 (MNHN EcOs 22340). — BIOCAL: stn CP 109, Ride de Norfolk, 22°10’S, 167°15.2’E, 495-515 m, 09.09.1985: 1 (MNHN EcOs 22341). — SMIB4: stn DW 59, 22°28’S, 167°22.5’E, 650 m, 10.03.1989: 1 (MNHN EcOs 22339). Philippines. MPE: stn 140303, 25 miles SE of Zamboanga, 297-372 m, 03.03.1914: 1 (ZMUC).

OTHER MATERIAL EXAMINED. — Ophiacantha severa Koehler, 1922a : MPE Kei Is: stn 56, Indonesia, 5°30.3’S, 132°51’E, 345 m, 10.05.1922, identified by Koehler (1930): 6 (ZMUC).

DESCRIPTION. — (New Caledonian material) Disc up to 6.5 mm d.d., arms at least 6 times d.d., disc covered in thin perforated overlapping plates, radial shields long and thin, exposed only at their distal tips; plates bearing a single spine, which is a small stump (0.2 mm high) with an angular stem and expanded convex apex bearing 8-20 divergent short thorns, often in two tiers. Oral shields rhombic, wider than long, with a lobed distal margin; adoral shields short, not separating the oral shield from the arm plate, beaded surface; jaw wide, bearing 1 bluntly pointed apical papilla and 3 oral

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FIG. 1. A-C, Ophiacantha longidens MNHN EcOs 22355; A, dorsal aspect; B, ventral aspect; C, disc spines; D-G, Ophiacantha fuscina n. sp. holotype MNHN EcOs 22358; D, dorsal aspect; E, ventral aspect; F, ventral arm plates; G, disc spines; H-J, Ophiacantha funebris MNHN EcOs 22340; H, dorsal aspect; I, ventral aspect; J, disc spines; K-M, Ophiacantha levispina MNHN EcOs 22336; K, dorsal aspect; L, ventral aspects; M, disc spines. SEM images. FIG. 1. A-C, Ophiacantha longidens MNHN EcOs 22355 ; A, vue dorsale; B, vue ventrale ; C, épines discales; D-G, Ophiacantha fuscina n. sp. holotype MNHN EcOs 22358 ; D, vue dorsale ; E, vue ventrale ; F, plaques des bras en vue ventrale ; G, épines du disque ; H-J, Ophiacantha funebris MNHN EcOs 22340 ; H, vue dorsale ; I, vue ventrale; J, épines discales ; K-M, Ophiacantha levispina MNHN EcOs 2233 ; K, vue dorsale ; L, vue ventrale ; M, épines discales (M). Images MEB.

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papillae on each side, inner 2 long (2.5 times as high as wide) and spiniform, distal papilla long and leaf-shaped, a gap exists between the apical and first oral papilla. Dorsal arm plates fan-shaped with a convex distal margin, widely separate; ventral plates wider than long, distal margin strongly convex, striated, just contiguous. Up to 9 arm spines, minutely thorny, uppermost longest, 4 arm segments in length, almost meeting dorsally on basal segments, 1 long leaf-like tentacle scale with a pointed or rounded tip, 2/3 the length of the ventral arm plate. DISTRIBUTION. — Indonesia (245-325 m), New Caledonia (435-700 m), Philippines (297-372 m). REMARKS. — The characters of the disc, including the small overlapping plates and long thin radial shields, exposed only at the tips, indicate that this species belongs to the genus Ophiacantha rather than Ophiomitrella (see Paterson 1985) and is transferred accordingly. This species is characterised by the robust disc spines, convex striated ventral arm plates and elongate oral papillae. The New Caledonian specimens are the first to be reported since the unique type. There are, however, additional specimens from Mortensen’s Pacific Expedition not reported by Koehler (1930). Specimens from Kei Is stn 12 were labelled ‘‘O. regularis’’ by Koehler, which is perhaps a manuscript name that was never published. Specimens from off Zamboanga appeared to have been identified by Mortensen and were probably not seen by Koehler. These specimens are all very similar and do not differ in any substantive way from the New Caledonian material. This species is similar to the description of the holotype of Ophiacantha severa Koehler, 1922a, having similar striated, almost contiguous ventral arm plates with a convex distal margin, long spiniferous tentacle scales, enlarged distal oral papillae, and minutely thorny arm spines. There are some slight differences, however, the disc spines are described as having only ‘‘half a dozen’’ terminal thorns, the oral shields are depressed distally and the tentacle scales are almost as long as the ventral arm plate. On the other hand, the paratype, and Koehler’s (1930) material, of O. severa differ in having elongate thorny disc spines. In addition, Koehler’s (1930) material has distinctly spatulate distal oral papillae. Possibly the material identified as O. severa represents more than one species.

Ophiacantha fuscina n. sp. Fig. 1D-G Ophiacantha longidens ¢ Koehler 1922a: 55-57, pl. 17(6-7) [Non Ophiacantha longidens Lyman, 1878a].

TYPE MATERIAL. — Holotype: MNHN EcOs 22358. Paratypes: MNHN EcOs 22809, 22799, 22357, 22359. TYPE LOCALITY. — New Caledonia, 23°21.4’S, 168°4.5’E, 260 m. MATERIAL EXAMINED. — New Caledonia. SMIB4: stn DW 55, 23°21.4’S, 168°4.5‘E, 260 m, 09.03.1989, holotype: 1 (MNHN EcOs 22358); paratype on SEM stub: 1 (MNHN EcOs 22809); paratype: 1 (MNHN EcOs 22799). — BIOCAL: stn DW 08, Bassin des Loyauté, 20°34.35’S, 166°53.9’E, 435 m, 12.08.1985, paratype: 1 (MNHN EcOs 22357). — SMIB4: stn DW 56,

23°20.6’S, 168°5.2’E, 230 m, 09.03.1989, paratype: 1 (MNHN EcOs 22359). Philippines. Albatross: stn 5153, Jolo Archipelago, Tawi Tawi Group, Tocanhi Point, 5°18.2’N, 120°2.9’E, 90 m, 19.02.1908, identified by Koehler (1922a) as Ophiacantha longidens: 1 (USNM 41236).

DESCRIPTION. — (Holotype) Disc 4.5 mm d.d., arms curled, longer than 30 mm. Disc covered in small perforated overlapping plates obscured by skin; spines densely covering the dorsal disc surface, typically delicate with a long slender pedicel and 2-7, typically 3-4, long fine curved terminal thorns, often aligned in a single plane, often webbed, 0.15-0.2 mm high, spines near margin and ventrally with a long pedicel and 3 short divergent thorns. Only the distal tips of the radial shields exposed, widely separate.

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Oral shields wider than long, with a flattened or slightly convex or slightly lobed distal margin; adoral shields short and wide, 2.5 times as wide as long, separating oral shields from arm plates; jaw as wide as long, with 1 blunt apical and 3-4 long curved leaf-shaped to lanceolate oral papillae. First dorsal arm plate twice as wide as long, with a convex distal border and an obtuse proximal angle; succeeding plates fan-shaped (convex distal margin) to bell-shaped (lobed distal margin) with an acute proximal angle and straight to slightly concave proximolateral sides, slightly separate; lateral arm plates with a high spine bearing ridge, striated; first ventral arm plate small, wider than long, not grooved; succeeding ventral arm plates wider than long with a lobed distal margin and acute lateral angles, broadly in contact, distal lobe striated; plates in middle of arm longer than wide with a strongly convex distal margin and a long tapered proximal angle, curved striations run parallel to the margin, narrowly contiguous. Eleven arms spines basally, almost meeting on the dorsal midline on the first 2 segments, uppermost longest, 3 arm segments in length, rounded, tapering evenly to a sharp point, smooth to minutely thorny; lower arm spines short flat and blunt, with irregular fine thorns, less than 1 segment in length. One tentacle scale, oval to spiniform, sometimes with some small thorns near the apex, 1/3 the length of the ventral arm plate; sometimes 2 scales on basal pores. Colour (dry): brownish-grey. Paratypes (4-4.5 mm d.d.) very similar to holotype, some specimens without ventral disc spines, specimens of 4 mm d.d. have up to 8 arm spines, the lowest spine can be slightly flattened and covered in irregular thorns. DISTRIBUTION. — Philippines (90 m), New Caledonia (230-435 m). REMARKS. — O. fuscina, is characterised by the dense covering of delicate disc spines, with typically three long curved thorns, often webbed and lying in a single plane like a trident, diminishing in size on the margin and ventral surface of the disc, the relatively smooth arm spines, the rounded tentacle scales, wide oral shields, three oral papillae, and the ventral arm plates with a strongly convex, striated, distal lobe. Koehler (1922a) reported a specimen which he called O. longidens with misgivings. A re-examination of the specimen showed that is not conspecific with the type of O. longidens (see below) but belongs to this new species. ETYMOLOGY. — Fuscina (Latin, feminine) = trident, in reference to the shape of disc spines.

Ophiacantha levispina Lyman, 1878 Fig. 1K-M Ophiacantha levispina Lyman, 1878a: 147-148, pl. 10(277). Ophiacantha levispina ¢ Lyman 1882: 196-197, pl. 25(1-3). — Clark, H.L. 1911: 198-199. — Fell 1958: 22-23. — McKnight 1993: 174, 186. Ophiacantha composita ¢ Koehler 1904: 120-121, pl. 23(7); 1922a: 46-47, pl. 23(5-7), 93(4). — Guille 1981: 430 [Non Ophiacantha composita Koehler, 1897]. ?Ophiacantha levispina ¢ Irimura 1982: 26-27, fig. 16, pl. 6(1-2). — Imaoka et al. 1991: 125, fig. 48. — Fujita et al. 1997: 258 — Irimura & Kubodera 1998: 139. TYPE MATERIAL. — Holotype: BMNH 1882.12.23.38. TYPE LOCALITY. — Indonesia, off Meangis Is, 930 m. MATERIAL EXAMINED. — Indonesia. Siboga expedition, Île de la Sonde, identified by Koehler (1904) as Ophiacantha composita: 3 (MNHN EcOs 20315). — Siboga: stn 178, Ceram Sea, 2°40’S, 128°37.5’E, 835 m, 02.09.1899, identified by Koehler (1904) as Ophiacantha composita: 10 (ZMA Ech O 2749). — Challenger: stn

214, Off Meangis Is, 4°33’N, 127°6’E, 930 m, 10.02.1875, holotype: 1 (BMNH 1882.12.23.38). New Caledonia. BIOCAL: stn DW 70, Ride de Norfolk, 23°24.7’S, 167°53.65’E, 965 m, 04.09.1985: 4 (MNHN EcOs 22338). — BIOCAL: stn DW 80, Bassin des Loyauté, 20°31.69’S,

DEEP-WATER

166°48.35’E, 900-980 m, 05.09.1985: 2 (MNHN EcOs 22336). — MUSORSTOM 5: stn CP 323, 21°18.52’S, 157°57.62’E, 970 m, 14.10.1986: 4 (MNHN EcOs 22337). — MUSORSTOM 5: stn CP 324, 21°15.01’S, 157°51.33’E, 970 m, 14.10.1986: 2 (MNHN

OPHIUROIDS FROM

NEW CALEDONIA

EcOs 22335). — MUSORSTOM 6: stn DW 458, Ride des Loyauté, 21°0.93’S, 167°29.96’E, 400 m, 20.02.1989: 4 (MNHN EcOs 22852).

OTHER MATERIAL EXAMINED. — Ophiacantha composita Koehler, 1897: Investigator: stn 11, Indian Ocean, WSW of Great Nicobar Island, 5°56’N, 91°5’E, 2957 m, 19.04.1888, syntypes: 2 (ZSI 116/7).

DESCRIPTION. — (New Caledonian material) Disc up to 6 mm d.d., arms > 30 mm; disc covered in small thin plates bearing a single slender spine (0.15-0.25 mm high) with a narrow pedicel and numerous flared terminal thorns of varying sizes, often webbed, spines continue ventrally until the oral shields; radial shields exposed only at their distal tip. Oral shields variable, usually broadly triangular with straight to curved proximolateral margins and a slightly convex distal margin with a small central lobe, as wide as to wider than long; adoral shields long with a radial lobe that can separate the oral shields from the lateral arm plate; jaw as wide as long, with a lanceolate apical papilla and 3 oral papillae, the inner 2 are leaf-shaped, the distal one is low, twice as wide as long, slightly tapered distally, arising from the junction of the oral plates and adoral shields; rarely a small oral tentacle scale opposes the large distal papilla. Dorsal arm plates bell-shaped with a convex to lobed distal margin and a tapered proximal angle, widely separate; ventral arm plates twice as wide as long, with a convex distal margin and obtuse proximal angle, separate; 9 pointed arm spines basally, uppermost longest, 4 arm segments in length, almost meeting dorsally, all spines smooth (microscopically rough), without obvious thorns; 1 small spiniform tentacle scale, 1/3 the length of the ventral arm plate. DISTRIBUTION. — Japan (?93-1700 m), Philippines (685-757 m), Indonesia (655-3112 m), New Caledonia (400-980 m), New Zealand (2232-2418 m). REMARKS. — O. levispina is characterised by the wide, low distal oral papillae, the triangular oral shields, and the wide ventral arm plates with the tiny tentacle scale. Lyman’s (1878a, 1882) diagrams of the ventral arm surface are inaccurate, re-examination of the holotype showed that the ventral arm plates are twice as wide as long and the tentacle scales are small and spiniform. Koehler (1897) differentiated his new species O. composita from O. levispina on the basis of the thorny arm spines. While this is true of Koehler’s (1897) Indian material, the specimens referred to O. composita by Koehler (1904, 1922a) and Guille (1982) from Indonesia and the Philippines do not have any thorns on the arm spines and can be referred to the current species. The shallow water (93-200 m) specimens from Japan referred to O. levispina by Irimura (1982) appear to differ in having bifid to trifid disc spines. Irimura’s figures show a relatively narrow oral shield and the distal oral papillae that are not particularly widened. Juveniles are described as having non-enlarged distal oral papillae. The smallest New Caledonian specimens (3 mm d.d.) have widened distal oral papillae. Irimura’s material may include more than one species, possibly O. adiaphora H.L. Clark, 1911. No morphological details are given for material subsequently referred to this species from Japan (Fujita et al. 1997; Irimura & Kubodera 1998). Ophiacantha is known elsewhere only from deeper water (> 400 m).

Ophiacantha longidens Lyman, 1878 Fig. 1A-C Ophiacantha longidens Lyman, 1878a: 144, pl. 10(274). Ophiacantha longidens ¢ Lyman 1882: 192, pl. 25(7-9). Ophiacantha confusa Koehler, 1905: 59-60, pl. 7(9-11). — Clark, H.L. 1921: 105; 1946: 184-185. — Rowe & Gates 1995: 371 [new synonymy]. Ophiacantha graphica Koehler, 1922a: 51-53, pl. 18(4-5). ¢ Koehler1930: 58-59 [new synonymy]. Ophiacantha tenuispina Clark, H.L., 1938: 210-211. ¢ Clark, H.L. 1946: 185. — Rowe & Gates 1995: 373 [new synonymy].

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Ophiacantha dumosa Clark, A.H., 1949: 18-19, fig. 6a-b [new synonymy]. Non Ophiacantha confusa ¢ Koehler 1922a: 47-49, pl. 19(1-2) [= Ophiacantha serrata Lyman, 1878a]. Non Ophiacantha longidens ¢ Koehler 1922a: 55-57, pl. 17(6-7) [= Ophiacantha fuscina]. Non Ophiacantha ?confusa ¢ Gibbs, Clark, A.M. & Clark, C.M. 1976: 115 [= Ophiacantha indica Ljungman, 1867].

TYPE MATERIAL. — Holotype: BMNH 1882.12.23.32. TYPE LOCALITY. — Philippines, Bohol Strait, 176-186 m. MATERIAL EXAMINED. — Hawaii. Albatross: stn 3865, Pailolo Channel, Maui Is, Nakalele Point, 21°9.3’N, 156°35.2’W, 468-518 m, 10.04.1902, holotype of O. dumosa: 1 (USNM E6896). Indonesia. Singapore, 01.10.1904, identified by Koehler (1930) as Ophiacantha graphica: 11 (ZMUC). — Siboga: stn 133, Kepulaum Talaud, off Lirung, 3°55’N, 126°40’E, 36 m, 25.07.1899, holotype of O. confusa: 1 (ZMA E2333). New Caledonia. BATHUS 3: stn CP 833, Ride de Norfolk, 23°2.75’S, 166°58.23’E, 441-444 m, 30.11.1993: 1 (MNHN EcOs 22853). — BIOCAL: stn DW 33, Ride de Norfolk, 23°9.71’S, 167°10.27’E, 675 m, 29.08.1985: 1 (MNHN EcOs 22354). — BIOCAL: stn DW 37, Ride de Norfolk, 22°59.99’S, 167°15.65’E, 350 m, 30.08.1985: 1 (MNHN EcOs 22353). — BIOCAL: stn DW 44, Ride de Norfolk, 22°47.3’S, 167°14.3’E, 440-450 m, 30.08.1985: 28 (MNHN EcOs 22355). — BIOCAL: stn CP 47, Ride de Norfolk, 22°53.04’S, 167°16.77’E, 550 m, 30.08.1985: 6 (MNHN EcOs 22348). — BIOCAL: stn DW 83, Bassin des Loyauté, 20°35.07’S, 166°53.99’E, 460 m, 06.09.1985: 1 (MNHN EcOs 22346). — CHALCAL 2: stn DW 82, Ride de Norfolk, 23°13.68’S, 168°4.27’E, 304 m, 31.10.1986: 1 (MNHN EcOs 22350). — MUSORSTOM 5: stn DW 272, 24°40.91’S, 159°43’E, 500-540 m, 09.10.1986: 2 (MNHN EcOs 22349). — MUSORSTOM 5: stn DW 337, 19°53.8’S, 158°38’E, 412-430 m, 15.10.1986: 7 (MNHN EcOs 22347). — MUSORSTOM 6: stn DW

406, Ride des Loyauté, 20°40.6’S, 167°6.8’E, 373 m, 15.02.1989: 82 (MNHN EcOs 22855). — MUSORSTOM 6: stn CP 464, Ride des Loyauté, 21°2.3’S, 167°31.6’E, 430 m, 21.02.1989: 1 (MNHN EcOs 22856). — MUSORSTOM 6: stn DW 471, Ride des Loyauté, 21°8’S, 167°54.1’E, 460 m, 22.02.1989: 41 (MNHN EcOs 22857). — MUSORSTOM 6: stn DW 478, Ride des Loyauté, 21°8.96’S, 167°54.28’E, 400 m, 22.02.1989: 68 (MNHN EcOs 22858). — MUSORSTOM 6: stn DW 479, Ride des Loyauté, 21°9.13’S, 167°54.95’E, 310 m, 22.02.1989: 1 (MNHN EcOs 22859). — SMIB4: stn DW 57, 23°21’S, 168°21’E, 210 m, 09.03.1989: 1 (MNHN EcOs 22356). — SMIB4: stn DW 62, 23°0.4’S, 167°21.8’E, 540 m, 10.03.1989: 1 (MNHN EcOs 22351). — SMIB4: stn DW 65, 22°55.3’S, 167°14.5’E, 400-420 m, 10.03.1989: 1 (MNHN EcOs 22352). — SMIB4: stn DW 69, 22°55.8’S, 167°14.3’E, 395-405 m, 10.03.1989: 1 (MNHN EcOs 22345). Australia. Port Curtis, off Gatecombe Head, 16-22 m, 01.07.1929, holotype of O. tenuispina: 1 (AM J6049). Philippines. MPE: stn 140327, off Jolo, 15 mi west, 465 m, 27.03.1914, identified by Koehler (1930) as Ophiacantha graphica: 8 (ZMUC). — Albatross expedition, unknown locality and date, holotype of O. graphica: 1 (USNM 41233). — Challenger: stn 209, Bohol Strait, 10°14’N, 123°54’E, 176-186 m, 22.01.1875, holotype: 1 (BMNH 1882.12.23.32).

OTHER MATERIAL EXAMINED. — Ophiacantha legata Koehler, 1922a: Albatross: stn 5536, Philippines, between Negros and Siquijor, Apo Is, 9°15.75’N, 123°22’E, 510 m, 19.09.1909, holotype: 1 (USNM 41373).

DESCRIPTION. — (New Caledonian material) Disc up to 8 mm d.d., covered in small slender spinelets with usually 3 (2-5) curved divergent sharp points arising from mid-way up the spinelet, up to 0.15-0.2 mm high. Oral shield wider than long, with slightly concave proximal sides meeting at a sharp point, and a curved distal border. Adoral shields meeting interradially, with a short radial lobe, faintly beaded surface. One large blunt apical and 3 long, bluntly-pointed oral papillae, additional 1-3 suboral papillae on larger specimens. Dorsal arm plates fan-shaped, separate, basal plates 2 times as wide as long, fine rugosities on distal margin of some basal plates. Lateral plates narrow with prominent spine ridge, transverse striations; meeting ventrally and dorsally. First ventral arm plate furrowed; second plate axe-head shaped, incurved around the large tentacle pores proximally; subsequent plates often wider than long, with a produced convex distal border, distal part of the plate raised, sometimes glassy with curved transverse striations. Up to 12 arm spines basally on large specimens, almost meeting at the dorsal midline; upper spines 4-5 segments long; sparsely thorny. One large lanceolate tentacle scale, with a rounded, pointed or thorny tip, 3/4 as long as the ventral arm plate on basal segments, rarely 2 scales on the first pore. Colour (dry) brown with white markings at the distal edge of each radial shield, sometimes a dark mark between radial shields of each pair; arms mottled brown with occasional white segments, sometimes a dark spot on each dorsal arm plate.

DEEP-WATER

OPHIUROIDS FROM

NEW CALEDONIA

DISTRIBUTION. — Philippines (176-465 m), Indonesia (36-245 m), New Caledonia (210-675 m), northern Australia (16-83 m), Hawaii (468-518 m). REMARKS. — Ophiacantha longidens is characterised by the small very slender disc spinelets with (usually) three divergent upwardly curved points that continue undiminished until the oral shields, numerous denticulate arm spines, three to six elongate oral papillae on each jaw side, the produced distal border on the ventral arm plates and the relatively-large thorny tentacle scale. There is some variability in the number of arm spines, the shape of the oral and adoral shields, the number of oral papillae and colour. There are also some growth differences: juvenile specimens have more serrate upper spines, fewer (typically only three) oral papillae, and the ventral arm plates have a convex rather than lobed distal border. There has been much confusion in the literature about the identity of this species. Lyman’s (1878a, 1882) descriptions are not very detailed, the figures are inaccurate (showing coarse disc spines and no tentacle scales) and the type specimen is relatively small (4 mm d.d.). Comparison of the type specimens of O. longidens, O. confusa, O. graphica, O. tenuispina, O. dumosa and the large numbers of specimens of varying sizes from New Caledonia show that they are all conspecific. Koehler (1922a) was misled by a comparison of his photographs of Albatross material with the holotype of O. longidens performed on his behalf by Bell. Consequently the specimens identified by Koehler (1922a) as O. longidens belong to another species (=O. fuscina, see above) and the specimen he described as O. graphica is actually the true O. longidens. The holotype of O. graphica is small (3.5 mm d.d.), and like small specimens of this species, has notably serrated upper arm spines. The second basal tentacle scale mentioned by Koehler (1922a) is actually a broken arm spine. Specimens later referred to this species by Koehler (1930) differ in minor ways. The disc spines have slightly fewer points (two to four) which sometimes bear one to two tiny secondary spinules along their length, and the tentacle scales are strongly spinose at their tips. More specimens are required before these differences can be regarded as significant. H.L. Clark (1938) differentiated O. tenuispina from O. longidens by the form of the disc spines and the greater number of arm spines. However, there is no difference in disc spines and the many specimens from New Caledonia show that the arm spine number is related to size. The holotype of O dumosa from Hawaii is relatively large (7 mm d.d.) but damaged, having lost most of its disc and upper arm spines. However, the remaining characters are identical to the larger New Caledonian specimens. Re-examination of specimens recorded under the name O. confusa showed that they belong to several different species, as predicted by H.L. Clark (1946). The unique type is small (3 mm d.d.) and very similar to the holotype of O. graphica with the exception that the serrations are predominantly restricted to one side of the upper arm spine. The unique holotype of O. legata from the Philippines is also similar in many respects, except that the disc spines are longer (to 0.3 mm high) and stouter than on O. longidens, often having small thorns on the spine stalk and strongly bifurcated tips on the long terminal thorns (Fig. 17H). Specimens of O. longidens often have a few larger spines with stalks that are twice as thick as the ordinary spines and short thick terminal thorns. However, they are never as consistently enlarged as on O. legata and consequently this species is retained as distinct from O. longidens pending the collection of more specimens from the Philippines. O. fuscina differs in having relatively smooth upper arm spines, smaller rounded tentacle scales, dense fur-like disc spines with two to four sharp points often webbed and arranged in a single plane like a trident, and three to four oral papillae in single row. Ophiacantha striolata Mortensen, 1933b from South Africa has similar disc spines to O. legata. From the type description, it appears to differ in having a triangular oral shield, shorter oral papillae, smaller tentacle scales and hook-like lower arm spines distally. Ophiacantha vorax Koehler, 1897 also has many similar features but differs in having disc spinelets with many thorns (Fig. 17F). A specimen from New Caledonia (MNHN EcOs 22345) was epizoic on coral.

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Ophiacantha pentagona Koehler, 1897 Fig. 2E-G Ophiacantha pentagona Koehler, 1897: 342-344, pl. 8 (56-57). Ophiacantha pentagona ¢ Koehler 1899: 53-54, pl. 4 (27-29); 1904: 110; 1922a: 59-61, pl. 21 (1,5-6), 93(5); 1930: 60. — Clark, H.L. 1911: 196-198; 1939: 43. — Matsumoto 1917: 116. — Murakami 1942: 5; 1944: 251. — McKnight 1975: 69; 1993: 174, 186. — Guille 1981: 430. — Liao & A.M. Clark 1995: 177, fig. 79. ?Ophiacantha pentagona ¢ Clark, A.M. 1965: 66. Non Ophiacantha pentagona ¢ Madsen 1967: 126 [= Ophiacantha vilis Mortensen, 1924].

TYPE MATERIAL. — Lectotype and paralectotypes: ZSI 3144/9 (designated herein), paralectotypes: BMNH 1898.7.11.12, MNHN EcOs 20403. TYPE LOCALITY. — India, Andaman Is, SE of Port Blair, 492 m. MATERIAL EXAMINED. — Indonesia. MPE Kei Is: stn 12, 5°30’S, 132°35’E, 325 m, 09.04.1922, identified by Koehler (1930): 2 (ZMUC). — MPE Kei Is: stn 28, 5°37’S, 132°54’E, 400 m, 17.04.1922, identified by Koehler (1930): 4 (ZMUC). — MPE Kei Is: stn 51, 5°46.5’S, 132°51’E, 348 m, 07.05.1922, identified by Koehler (1930): 2 (ZMUC). — MPE Kei Is: stn 56, 5°30.3’S, 132°51’E, 345 m, 10.05.1922, identified by Koehler (1930): 10 (ZMUC). — MPE Kei Is: stn 58, 5°29’S, 132°37’E, 290 m, 12.05.1922, identified by Koehler (1930): 3 (ZMUC). — Siboga: stn 74, Makassar Strait, west of Makassar, 5°3.5’S, 119°0’E, 450 m, 08.06.1899, identified by Koehler (1904): 6 (ZMA Ech O 6197.1). India. Investigator: stn 13, 7 mi SE of Ross Is, Port Blair, Andaman Is, 492 m, 25.04.1888, lectotype and paralectotypes: 5 (ZSI 3144/9). — Investigator expedition, Andaman Is, 446-697 m, paralectotypes: 3 (MNHN EcOs 20403); paralectotype: 1 (BMNH 1898.7.11.12). New Caledonia. BIOCAL: stn DW 37, Ride de Norfolk,

22°59.99’S, 167°15.65’E, 350 m, 30.08.1985: 3 (MNHN EcOs 22363). — BIOCAL: stn DW 46, Ride de Norfolk, 22°53.05’S, 167°17.08’E, 570-610 m, 30.08.1985: 3 (MNHN EcOs 22360). — CHALCAL 1: stn CP 14, Îles Chesterfield, 21°13.5’S, 158°50.2’E, 66 m, 24.07.1984: 1 (MNHN EcOs 22362). — MUSORSTOM 6: stn DW 391, Ride des Loyauté, 20°47.35’S, 167°5.7’E, 390 m, 13.02.1989: 3 (MNHN EcOs 22364). — MUSORSTOM 6: stn DW 393, Ride des Loyauté, 20°48.29’S, 167°9.54’E, 420 m, 13.02.1989: 13 (MNHN EcOs 22861). — MUSORSTOM 6: stn DW 406, Ride des Loyauté, 20°40.6’S, 167°6.8’E, 373 m, 15.02.1989: 4 (MNHN EcOs 22862). — MUSORSTOM 6: stn DW 407, Ride des Loyauté, 20°40.7’S, 167°6.6’E, 360 m, 15.02.1989: 1 (MNHN EcOs 22863). — MUSORSTOM 6: stn DW 459, Ride des Loyauté, 21°1.39’S, 167°31.47’E, 425 m, 20.02.1989: 1 (MNHN EcOs 22864). — MUSORSTOM 6: stn DW471, Ride des Loyauté, 21°8’S, 167°54.1’E, 460 m, 22.02.1989: 8 (MNHN EcOs 22865).

OTHER MATERIAL EXAMINED. — Ophiacantha baccata Mortensen, 1933: Meiring Naude SM expedition, South Africa, off Natal, 24°40’S, 35°28’E, 347 m, identified by Clark, A.M. (1977): 1 (BMNH 1975.10.31.281). — Meiring Naude SM: stn 23, South Africa, off Natal, 27°44.4’S, 32°42.8’E, 400-450 m, 26.05.1975,

identified by Clark, A.M. (1977): 1 (BMNH 1976.7.28.9). Ophiacantha brachygnatha H.L. Clark, 1928: MFG: stn 1, SE Australia, 45 Km SSW of Portland, 38°40’S, 141°20’E, 293-585 m, 14.05.1979: 20 (MoV F52735).

DESCRIPTION. — (New Caledonian material) Disc up to 4.5 mm d.d., constricted interradially; arms moniliform, curved under body, at least 5 times d.d. in length. Disc plates obscured by thin skin, spines densely cover the disc, only distal tip of radial shield exposed, spines small to 0.15 mm high, tricolumnar pedicel typically bearing 3 sharp divergent thorns that often bifurcate near their base, rarely multifid. Oral shield small, twice as wide as long, with an obtuse proximal angle and a round to lobed distal margin; adoral shields extend beyond oral shields, but not surrounding them laterally, strongly beaded, jaw wider than long, bearing 1 large bluntly pointed apical and 3 spiniform oral papillae. Dorsal arm plates wider than long, widely separate, with slightly convex distal margin and a strongly convex proximal margin becoming 3-sided on some specimens; ventral arm plates 1.5 to 2 times as wide as long, distal margin almost straight, proximal margin straight or slightly convex or produced into a small angle centrally, separate; up to 7 slender, pointed arm spines basally, uppermost greater than 2 segments in length, finely serrated, lower spines thorny; 1 thin, elongate, pointed tentacle scale, 1/2 as long as the ventral arm plate.

DEEP-WATER

OPHIUROIDS FROM

NEW CALEDONIA

FIG. 2. A-D, Ophiacantha cornuta MNHN EcOs 22632; A, dorsal aspect; B, ventral aspect; C, arm spines; D, disc spines; E-G, Ophiacantha pentagona MNHN EcOs 22363; E, dorsal aspect; F, ventral aspect; G, disc spines; H-K, Ophiacantha serrata MNHN EcOs 22366; H, dorsal aspect; I, ventral aspect; J, arm spines; K, disc spines. SEM images. FIG. 2. A-D, Ophiacantha cornuta MNHN EcOs 22632 ; A, vue dorsale ; B, vue ventrale ; C, épines des bras ; D, épines discales ; E-G, Ophiacantha pentagona MNHN EcOs 22363 ; E, vue dorsale ; F, vue ventrale ; G, épines discales ; H-K, Ophiacantha serrata MNHN EcOs 22366 ; H, vue dorsale ; I, vue ventrale ; J, épines des bras ; K, épines discales. Images MEB.

DISTRIBUTION. — Gulf of Aden and Arabian Sea (38-1415 m), Maldives (515-525 m), Andaman Is (446-697 m), Japan (100-1727 m), Ryukyu Is, S. China (78-114 m), Indonesia (204-827 m), Philippines (170-717 m), New Caledonia (66-610 m), New Zealand (356-1936 m). REMARKS. — This species has been characterised by the petaloid disc, small thorny disc spines, moniliform arms, short slender arm spines, beaded adoral plates, wide ventral arm plates and a minute tentacle scale. However, it is likely to be a species-complex as there are differing morphological forms in various parts of its reported range. An unknown taxonomist has separated the types in the ZSI into two forms. Form ‘‘a’’ (to 7.5 mm d.d.) has up to six smooth arm spines, to 2.5 segments in length, that do not meet along the basal midline. The spines are without thorns except on the lowermost spine on distal segments which is curved with small thorns along the ventral side, probably functioning as a hook. The disc

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spines are minute and difficult to make out with a low powered microscope. Form ‘‘b’’ (3-5 mm d.d.) has up to nine arm spines basally that meet on the dorsal midline. The uppermost arm spines have minute thorns which become more prominent on the lower spines. The disc spines have 2-3 thorns, sometimes these thorns bifurcate at the tip or have tiny secondary thorns along their length. Koehler’s description includes both forms with the difference in arm spines being attributed to interspecific variation. A specimen from form ‘‘b’’ is here designated as the lectotype. The paralectotypes in the BMNH and MNHN are similar to form ‘‘b’’, except the spines are longer, to 0.3 mm in length, with a long slender pedicel and 3-7 thorns, often webbed. They are similar to spines illustrated by Koehler (1922a). The syntypes at the MNHN also include one specimen of O. pacata Koehler, 1922a, formerly known only from the Philippines. The New Caledonian specimens are similar to the form ‘‘b’’ of the syntypes, except that the disc spines are more bifurcated-trifid than multifid. On the other hand specimens identified by A.M. Clark (1965) from Japan (Sagami Sea, 180 m, 25 Dec 1904, BMNH 1963.11.26.24-25) have smooth arm spines and very small disc spines (approaching the size of O. serrata) and are more similar to form ‘‘a’’. H. L. Clark (1911) suspected that more than one species was present in his NE Pacific samples. A thorough revision of this species-complex is required. Two other species are very close to O. pentagona. Ophiacantha baccata Mortensen, 1933b from eastern South Africa was differentiated from O. pentagona on the basis that O. pentagona did not have moniliform arms, which is not correct. Examination of A.M. Clark‘s (1977) material from off Natal indicates that Ophiacantha baccata is very similar to O. pentagona, differing only in its smaller size and by having relatively coarse plating with larger beading. Ophiacantha brachygnatha H.L. Clark, 1928 from off SE Australia is also similar. It differs from the New Caledonian material in having arms that are less moniliform than O. pentagona, dorsal arm plates that are longer than wide, and longer ventral arm plates, only 1.5 times as wide as long.

Ophiacantha placida (Koehler, 1904) n. comb. Fig. 3A-E Ophiomitrella placida Koehler, 1904: 137-138, pl. 31 (3-4). Ophiacantha ficta Koehler, 1904: 121-122, pl. 16 (1-4) [new synonymy]. Ophiomitra microphylax Clark, H.L., 1911: 184-185, fig. 84 [new synonymy]. Ophiacantha placida ¢ Clark, H.L. 1915: 207. Ophiophthalmus placida ¢ Matsumoto 1917: 106. Ophiomelina placida ¢ Koehler 1922a: 130-131, pl. 30 (8-9), 94 (3).

TYPE MATERIAL. — Syntypes: ZMA E2424(5), E2425, E2426(4), NMHN EcOs 20346. TYPE LOCALITY. — Indonesia, Kei Is and off West Timor, 204-304 m. MATERIAL EXAMINED. — Indonesia. MPE Kei Is expedition, Kei Islands: 1 (MNHN EcOs 20338). — Siboga: stn 251, Kapulauan Kai (Kei Islands), 5°28.4’S, 132°0.2’E, 204 m, 08.12.1899, holotype of O. ficta: 1 (ZMA E2343). — Siboga expedition, Île de la Sonde, syntype: 1 (MNHN EcOs 20346). — Siboga: stn 251, Kapulauan Kai (Kei Islands), 5°28.4’S, 132°0.2’E, 204 m, 08.12.1899, syntypes: 5 (ZMA E2424). — Siboga: stn 253, Kapulauan Kai (Kei Islands), 5°48.2’S, 132°13’E, 304 m, 10.12.1899, syntype: 1 (ZMA E2425). — Siboga: stn 302, West Timor, Salut Roti, 10°27.9’S, 123°28.7’E, 216 m, 02.02.1900, syntypes: 4 (ZMA E2426). Japan. Albatross: stn 4933, Eastern Sea, off Yagoshima, 30°59’N, 130°29.8’E, 282 m, identified by Clark, H.L. (1911) as Ophiomitra

microphylax: 1 (ZMA Ech O 6548); paratype of O. microphylax: 1 (AM J2735). New Caledonia. BIOCAL: stn DW 44, Ride de Norfolk, 22°47.3’S, 167°14.3’E, 440-450 m, 30.08.1985: 50 (MNHN EcOs 22427). — BIOCAL: stn CP 47, Ride de Norfolk, 22°53.04’S, 167°16.77’E, 550 m, 30.08.1985: 1 (MNHN EcOs 22424). — CHALCAL 1: stn CP8, Îles Chesterfield, 19°43.8’S, 158°35.25’E, 348 m, 19.07.1984: 1 (MNHN EcOs 22420). — MUSORSTOM 5: stn DW 337, 19°53.8’S, 158°38’E, 412-430 m, 15.10.1986: 23 (MNHN EcOs 22421). — MUSORSTOM 5: stn DW 340, 19°48.5’S, 158°40.9’E, 675-680 m, 16.10.1986: 1 (MNHN EcOs 22418). — MUSORSTOM 5: stn DC362, 19°52.9’S, 158°40’E, 410 m,

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FIG. 3. A-E, Ophiacantha placida MNHN EcOs 22427; A, dorsal aspect; B, ventral aspect; C, disc spines; D, arm spines; E, tentacle scales; F-H, Ophiacantha richeri n. sp. holotype MNHN EcOs 23818; F, dorsal aspect; G, ventral aspect; H, disc spines. SEM images, scale bars in mm. FIG. 3. A-E, Ophiacantha placida MNHN EcOs 22427 ; A, vue dorsale ; B, vue ventrale ; C, épines discales ; D, épines des bras ; E, écailles des tentacules ; F-H, Ophiacantha richeri n. sp. holotype MNHN EcOs 23818 ; F, vue dorsale ; G, vue ventrale ; H, épines discales. Images MEB, échelles en mm.

19.10.1986: 2 (MNHN EcOs 22425). — MUSORSTOM 5: stn CP 373, 19°52.92’S, 158°38.66’E, 380-390 m, 20.10.1986: 1 (MNHN EcOs 22426). — MUSORSTOM 5: stn DC379, 19°53.2’S, 158°39.5’E, 370-400 m, 20.10.1986: 2 (MNHN EcOs 22428). — SMIB4: stn DW 64, 22°55.3’S, 167°16.4’E, 455-460 m, 10.03.1989: 12 (MNHN EcOs 22417). — SMIB4: stn DW 65,

22°55.3’S, 167°14.5’E, 400-420 m, 10.03.1989: 6 (MNHN EcOs 22422). — SMIB4: stn DW 68, 22°55’S, 167°16’E, 440 m, 10.03.1989: 7 (MNHN EcOs 22423). — SMIB4: stn DW 69, 22°55.8’S, 167°14.3’E, 395-405 m, 10.03.1989: 1 (MNHN EcOs 22419).

DESCRIPTION. — (New Caledonian material) Disc 3-10 mm d.d., slightly indented interradially, arms moniliform, at least 9 times d.d. in length. Disc covered in small imbricating plates bearing small spines with a cylindrical to conical pedicel and usually 3 small divergent thorns, typically 0.15 mm high, reduced to conical granules near margin, only a few ventrally; radial shields bar-like, separate, only distal section exposed, up to 1/7 d.d. Oral shields rhombic, as wide as long, distal sides thickened, creating a shallow furrow at the distal angle; adoral shields long and narrow, extending around oral shields and separating them from the arm plates; jaw as long as wide, bearing 1 apical and 3-4 oral papillae on each side, outer papillae slightly wider and more angular than inner ones, in addition 1-2 small rounded oral tentacle scales occur distally on the adoral shield and occasionally some suboral papillae occur in large specimens. Dorsal arm plates wider than long, curved around arm, proximal section sunken, almost contiguous on basal plates of large specimens; ventral plates up to 2 times as wide as long, with a wide convex distal border and a rounded to obtuse proximal angle, sometimes with large spines along the proximal margin; up to 10 arm spines basally, uppermost longest, slightly denticulate, 5 segments in length, distal and lower spines thorny, 2 segments in length; 3-4 thick angular tentacle scales cluster around pores on basal segments, then 2, afterward one lanceolate to oval scale with a thorny tip, 1/2 to 2/3 as long as the ventral arm plate. DISTRIBUTION. — Indonesia (204-763 m), Japan (192-282 m), New Caledonia (348-680 m).

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REMARKS. — The unique 10 mm d.d. type of O. ficta is very similar to the type specimens of O. placida. Koehler (1904) did not compare his two species, placing them in separate genera. However, there appears to be no visible characters that can separate the two species. As first reviewers, we select O. placida as the species name, as it is better known and the designated type species of Ophiomelina, even though O. ficta has page priority. Ophiomitra microphylax from Japan is also synonymous with O. placida. Specimens we have examined have the furrowed oral shields, wide arm plates, and denticulate arm spines of O. placida. Clark’s (1911) figures show tiny tentacle scales and the description notes six arm spines, however, the specimens have up to nine arm spines basally and tentacle scales that are half as long as the ventral arm plate. The reassignment of this species to Ophiacantha is discussed under that genus.

Ophiacantha richeri n. sp. Fig. 3F-H TYPE MATERIAL. — Holotype: MNHN EcOs 23818. Paratypes: MNHN EcOs 22416(1), 22869(6), 22870(1). TYPE LOCALITY. — New Caledonia, 22°39.66’S, 166°27.41’E, 1618-1740 m. MATERIAL EXAMINED. — New Caledonia. BIOCAL: stn CP 26, Sud ouest, 22°39.66’S, 166°27.41’E, 1618-1740 m, 28.08.1985, holotype: 1 (MNHN EcOs 23818); paratype: 1 (MNHN EcOs 22416). — BATHUS 3: stn DW 776, Ride des Loyauté, 24°44.24’S,

170°8.01’E, 770-830 m, 24.11.1993, paratypes: 6 (MNHN EcOs 22869). — BATHUS 3: stn DW 778, Ride des Loyauté, 24°43.49’S, 170°7.07’E, 750-760 m, 24.11.1993, paratype: 1 (MNHN EcOs 22870).

DESCRIPTION. — (Holotype) Disc 2.5 mm d.d., petaloid, incised interradially, rounded lateral edge to disc; arms up to 15 mm long, strongly moniliform, twisted. Disc covered in a thin skin that obscures the underlying plates, radial shields not exposed, disc spines small, up to 0.12 mm high, with a slender pedicel that branches at greater than half the spine height into 3 terminal thorns, thorns can bifurcate near their tip. Ventral disc surface covered in thin overlapping plates bearing minutely-thorny conical granules that continue to the oral shield. Oral shield small, 2 times as wide as long, almost rhombic, with an obtuse proximal angle and a convex distal margin; adoral shields 3-4 times as wide as their proximal length, extending under and around oral shields, separating oral shields from arm plates; jaw as wide as long, bearing one large leaf-like apical papilla, and 3 slightly-smaller bluntly pointed oral papillae, the outer one slightly enlarged. Dorsal arm plates small fan-shaped, longer than wide, with a convex distal edge and an acute proximal angle, widely separate. First ventral arm plate pentagonal, incised proximally, with straight distal and distolateral sides, separate from the second plate. Succeeding plates 2 times as wide as long, pentagonal with a flat to slightly convex distal margin, straight lateral sides and an obtuse proximal angle, widely separate. Three arm spines on the first segment, small subequal and thorny. Four spines on the second segment, the uppermost is elongated and slender. Third segment (first free segment after the disc) with 5 slender arm spines, joining on the dorsal midline, uppermost 2 spines over 2 segments in length, serrate, lower spines thorny. Next three segments with four spines, upper two elongated. Succeeding segments with three small spines, uppermost longest, longer than 1 segment, the lowermost becoming slightly curved distally; 1 oval tentacle scale, thorny tip, 2/3 as long as the ventral arm plate. A larger paratype (MNHN EcOs 22416) (3 mm d.d.) with additional arm spines: 5 on the second segment, 6 on the third (meeting dorsally), five on the next few, falling to three distally. DISTRIBUTION. — New Caledonia (750-1740 m). REMARKS. — These specimens were originally identified as Ophiacantha moniliformis (Koehler, 1904) (renamed O. renekoehleri in this paper, see remarks under Ophiacantha), but examination of the syntypes of that species (4.5-5.0 mm

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d.d.) showed that there are discernable differences. The syntypes have up to six arm spines, the longest of which are three segments in length. The disc has a rather sharp margin that is lifted away from the dorsal side of the arms. The distal ends of the radial shields are visible. Most of the disc spines have rubbed off, but the remaining spines are typically tiny conical granules, 0.05-0.1 mm high, often with three minute thorns near the centre of the dorsal disc surface. The oral shields are variable and can be as wide as long, or wider than long with concave proximolateral sides. The tentacle scales are rounded, not thorny, and only half the ventral arm plates in length. Overall the morphology of the two species is similar, both having a fragile petaloid disc, minute disc spines, strongly moniliform arms, slender serrate arm spines, the lowermost being slightly curved, elongated adoral shields and three bluntly pointed oral papillae. Several other Indo-Pacific Ophiacantha species also have enlarged adoral shields that extend around the oral shield. Ophiacantha dallasii Duncan, 1879 and O. hospes Koehler, 1930 differ in having reduced triangular oral shields, usually much smaller than the enlarged adoral shields. Adult specimens of Ophiacantha placida have four oral papillae. Juvenile O. placida with three oral papillae can be distinguished from the new species by their more robust form; the arms are less moniliform and the arm plates closer together. Ophiacantha placida is also found at shallower depths (192-763 m). Another similar species is O. exilis Koehler, 1992a from Indonesia in 1280 m, which Koehler placed in Ophiomitrella but which appears to be better placed in Ophiacantha, given the long radial shields which are only exposed distally, the moniliform arms, minute thorny disc spines and long thin adoral shields. The holotype and only known specimen (5 mm d.d.) is larger than any specimen of O. renekoehleri which makes direct comparison difficult. Nevertheless, O. exilis appears to differ in having four lateral oral papillae, the outermost one widened at the base, and up to eight arm spines. ETYMOLOGY. — Named in honour of Dr. Bertrand Richer de Forges (IRD) for his work organising the expeditions around New Caledonia.

Ophiacantha serrata Lyman, 1878 Fig. 2H-K Ophiacantha serrata Lyman, 1878a: 148, pl. 10 (272-273). Ophiacantha serrata ¢ Lyman 1882: 197-198, pl. 15 (6-8). — Baker 1979: 36. — McKnight 1993: 174, 187. Ophiacantha fausta Koehler, 1904: 104-105, pl. 20 (2-3); 1930: 59 [new synonymy]. Ophiacantha confusa ¢ Koehler 1922a: 47-49, pl. 19 (1-2). TYPE MATERIAL. — Holotype: BMNH 1882.12.23.40. TYPE LOCALITY. — Papua New Guinea, Admiralty Is, off Nares Harbour, 279 m. MATERIAL EXAMINED. — Indonesia. MPE Kei Is: stn 56, 5°30.3’S, 132°51’E, 345 m, 10.05.1922, identified by Koehler (1930) as Ophiacantha fausta: 1 (ZMUC). — Siboga: stn 253, Kapulauan Kai (Kei Islands), 5°48.2’S, 132°13’E, 304 m, 10.12.1899, syntypes of O. fausta: 2 (ZMA E2342). New Caledonia. MUSORSTOM 5: stn DW 335, 20°3.24’S, 158°45.35’E, 315 m, 15.10.1986: 2 (MNHN EcOs 22366). — MUSORSTOM 6: stn DW 412, Ride des Loyauté, 20°40.6’S, 167°3.75’E, 437 m, 15.02.1989: 1 (MNHN EcOs 22873). —

MUSORSTOM 6: stn DW 451, Ride des Loyauté, 20°59’S, 167°24.5’E, 330 m, 20.02.1989: 2 (MNHN EcOs 22874). — MUSORSTOM 6: stn DW 457, Ride des Loyauté, 21°0.42’S, 167°28.71’E, 353 m, 20.02.1989: 2 (MNHN EcOs 22875). — SMIB4: stn DW 55, 23°21.4’S, 168°4.5’E, 260 m, 09.03.1989: 3 (MNHN EcOs 22365). Papua New Guinea. Challenger: stn 219, Admiralty Is, off Nares Harbour, 1°50’S, 146°39.6’E, 279 m, 10.03.1875, holotype: 1 (BMNH 1882.12.23.40).

DESCRIPTION. — (New Caledonian material) Up to 8 mm d.d., disc flat or sunken, the underlying radial shields visible as long thin spokes. Minute disc spines, 0.05 mm high, with a perforated disc-like base, short columnar pedicel terminating

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in 3 (less commonly 2-4) divergent points; absent on ventral disc surface. Oral shields broadly triangular, with an acute proximal angle (rarely rounded) and a straight, convex or sometimes lobed distal border. Adoral shields large, trapezoid with relatively straight edges. One large wide apical and 4 thin, elongate oral papillae. Arms strongly moniliform, dorsal arm plates fan-shaped, curved, widely separate. Ventral arm plates wider than long, broadly rectangular with concave lateral sides around tentacle pore, separate. Up to 10 arm spines basally, uppermost 4 segments in length, meet on the dorsal midline; all arm spines hollow, denticulate with 2 rows of alternating thorns on the upper and lower edge of most spines. One thin blunt tentacle scale, 1/2 to 2/3 of an arm segment in length. DISTRIBUTION. — Philippines (232 m), Indonesia (304-345 m), Papua New Guinea (279 m), New Caledonia (260-437 m), Norfolk Ridge (500 m). REMARKS. — This species is characterised by the minute disc spines (that appear like fine granules under low magnification), moniliform arms, serrated arm spines, broadly triangular oral shields usually with an acute proximal point, and short thin tentacle scales. Koehler (1905) differentiated O. fausta from O. serrata by the relatively smooth arm spines and yet later included a specimen with thorny arm spines in his species (Koehler 1930). The difference is not great and due to the large size of the types of O. fausta (7 & 8 mm d.d.) as Koehler (1930) suggests. The structure and form of the other characters is very similar between the two nominal species. Koehler’s (1922a) photograph of a specimen identified as O. confusa is also clearly this species.

Ophiacantha vepratica Lyman, 1878 Ophiacantha vepratica Lyman, 1878a: 137-138, pl. 10 (245-247). Ophiacantha vepratica ¢ Lyman 1882: 182-183, pl. 13 (7-9). — Fell 1958: 25. Ophiacantha augusta Koehler, 1904: 105-106, pl. 19 (5-6) [new synonymy]. Non Ophiacantha vepratica ¢ Lyman 1878b: 230 [= Ophiacantha curima H.L. Clark, 1915]. Non Ophiacantha vepratica ¢ Koehler 1914: 94-95, pl. 13 (6) [= Ophiacantha metallacta H.L. Clark, 1915].

TYPE MATERIAL. — Holotype: BMNH 1882.12.23.37. Paratype: MCZ 2019. TYPE LOCALITY. — Off Kermadec Islands, 1116 m. MATERIAL EXAMINED. — Indonesia. Siboga: stn 122, eastern Celebes Sea, off NE tip of Sulawesi, 1°58.5’N, 125°0.5’E, 11651264 m, 17.07.1899, syntype of O. augusta: 1 (ZMA E2329). — Siboga: stn 280, northern Timor Sea, west of Leti, 8°17.4’S, 127°30.7’E, 1224 m, 15.01.1900, syntype of O. augusta: 1 (ZMA E2339).

New Caledonia. BIOCAL: stn CP 74, Ride de Norfolk, 22°14.06’S, 167°29.01’E, 1300-1475 m, 04.09.1985: 1 (MNHN EcOs 22367). New Zealand. Challenger: stn 171, Kermadec Islands, 28°33’S, 177°50’W, 1116 m, 15.07.1874, holotype: 1 (BMNH 1882.12.23.37).

DESCRIPTION. — (New Caledonian material) Disc 6 mm d.d., 2 types of disc spines, small conical to cylindrical granules (0.1-0.2 mm high) microscopically thorny at the tip, and a few long spines, smooth to minutely thorny, 1.0 mm high. Oral shields small, as wide as long, with a strongly convex distal margin, adoral shields short, not separating the oral shields from the arm plates; jaw elongate, with a blunt apical and 3 oral papillae, inner one pointed, outer ones rounded. Arms not moniliform, small triangular dorsal arm plates, widely separate, ventral arm plates 2.5 times as wide as long with only a slightly convex distal margin, widely separate. Up to 9 arm spines basally, uppermost long and smooth, meeting dorsally, 3 arm segments in length, middle spines minutely thorny, reducing to 7 arm spines further out along arm; 1 oval tentacle scale, almost as long as the ventral arm plate.

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DISTRIBUTION. — Indonesia (1165-1264 m), New Caledonia (1300-1475 m), Kermadec Islands (1116 m), Chatham Islands (484-558 m). REMARKS. — This species is characterised by the presence of both small granules and longer spines on the dorsal disc surface. The disc spines bear some resemblance to those on Ophiolimna species, particularly O. bairdi (Lyman, 1883). On the smaller O. angusta syntype there are even a few Ophiolimna-like granules on the distal border of one of the oral shields. However the two genera can be readily separated by characters of the oral frame. The syntypes of O. angusta (5 & 7 mm d.d.) are very similar to the holotype of O. vepratica. Most of the features used by Koehler (1904) to separate the two species have arisen from the diagrammatic illustrations of the type of O. vepratica. The form of the disc spines, arm spines and oral frame are very similar, as are the density of disc spines and numbers of arm spines. The distal oral papillae and tentacle scales are slightly more rounded on the O. angusta syntypes (particularly the smaller specimen) but given the constancy of the other characters this can be attributed to individual variation. Lyman (1882) refers to some juvenile specimens (4-6 mm d.d.) from the same station as the O. vepratica holotype. There were four juvenile specimens (2-3 mm d.d.) in the same jar as the holotype in the BMNH. However, these specimens are similar to Ophiomitrella stellifera or O. subjecta, and cannot be considered paratypes. Another ‘‘cotype’’ (not examined) is apparently lodged in the MCZ (H.L. Clark 1915). Three other species are very similar. Judging from their type descriptions, O. curima H.L. Clark, 1915 from the Bahamas differs in having smooth arm spines, O. metallacta H.L. Clark, 1915 from the Western Atlantic has no elongated disc spines, and the South African O. scutigera Mortensen 1933b has diamond-shaped oral shields, convex striated ventral arm plates and naked radial shields. We present here notes on other Indo-Pacific species of Ophiacantha.

Ophiacantha dallasii Duncan, 1879 Fig. 17I Ophiacantha dallasii Duncan, 1879: 471-473, pl. 11 (25-27). Ophiacantha dallasii ¢ Döderlein 1896: 291, pl. 14 (3), 16 (12). — Pfeffer 1900: 83. — Koehler 1905: 55(in part). — Koehler 1922a: 49-50, pl. 16 (1-3). Ophiothamnus gracilis Studer, 1882: 24, pl. 3 (11a-e) [new synonymy]. Ophiacantha dallasi ¢ Koehler 1930: 58. Ophiacantha ameleta Clark, H.L., 1938: 209-210 [new synonymy]. Ophiacantha gracilis ¢ Clark, H.L. 1946: 186. — Cherbonnier & Guille 1978: 19-21, fig. 3, pl. 3 (3-4). ?Ophiacantha ameleta ¢ Clark, H.L. 1939: 42.

TYPE MATERIAL. — Syntypes: BMNH 1880.1.3.1217(4). TYPE LOCALITY. — China, Bo Hai Sea, 93 m. MATERIAL EXAMINED. — China. Bo Hai Sea, 38°19’N, 120°7’E, 93 m, syntypes of O. dallasii: 4 (BMNH 1880.1.3.1217). Indonesia. MPE Kei Is: stn 18, Doe Roa Strait, 5°’S, 132°’E, 40 m, 12.04.1922, identified by Koehler (1930): 1 (ZMUC). — MPE Kei Is: stn 20, Doe Roe Basin, 5°’S, 132°’E, 50 m, 14.04.1922, identified by Koehler (1930): 1 (ZMUC). — MPE Kei Is: stn 22, 5°30.6’S, 132°51’E, 340 m, 15.04.1922, identified by Koehler (1930): 2 (ZMUC). — MPE Kei Is: stn 26, 5°38’S, 132°55.3’E, 90

m, 16.04.1922, identified by Koehler (1930): 8 (ZMUC). — MPE Kei Is: stn 57, 5°32’S, 132°49.4’E, 200 m, 10.05.1922, identified by Koehler (1930): 2 (ZMUC). Indian Ocean. John Murray expedition, no data, identified by Clark, H.L. (1939) as Ophiacantha ameleta: 1 (BMNH 1948.5.26.16). Philippines. MPE: stn 140306, Mindanao, 6 miles NNE of Sacol, 65 m, identified by Koehler (1930): 1 (ZMUC).

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OTHER MATERIAL EXAMINED. — Ophiacantha hospes Koehler, 1930: MPE Kei Is expedition, Indonesia, Kombir, Banda, 75-90 m, 01.06.2022, syntype: 1 (ZMUC). Ophiacantha vagans Koehler, 1898: Investigator expedition, Indian Ocean, 2 mi NW of Great

Western Torres Is, Mergui Archipelago, 74 m, syntype: 1 (ZSI ZEV 296/7). — Investigator: stn 91, Indian Ocean, 8 mi SE of Bawanapadu Beacon, Ganjam coast, 15°’N, 80°’E, 52 m, 20.02.1890, syntype: 1 (ZSI 5153/7).

DISTRIBUTION. — Madagascar (40-77 m), Korea (93 m), Indonesia (15-340 m), Philippines (27-294 m), northern Australia from Dampier WA to Murray Is, Qld (0-400 m). REMARKS. — H.L. Clark (1938, 1946) distinguished O. gracilis from O. dallasii, by the form of the uppermost arm spines, which are elongated on the first free segments of O. gracilis and supposedly subequal on O. dallasii. But Clark was misled by Duncan’s (1879) figures. Re-examination of four syntypes of O. dallasii, showed that elongated upper arm spines are present, although in most instances they are broken off. On the largest specimen (4.5 mm d.d., dry) there are up to seven arm spines on the first free segment after the disc (the third arm segment) which meet on the dorsal midline, the next segment has five spines, and thereafter four. Most of the upper spines have broken off but their bases are still clearly visible; remaining ones measure up to 2 segments in length. The smaller specimens have enlarged upper spines on the first two free segments, the number of spines being six, five and four on the first three free segments. The lower spines are short (less than a segment in length) and sharp. Duncan’s figures also misrepresent the orientation of the adoral shields, which are placed almost at right angles to each other interradially, extending beyond the small oral shield distally (particularly on small specimens). The adoral shields are also beaded. There can be up to three minute tentacle scales on basal pores, thereafter one. The disc spines are slender with two to three long divergent thorns (Fig. 17I). These thorns can occasionally bifurcate near the tip. The outer of the three oral papillae is slightly widened, the arms are moniliform and the colour is mottled. Consequently, O. gracilis is considered a synonym of O. dallasii. The type locality of O. dallasii is between China and Korea, although it has never subsequently been reported from China, Korea or Japan, the species being primarily tropical in distribution. Two other species have similar oral frames. O. hospes Koehler, 1930, which is only known from the unique type specimen from Indonesia, is distinguished by its larger tentacle scales and multifid disc spinelets (Fig. 17K). Ophiacantha vagans Koehler, 1898 from 52-74 m from the Bay of Bengal has smooth sharp disc spines. Unfortunately, the types of O. vagans have largely disintegrated and the shape and size of the disc spines could not be checked. Some specimens previously identified as O. gracilis have predominantly short sharp disc spines without terminal thorns and may be better placed in O. vagans. For example, Koehler (1905) mentioned some like this from Indonesia and the specimen identified by H.L. Clark (1939) as O. ameleta from the western Indian Ocean also has this form (Fig. 17J).

Ophiacantha indica Ljungman, 1867 Fig. 17L Ophiacantha indica Ljungman, 1867: 326. Ophiacantha indica ¢ Koehler 1905: 56; 1930: 59-60. Ophiacantha discoidea Lyman, 1879: 57, pl. 15 (405-407). — Lyman 1882: 196, pl. 26 (1-3). — Clark, H.L. 1921: 105-106, pl. 12 (4); 1938: 209; 1946: 186. — Rowe & Gates 1995: 371 [new synonymy]. Ophiacantha decora Koehler, 1898: 81-83, pl. 5 (44-46). — Koehler1900: pl. 16 (10-12). Ophiacantha ?confusa ¢ Gibbs, Clark, A.M. & Clark, C.M. 1976: 115 [Non Ophiacantha longidens Lyman, 1878a].

TYPE MATERIAL. — Holotype: SMNH Type-1403. TYPE LOCALITY. — Indonesia, between Batavia and Singapore. MATERIAL EXAMINED. — Indonesia. MPE Kei Is: stn 62, 5°29.4’S, 132°50’E, 290 m, 15.04.1922, identified by Koehler

(1930): 1 (ZMUC). — MPE Kei Is: stn 70, Java Sea, Sunda Strait, 5°40’S, 106°21’E, 35 m, 28.07.1922, identified by Koehler

DEEP-WATER

(1930): 1 (ZMUC). — Singapore, 01.10.1904, identified by Koehler (1930): 6 (ZMUC). — Eugenie expedition, between Batavia and Singapore, holotype: 1 (SMNH Type-1403). India. Investigator expedition, off Honavar, 52 m, syntypes of O. decora: 5 (ZSI ZEV 319/7). Sri Lanka. Investigator expedition, off south coast, 6°6.5’N, 81°23’E, 59 m, 11.11.1889, syntypes of O. decora: 5 (ZSI ZEV 318/7). Myanmar. Investigator expedition, 2 mi NW of Great Western Torres Is, Mergui Archipelago, 74 m, syntypes of O. decora: 5 (ZSI 5129/7). Australia. Alert expedition, off Albany Island, 10°43’S, 142°36’E, 5-7 m: 1 (BMNH 1881.10.26.209). — Moreton Bay,

OPHIUROIDS FROM

NEW CALEDONIA

between Peel Is and Cleveland, 27°25’S, 153°20’E, identified by Rowe as O. discoidea: 28 (AM G10971). — Torres Strait, Murray Islands, 01.01.1907, identified by H.L. Clark (1938) as Ophiacantha discoidea: 1 (AM J6358); identified by Clark, H.L. (1938) as Ophiacantha discoidea: 1 (AM J6381). — RS-UQ: stn K3(A), Great Barrier Reef, 11°50’S, 143°34.2’E, 64 m, 31.10.1973, identified by Gibbs, Clark, A.M. & Clark, C.M. as Ophiacantha ?confusa: 1 (BMNH 1975.6.27.14). — Challenger: stn 190, Arafura Sea, 8°56’S, 136°5’E, 91 m, 12.09.1874, holotype of O. discoidea: 1 (BMNH 1882.12.23.329). — Off Port Hedland, 19°39’S, 116°13’E, 122 m, 01.06.1980: 1 (AM J14091). Philippines. MPE: stn 140317, off Jolo, 46 m, 14.03.1914, identified by Koehler (1930): 2 (ZMUC).

DESCRIPTION. — Disc up to 7 mm d.d., covered in numerous spines obscuring underlying plates, spines with 2-3 terminal thorns, thorns sometimes bifurcate, spines near the centre of the disc often covered by thick skin at the apex, giving them a messy, coarse appearance. Oral shields roughly triangular with an acute to obtuse proximal angle and a straight to rounded, sometimes lobed, distal margin, often slightly swollen; adoral shields long and thin, often extending as far as the lateral angles of the oral shields, faintly beaded; jaw longer than wide with a large leaf-shaped apical and 3 bluntly pointed oral papillae. Dorsal arm plates triangular with a slightly convex distal margin, just separate basally; ventral arm plates roughly triangular with a proximal angle and convex distal margin, separate; up to 9 arm spines, longest 2 segments in length, rough surface, middle spines can have a few thorns; one small pointed tentacle scale, 1/3 to 1/2 the length of the ventral arm plate. Colour (preserved) mottled brown disc, dark or white markings over radial shields, arms lightly banded, oral shields sometimes with a broad dark stripe. DISTRIBUTION. — India (37-75 m), Philippines (46 m), Indonesia (9-290 m), NE Australia from Murray Is to Moreton Bay (littoral-91 m), NW Australia (5-122 m). REMARKS. — This species has been known under two names. Koehler who examined Ljungman’s types used O. indica, while H.L. Clark, who had access to Lyman’s types, used O. discoidea. The type specimens are very similar, differing only in the shape of the oral shield which is slightly lobed on the distal margin in O. indica and slightly convex on O. discoidea. However, the shape of the oral shield is quite variable on these specimens, and a continuum exists between the two forms. The syntypes of O. decora are also typical of this species, as noted by Koehler (1905). This species is widespread on tropical east Indo-West Pacific continental shelves. It probably lives in or on sandy substrates. The skin-covered disc spines appear to trap sediment, possibly as a camouflage. The arms are usually broken, however, on two specimens the remaining sections are at least eight times the disc diameter, which implies a suspension feeding habit.

Ophiacantha duplex Koehler, 1897 Fig. 17A-E Ophiacantha duplex Koehler, 1897: 352-353, pl. 8 (66-67). Ophiacantha duplex ¢ Koehler 1899: 60-62, pl. 8 (67), 9 (69-70); 1904: 109; 1922a: 50-51, pl. 16 (7-8). ?Ophiacantha clandestina Koehler, 1904: 108-109, pl. 19 (1-4). ?Ophiacantha audax Koehler, 1905: 57-58, pl. 7 (1-4). ?Ophiacantha suspecta Koehler, 1905: 58-59, pl. 7 (5-8). ?Ophiacantha diploa Clark, H.L., 1911: 207-208.

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TYPE MATERIAL. — Holotype: ZSI 6005/7. TYPE LOCALITY. — Sri Lanka, off Colombo, 1255 m. MATERIAL EXAMINED. — Indonesia. Siboga: stn 45, Flores Sea, south of Pelokang, 7°24’S, 118°15.2’E, 794 m, 06.04.1899, identified by Koehler (1904): 1 (ZMA E6168). — Siboga: stn 51, western Flores, Teluk Molo, Madura Bay, 69-91 m, 19.04.1899, holotype of O. audax: 1 (ZMA E2328); holotype of O. suspecta: 1 (ZMA E2360). — Siboga: stn 85, Makassar Strait, west of Donggala, Sulawesi, 0°36.5’S, 119°29.5’E, 724 m, 17.06.1899, syntypes of O. clandestina: 3 (ZMA E2331). — Siboga: stn 87, Makassar Strait, west of Donggala, Sulawesi, 0°32’S,

119°39.8’E, 655 m, 19.06.1899, syntype of O. clandestina: 1 (ZMA E2332). Sri Lanka. Investigator: stn 2, Off Colombo, 6°32’N, 79°37’E, 1255 m, 05.05.1886, holotype: 1 (ZSI 6005/7). Malaysia. Madras-Penang Cable Co. expedition, 6°50’N, 97°25’E, 930 m: 3 (BMNH 1929.7.16.2-3). Philippines. Albatross: stn 5348, Palawan Passage, off Point Tabonan, 10°57.75’N, 118°38.25’E, 686 m, 27.12.1908, identified by Koehler (1922a): 1 (MNHN EcOs 20322).

OTHER MATERIAL EXAMINED. — Ophiacantha vorax Koehler, 1897: Investigator: stn 108, Indian Ocean, Laccadive Sea, 7°4’N, 72°34.3’E, 1939 m, 05.04.1890, syntype: 1 (ZSI 6006/7); syntypes: 2 (MNHN EcOs 20353); syntype: 1 (BMNH 1898.7.11.15). — John Murray expedition: stn 26, Indian Ocean, Gulf of Aden,

2312 m, identified by Clark, H.L. (1939): 4 (BMNH 1949.1.10.406). — Siboga: stn 76, Indonesia, Makassar Strait, 4°22.1’S, 118°16.9’E, 2029 m, 09.06.1899, identified by Koehler (1904): 1 (ZMA E6202.1).

DESCRIPTION. — Disc up to 8 mm d.d, radial shields long, thin, exposed at distal tip. Disc covered in dense spinelets of two sorts: 1) small slender spinelets with 2-4 (usually 3) sharp terminal thorns, sometimes other thorns irregularly on pedicel, 0.3-0.4 mm high, reduced to small blunt stumps marginally, 2) long slender spinelets, smooth or thorny, 0.6-1.2 mm d.d., scattered centrally and in the interradii. Ventral surface with simple short sharp spinelets. Oral shield fan-shaped or trapezoid, wider than long with a bluntly-pointed proximal angle, and a convex, angled or slightly lobed distal edge. Adoral shields separated interradially, with a radial lobe that extends past and sometimes around the end of the oral shield. One large blunt apical and 3 long bluntly-pointed oral papillae. Arms often curled ventrally or at tip, probably epizoic. Dorsal arm plates fan-shaped, separate. Ventral arm plates as wide or wider than long, with a curved distal edge and obtuse proximal angle. Basal arm segments with up to 10 arm spines basally, often meeting dorsally, arm spines up to 4 segments in length, sometimes with thorns in 1-2 rows. Lowermost arm spine of distal segments modified into a hooklet with 4 short sharp teeth. One long narrow tentacle scale, shape varies from triangular with a pointed tip to oval with a rounded tip, from 1/2 to as long as a ventral arm plate. DISTRIBUTION. — Indonesia (69-794 m), India (1255 m), Malaysia (930 m), Philippines (686 m), Japan (812 m). REMARKS. — The nominal species O. clandestina, O. suspecta, O. audax and O. diploa are all very similar to O. duplex and probably synonymous. However, there is much morphological variation in this confusing series of specimens, and without more material it is difficult to determine if there is one or more species. Ophiacantha duplex is characterised by having two distinct kinds of disc spines (short slender multifid spinelets and longer thorny spines, Fig. 17A), numerous slender arm spines that have rows of sharp conical thorns, and one long narrow pointed tentacle scale. Examination of specimens referred to O. duplex by Koehler from the Albatross and Siboga expeditions, also revealed the presence of a characteristic hook-shaped lowermost arm spine on distal segments (the arms on the type are not long enough to see this feature, Fig. 17B). The syntypes of O. clandestina are similar except they have relatively few of the smaller multifid disc spines (previously unreported, Fig. 17D) and the dorsal row of thorns on the proximal arm spines are more developed. The unique holotypes of O. audax and O. suspecta were collected from the same ‘‘Siboga’’ station. Both specimens are damaged. The 4 mm d.d. holotype of O. audax has lost most of the arms so it is now impossible to determine whether it once possessed the hook-like lower arm spines. The remaining arm stumps have similar thorny arm spines, pointed tentacle scales and arm plates to O. duplex. The disc spines vary; the smaller multifid spines

DEEP-WATER

OPHIUROIDS FROM

NEW CALEDONIA

frequently have additional thorns on the pedicel and the larger spines are smooth or with thorns near the base (Fig. 17C). The holotype of O. suspecta has the thorny proximal arm spines and the specialised hook-like lowest arm spine distally. The dorsal disc surface is damaged, but the remaining spines are relatively simple, with smaller bifid spinelets (0.35 mm) and smooth larger spines (0.45 mm). The description of O. diploa is very similar to O. duplex, except that the arm spines are relatively smooth, the very fine thorns being only distinguishable under high-magnification (H.L. Clark 1911, Koehler 1922a). There are some specimens from off Malaysia in the BMNH (1929.7.16.2-3) that exactly match this description. Until more material is available it is inappropriate to reduce all these nominal species to synonymy. In particular the types of O. audax and O. suspecta differ in being from relatively shallow water (65 m) although Irimura et al. (1995) record a similar depth range for specimens of O. ‘‘diploa’’(80-1160 m). The species Ophiacantha prionota H.L. Clark, 1911 from Japan and O. pacata Koehler, 1922a from off Borneo are also similar to O. duplex in many features. The absence of the thorny disc spinelets on these two species (again known only from the holotypes) may be an accident of preservation or intraspecific variation. Neither description mentions hook-like arm spines. More material is required. Another similar species is Ophiacantha vorax Koehler, 1897 known from abyssal depths off the Gulf of Aden (1893-2312 m), India (1940 m), Japan (1207-1707 m), Philippines (1525 m) and Indonesia (1788-2029 m). Unfortunately, the type specimen in the ZSI has disintegrated, but, although Koehler (1897, 1899) mentioned only a single specimen, there are other specimens from the same locality labelled ‘‘type’’ in the BMNH and the MNHN. These specimens and those collected by the Siboga (Koehler 1904) can be clearly distinguished from O. duplex by the small multifid spinelets (0.25-0.3 mm, Fig. 17F), the absence of larger disc spines, and the smooth arm spines.

Genus OPHIOTRETA Verrill, 1899 Type species: Ophiacantha lineolata Lyman, 1883.

Ophiotreta eximia (Koehler, 1904) Figs 4E-G, 17S Ophiacantha eximia Koehler, 1904: 116-117, pl. 21 (3-5). Ophiacantha dilecta Koehler, 1904: 117-118, pl. 22 (3-4) [new synonymy]. Ophiotreta dilecta ¢ Clark, H.L. 1915: 216. — Koehler 1922a: 71. Ophiotreta eximia ¢ Clark, H.L. 1915: 216; 1939: 53. — Koehler 1922a: 70-71, pl. 8 (5-6), 93 (7). Non Ophiotreta eximia ¢ Koehler 1930: 65 [= Ophiotreta larissae (Baker, 1979)].

TYPE MATERIAL. — Syntypes: ZMA E2339(3), E2340(2), E2341, MCZ 3509. TYPE LOCALITY. — Indonesia, Flores Sea and Makassar Strait, 724-794 m. MATERIAL EXAMINED. — Indonesia. Siboga: stn 45, Flores Sea, south of Pelokang, 7°24’S, 118°15.2’E, 794 m, 06.04.1899, syntypes of O. dilecta: 3 (ZMA E2336). — Siboga: stn 85, Makassar Strait, west of Donggala, Sulawesi, 0°36.5’S, 119°29.5’E, 724 m, 17.06.1899, syntype of O. dilecta: 1 (ZMA E2337); syntypes: 2 (ZMA E2340).

New Caledonia. BIOCAL: stn CP 57, Ride de Norfolk, 23°43.3’S, 166°58.1’E, 1490-1620 m, 01.09.1985: 1 (MNHN EcOs 22500). — MUSORSTOM 5: stn CP 323, 21°18.52’S, 157°57.62’E, 970 m, 14.10.1986: 1 (MNHN EcOs 22501).

OTHER MATERIAL EXAMINED. — Ophiotreta imperita (Koehler, 1904): Siboga: stn 271, Indonesia, Kapulauan Aru, west of Dobo,

5°46.7’S, 134°0’E, 1520-1788 m, 21.12.1899, holotype: 1 (ZMA E2344).

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FIG. 4. A-D, Ophiotreta stimulea MNHN EcOs 22496; A, dorsal aspect; B, long disc spines; C, short disc spines of different individual; D, ventral aspect; E-G, Ophiotreta eximia MNHN EcOs 22500; E, dorsal aspect; F, disc spines; G, ventral aspect (G); H-L, Ophiotreta matura MNHN EcOs 22503; H, dorsal aspect; I, ventral aspect; J, arm spines; K, hook-shaped ventral-most arm spine; L, disc spines. SEM images, scale bars in mm. FIG. 4. A-D, Ophiotreta stimulea MNHN EcOs 22496 ; A, aspect dorsal; B, longues épines du disque ; C, courtes épines du disque d’un individu différent ; D, vue ventrale ; E-G, Ophiotreta eximia MNHN EcOs 22500 ; E, vue dorsale ; F, épines du disque ; G, vue ventrale ; H-L, Ophiotreta matura MNHN EcOs 22503 ; H, vue dorsale ; I, vue ventrale ; J, épines des bras ; K, formes en crochets des principales épines des bras ; L, épines discales. Images MEB, échelles en mm.

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OPHIUROIDS FROM

NEW CALEDONIA

DESCRIPTION. — (New Caledonian material) Disc 5 and 8 mm d.d., arms > 7 times d.d. Disc spines long, 0.5-0.8 mm high, slender, 10 times as high as wide, with small adpressed thorns and 2-3 small non-flaring terminal thorns. Oral shields broadly triangular with an obtuse proximal angle and a convex or lobed distal margin; adoral shields long and narrow, extending to, or just beyond the lateral angle of the oral shield; jaw longer than wide, 3 apical and 5 spiniform oral papillae, distal 1-2 papillae enlarged, sometimes the last papilla is much reduced. Dorsal arm plates fan-shaped, as wide as long, dorsal edge covered in minute spines, separate; ventral arm plates pentagonal, as wide as long, with a truncate to concave distal margin and a proximal angle, slightly thickened distally, covered in minute thorns; up to 12 arm spines, uppermost longest, 6 arm segments in length, meet over dorsal midline, smooth, lower spines covered in sharp thorns, lowermost spine on distal segments slightly curved with elongated thorns near the tip, but not hook-shaped; one large pointed tentacle scale, longer than the ventral arm plate, thorny apex, sometimes 2 on the pores of the first segment. Colour (dry): grey/purple. DISTRIBUTION. — Gulf of Aden and Arabian Sea (1270-1893 m), Indonesia (724-1788 m), Philippines (7631525 m), New Caledonia (970-1620 m). REMARKS. — The types of O. eximia are much larger (11-21 mm d.d.) than the New Caledonian specimens which makes comparison difficult. There does appear to be some modification of characters with increasing size, the disc spines become relatively shorter and stouter, the upper arm spines become progressively smoother and there are more oral papillae. The largest types differ in having relatively short disc spines (0.2-0.5 mm high, two to six times as high as wide), numerous oral papillae, including several in a suboral cluster near the jaw apex, wider ventral arm plates that are broadly in contact, and two tentacle scales basally. Nevertheless the smaller types are intermediate in form, the disc spines are 0.7-0.8 mm long and all specimens share characters such as the thickened distal edge of the ventral arm plate, the covering of minute thorns on the arm plates, the thorny arm spines and the long tapered tentacle scales. The type specimens of O. dilecta collected from two of the same stations as O. eximia are very similar. Koehler separated the two species by the smaller arm plates and the longer, thinner, smoother arm spines. However, re-examination of the 15 mm d.d. types of O. dilecta shows that they fall within the range of variation shown in the type series of O. eximia. This species is similar to O. matura but that species has stouter disc spines with flared terminal thorns, more thorny upper arm spines and arm plates, and hooked lowermost arm spines on distal segments. Ophiotreta imperita (Koehler, 1904), transferred here from Ophiacantha, also shares the rugose arm plates and curved lower arm spines, but the unique (8 mm d.d.) type differs in having disc spines with irregular erect thorns (0.5 mm high) that are not flared at the tip (Fig. 17Q) and shorter arm spines (to 2.5 segments in length).

Ophiotreta larissae (Baker, 1979) Figs 5E, 17N Ophioprium larissae Baker, 1979: 36-38, fig. 6a-f. Ophiotreta eximia ¢ Koehler1930: 65 [Non Ophiotreta eximia (Koehler, 1904)]. Ophiotreta speciosa Guille, 1981: 429-430, fig. 1d-f, pl. 4 (22-23) [new synonymy]. Ophiotreta larissae ¢ Paterson 1985: 56.

TYPE MATERIAL. — Holotype: NMNZ Ech 1855. Paratypes: NMNZ Ech 1856(20), ZMUC, IOUSSR, AM, USNM. TYPE LOCALITY. — Australia, south of Norfolk Island, 500 m.

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FIG. 5. A-D, Ophiotreta valenciennesi MNHN EcOs 22510; A, dorsal aspect; B, ventral aspect; C, dorsal arm plates; D, disc spines; E, Ophiotreta larissae MNHN EcOs 22505, dorsal aspect. SEM images except E, scale bars in mm. FIG. 5. A-D, Ophiotreta valenciennesi MNHN EcOs 22510 ; A, vue dorsale ; B, vue ventrale ; C, plaques dorsales des bras ; D, épines discales ; E, Ophiotreta larissae MNHN EcOs 22505, vue dorsale. Images MEB sauf E, échelles en mm.

MATERIAL EXAMINED. — Indonesia. MPE Kei Is: stn 50, 5°34’S, 132°25.7’E, 233 m, 04.05.1922, identified by Koehler (1930) as Ophiotreta eximia: 1 (ZMUC). New Caledonia. MUSORSTOM 6: stn DW 412, Ride des Loyauté, 20°40.6’S, 167°3.75’E, 437 m, 15.02.1989: 1 (MNHN EcOs 22983). — MUSORSTOM 6: stn CP 464, Ride des Loyauté, 21°2.3’S, 167°31.6’E, 430 m, 21.02.1989: 1 (MNHN EcOs 22505).

Australia. DM: stn 1255, South of Norfolk Island, 29°46.6’S, 168°58.9’E, 500 m, 01.01.1976, paratype: 1 (ZMUC). Philippines. MUSORSTOM 1: stn CP 55, off Lubang, 13°55’N, 120°12’E, 194-200 m, 26.03.1976, holotype of O. speciosa: 1 (MNHN EcOs 20390).

DESCRIPTION. — (New Caledonian specimen) Disc 11 mm d.d., dorsal disc spines up to 0.25 mm high, with slender pedicel and 2-3 long terminal points, marginal spines can be up to 0.35 mm long, spines near the radial shields and ventrally are small, conical, smooth or with minute terminal thorns. Oral shields roughly arrow-head-shaped, wider than long, with a lobed distal margin and an obtuse proximal angle; adoral shields long, extending to the lateral angle of the oral shield, broadened radially; jaw wider than long with 1-2 apical and 7-8 oral papillae, inner pointed and outer rounded to leaf-shaped. Dorsal arm plates bell-shaped, dorsal margin lobed, bearing some spines similar to those on the radial disc margin, as wide as long, just separate; ventral arm plates wider than long, widest distally, with a convex raised distal margin, excavate lateral sides and an obtuse proximal angle, separate; up to 8 arm spines, smooth to microscopically thorny, long slender and pointed, uppermost longest, 4 segments in length; 2 leaf-like tentacle scales on basal pores, incompletely covering the pore, 1 tentacle scale from the fifth segment, not as long as the ventral arm plate. Colour (dry) tan with dark spoke-like stripes between white stripes over the hidden radial shields, arms irregularly darkened dorsally with broad white longitudinal stripe.

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OPHIUROIDS FROM

NEW CALEDONIA

DISTRIBUTION. — Philippines (194-200 m), Indonesia (233-400 m), New Caledonia (430-437 m), Norfolk Island Ridge (500 m). REMARKS. — We can find no difference between the type specimens or descriptions of O. speciosa and O. larissae. Guille (1981) did not consider O. larissae, perhaps because Baker (1979) had placed it in Ophioprium. The 19 mm d.d. specimen identified as O. eximia by Koehler (1930) also proved upon examination to be this species. Ophiotreta larissae is characterised by the colour pattern, the slender disc spines which are reduced to conical granules near the radial margin, and the smooth arm spines.

Ophiotreta matura (Koehler, 1904) Figs 4H-L, 17R Ophiacantha matura Koehler, 1904: 112-113, pl. 23 (2-4). Ophiotreta matura ¢ Koehler 1922a: 76-81, pl. 12 (1-6), 13 (1-5), 14 (1-5), 15 (1-3), 93 (2); 1930: 66. — Clark, H.L. 1939: 53-54. — Clark, A.M. & Courtman-Stock 1976: 121. — Clark, A.M. 1977: 141. Ophioprium kapalae Baker, 1979: 38-39, fig. 6g-m [new synonymy]. Ophiotreta kapalae ¢ Paterson 1985: 56.

TYPE MATERIAL. — Syntypes: ZMA E2349(2). TYPE LOCALITY. — Indonesia, Kei Is, 397 m. MATERIAL EXAMINED. — Australia. K76 expedition, off Broken Bay, 33°32’S, 153°0’E, 823 m, 19.08.1976, holotype of O. kapalae: 1 (AM J10106); paratype of O. kapalae: 1 (AM J10107). Indonesia. Siboga: stn 256, Kapulauan Kai (Kei Islands), 5°26.6’S, 132°32.5’E, 397 m, 11.12.1899, syntypes: 2 (ZMA E2349).

New Caledonia. BIOCAL: stn CP 54, Ride de Norfolk, 23°10.3’S, 167°42.98’E, 950-1000 m, 01.09.1985: 1 (MNHN EcOs 22502). — BIOCAL: stn CP 75, Ride de Norfolk, 22°18.65’S, 167°23.3’E, 825-860 m, 04.09.1985: 3 (MNHN EcOs 22503).

DESCRIPTION. — (New Caledonian material) Disc 4-8 mm d.d., covered in thin skin and disc spines that obscure the underlying plates; disc spines long, thorny, several flaring thorns at the apex. Oral shields wider than long, with an obtuse proximal angle, and a convex to lobed distal margin; adoral shields short and thick, often (but not always) slightly rounding the lateral angle of the oral shields and separating the oral shield from the lateral arm plates; jaw as wide as long, bearing 1-2 apical and up to 7 spiniform oral papillae on each jaw side, sometimes additional suboral papillae. Dorsal arm plates separate, spinous near the distal margin; ventral arm plates as wide as long, with a strongly convex, often lifted, distal margin; up to 11 hollow arm spines basally, meeting along the dorsal midline, smooth or with minute thorns, uppermost 5 segments long, middle to lower spines thorny, lowest spine notably curved to hook-like on distal segments; one very large tentacle scale, two on basal pores, wide and rounded proximally, tapering to a sharp, often thorny tip, often longer than the ventral arm plate. Colour (dry) slightly greenish. DISTRIBUTION. — South eastern Africa (472-700), Gulf of Aden (1270 m), Indonesia (239-1022 m), Philippines (239-4161 m), New Caledonia (825-1000 m), eastern Australia (823 m). REMARKS. — The syntypes (7 and 13 mm d.d.) differ slightly from the New Caledonian material in having a few small conical granules as well as the longer thorny disc spines, the tentacle scale can be rounded at the tip, and the outer oral papillae a little larger than the others. However the other characters are similar, particularly the slightly flared shape of the longer disc spines and the hook-like lowermost arm spine. Ophioprium kapalae is a synonym. Baker (1979) placed his new species in Ophioprium and thus did not compare it with O. matura. The types of O. kapalae are comparatively large

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(to 22 mm d.d.), however, they do not differ in any substantive way from the O. matura syntypes. They possess the hooked lower arm spines, although these were not mentioned by Baker (1979) in his description.

Ophiotreta stimulea (Lyman, 1878) Figs 4A-D, 17O Ophiacantha stimulea Lyman, 1878a: 141, pl. 9 (225-228). Ophiacantha stimulea ¢ Lyman 1882: 188, pl. 13 (4-6). — Studer 1882: 24. Ophiacantha abnormis Lyman, 1879: 59, pl. 15 (411-413). — Lyman 1882: 189-190, pl. 26 (4-6). — Clark, H.L. 1939: 41-42 [new synonymy]. Ophiacantha gratiosa Koehler, 1897: 346-348, pl. 8 (60-61). — Koehler 1899: 56-58, pl. 8 (68), 9 (71-72) [new synonymy]. Ophiacantha inutilis Koehler, 1904: 111-112, pl. 21 (6-8). — Clark, H.L. 1911: 208-209. — Matsumoto 1917: 117-118. — Murakami 1942: 3 [new synonymy]. Ophiotreta gratiosa ¢ Koehler 1922a: 71-76, pl. 11 (1-7), 95 (1); 1930: 65-66. — Guille 1981: 427-429. — Imaoka et al. 1991: 130, fig. 53. — Liao & Clark A.M.1995: 179-180, fig. 81.

TYPE MATERIAL. — Holotype: BMNH 1882.12.23.26. TYPE LOCALITY. — Australia, off Sydney, 744-762 m. MATERIAL EXAMINED. — Australia. Challenger: stn 164b, off Port Jackson, 34°14’S, 151°30’E, 744-762 m, 12.06.1874, holotype: 1 (BMNH 1882.12.23.26). Indonesia. Siboga: stn 253, Kapulauan Kai (Kei Islands), 5°48.2’S, 132°13’E, 304 m, 10.12.1899, syntype of O. inutilis: 1 (ZMA E2346). Indian Ocean. John Murray expedition: stn 54, South Arabian coast, 1046 m, identified by Clark, H.L. (1939) as Ophiacantha abnormis: 6 (BMNH 1949.1.10.1-3). India. Investigator expedition, off South Sentinel Island, Andaman Islands, 11°N, 92°E, 446-539 m, syntype of O. gratiosa: 1 (ZSI 6004/7). — Investigator expedition, Bay of Bengal, 358 m, syntypes of O. gratiosa: 5 (ZSI 6003/7). — Investigator: stn 56, Between North and South Sentinel Island, Andaman Islands, 12°N, 92°E, 409-446 m, 24.04.1889, syntype of O. gratiosa: 1 (ZSI 5170/7). — Investigator: stn 136, Arabian Sea, 15°41’N, 72°43’E, 825 m, 04.05.1892, syntypes of O. gratiosa: 10 (ZSI 6002/7); syntype of O. gratiosa: 1 (BMNH 1898.7.11.13); syntypes of O. gratiosa: 3 (MNHN EcOs 20328). New Caledonia. BATHUS 3: stn CP 833, Ride de Norfolk, 23°2.75’S, 166°58.23’E, 441-444 m, 30.11.1993: 7 (MNHN EcOs 22990). — BIOCAL: stn DW 33, Ride de Norfolk, 23°9.71’S, 167°10.27’E, 675 m, 29.08.1985: 7 (MNHN EcOs 22492). — BIOCAL: stn DW 39, Ride de Norfolk, 22°55.06’S, 167°22.84’E, 650 m, 30.08.1985: 2 (MNHN EcOs 22494). — BIOCAL: stn DW 41, Ride de Norfolk, 22°45.13’S, 167°11.74’E, 380-410 m, 30.08.1985: 1 (MNHN EcOs 22499). — BIOCAL: stn DW 51, Ride de Norfolk, 23°5.27’S, 167°44.95’E, 680-700 m, 31.08.1985: 6 (MNHN EcOs 22496). — BIOCAL: stn CP 55, Ride de Norfolk, 23°19.8’S, 167°30.7’E, 1160-1175 m, 01.09.1985: 1 (MNHN EcOs 22488). — BIOCAL: stn C P61, Ride de Norfolk, 24°11.7’S, 167°31.8’E, 1070 m, 02.09.1985: 1 (MNHN EcOs 22493). —

BIOCAL: stn CP 62, Ride de Norfolk, 24°19.06’S, 167°48.65’E, 1395-1410 m, 02.09.1985: 1 (MNHN EcOs 22497). — BIOCAL: stn CP 69, Ride de Norfolk, 23°51.38’S, 167°58.68’E, 1220-1225 m, 03.09.1985: 1 (MNHN EcOs 22489). — BIOCAL: stn CP 75, Ride de Norfolk, 22°18.65’S, 167°23.3’E, 825-860 m, 04.09.1985: 7 (MNHN EcOs 22487). — BIOCAL: stn CP109, Ride de Norfolk, 22°10’S, 167°15.2’E, 495-515 m, 09.09.1985: 1 (MNHN EcOs 22498). — MUSORSTOM 5: stn CP 323, 21°18.52’S, 157°57.62’E, 970 m, 14.10.1986: 2 (MNHN EcOs 22486). — MUSORSTOM 6: stn DW 391, Ride des Loyauté, 20°47.35’S, 167°5.7’E, 390 m, 13.02.1989: 4 (MNHN EcOs 22995). — MUSORSTOM 6: stn CP 427, Ride des Loyauté, 20°23.35’S, 166°20’E, 800 m, 17.02.1989: 2 (MNHN EcOs 22996). — MUSORSTOM 6: stn CP 464, Ride des Loyauté, 21°2.3’S, 167°31.6’E, 430 m, 21.02.1989: 1 (MNHN EcOs 22495). — MUSORSTOM 6: stn CP 467, Ride des Loyauté, 21°5.13’S, 167°32.11’E, 575 m, 21.02.1989: 1 (MNHN EcOs 22998). — MUSORSTOM 6: stn DW 487, Ride des Loyauté, 21°23.3’S, 167°46.4’E, 500 m, 23.02.1989: 2 (MNHN EcOs 22999). — SMIB4: stn DW 58, 22°59.6’S, 167°24.2’E, 480-560 m, 09.03.1989: 10 (MNHN EcOs 22490). — SMIB4: stn DW 63, 22°58.7’S, 167°21.1’E, 520 m, 10.03.1989: 1 (MNHN EcOs 22491). Philippines. Challenger: stn 210, Mindanao Sea, 9°26’N, 123°45’E, 697 m, 25.01.1874, identified by Lyman (1882) as Ophiacantha abnormis: 1 (BMNH 1956.10.2.43). — MUSORSTOM 1: stn CP 49, W of Lubang Island, 13°49’N, 120°0’E, 750-925 m, 25.03.1976, identified by Guille (1981) as Ophiotreta gratiosa: 1 (MNHN EcOs 3402). — Challenger: stn 207, south of Sibuyan Is, 12°21’N, 122°15’E, 1302 m, 13.01.1875, holotype and paratypes of O. abnormis: 6 (BMNH 1882.12.23.222).

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OTHER MATERIAL EXAMINED. — Ophiotreta nefasta Koehler, 1930: MPE Kei Is: stn 4, Indonesia, 5°31.5’S, 132°38’E, 250 m, 04.04.2022, holotype: 1 (ZMUC).

DESCRIPTION. — (New Caledonian material) 1.5 to 12 mm d.d., arms at least 5.5 times d.d.. Disc covered in small overlapping plates bearing elongate spines, varying from 2 to 7 times as high as wide, tapered to a blunt point, rough (microscopically thorny), smaller near margin. Only the distal tips of the radial shields exposed. Oral shields as wide as to wider than long, rhombic, or triangular with a convex to lobed distal margin and a rounded proximal angle; adoral shields long and narrow separating the oral shields from the arm plates, jaw longer than wide with 5-6 oral papillae on each side, 1-2 apical in position, inner papillae spiniform, outer papilla enlarged with a pointed or round tip. Dorsal arm plates fan-shaped with a convex to slightly lobed distal margin and an acute proximal angle, just in contact, basal plates bearing spines similar to disc, succeeding plates with a few small pointed spines at the centre of the distal margin; ventral arm plates wider than long, broadly in contact, centre of distal margin straight or slightly notched, often raised; up to 8 smooth arm spines (only rarely with some thorns on ventral spines), bluntly pointed, not meeting over the dorsal midline, uppermost longest, greater than 4 segments in length; 1 large tentacle scale, sometimes 2 basally, oval to pointed, 3/4 the length of the ventral arm plate. Colour (dry) cream or fawn. DISTRIBUTION. — South Arabia (1046 m), India (358-825 m), Japan (130-2740 m), S. China (200-472 m), Philippines (231-1302 m), Indonesia (289-527 m), New Caledonia (380-1410 m), E. Australia (744-762 m). REMARKS. — The New Caledonian material varies morphologically, particularly in the shape of the oral shields, the length of the disc spines, the shape of the tentacle scales and the extent to which the arm plates are separate or contiguous. The disc spines can vary from being predominantly short (0.24 mm high, twice as high as wide) to predominantly long and elongate (0.8 mm high, more than six times as high as wide). None of the variations appear to be correlated in a consistent way. We have observed a similar range of variation within the syntype series of O. gratiosa, and Koehler (1922a) noted similar variations across his extensive collection of specimens from the Philippines when he synonymised O. inutilis with O. gratiosa. H.L. Clark (1939) synonymised O. gratiosa with O. abnormis after examining type specimens in the MCZ. Our examination of the types of O. abnormis, O. gratiosa and O. inutilis confirm the synonymy. The types of O. abnormis have long slender adoral shields, that separate the oral shield from the lateral arm plates, not the short ones described and figured by Lyman. Moreover, examination of the unique type specimen (6 mm d.d.) of O. stimulea from off Sydney, Australia, showed that it is also a juvenile of this species. Unfortunately this name has priority. Ophiotreta stimulea is characterised within Ophiotreta by the relatively coarse conical to elongate disc spines, the large single tentacle scale and the smooth arm spines. The species of Ophiotreta can be difficult to distinguish. Some specimens of O. stimulea with long disc spines approach O. matura, but that species can be distinguished by its short thick adoral shields and the smaller but more numerous spines on the dorsal arm plates. Some specimens of O. stimulea with enlarged distal oral papillae also approach Ophiotreta spatulifera Koehler, 1922a. The unique 8 mm d.d. type of O. spatulifera appears from Koehler’s photographs to differ from O. stimulea in having shorter but wider adoral shields and fewer oral papillae, the two distal ones being greatly enlarged and spatulate. Ophiotreta nefasta Koehler (1930) is known from a single small (3.5 mm d.d.) specimen collected from the Kei Islands. This specimen has many features in common with O. stimulea but appears to differ in having two distinct kinds of disc spines, long slender microscopically thorny spines with a bifid/trifid tip and low granules (Fig. 17M), rather than a series of spines of varying heights as in O. stimulea (Fig. 17O). The characters of the jaw of O. nefasta show a possible relationship to the Ophiotominae Paterson, 1985 (as defined by Paterson 1985). The jaw is elongate, the oral tentacle pore is large and superficial, and the two distal oral papillae are small and spiniform, functioning as oral tentacle scales. The arm tentacle pores, however, are more like the Ophiacanthinae, being small and completely covered by a large oval tentacle scale. More, preferably larger, material is required in order to clarify its relationships. Finally, H.L. Clark (1911) drew attention to the similarity between O. stimulea and Ophiacantha atopostoma H.L. Clark, 1911 from the Bering Sea. The disc

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spines, arm spines and numerous oral papillae are similar to O. stimulea, but Clark’s (1911) figures show relatively short adoral shields, that do not separate the oral shield from the first lateral arm plate. However, the distal extension of the adoral shields can be difficult to see in some specimens and the unique 10 mm d.d. type of O. atopostoma was described as being in poor condition. Resolution of the status of O. atopostoma requires re-examination of the type specimen and preferably additional material from the area.

Ophiotreta valenciennesi (Lyman, 1879) Figs 5A-D, 17P Ophiacantha valenciennesi Lyman, 1879: 57-58, pl. 15 (408-410). Ophiacantha valenciennesi ¢ Lyman 1882: 183-184, pl. 26 (7-8). — Koehler 1904: 110-111. Ophiacantha bisquamata Matsumoto, 1915: 62-63. — Matsumoto 1917: 120-122, fig. 31. — Murakami 1944: 251. — Clark, A.H. 1949: 17 [new synonymy]. Ophiotreta valenciennesi ¢ Koehler1922a: 84, pl. 16 (4), 93 (6); 1930: 66-67(in part). Ophiotreta bisquamata ¢ Koehler 1930: 64-65.

TYPE MATERIAL. — Holotype: BMNH 1882.12.23.456. TYPE LOCALITY. — Indonesia, Kei Is, 239 m. MATERIAL EXAMINED. — Indonesia. MPE Kei Is: stn 49, 5°37.2’S, 132°23’E, 245 m, 03.05.1922, identified by Koehler (1930) as Ophiotreta bisquamata: 1 (ZMUC). — MPE Kei Is: stn 52, 5°46’S, 132°49.5’E, 352 m, 07.05.1922, identified by Koehler (1930) as Ophiotreta bisquamata: 1 (ZMUC). — Siboga: stn 119, Sulawesi, north-west of Menado, 1°33.5’N, 124°41’E, 1901 m, 13.07.1899, identified by Koehler (1904): 1 (ZMA Ech O 6199.1). — Siboga: stn 156, Irian Jaya, eastern Halmahera Sea, east of Gag Is., 0°29.2’S, 130°5.3’E, 469 m, 15.08.1899, identified by Koehler (1904): 2 (ZMA Ech O 6199.2). — Siboga: stn 251, Kapulauan Kai (Kei Islands), 5°28.4’S, 132°0.2’E, 204 m, 08.12.1899, identified by Koehler (1904): 1 (ZMA Ech O 6199.3). — Challenger: stn 192, Ki (Kei) Is, 5°42’S, 132°25’E, 239 m, 26.09.1874, holotype: 1 (BMNH 1882.12.23.456). New Caledonia. BATHUS 3: stn CP 833, Ride de Norfolk, 23°2.75’S, 166°58.23’E, 441-444 m, 30.11.1993: 1 (MNHN EcOs 23000). — CHALCAL 2: stn DW 79, Ride de Norfolk, 23°40.5’S, 168°0.1’E, 243 m, 30.10.1986: 1 (MNHN EcOs 22506). — MUSORSTOM 5: stn CP 275, 24°46.6’S, 159°40.3’E, 285 m, 09.10.1986: 1 (MNHN EcOs 22507). — MUSORSTOM 5: stn CP 279, 24°8.72’S, 159°37.76’E, 260-270 m, 10.10.1986: 1 (MNHN

EcOs 22509). — MUSORSTOM 5: stn DW 304, 22°10.34’S, 159°25.51’E, 385-420 m, 12.10.1986: 2 (MNHN EcOs 22510). — MUSORSTOM 6: stn DW 391, Ride des Loyauté, 20°47.35’S, 167°5.7’E, 390 m, 13.02.1989: 12 (MNHN EcOs 23002). — MUSORSTOM 6: stn DW 398, Ride des Loyauté, 20°47.19’S, 167°5.65’E, 370 m, 13.02.1989: 2 (MNHN EcOs 23003). — MUSORSTOM 6: stn DW 406, Ride des Loyauté, 20°40.6’S, 167°6.8’E, 373 m, 15.02.1989: 4 (MNHN EcOs 23004). — MUSORSTOM 6: stn CP 408, Ride des Loyauté, 20°41.1’S, 167°7.45’E, 380 m, 15.02.1989: 1 (MNHN EcOs 23005). — MUSORSTOM 6: stn CP 464, Ride des Loyauté, 21°2.3’S, 167°31.6’E, 430 m, 21.02.1989: 1 (MNHN EcOs 23006). — MUSORSTOM 6: stn DW 480, Ride des Loyauté, 21°8.5’S, 167°55.98’E, 380 m, 22.02.1989: 1 (MNHN EcOs 23007). — MUSORSTOM 6: stn CP 481, Ride des Loyauté, 21°21.85’S, 167°50.3’E, 300 m, 23.02.1989: 1 (MNHN EcOs 23008). — SMIB4: stn DW 44, 24°46’S, 168°8.2’E, 300 m, 08.03.1989: 1 (MNHN EcOs 22508). — SMIB4: stn DW 46, 24°46.7’S, 168°8.5’E, 260 m, 08.03.1989: 1 (MNHN EcOs 22511). Philippines. MPE: stn 140309, 7°25’N, 123°14’E, 465 m, identified by Koehler (1930) as Ophiotreta bisquamata: 1 (ZMUC).

OTHER MATERIAL EXAMINED. — Ophiotreta durbanensis (Mortensen, 1933b): Meiring Naude SM: stn 23, South Africa, off Natal, 27°44.4’S, 32°42.8’E, 400-450 m, 26.05.1975, identified by Clark, A.M. (1977): 1 (BMNH 1976.7.28.12). — Meiring Naude SM: stn

86, South Africa, off Natal, 27°59.5’S, 32°40.8’E, 550 m, 22.05.1976, identified by Clark, A.M. (1977): 1 (BMNH 1976.10.21.147).

DESCRIPTION. — (New Caledonian material) Disc 8 to 15 mm d.d., disc covered in thin small overlapping plates bearing conical to hemispherical granules, up to 0.15 mm high, microscopically thorny; only the tips of the radial shields are exposed. Oral shields arrow-head-shaped, longer than wide, usually widest at the distal end, with a lobed distal margin

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and rounded lateral and proximal angles; adoral shields long and narrow, not meeting within, extending around the lateral angle of the oral shield, separating it from the ventral arm plates; jaw as wide as long, bearing 1-2 apical and 4-6 oral papillae, inner oral papillae spiniform, pointed, outer papilla enlarged, leaf-shaped to spatulate, functioning as an oral tentacle scale. Dorsal arm plates triangular with a slightly lobed distal margin, widest distally, tapering to a proximal angle, just in contact basally, basal plates bearing a few small pointed spines on the distal margin; ventral arm plates wider than long, with a convex distal margin and an acute proximal angle, just contiguous; 6 smooth (microscopically thorny) arm spines, uppermost longest, 4 segments in length, with a truncate tip; two small oval tentacle scales over each pore, 1/2 as long as the ventral arm plate, inner scale slightly smaller. Colour (dry) light brown, often with dark markings on the disc and banded arms. There can be a longitudinal white line that runs along the dorsal arm surface, often bordered by a darker line on each side. DISTRIBUTION. — Tropical Atlantic (as O. valenciennesi rufescens) (640-1440 m), Japan (140-158 m), Ryukyu Is, Philippines (311-465 m), Indonesia (204-1901 m), New Caledonia (243-444 m), Hawaii (238-276 m). REMARKS. — This species is characterised within Ophiotreta by the conical to hemispherical disc granules and the presence of two tentacle scales on most arm pores. Ophiotreta bisquamata is regarded here as a synonym of O. valenciennesi. From Matsumoto’s description and figures, the main differences from O. valenciennesi appear to be the more rounded oral shields that are widest at the distal end, the fewer oral papillae, the relatively narrow ventral arm plates and the lack of spines on the distal margin of the dorsal arm plates. Within the current material there is a continuous range of variation between specimens with oral shields widest proximally with a large distal lobe (similar to the holotype of O. valenciennesi) and widest distally with a small distal lobe (similar to Matsumoto’s figure of the holotype of O. bisquamata). The other distinguishing features are almost certainly due to the small size of the holotype of O. bisquamata (6 mm d.d.). Indeed Murakami (1944) found larger specimens from Japan with wider ventral arm plates and up to eight arm spines. Koehler (1930) referred several other small specimens to O. bisquamata from the Kei Islands. These specimens are unusual in having much enlarged distal oral papillae that are almost as wide as long, but the other features are consistent with O. valenciennesi. A.H. Clark (1949) reported a single 9 mm d.d. specimen of O. bisquamata from Hawaii with granules along the edge of basal dorsal arm plates. Another similar species is O. durbanensis Mortensen, 1933b from off South Africa. It also has two tentacle scales and disc granules. It differs, however, in also having some elongate disc spines as well as granules. Koehler’s (1930) specimen of O. valenciennesi recorded from SE Australia is not this species but an ophiocomid, Clarkcoma bollonsi (see O’Hara 1990). A separate subspecies, O. valenciennesi rufescens Koehler, 1896b, has been recorded from the tropical Atlantic, differing in having shorter adoral shields that do not separate the oral shield from the lateral arm plate (Paterson 1985). We present here notes on Indo-Pacific species of Ophialcaea Verrill, 1899.

Genus OPHIALCAEA Verrill, 1899 Type species: Ophiacantha tuberculosa Lyman, 1878a (designated by H.L. Clark, 1915).

Ophialcaea tuberculosa (Lyman, 1878) Ophiacantha tuberculosa Lyman, 1878a: 137, pl. 8 (204-205). Ophiacantha tuberculosa ¢ Lyman 1882: 181, pl. 10 (1-3). Ophiacantha congesta Koehler, 1904: 103-104, pl. 24 (1-2) [new synonymy].

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Ophialcaea congesta ¢ Clark, H.L. 1915: 217. — Clark, A.M. 1965: 41-42. — Guille 1981: 424. Ophialcaea tuberculosa ¢ Clark, H.L. 1915: 217. Ophialcoea congesta ¢ Koehler 1922a: 85, pl. 15 (6-7).

TYPE MATERIAL. — Holotype: BMNH 1882.12.23.315. Paratype: MCZ 2018. TYPE LOCALITY. — Philippines, Mindanao Sea, 697 m. MATERIAL EXAMINED. — Philippines. Albatross: stn 5219, between Marinduque and Luzon, Mompog Island, 13°21’N, 122°18.75’E, 969 m, 23.04.1908, identified by Clark, A.M. (1965) as Ophialcaea congesta: 1 (MNHN EcOs 20316). — Albatross: stn 5119, Balyan Bay and Verde Island passage, 13°45.8’N, 120°30.5’E, 721 m, 21.01.1908, identified by Clark, A.M. (1965)

as Ophialcaea congesta: 1 (BMNH 1963.11.26.29). — MUSORSTOM 1: stn CP 47, 13°41’N, 120°30’E, 685-757 m, 25.03.1976, identified by Guille (1981) as Ophialcaea congesta: 7 (MNHN EcOs 20354). — Challenger: stn 210, Mindanao Sea, 9°26’N, 123°45’E, 697 m, 25.01.1874, holotype: 1 (BMNH 1882.12.23.315).

DESCRIPTION. — Disc up to 11 mm d.d, covered in spaced low conical tubercles that obscure the underlying plates including the radial shields which are observable only as raised bars; the tubercles occasionally support a long hair-like thorn at the apex. Oral shields wider than long, with an acute proximal angle, slightly concave proximo-lateral sides, and a flat or slightly convex distal margin; adoral shields short and thick, conspicuously beaded, 1 apical and 3 oral papillae, outer oral papillae widened and sometimes notched along the apex; occasionally there is an additional suboral papilla. Dorsal arm plates trapezoid with slightly convex distal margin, wider than long, broadly in contact, with rows of tiny granules near distal margin. Ventral arm plates broadly in contact, wider than long, distal margin with rounded, sometimes spiniferous corners and a notched centre. Lateral arm plates are beaded. Arm spines short and thick, up to 5 basally then 4, upper basal ones slightly longer and thicker, 1.5 segments in length. The single tentacle scale is small and lanceolate, 1/2 the length of the ventral arm plate. DISTRIBUTION. — Philippines (685-969 m), Indonesia (450-798 m). REMARKS. — Lyman’s figures of O. tuberculosa are quite diagrammatic, the arm spines are thicker and more rounded than they appear on his figure, and the dark stripe drawn between the radial shields is an artificial depression caused by constriction of the disc. Koehler (1904) did not compare O. congesta with O. tuberculosa, but was later misled by Lyman’s poor diagrams when he did distinguish the two species (Koehler 1992a). The two species are synonymous, the type specimens being almost identical and similar to the photographs given by Koehler (1922a).

Subfamily OPHIOTOMINAE Paterson, 1985 Genus OPHIOLIMNA Verrill, 1899 Ophiolimna Verrill, 1899a: 40, 44. Ophiolimna ¢ Matsumoto 1917: 101-102. — Paterson 1985: 52-53. Toporkovia D’yakonov, 1954: 130. — Fell 1961: 43 [new synonymy].

Type species: Ophiacantha bairdi Lyman, 1883. REMARKS. — This synonymy is discussed under the species Ophiolimna antarctica.

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Ophiolimna antarctica (Lyman, 1879) Fig. 6K-N Ophioconis antarctica Lyman, 1879: 44-45, pl. 14 (380-382). Ophioconis antarctica ¢ Lyman 1882: 107-108, pl. 23 (1-3). — Hertz 1927: 40-41. Ophiocantha polaris Koehler, 1901: 32-33, pl. 3 (19-21). Ophiolimna antarctica ¢ Matsumoto 1917: 101. — Clark, H.L. 1939: 54. Ophiacantha antarctica ¢ Mortensen 1936: 254. Toporkovia fragilis D’yakonov, 1954: 130-132, fig. 47. Toporkovia antarctica ¢ Fell 1961: 43-44, fig. 5, pl. 16 (1), 17 (1), 18 (1). — Madsen 1967: 127. — Baker 1977: 159-160. Toporkovia antarctica fragilis ¢ Belyaev & Ivanov 1961: 1258. ?Ophioconis papillata ¢ Clark, H.L. 1911: 28-30, fig. 4.

TYPE MATERIAL. — Holotype: BMNH. Paratypes: MCZ 164(3), 165, 239(2) (not seen). TYPE LOCALITY. — Off Kerguelen, 253 m. MATERIAL EXAMINED. — New Caledonia. BIOCAL: stn DW 08, Bassin des Loyauté, 20°34.35’S, 166°53.9’E, 435 m, 12.08.1985: 1 (MNHN EcOs 22401). — BIOCAL: stn DW 33, Ride de Norfolk, 23°9.71’S, 167°10.27’E, 675 m, 29.08.1985: 10 (MNHN EcOs

22404). — BIOCAL: stn DW 44, Ride de Norfolk, 22°47.3’S, 167°14.3’E, 440-450 m, 30.08.1985: 25 (MNHN EcOs 22403). — BIOCAL: stn DW 51, Ride de Norfolk, 23°5.27’S, 167°44.95’E, 680-700 m, 31.08.1985: 7 (MNHN EcOs 22402).

DESCRIPTION. — Disc up to 3 mm d.d., dorsal and ventral disc surface covered in a dense coat of cylindrical to conical stumps (0.06-0.12 mm high), higher than wide, which completely cover the radial shields, slightly elongated spines (to 0.15 mm) can occur around the edge of the oral shields and on the oral plates. Oral shields triangular with rounded proximal and lateral angles and a straight to slightly convex distal side. Adoral shields long, continue around the lateral sides of the oral plate. Elongate jaw with 2 apical and 4-5 oral papillae, distal papilla enlarged, squarish to rectangular (2 times as wide as long). Dorsal arm plates fan to bell-shaped, with a straight to convex distal border, slightly carinate, longer than wide, separate. Ventral arm plates wider than long, often with a slightly notched distal border, separate. Lateral and ventral arm plates strongly striated. Four arm spines, uppermost longest, flattened, terminating in a sharp point. One large oval to leaf-shaped tentacle scale, almost as long as the ventral arm plate, completely covering the small pore. DISTRIBUTION. — Zanzibar (2926 m), Maldives (1824-2051 m), Japan (1270 m), NW Pacific (140-700 m), New Caledonia (435-700 m), New Zealand (512-1006 m), circumpolar Antarctica and subantarctic (180-900 m). REMARKS. — This species has a complex nomenclature. It was originally placed in the ophiodermatid genus Ophioconis. H.L. Clark (1911) noted its close similarity with the Ophiacanthidae (p. 30) and in particular (p. 230) with Ophiacantha bairdi Lyman, 1883, although he later retained it without comment under the Ophiodermatidae Ljungman, 1867 (H.L. Clark, 1915). Matsumoto (1915) took the step of transferring the species to Ophiolimna and the Ophiacanthidae. Hertz (1927) retained the genus name Ophioconis for O. antarctica when she synonymised it with O. polaris, even though Koehler (1922a) had also earlier transferred this species to Ophiolimna. Mortensen (1936) following H.L. Clark (1915) did not recognise Ophiolimna, placed the species in Ophiacantha, and proposed a replacement name (O. disjuncta) for Ophiacantha antarctica Koehler, 1901. A few years later H.L. Clark (1939) appeared to accept Matsumoto’s decision, recording several specimens from abyssal depths in the NE Indian Ocean as Ophiolimna antarctica without comment. D’yakonov (1954) described a new genus Toporkovia in the Ophiodermatidae based on the new species T. fragilis. D’yakonov did not compare the new genus or species with the two Ophiolimna species also recorded from the USSR (O. bairdi and O. papillata). Fell (1961), recognising the similarity between the boreal T. fragilis and specimens from the Ross Sea, transferred O. antarctica to Toporkovia. No mention was made of the genus name Ophiolimna. In a postscript, Fell (1961) recorded comments by

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FIG. 6. A-G, Ophiolimna placentigera MNHN EcOs 22410; A, dorsal aspect; B, ventral aspect; C, arm spine; D, arm spine articulation; E, dorsal arm plates; F, ventral arm plates; G, disc spines; H-J, Ophiolimna perfida MNHN EcOs 22405; H, ventral aspect; I, dorsal aspect; J, disc spines; K-N; Ophiolimna antarctica MNHN EcOs 22403; K, dorsal aspect; L, striated arm plates dorsal; M, ventral aspect; N, disc granules. SEM images, scale bars in mm. FIG. 6. A-G, Ophiolimna placentigera MNHN EcOs 22410 (A-G) ; A, vue dorsale ; B, vue ventrale ; C, épines des bras ; D, articulation des épines des bras ; E, plaques dorsales des bras ; F, plaques ventrales des bras ; G, épines discales ; H-J, Ophiolimna perfida MNHN EcOs 22405 ; H, vue ventrale ; I, vue dorsale ; J, épines discales ; K-N, Ophiolimna antarctica MNHN EcOs 22403 ; K, vue dorsale ; L, plaques dorsales striées des bras ; M, vue ventrale ; N, granules discaux. Images MEB, échelles en mm.

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the Russian biologists Dr. G.M. Belyaev and Dr. Z Baranova, that T. fragilis, O. antarctica and O. papillata were probably synonymous. In the subsequent paper however, Belyaev & Ivanov (1961) treat fragilis as a subspecies of T. antarctica. Madsen (1967) transferred Toporkovia back to the Ophiacanthidae, although this was ignored by Baker (1977) who retained it in the Ophiodermatidae. Baker (1977), following earlier suggestions by Fell (1961), also stated that T. antarctica was a bipolar taxon, missing H.L. Clark’s (1939) records from the Indian Ocean. This confusing synonymy is caused by the lack of attention by several authors to earlier literature and the similarity of this species to other taxa in both the Ophiacanthidae and Ophiodermatidae. This species also shares some characters with the Ophioleucidae, particularly the striated arm plates, granulated disc surface and elongated jaw. However, we agree with Matsumoto (1917), Koehler (1922a) and Madsen (1967) that this species is an ophiacanthid. The hollow arm spines and comma-shaped arm spine articulations are ophiacanthid characters. Ophiolimna antarctica is very similar to the type species of Ophiolimna, O. bairdi, differing mainly in the form of the disc spines, some of which can be elongated in O. bairdi. The genus name Toporkovia is thus a junior synonym of Ophiolimna. The species Mortensen (1936) described as O. disjuncta can revert back to the prior name Ophiacantha antarctica as previously noted by Fell (1961). Ophiolimna antarctica is not a bipolar taxon, but a deep water species, widely distributed throughout the Indo-west Pacific. The Ophiodermatidae is chiefly a tropical family that does not occur in polar waters. The New Caledonian specimens are smaller than those recorded from elsewhere. Larger specimens (up to 8 mm d.d.) have more arm spines (up to 7 basally), the upper two being up to 4 arm segments long, and arm plates that are contiguous or only just separate (Lyman 1879; D’yakonov 1954; Fell 1961). Ophiolimna antarctica is a smaller species than the two other species of Ophiolimna found around New Caledonia discussed below. It is clearly distinguished by the presence of disc stumps on the radial shields.

Ophiolimna perfida (Koehler, 1904) Fig. 6H-J Ophiacantha perfida Koehler, 1904: 118-119, pl. 23 (5-6). Ophiacantha lambda Clark, H.L., 1911: 231-232, fig. 108. Ophiolimna lambda ¢ Matsumoto 1917: 103. Ophiolimna perfida ¢ Koehler 1922a: 64-66, pl. 9 (7-9), 92 (6). — Guille 1981: 431-433. Ophiolimna sp. ? O. perfida ¢ Clark, A.M. 1977: 139-140.

TYPE MATERIAL. — Syntypes: ZMA E2581-E2587, E2531, MOM, MCZ 1986. TYPE LOCALITY. — Indonesia, 411-959 m. MATERIAL EXAMINED. — New Caledonia. BIOCAL: stn CP 75, Ride de Norfolk, 22°18.65’S, 167°23.3’E, 825-860 m, 04.09.1985: 2 (MNHN EcOs 22405). — BIOCAL: stn DW 80, Bassin des Loyauté, 20°31.69’S, 166°48.35’E, 900-980 m, 05.09.1985: 2 (MNHN EcOs 22406). — MUSORSTOM 5: stn CP 323, 21°18.52’S, 157°57.62’E, 970 m, 14.10.1986: 4 (MNHN EcOs 22407). — MUSORSTOM 6: stn DW 488, Ride des Loyauté, 20°49.2’S, 167°6.44’E, 800 m, 24.02.1989: 2 (MNHN EcOs 22925). Philippines. Albatross: stn 5618, Molucca Passage, off Mareh Island, 0°37’N, 127°15’E, 763 m, 27.11.1909, identified by Koehler (1922a): 1 (MNHN EcOs 20359). DESCRIPTION. — Disc up to 9 mm d.d., covered in conical stumps, slightly higher than wide near margin, 2 times as high as wide near disc centre, up to 0.25 mm high and 0.12 mm diameter, microscopically perforated. Radial shields widely separate, oval, not covered in disc stumps. Spherical disc stumps present on oral plates and adjacent areas of the adoral

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shields. Oral shields wider than long, convex proximal margin and convex to truncate distal margin; adoral shields long, surrounding the oral shield; jaw longer than wide, 1-2 apical and 4 oral papillae, outer papilla twice as wide as long. Dorsal arm plates fan-shaped to rhombic depending on how angular the distal margin is, with pointed proximal angles, as wide as long, just contiguous. Ventral arm plates wider than long, slightly notched on distal border, separate. Up to 6 arm spines, cylindrical with a bluntly pointed tip, smooth, hollow, upper spine often small, second spine longest, up to 2.5 segments in length. Single large oval tentacle scale covering large pore, proximal scales elongated and orientated obliquely. DISTRIBUTION. — Natal (780 m), Japan (813 m), Philippines (563-1125 m), Indonesia (411-1280 m), New Caledonia (800-980 m). REMARKS. — The relationship between this species and O. antarctica and O. placentigera is discussed under those species.

Ophiolimna placentigera (Lyman, 1880) n. comb. Fig. 6A-G Ophiacantha placentigera Lyman, 1880: 9, pl. 2 (20-22). Ophiacantha placentigera ¢ Lyman 1882: 181-182, pl. 28 (15-17).

TYPE MATERIAL. — Holotype: BMNH 1882.12.23.79. TYPE LOCALITY. — Fiji, west of Kandavu, 2511 m. MATERIAL EXAMINED. — Fiji. Challenger: stn 175, west of Kandavu, 19°2’S, 177°10’E, 2511 m, 12.08.1874, holotype: 1 (BMNH 1882.12.23.79). New Caledonia. BIOCAL: stn CP 23, Sud ouest, 22°45.8’S, 166°20.33’E, 2040 m, 28.08.1985: 6 (MNHN EcOs 22410). — BIOCAL: stn CP 26, Sud ouest, 22°39.66’S, 166°27.41’E, 1618-

1740 m, 28.08.1985: 1 (MNHN EcOs 22409). — BIOCAL: stn CP 27, Ride de Norfolk, 23°5.5’S, 166°26.4’E, 1740 m, 28.08.1985: 6 (MNHN EcOs 22408). — BIOCAL: stn CP 72, Ride de Norfolk, 22°9’S, 167°33.2’E, 2100-2110 m, 04.09.1985: 9 (MNHN EcOs 22411).

DESCRIPTION. — Disc up to 11 mm d.d., covered in spines that are 3 times as high as wide (0.45 mm long), marginal spines conical (0.25 mm long), central spines terminating in flared thorns, radial shields naked, small, oval, widely separate; ventral surface with scattered spherical granules, present on oral plates and adjacent areas of adoral shields. Oral shields wider than long, with rounded distal margin and rounded to angular proximal margin; adoral shields long, separating oral shields from first lateral arm plate; jaw as wide as long with 2 apical and 4-5 oral papillae, outer papilla enlarged, 1.5 times as wide as high, rarely split into 2 smaller papillae. Arms slightly noded, constricted between segments; dorsal arm plates bell-shaped, wider than long, with a produced distal margin, separate; ventral arm plates wider than long with a rounded distal margin, separate; lateral arm plates striated; up to 6 arm spines, rounded, hollow, smooth, blunted pointed, up to 2 arm segments in length; one oval tentacle scale covering a large pore, slightly enlarged basally. DISTRIBUTION. — Fiji (2511 m), New Caledonia (1618-2110 m). REMARKS. — The specimens from New Caledonia are the first to be collected since the holotype. This species is transferred to Ophiolimna as it has the characteristic hollow perforated disc spines, enlarged outer oral papillae, large tentacle pores and long adoral shields of that genus. On the holotype there are a few spherical granules on the oral plates that were unreported in Lyman’s original description. Lyman (1882) emphasised a raised trapezoid section on the proximal edge of the ventral arm plates. This feature is difficult to see on the holotype and only appears to occur on some basal plates,

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not every plate as figured by Lyman. It is possibly a preservation artefact caused by the fragmentation of the plates. It does not occur on the New Caledonian material. This species is similar to O. perfida, differing in the shape of the disc spines, the noded arms, raised dorsal arm plates, and the short robust arm spines. It also occurs at a greater depth.

Genus OPHIOLOGIMUS H.L. Clark, 1911 Type species: Ophiologimus hexactis H.L. Clark, 1911.

Ophiologimus quadrispinus H.L. Clark, 1925 Fig. 7H-J Ophiologimus quadrispinus Clark, H.L., 1925: 90, pl. 9 (a-b). Ophiologimus quadrispinus ¢ Clark, A.H. 1949: 26-27.

TYPE MATERIAL. — Holotype: BPBM 478 (not seen). TYPE LOCALITY. — Hawaii, Laysan Is, 372 m. MATERIAL EXAMINED. — New Caledonia. BIOCAL: stn DW 33, Ride de Norfolk, 23°9.71’S, 167°10.27’E, 675 m, 29.08.1985: 2 (MNHN EcOs 22414). — BIOCAL: stn DW 83, Bassin des Loyauté, 20°35.07’S, 166°53.99’E, 460 m, 06.09.1985: 1 (MNHN EcOs 22413). — MUSORSTOM 5: stn DC375, 19°52.2’S, 158°29.7’E, 300 m, 20.10.1986: 1 (MNHN EcOs 22412). — MUSORSTOM 6: stn DW 391, Ride des Loyauté, 20°47.35’S, 167°5.7’E, 390 m, 13.02.1989: 1 (MNHN EcOs 22927). — MUSORSTOM 6: stn DW 392, Ride des Loyauté, 20°47.32’S,

167°4.6’E, 340 m, 13.02.1989: 8 (MNHN EcOs 22928). — MUSORSTOM 6: stn DW 395, Ride des Loyauté, 20°47.57’S, 167°5.32’E, 400 m, 13.02.1989: 1 (MNHN EcOs 22929). — MUSORSTOM 6: stn DW 398, Ride des Loyauté, 20°47.19’S, 167°5.65’E, 370 m, 13.02.1989: 3 (MNHN EcOs 22930). — MUSORSTOM 6: stn DW 479, Ride des Loyauté, 21°9.13’S, 167°54.95’E, 310 m, 22.02.1989: 1 (MNHN EcOs 22931). — MUSORSTOM 6: stn DW 480, Ride des Loyauté, 21°8.5’S, 167°55.98’E, 380 m, 22.02.1989: 3 (MNHN EcOs 22932).

DESCRIPTION. — Disc 2 to 6.5 mm d.d., 4-7, usually 5, arms. Disc often torn, but remaining surface covered in small overlapping translucent perforated plates embedded in a thin skin, no spines, plated skin extends onto the basal dorsal arm surface; radial shields hidden beneath the skin, sometimes its presence is obvious as a small oval depression or mound, widely separate. Jaw and arms covered in a thin skin that obscures the plates. Oral shields wider than long, proximal margin strongly convex, distal margin weakly convex or lobed, rounded lateral angles; adoral shields long and narrow, extending as a lobe beyond the lateral angle of the oral shield; jaw longer than wide, oral plates tumid proximally, 7-8 oral papillae, inner oral papillae small and spiniform; 2-3 distal oral tentacle scales, slightly enlarged, rounded to spatulate. Dorsal arm plates trapezoid, as wide as long, convex distal and concave proximal margin, broadly contiguous; ventral arm plates longer than wide, convex distal margin, concave lateral margins around large tentacle pore, broadly contiguous; 4 arm spines on basal segments thereafter 3, subcylindrical to flattened, bluntly-pointed, sometimes wider at the base, subequal or lowest a little wider and uppermost slightly longer, short, less than 1 segment in length, distal upper and middle arm spines modified into hooks with 1-2 small teeth besides the terminal one; 1-2 tentacle scales, oval, sculptured surface near tip. Colour (dry) yellowish-brown. DISTRIBUTION. — Hawaii (238-523 m), New Caledonia (300-675 m). REMARKS. — The characters of the disc surface (hidden radial shields, small overlapping plates, no spines), jaw (elongate, numerous oral papillae and tentacle scales) and arm spines (short, few blunt) clearly identify these specimens as

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FIG. 7. A, B, Ophiotrema sp. MNHN EcOs 22485; A, ventral disc and arm; B, dorsal arm plates; C-G, Ophiopristis dissidens MNHN EcOs 22478; C, dorsal aspect; D, disc spines; E, ventral aspect; F, ventral arm plates; G, arm spines; H-J, Ophiologimus quadrispinus MNHN EcOs 22413; H, jaw; I, ventral arm; J, tentacle scales; K, Ophiomedea liodisca MNHN EcOs 22415, ventral aspect. SEM images except K, scale bars in mm. FIG. 7. A, B, Ophiotrema sp. MNHN EcOs 22485 ; A, disque ventral et bras ; B, plaques dorsales des bras ; C-G, Ophiopristis dissidens MNHN EcOs 22478 ; C, vue dorsale ; D, épines discales ; E, vue ventrale ; F, plaques ventrales des bras ; G, épines des bras ; H-J, Ophiologimus quadrispinus MNHN EcOs 22413 ; H, mâchoire ; I, bras ventraux ; J, écailles des tentacules ; K, Ophiomedea liodisca MNHN EcOs 22415, vue ventrale. Images MEB sauf K, échelles en mm.

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Ophiologimus H.L. Clark, 1911. Three species have been referred to this genus, O. hexactis H.L. Clark, 1911 from Japan, O. secundus Koehler, 1914 from the West Indies and O. quadrispinus H.L. Clark, 1925 from Hawaii. H.L Clark (1925) doubted that O. secundus was really congeneric with the others, as it has visible radial shields, different shaped arm plates and a single pointed tentacle scale. Of the two Indo-Pacific species, the New Caledonian specimens are closest in form to the five-armed O. quadrispinus, differing only in having typically three rather than four arm spines on most of the arm. The additional arm spine is possibly due to the larger size (7-8 mm d.d.) of H.L. Clark’s (1925) and A.H. Clark’s (1949) specimens of O. quadrispinus, although more material is required before a definitive synonymy can be made. The holotype of the closely related O. hexactis has six arms, three arm spines (at 5 mm d.d.) and no plates on the ventral disc surface adjacent to the oral shield. However, Murakami (1942) found specimens with ventral disc plates and four arm spines basally. Radial shields are hidden in larger specimens but small ones are visible in juveniles (Murakami 1942). Fujita et al. (1997) found one specimen of O. hexactis with only five arms. It is unclear whether five and six armed forms represent different species, and whether O. quadrispinus can be distinguished from O. hexactis. Of the New Caledonian material, one lot (MUSORSTOM 6, stn DW 392) had one four-armed and seven six-armed individuals. All the other lots had exclusively five-armed individuals. These specimens appeared to have no other morphological character that could be used to distinguish them. On the other hand, Japanese populations of O. hexactis are almost all six-armed. The hook-like distal arm spines on the New Caledonian material have not been reported by previous authors.

Genus OPHIOMEDEA Koehler, 1906 Type species: Ophiomedea duplicata Koehler, 1906.

Ophiomedea liodisca (H.L. Clark, 1911) Fig. 7K Ophiophrura liodisca Clark, H.L., 1911: 249-250, fig. 121. Ophiophrura liodisca ¢ Matsumoto 1917: 100. — Murakami 1942: 2. Ophiomedea liodisca ¢ Koehler1922a: 97-98.

TYPE MATERIAL. — Holotype: USNM 25672 (not seen). TYPE LOCALITY. — Japan, off Omai Saki Light, 883-939 m. MATERIAL EXAMINED. — New Caledonia. BIOCAL: stn DW 33, Ride de Norfolk, 23°9.71’S, 167°10.27’E, 675 m, 29.08.1985: 1 (MNHN EcOs 22415). OTHER MATERIAL EXAMINED. — Ophiomedea discrepans Koehler, 1922a: MPE: stn 140308, Philippines, Mindanao, 7 miles S of Olutanga, 400-558 m, 08.03.1914, identified by Koehler (1930): 1 (ZMUC).

DESCRIPTION. — Disc (torn) approximately 6 mm d.d.; remaining disc, near the arm base and ventrally, covered in small circular translucent plates, no visible radial shields. Oral shield wider than long, oval; long narrow adoral shields that extend past the oral shields. Jaw longer than wide; 2 spiniform apical and 4-5 small spiniform oral papillae, one often lying underneath the others, confluent with 3 elongate flat oral tentacle scales, 2 on the oral plate and the most distal arising from the adoral shield. Dorsal arm plates kite-shaped or rhomboid, longer than wide, narrowly contiguous. Ventral arm plates

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longer than wide, widest distally, with large incisions on either side forming the margin of the oral pore, widely contiguous. Arm spines 5 near base then 4, flattened, lanceolate, uppermost longest, 1.5 arm segments in length; 3, rarely 4 tentacle scales, typically 2 small lanceolate scales on lateral arm plate and 1 large scale on ventral arm plate, orientated transversely; some pores with 3 scales on the lateral arm plates or 2 scales on the ventral arm plate. DISTRIBUTION. — Japan (884-940 m), New Caledonia (675 m). REMARKS. — The New Caledonian specimen is very similar to H.L. Clark’s (1911) description of the holotype; the holotype only differing in having a slightly narrower oral shield with a truncate distal margin. The 8 mm d.d. holotype of O. discrepans Koehler, 1922a from the Philippines differs in having a dense covering of granules on the disc surface and only two elongated distal oral papillae. However, the difference between the two species is not as distinct as it appears. There are no obvious disc granules on the New Caledonian specimen, however, these may have fallen off during collection or preservation as the disc is extensively damaged and disc granules are frequently lost from ophiotomin specimens. A second specimen was recorded by Koehler (1930) also from the Philippines. Examination of this specimen showed that it was similar to the New Caledonian specimen in having three elongated distal oral papillae and no disc granules but differed in having smaller oral papillae and finer arm spines. More material is required before a conclusive distinction can be made between these nominal species.

Genus OPHIOPRISTIS Verrill, 1899 Ophiopristis Verrill, 1899a: 40, 44. Ophiopristis ¢ Paterson 1985: 53.

Type species: Ophiacantha hirsuta Lyman, 1875. OTHER MATERIAL EXAMINED. — Ophiopristis axiologus H.L. Clark, 1909: Thetis: stn 57, E Australia, off Watamolla, 100-109 m, holotype: 1 (AM J920). — SE Australia, 5 miles E of Port Hacking, 100 m, 01.02.1945, identified by Baker (1979): 1 (AM J6683). — BSS: stn 174S, SE Australia, Eastern Bass Strait, 25 km NE of Deal Island, Tasmania, 39°16.8’S, 147°33.2’E, 57 m, 18.11.1981, identified by O’Hara (1990): 1 (MoV F52681). Ophiopristis dissidens (Koehler, 1905): Siboga: stn 89, Indonesia, Pulu Kaniungan Ketjil, 11 m, 21.06.1899, holotype: 1 (ZMA E2338). Ophiopristis hirsuta

(Lyman, 1875): Blake expedition, West Indies, off Montserrat, 164 m: 1 (SMNH Utl. Oph 378). Ophiopristis luctosa (Koehler, 1904): Siboga: stn 302, Indonesia, West Timor, Salut Roti, 10°27.9’S, 123°28.7’E, 216 m, 02.02.1900, holotype: 1 (ZMA E2348). Ophiopristis procera (Koehler, 1904): Siboga expedition, Indonesia, Île de la Sonde, syntype: 1 (MNHN EcOs 20406). — Siboga: stn 266, Indonesia, Kapulauan Kai (Kei Islands), 5°56.5’S, 132°47.7’E, 595 m, 19.12.1899, syntypes: 3 (ZMA E2250).

REMARKS. — Re-examination of type material of O. procera Koehler, 1904, O. luctosa Koehler, 1904, and O. dissidens Koehler, 1905 from Indonesia, Ophiacantha vestita Koehler, 1897 from the Bay of Bengal, and the type description of Ophiacantha mitsuii Murakami, 1942 from Japan, indicates that they are congeneric with Ophiopristis hirsutus (Lyman, 1875) from the Caribbean. In re-establishing the genus Ophiopristis, Paterson (1985) defined it as having a series of rounded oral papillae that are confluent with a series of elongated oral tentacle scales, long adoral shields that separate the oral shield from the ventral arm plate, leaf-like tentacle scales that cover the small pore, concealed radial shields and disc covered in plates that carry a spinelet. In addition all the species listed above have characteristic flattened arm spines, with a row of sharp thorns along each edge, and the disc spines are long and hollow with pointed or furcated tips. These six species are all very similar and at least some may eventually be found to be synonymous, in particular O. mitsuii is very similar to O. dissidens. All the Indo-Pacific species are currently known from only a few specimens. However, there are slight differences that prevent their synonymy at this time. Ophiopristis vestita, O. mitsuii, O. procera and O. luctosa all have a single tentacle scale on most pores (two basally). It is lanceolate on O. vestita and O. mitsuii but rounded in the other

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two species. The holotype of O. dissidens has two scales until the tenth segment and O. hirsuta has typically two scales. The disc spines on O. luctosa, O. dissidens, O. mitsuii, O. vestita and O. hirsuta are usually smooth with a pointed or minutely bifurcated tip; on O. procera they are irregularly terminated, often with a subterminal tooth, and a truncate or bifid tip. The arm spines are finer and less thorny on O luctosa and O. vestita than the other species. The distal oral papillae are more elongate on O. procera, O. luctosa, O. mitsuii and O. dissidens than O. vestita and O. hirsuta. Ophiopristis procera and O. luctosa have a series of short spines on the distal edge of the oral shield; O. vestita has a few on the basal dorsal arm plates. Paterson (1985) also referred to Ophiopristis a small species from SE Australia, O. axiologus H.L. Clark, 1909. However, this species differs from the above species in having an opposing series of oral tentacle scales on the first ventral arm plate, short smooth bottle-shaped arm spines, spiniform tentacle scales that are orientated transversely across the arm, and short stellate disc stumps. It probably requires its own genus, however, establishment of such a genus should be done in context of a general genus-level revision within the Ophiacanthidae which is beyond the scope of the current work. The New Caledonian material from BIOCAL station DW 64 is most similar to O. dissidens with elongate distal oral papillae, flat thorny arm spines, multiple tentacle scales and smooth disc spines with a bifid tip. The 3.5 mm d.d. specimen from BIOCAL stn DW 83 is more like O. luctosa with a single oval tentacle scale, spines on the distal edge of the oral shield and disc spines with a divided tip. The material is described below.

Ophiopristis dissidens (Koehler, 1905) n. comb. Fig. 7C-G Ophiacantha dissidens Koehler, 1905: 56-57, pl. 7 (12-15).

TYPE MATERIAL. — Holotype: ZMA E2338. TYPE LOCALITY. — Indonesia, Kaniungan Ketjil, 11 m. MATERIAL EXAMINED. — Indonesia. Siboga: stn 89, Pulu Kaniungan Ketjil, 11 m, 21.06.1899, holotype: 1 (ZMA E2338).

New Caledonia. BIOCAL: stn DW 64, Ride de Norfolk, 24°47.93’S, 168°9.12’E, 250 m, 03.09.1985: 4 (MNHN EcOs 22478).

DESCRIPTION. — (New Caledonian material) Disc pentagonal, up to 4.5 mm d.d., disc plates small rounded translucent, overlapping, with a single long hollow smooth glassy spine that terminates in several flaring webbed thorns, up to 0.4 mm high. Radial shields largely overlain by plates, exposed distal sections triangular, widely separated. Oral shields wider than long, with a rounded proximal side and a round to truncate distal side; adoral shields long and narrow, separating the oral shield from the first ventral arm plate; oral plates and adoral shields lightly beaded; jaw longer than wide; 3-4 square to spiniform oral papillae and 2-3 elongate spatulate oral tentacle scales arising from the adoral shield. Dorsal arm plates rounded-triangular with a slightly convex distal edge, separate, just wider than long; ventral arm plates as wide as long, with lateral incisions around the large tentacle pore. Six arm spines on first segment, 4 after the third segment, laterally compressed, with a row of perforations near each lateral margin which bears a row of sharp webbed thorns, apex truncate or bluntly rounded, lowest spine often hook-like with longer ventral thorns; 2-3 tentacle scales, reducing to one after the twelfth segment, oval to spiniform. Colour (dry) yellow-brown, with dark brown disc and arm spines and a brown line running discontinuously along the dorsal surface of each arm. DISTRIBUTION. — Indonesia (11 m), New Caledonia (250 m). REMARKS. — The New Caledonian specimens are very similar to the holotype being characterised by two to three elongate distal oral papillae, flat thorny arm spines, multiple tentacle scales and smooth disc spines with a bifid tip.

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Ophiopristis luctosa (Koehler, 1904) n. comb. Ophiacantha luctosa Koehler, 1904: 115-116, pl. 20 (4-5), 21 (1-2).

TYPE MATERIAL. — Holotype: ZMA E2348. TYPE LOCALITY. — Indonesia, West Timor, 216 m. MATERIAL EXAMINED. — Indonesia. Siboga: stn 302, West Timor, Salut Roti, 10°27.9’S, 123°28.7’E, 216 m, 02.02.1900, holotype: 1 (ZMA E2348). New Caledonia. BIOCAL: stn DW 83, Bassin des Loyauté, 20°35.07’S, 166°53.99’E, 460 m, 06.09.1985: 1 (MNHN EcOs

22479). — MUSORSTOM 6: stn DW 393, Ride des Loyauté, 20°48.29’S, 167°9.54’E, 420 m, 13.02.1989: 1 (MNHN EcOs 22978). — MUSORSTOM 6: stn DW 406, Ride des Loyauté, 20°40.6’S, 167°6.8’E, 373 m, 15.02.1989: 1 (MNHN EcOs 22979).

DESCRIPTION. — (New Caledonian material) Disc 3-5 mm d.d., pentagonal, covered in very-thin, perforated, rounded plates bearing long thin sharp hollow smooth spines, 0.4 mm (rarely up to 0.7 mm) high, terminating in 1-3 minute thorns. Radial shields largely obscured. Oral shields as wide as long, with a convex proximal and a produced distal margin, sometimes truncate, distal margin usually bears a few small thorny spines; adoral shields long, separating the oral shield from the first ventral arm plate; jaw longer than wide, with 3-5 small rounded oral papillae and 2 enlarged oral tentacle scales, inner scale long and spiniform which can reach half way to jaw apex, distal scale rounded or leaf shaped. Arms slightly moniliform, dorsal arm plates triangular with a straight, slightly convex or slightly noded distal edge, widely separate. Ventral arm plates 2 times as wide as long, roughly quadrangular with a small point in the middle of the proximal edge and slightly convex distally, glassy, just contiguous. Up to 6 arm spines basally, then 5, spines flattened with a row of small thorns along each edge, some longer thorns on basal spines. Lowest spines with longer ventral thorns, giving them a hook-like appearance; lowest spine distally with some ventrally directed thorns but not a true hook-shape. One large circular to oval tentacle scale, 2/3 the length of the ventral arm plate, rarely a second one basally, partially overlapped by the first. Colour (dry) pale yellow with a few broad brown bands on the arms. DISTRIBUTION. — Indonesia (216 m), New Caledonia (373-460 m). REMARKS. — The small specimens from New Caledonia are small and damaged, however the single tentacle scale (two basally) and thicker arm spines appear to differentiate it from O. dissidens. They are closest in form to O. luctosa sharing thin pointed disc spines, concealed radial shields and (at least on one specimen) spines on the distal edge of the oral shield. The previously unique 8 mm d.d. holotype differs in having slightly longer disc spines (0.85 mm) which may be related to its large size. We present here notes on other Indo-Pacific species of Ophiopristis.

Ophiopristis vestita (Koehler, 1897) n. comb. Ophiacantha vestita Koehler, 1897: 344-346, pl. 8 (58-59). Ophiacantha vestita ¢ Koehler 1899: 54-56, pl. 3 (18-20).

TYPE MATERIAL. — Lectotype: ZSI 4730/7, paralectotype ZSI 6001/7 (designated herein). TYPE LOCALITY. — India, off Coromandel coast, 362-390 m.

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MATERIAL EXAMINED. — India. Investigator: stn 164, Coromandel Coast, 13°41.5’N, 80°32’E, 362-390 m, 01.02.1894, lectotype: 1 (ZSI 4730/7). — Investigator expedition, Andaman Sea, 465 m, paralectotype: 1 (ZSI 6001/7).

DISTRIBUTION. — India and Andaman Is (362-390 m). REMARKS. — The largest of the two syntypes (ZSI 4730/7, 10 mm d.d.), designated here as the lectotype, differs slightly from Koehler’s (1897, 1899) description and figures. Figure 20 in Koehler (1899) shows disc spines with prominent thorns along their length, although thorns were not mentioned in the description or illustrated in the original reference (Koehler, 1897). No thorns were found on the disc spines remaining on the lectotype, which are long and smooth with a truncate, rounded or minutely bifurcate tip. The arm spines are long and slender, the uppermost three segments in length. The lowest arm spine is relatively smooth, without the prominent thorns along each side. There are a few small supplementary spines on the basal dorsal arm plates. The tentacle scales are relatively elongate, sometimes exceeding the length of the ventral arm plate. The oral shields have a pronounced distal lobe. Only proximal oral papillae remain on the specimen. The smaller syntype (ZSI 6001/7, 4 mm d.d.) is quite different and either represents a distinct ontogenetic stage or, more probably, a different species. The disc spines are short, smooth and sharp; the arm spines are smooth without thorns; the tentacle scales are only half the length of the ventral arm plate, which has a notched distal margin, and the oral shield is almost rhomboid, lacking a prominent distal lobe. There are 5-6 oral papillae, the outer papilla is slightly longer than the others.

Genus OPHIOTREMA Koehler, 1896 Type species: Ophiotrema alberti Koehler, 1896.

Ophiotrema sp. Fig. 7A-B MATERIAL EXAMINED. — New Caledonia. MUSORSTOM 5: stn DC321, 21°20.4’S, 158°2.26’E, 1000 m, 14.10.1986: 1 (MNHN EcOs 22485). — MUSORSTOM 5: stn CP 324, 21°15.01’S, 157°51.33’E, 970 m, 14.10.1986: 1 (MNHN EcOs 22484).

DESCRIPTION. — Disc missing, oral frame 3-3.5 mm diameter, arms > 10 mm. Oral shield wider than long, with an obtuse proximal angle and a convex to lobed distal margin, adoral shields long and narrow, separating the oral shields from the first lateral arm plate, jaw longer than wide, oral plates long and narrow bearing numerous oral papillae, apical papilla long and spiniform, next 4 papillae small spiniform to rounded, outer 2-3 papillae (oral tentacle scales) very long and slender, the 2 proximal oral tentacle scales longest, arising from the oral plate, the distalmost scale small, arising from the adoral shield on the distal side of the pore. Basal dorsal arm plates lost, remaining plates very thin, perforated, separate, longer than wide, widest distally with a convex distal margin, tapered proximally; ventral arm plates as wide as long, widest distally, excavate laterally around the large oral tentacle pores, with a flat proximal margin and a slight notch in the centre of the distal margin; four arm spines, subequal, 1.5 segments long, usually smooth (microscopically rugose), specimen from station 324 with some sparse irregular thorns on the upper spines, cylindrical, bluntly pointed; 3 elongate slender tentacle scales, don’t cover pore, 2 arising from the lateral arm plate and one from the ventral arm plate. DISTRIBUTION. — New Caledonia (970-1000 m). REMARKS. — The New Caledonian material is in poor condition, lacking the disc. Nevertheless, the presence of large tentacle pores armed with long slender spine-like tentacle scales indicates that they belong to the genus Ophiotrema. They

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are similar, but not identical, to the unique type of O. tertium Koehler, 1922a collected from the Philippines (1335 m). This specimen was 11-15 mm d.d., at least twice the size of the current material, and differs in having a comparatively larger oral shield with a concave distal margin, no spine-like oral tentacle scales (possibly rubbed off), up to six arm spines basally, and a different arrangement of tentacle scales, with three on the ventral plate and one on the lateral plate. The disc of O. tertium is covered in thick skin, bearing granules and thick elongated spines. A related species O. megatreta (H.L. Clark, 1911) has been recorded from Japan. The holotype was large (approximately 25 mm d.d.) and missing the disc. It appears to differ in having six arm spines and no spine-like oral or arm tentacle scales. Without better quality material of various sizes it is not possible to properly differentiate these forms, and the identity of the New Caledonian material remains in doubt. The specimen from 5127 m in the North Atlantic, described and figured by Paterson (1985: 58, fig. 23) as O. tertium, does not appear to be conspecific with Koehler‘s type, having shorter, thicker tentacle scales, granules on the oral plates, and numerous apical oral papillae.

Subfamily OPHIOPLINTHACINAE Paterson, 1985 Genus OPHIOPLINTHACA Verrill, 1899 Ophioplinthaca Verrill, 1899b: 351. Ophioplinthaca ¢ Koehler 1904: 123. Ophiomytis Koehler, 1904: 142 [new synonymy].

Type species: Ophiomitra dipsacos Lyman, 1878a. OTHER MATERIAL EXAMINED. — Ophioplinthaca laudator Koehler, 1930: MPE: stn 270314, off Jolo, 465 m, 27.03.1914, holotype: 1 (ZMUC). Ophioplinthaca weberi (Koehler, 1904): Siboga: stn

297, Indonesia, West Timor, east of Roti, 10°39’S, 123°40’E, 520 m, 27.01.1900, holotype: 1 (ZMA E2434).

REMARKS. — Ophioplinthaca is a clearly defined genus, characterised by the deep interradial incisions into the disc which are lined distally by enlarged disc plates. Verrill (1899b) and Koehler (1904) also characterise the genus by the single row of oral papillae, however, several species have supplementary oral or apical papillae (e.g. O. plicata Lyman, 1878a, O. amezianeae n. sp.). The species Ophiomitra semele A.H. Clark, 1949 is here considered to be an Ophioplinthaca. Although it has multiple apical papillae, it has deep interradial incisions and enlarged marginal disc plates, and bears a much greater resemblance to other Indo-Pacific species of Ophioplinthaca than Ophiomitra. Other genera in the Ophioplinthacinae with deep interradial incisions include Ophiomytis Koehler, 1904, Ophiodictys Koehler, 1922a, Ophiothamnus Lyman, 1869 and the new genus Ophiohamus, described below. Of these, Ophiomytis bears the greatest resemblance to Ophioplinthaca, having both the deep incisions and expanded interradial disc plates. Koehler (1904) distinguished it by the numerous apical papillae, massive radial shields, and the lack of disc granules. However, these characters exist in varying combinations within Ophioplinthaca and the two genera are regarded here as synonymous. The disc stumps on Ophioplinthaca species can be lost during collection and preservation, and their absence is not a reliable diagnostic character. In fact, the only known species of Ophiomytis, O. weberi Koehler, 1904 is very similar in general appearance to another species from Indonesia, Ophioplinthaca defensor Koehler, 1930, which appears to differ only in possessing spherical to conical disc granules (Fig. 18H) and slightly longer tentacle scales. On the other hand, both Ophiodictys and Ophiohamus have unusual hooked arm spines that clearly set them apart from Ophioplinthaca species. Ophiothamnus has a distinct oral armature, with a much widened, sometimes operculiform outer oral papilla. Although the genus Ophioplinthaca is clearly defined, the species limits within the genus are not. Many characters that can be usually used to diagnose species within the Ophiacanthidae tend to be very variable in Ophioplinthaca. These

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characters include the shape, size and number of oral papillae, oral and adoral shields, and arm plates. In this review, the size and shape of the radial shields and the form of the disc stumps are used as the primary criteria for defining each species. Of the Indo-Pacific species currently referred to Ophioplinthaca, O. laudator Koehler, 1930 appears atypical. The unique holotype (7 mm d.d.) has relatively shallow interradial disc incisions and enlarged adoral shields, similar to some Ophiocamax species. However, the Indo-Pacific species of Ophiocamax generally have numerous oral papillae, minute spines covering the arm plates, and complex disc spines with several whorls of thorns. Ophioplinthaca laudator on the other hand has a single row of oral papillae, one apical papilla, non-spinous arm plates, and cylindrical to spine-like disc stumps with about 5 terminal thorns (Fig. 18K). More material is needed to clarify its relationships.

Ophioplinthaca amezianeae n. sp. Fig. 9D-G TYPE MATERIAL. — Holotype: MNHN EcOs 22457. Paratypes: MNHN EcOs 22458, 22459, 22800, 22806. TYPE LOCALITY. — New Caledonia, 23°56.5’S, 166°40.6’E, 2660-2750 m. MATERIAL EXAMINED. — New Caledonia. BIOCAL: stn CP 58, Ride de Norfolk, 23°56.5’S, 166°40.6’E, 2660-2750 m, 01.09.1985, holotype: 1 (MNHN EcOs 22457). — BIOCAL: stn CP 26, Sud ouest, 22°39.66’S, 166°27.41’E, 1618-1740 m, 28.08.1985, paratype: 1 (MNHN EcOs 22458). — BIOCAL: stn

CP 58, Ride de Norfolk, 23°56.5’S, 166°40.6’E, 2660-2750 m, 01.09.1985, paratype on SEM stub: 1 (MNHN EcOs 22800); paratypes: 6 (MNHN EcOs 22806). — BIOCAL: stn DS 59, Ride de Norfolk, 23°56.21’S, 166°41.1’E, 2650 m, 02.09.1985, paratypes: 2 (MNHN EcOs 22459).

DESCRIPTION. — (Holotype). Disc 14.5 mm d.d., arms > 4 times d.d. in length (probably much longer), disc incised interradially to 1/8 d.d., creating a wedge over each arm base, wedges tumid in contrast to the sunken centre and interradii of disc. Disc plates overlapping, granular surface with large pore surrounded by a circle of smaller pores where spines are attached, of varying size, 0.4-0.7 mm diameter; plates enlarged distal to the radial shields interradially and between the radial shields radially. Radial shields separate, roughly triangular, 2 times as long as wide, attenuated proximally, with a truncate distal edge and rounded distolateral and proximal angles, separated by a row of enlarged disc plates, parallel. Disc spines tall and slender, with a rounded base tapering to a sharp point or terminating in 2-3 small thorns, with additional irregular flanged thorns arising mid-length along the spine. Spines near disc margin are smaller and conical with fewer thorns. Ventral disc surface covered in small plates and conical spines, smaller than those on the distal surface. Bursal slits extending from the oral shields to the dorsal disc surface, gaping. Oral shields arrow-head shaped, as wide as long, with an acute proximal angle, slightly concave proximolateral sides, rounded lateral angles and a distal lobe, thickened along the distal edge and frequently grooved centrally. Adoral shields 3 times as wide as long, extending just beyond (but not around) the lateral angles of the radial shields, with a slightly concave proximal border, just meeting interradially and adjoining the first ventral arm plate radially. Jaw as wide as long, oral plates swollen proximally, with 1 oval apical and 4-5 spiniform pointed lateral oral papillae, up to 4 times as high as wide. Dorsal arm plates fan to bell-shaped, with an obtuse proximal angle, straight to slightly convex to slightly concave proximolateral sides and a convex distal margin, just separate. First ventral arm plates trapezoid, widest distally, sunken into the jaw slit proximally, 2 times as wide as long, contiguous with the second plate. Succeeding plates 2-3 times as wide as long, with an obtuse proximal angle (slightly sunken), straight to wavy proximolateral sides, rounded lateral angles and a slightly convex to wavy distal edge (which is often thickened in the centre), widely separate. Lateral arm plates meeting above and below, with a low ridge bearing up to 10 arm spines, widely separated dorsally by the arm plates, uppermost arm spines up to 3 segments long, lowermost 1.5-2 segments, all with conspicuous thorns. Tentacle scales spiniform, with a rounded base tapering to a sharp or blunt point, covered in irregular thorns, particularly on distal arm segments, 2-3 scales encircle the first pore, 1-2 around the second pore and one thereafter, longer than the ventral arm plate.

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Colour (dry): white. (Paratypes). The large specimen (14 mm d.d.) from station BIOCAL DS 59 has additional small suboral papillae on the swollen proximal end of the oral plates and sometimes on the side of the jaw adjacent to the oral papillae. The smallest (3 mm d.d.) paratype (from the same station) has smaller radial shields, 1/6 d.d. in length, just longer than wide, often contiguous distally. The disc spines are relatively slender with 2-3 long divergent points, and sometimes extra thorns along their length. The arms are moniliform and the 6 arm spines are relatively slender, with the lateral thorns longer than the width of the arm spine. There are only 3 spiniform oral papillae, the ventral arm plates are as long as wide, and the thorny tentacle scales are longer than the ventral arm plate. DISTRIBUTION. — New Caledonia (1618-2750 m). REMARKS. — This species is characterised within Ophioplinthaca by the form of the disc spines, which in adults are tall and slender with conspicuous lateral thorns. It is similar to O. rudis, which differs in having taller disc spines with smaller more regularly arranged thorns, shorter tentacle scales and one regular row of angular oral papillae. In New Caledonia, the two species occupy different depths, O. rudis being an animal of the upper slope (to 1650 m). ETYMOLOGY. — Named after Dr. Nadia Améziane, echinoderm curator, Muséum national d’Histoire naturelle.

Ophioplinthaca bythiaspis (H.L. Clark, 1911) Fig. 8A-C Ophiomitra bythiaspis Clark, H.L., 1911: 185-187, fig. 85. Ophioplinthaca chelys ¢ Koehler 1904: 131; 1922a: 131-132, pl. 19(3-4) [Non Ophioplinthaca chelys (Thomson, 1877)]. Ophiomitra bythiaspis ¢ Matsumoto 1917: 131. — Irimura et al. 1995: 42. Ophioplinthaca bythiaspis ¢ Clark, H.L. 1915: 212.

TYPE MATERIAL. — Holotype: USNM 25636 (not seen). TYPE LOCALITY. — Japan, off eastern coast, 1753 m. MATERIAL EXAMINED. — Indonesia. Siboga: stn 135, north eastern Molucca Sea, 1°34’N, 126°54’E, 1994 m, 29.07.1899, identified by Koehler (1904) as O. chelys: 1 (ZMA Ech O 6634.2). New Caledonia. BIOCAL: stn CP 23, Sud ouest, 22°45.8’S, 166°20.33’E, 2040 m, 28.08.1985: 1 (MNHN EcOs 22462). —

BIOCAL: stn CP 57, Ride de Norfolk, 23°43.3’S, 166°58.1’E, 1490-1620 m, 01.09.1985: 1 (MNHN EcOs 22460). — BIOCAL: stn CP 68, Ride de Norfolk, 24°0.37’S, 168°7.3’E, 1430 m, 03.09.1985: 1 (MNHN EcOs 22461).

OTHER MATERIAL EXAMINED. — Ophioplinthaca chelys (Thomson, 1877): Challenger: stn 84, 30°38’N, 18°5’W, 2056 m, 18.07.1873, identified by Thomson (1877): 3 (MNHN EcOs 20377).

DESCRIPTION. — (New Caledonian material) Disc up to 13 mm d.d., deeply incised interradially, covered in coarse imbricating plates, primary plates obvious in the centre of the disc, disc plates bearing a sparse covering of granules, spherical to conical to cylindrical in shape with a few minute terminal thorns, 0.3-0.4 mm high, 0.25 mm diameter. Radial shields 4 times as long as wide, rectangular to slightly attenuated proximally, separated by 1-2 rows of disc plates, sunken below the level of the other disc plates. Oral shields diamond-shaped to pentagonal, with the distal edge either convex or with a truncate central portion. Adoral plates 2-2.5 times as wide as long, not extending beyond the lateral angles of the oral shields. Jaw slightly wider than long, one apical and 4-5 oral papillae, subequal in height, 2 outer ones slightly widened. Arms slightly noded, dorsal arm plates on the swollen part of the node, convex, fan-shaped with a rounded

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FIG. 8. A-C, Ophioplinthaca bythiaspis MNHN EcOs 22460; A, dorsal aspect; B, ventral aspect; C, disc granules; D-H, Ophioplinthaca globata MNHN EcOs 22465; D, dorsal aspect; E, ventral aspect; F, disc granules; G, different individual ventral aspect; H, disc granules; I-L, Ophioplinthaca hastata MNHN EcOs 22466; I, dorsal aspect; J, ventral aspect; K-L, variation in disc granules in different individuals; M-P, Ophioplinthaca plicata MNHN EcOs 22634; M, dorsal aspect; N, ventral aspect; O, ventral arm plates; P, disc granules. SEM images, scale bars in mm. FIG. 8. A-C, Ophioplinthaca bythiaspis MNHN EcOs 22460 ; A, vue dorsale ; B, vue ventrale ; C, granules discaux ; D-H, Ophioplinthaca globata MNHN EcOs 22465 ; D, vue dorsale ; E, vue ventrale ; F, granules discaux ; G, faces ventrales de différents individus ; H, granules discaux ; I-L, Ophioplinthaca hastata MNHN EcOs 22466 ; I, vue dorsale ; J, vue ventrale ; K-L, variation des granules discaux chez différents individus ; M-P, Ophioplinthaca plicata MNHN EcOs 22634 ; M, vue dorsale ; N, vue ventrale ; O, plaques ventrales des bras ; P, granules discaux. Images MEB, échelles en mm.

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proximal angle and a convex distal edge, completely separate from succeeding plates. Ventral arm plates twice as wide as long, with a convex to wavy distal edge and an obtuse proximal angle, separate after the third plate. Up to 6 arm spines basally, uppermost 2 segments in length, lower spines with rows of conspicuous thorns, hollow. One oval to bottle-shaped tentacle scale, almost as long as the ventral arm plate. DISTRIBUTION. — Japan (1600-1830 m), Philippines (1280 m), Indonesia (1165-2081 m), New Caledonia (14302040 m). REMARKS. — The large 13 mm d.d. specimen from BIOCAL station CP 23 differs slightly from the other specimens in having only four oral papillae, the outermost a small adpressed papilla around the oral tentacle pore; relatively large adoral shields, only twice as wide as long; cylindrical rather than conical or spherical disc stumps; and long robust arms (to 140 mm). The type description of O. bythiaspis differs slightly from all the New Caledonian specimens, having a cluster of small granules near the second last oral papilla, slightly longer adoral shields that extend a little past the lateral angles of the oral shield and up to three rows of disc plates separating the radial shields. The single type specimen is relatively large (12 mm d.d.) which may account for some of these differences. Koehler (1904, 1922a) identified his Indo-Pacific material as the Atlantic species O. chelys (Thomson, 1877). This species is very similar and may be synonymous. The specimens of O. chelys we have examined (from the type locality) have disc stumps that are cylindrical with a crown of terminating thorns. However, the specimen (presumably the holotype) illustrated by Paterson (1985) has conical to spherical granules. Koehler (1904) described some specimens with pedunculate thorny granules and later photographed a specimen that appears to have granules with three terminal lobes (Koehler 1922a). Another similar species is O. athena A.H. Clark, 1949 from Hawaii. The description and photograph of the unique 14 mm d.d. holotype appears very similar to the large New Caledonian specimen from station BIOCAL CP 23. Like other groups of Ophioplinthaca species, the relationship between O. chelys, O. bythiaspis and O. athena is unclear from the small number of specimens available. In the interim, it appears best to assume that the New Caledonian material belongs to the Japanese O. bythiaspis rather than the Atlantic species O. chelys. On the other hand, the other Indo-Pacific species with narrow, separate, sunken radial shields, O. citata Koehler, 1904, clearly differs in having numerous (up to nine) arm spines and contiguous arm plates.

Ophioplinthaca citata Koehler, 1904 Fig. 9H-J Ophioplinthaca citata Koehler, 1904: 130-131, pl. 14 (5-7).

TYPE MATERIAL. — Syntypes: ZMA E2444(2), E2445. TYPE LOCALITY. — Indonesia, off Gag Is, Irian Jaya and off Kei Islands, 204-469 m. MATERIAL EXAMINED. — Indonesia. Siboga: stn 156, Irian Jaya, eastern Halmahera Sea, east of Gag Is., 0°29.2’S, 130°5.3’E, 469 m, 15.08.1899, syntypes: 2 (ZMA E2444). — Siboga: stn 251, Kapulauan Kai (Kei Islands), 5°28.4’S, 132°0.2’E, 204 m, 08.12.1899, syntype: 1 (ZMA E2445).

New Caledonia. BATHUS 3: stn CP 833, Ride de Norfolk, 23°2.75’S, 166°58.23’E, 441-444 m, 30.11.1993: 3 (MNHN EcOs 22965). — BIOCAL: stn DW 46, Ride de Norfolk, 22°53.05’S, 167°17.08’E, 570-610 m, 30.08.1985: 1 (MNHN EcOs 22463). — MUSORSTOM 6: stn CP 465, Ride des Loyauté, 21°3.55’S, 167°32.25’E, 480 m, 21.02.1989: 1 (MNHN EcOs 22967).

DESCRIPTION. — (New Caledonian material) Disc 9-10 mm d.d., tumid; arms > 45 mm, epizoic on primnoid octocoral. Radial shields 1/4 d.d. in length, 3-4 times as long as wide, attenuated proximally, completely separated by 1-2 rows of disc plates, parallel, sunken beneath the level of the other disc plates. Disc stumps small, 0.25-0.4 mm high, 1.5-2

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FIG. 9. A-C, Ophioplinthaca rudis MNHN EcOs 22474; A, dorsal aspect; B, ventral aspect; C, disc spines; D-G, Ophioplinthaca amezianae n. sp. holotype MNHN EcOs 22457; D, dorsal aspect; E, ventral aspect; F, ventral arm plates; G, disc spines; H-J, Ophioplinthaca citata MNHN EcOs 22463; H, dorsal aspect; I, ventral aspect; J, disc spine. SEM images, scale bars in mm. FIG. 9. A-C, Ophioplinthaca rudis MNHN EcOs 22474 ; A, vue dorsale ; B, vue ventrale ; C, épines discales ; D-G, Ophioplinthaca amezianae n. sp. holotype MNHN EcOs 22457 ; D, vue dorsale ; E, vue ventrale ; F, plaques ventrales des bras ; G, épines discales ; H-J, Ophioplinthaca citata MNHN EcOs 22463 ; H, vue dorsale ; I, vue ventrale ; J, épines discales. Images MEB, échelles en mm.

times as high as wide, cylindrical, with a terminal crown of thorns. Oral shield diamond-shaped, with an obtuse proximal angle, rounded laterals and an obtuse to lobed distal angle, 2 times as wide as long. Adoral shields 3 times as wide as long. Jaw as wide as long, with 1 apical and 3-4 oral papillae, papillae typically 2 times as high as wide, rounded or slightly flattened and tapering to a blunt tip, some papillae expanded near the tip, outer papillae can be small and scale-like. Dorsal arm plates fan to bell-shaped, as wide as long, with an acute proximal angle, straight to concave proximolateral sides and a convex distal edge, just contiguous except for the first few and distal segments. Ventral arm plates proximally 2 times as wide as long, diamond-shaped, with an obtuse proximal angle, expanded lateral wings, and a notched obtuse distal angle, just contiguous, distal plates roughly rectangular with small lateral wings, notched distal edge. Up to 9 arm spines basally, almost meeting on the dorsal midline, uppermost 4 segments in length, lower spines finely thorny, hollow. Tentacle scale oval to elliptical, almost as long as the ventral arm plate, several erect scales can enclose basal pores.

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DISTRIBUTION. — Indonesia (204-469 m), New Caledonia (441-610 m). REMARKS. — The New Caledonian material is very similar to the larger syntype. Although not shown on Koehler’s (1904) figures, the ventral plates are conspicuously notched on the distal margin. This syntype has seven arm spines basally, the same number as a similar-sized specimen here (9 mm d.d., MNHN EcOs 22967). The smaller syntype (6 mm d.d.) differs in having radial shields that are widened and contiguous basally. Ophioplinthaca citata can be distinguished from other Ophioplinthaca species by the combination of narrow separate radial shields, cylindrical disc stumps with a terminal crown of thorns, numerous arm spines, and contiguous dorsal and ventral arm plates, the latter having a conspicuous notch on the distal margin.

Ophioplinthaca globata Koehler, 1922 Fig. 8D-H Ophioplinthaca globata Koehler, 1922a: 132-137, pl.24 (7-8), 25 (1-8), 94 (6). Ophioplinthaca globata ¢ Koehler1930: 83-84.

TYPE MATERIAL. — Lectotype: USNM E1045 (designated by A.H. Clark, see Ahearn 1992). Paralectotypes USNM E68-E79, E4883, E4885, E4902, MNHN EcOs 22037, 22378. TYPE LOCALITY. — Philippines, Mindoro, 518 m. MATERIAL EXAMINED. — New Caledonia. BIOCAL: stn DW 33, Ride de Norfolk, 23°9.71’S, 167°10.27’E, 675 m, 29.08.1985: 5 (MNHN EcOs 22464). — BIOCAL: stn DW 51, Ride de Norfolk, 23°5.27’S, 167°44.95’E, 680-700 m, 31.08.1985: 8 (MNHN EcOs 22465). — MUSORSTOM 6: stn CP 438, Ride des Loyauté, 20°23’S, 166°20.1’E, 780 m, 18.02.1989: 1 (MNHN EcOs 22968).

Philippines. Albatross: stn 5119, Balyan Bay and Verde Island passage, 13°45.8’N, 120°30.5’E, 721 m, 21.01.1908, paralectotype: 1 (MNHN EcOs 20367). — Albatross: stn 5424, Jolo Sea, Cagayan Island, 9°37.8’N, 121°12.6’E, 622 m, 31.03.1909, paralectotype: 1 (MNHN EcOs 20378).

OTHER MATERIAL EXAMINED. — Ophioplinthaca manillae Guille, 1981: MUSORSTOM 1: stn CP 51, Philippines, W of Lubang Island, 13°49’N, 120°4’E, 170-200 m, 25.03.1976, holotype: 1 (MNHN EcOs 20379).

DESCRIPTION. — (New Caledonian material). Disc 6-9.5 mm d.d., arms curled, some specimens epizoic on cnidarians. Radial shields 1/5-1/8 d.d. in length, 1-2 times as long as wide, contiguous distally or completely separated by a few plates, rounded to elongated-triangular. Disc stumps variable, many cylindrical to conical, the upper half covered in obvious thorns, others with only 3 terminal thorns, or trifid with bifurcated tips, up to 0.45 mm in height. Oral shields diamond-shaped with rounded angles, or more triangular with an acute proximal angle and a truncate or notched distal edge. Adoral shields 3-4 times as wide as long, can extend beyond the lateral angles of the oral shield. Jaw as long as wide with 1 apical and 3-4 oral papillae, cylindrical to capitate, 2-3 times as long as wide, some distal papillae with a notched or thorny tip, small granules sometimes present at distal edge of the jaw slit. Dorsal arm plates bell-shaped, as wide as long, separate. Ventral arm plates wider than long, with a round to obtusely angular proximal lobe and a wide distal margin that is slightly produced centrally, just contiguous proximally. Up to 6 arm spines on basal segments, uppermost longest, 3 segments in length, thorny. Tentacle scale oval, almost as long as the ventral arm plate, terminally spiniferous on larger specimens, 2 scales on the pores of the first arm segment. DISTRIBUTION. — Philippines (411-1013 m), Indonesia (885 m), New Caledonia (675-780 m).

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OPHIUROIDS FROM

NEW CALEDONIA

REMARKS. — The syntypes that we have examined differ slightly from the New Caledonian material in having notched to thorny oral papillae and conspicuously thorny tentacle scales. But this is evidently a very variable species or species complex. Koehler (1922a) described the various types of disc stumps that can be present, ranging from cylindrical thorny stumps to elongated trifid spines, to complex trilobed stumps with bifurcating tips. The specimens with the bifurcated trilobed stumps are similar to the unique holotype of O. manillae Guille, 1981 which is either a synonym, or is a name available for specimens with these complex stumps if more than one species is involved. As with many Ophioplinthaca species, more material than is presently available will be required to resolve specific limits. Several other nominal species are also close to O. globata. Ophioplinthaca hastata Koehler, 1922a has larger capitate to clavate disc stumps and O. clothilde A.H. Clark, 1949 has stumps that are described as ‘‘terminating in a flaring irregular crown of a dozen or so spinules’’.

Ophioplinthaca hastata Koehler, 1922 Fig. 8I-L Ophioplinthaca hastata Koehler, 1922a: 137-140, pl.18 (6-8), 94 (7).

TYPE MATERIAL. — Holotype: USNM 41002. Paratype: USNM 41002 (not seen). TYPE LOCALITY. — Indonesia, off Borneo, 635 m. MATERIAL EXAMINED. — New Caledonia. BIOCAL: stn CP 32, Ride de Norfolk, 23°6.98’S, 166°51.2’E, 825 m, 29.08.1985: 7 (MNHN EcOs 22466).

DESCRIPTION. — (New Caledonian material). Disc up to 8 mm d.d.. Radial shields 1/6 d.d. in length, rounded triangular, 1.5 times as long as wide, contiguous or just separate distally. Disc stumps stout, capitate, with a convex to flaring head bearing numerous small thorns, up to 0.16 mm in diameter, 2-3 times as high as wide. Oral shields diamond-shaped to triangular, the distal margin slightly convex, having an obtuse angle ventrally or with a small central lobe. Adoral shields 3 times as long as wide, can extend beyond the lateral angles of the oral shields. Jaw slightly longer than wide, with 1 apical and 4-5 lateral oral papillae, 1-2 suboral in position, spiniform to club-shaped, outer papilla largest, sometimes with small granules at the distal end of the jaw. Dorsal arm plates bell-shaped, as wide as long, separate. Ventral arm plates 2 times as wide as long, with an obtuse angle proximally and an expanded, slightly convex distal margin, separate. Up to 7 arm spines basally, short and bluntly pointed, thorny near tip, uppermost almost 3 segments in length. One tentacle scale on most plates (2 on the first pore), clavate, terminally spiniferous, longer than the ventral arm plate in length. DISTRIBUTION. — Philippines (368 m), Borneo (635 m), New Caledonia (825 m). REMARKS. — The New Caledonian specimens are very similar to Koehler’s (1922a) photographs of the type series, with the exception that the disc stumps in the types were slightly more elongated, up to four times as high as wide. The similarity of O. hastata to O. globata is striking, and O. hastata may only be an extreme variant of this most variable species. Ophioplinthaca abyssalis Cherbonnier & Sibuet, 1972 appears to be the Atlantic equivalent of O. hastata, differing only in the slightly more elongate disc spines (as drawn by Paterson 1985) and curved lower arm spines.

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Ophioplinthaca plicata (Lyman, 1878) Figs 8M-P, 18G Ophiomitra plicata Lyman, 1878a: 150, pl. 8 (209-212), 9 (233-235). Ophiomitra plicata ¢ Lyman 1882: 203-204, pl. 10 (7-9). Ophioplinthaca vicina Koehler, 1904: 129-130, pl. 25 (1-3) [new synonymy]. Ophioplinthaca incisa ¢ Baker & Devaney 1981: 174. — O’Hara 1990: 301-302, fig. 2j. ?Ophioplinthaca pulchra ¢ McKnight 1975: 70; 1993: 174, 187 [Non Ophioplinthaca pulchra Koehler, 1904]. Non Ophioplinthaca vicina ¢ Litvinova 1981: 126-127, fig. 3 (5-6) [= Ophioplinthaca defensor Koehler, 1930].

TYPE MATERIAL. — Holotype: BMNH 1882.12.23.186. Paratypes: BMNH 1882.12.23.183, MCZ 2062. TYPE LOCALITY. — Philippines, west of Luzon Is, 1953 m. MATERIAL EXAMINED. — Indonesia. Siboga: stn 226, Banda Sea, between Lucipara and Mai Islands, Mid channel between the Lucipara and Schildpad Islands, 5°26.7’S, 127°36.5’E, 1595 m, 11.11.1899, holotype of O. vicina: 1 (ZMA E2454). — Challenger: stn 214, Off Meangis Is, 4°33’N, 127°6’E, 930 m, 10.02.1875, paratype: 1 (BMNH 1882.12.23.313). New Caledonia. BIOCAL: stn CP 31, Ride de Norfolk, 23°7.26’S, 166°50.45’E, 850 m, 29.08.1985: 1 (MNHN EcOs 22469). — BIOCAL: stn CP 68, Ride de Norfolk, 24°0.37’S, 168°7.3’E, 1430 m, 03.09.1985: 1 (MNHN EcOs 22633). — BIOCAL: stn CP 74, Ride de Norfolk, 22°14.06’S, 167°29.01’E, 1300-1475 m, 04.09.1985: 12 (MNHN EcOs 22634). — BIOCAL: stn CP 75, Ride de Norfolk, 22°18.65’S, 167°23.3’E, 825-860 m, 04.09.1985: 3 (MNHN EcOs 22468). — MUSORSTOM 6: stn CP 465, Ride des Loyauté, 21°3.55’S, 167°32.25’E, 480 m, 21.02.1989: 1 (MNHN EcOs 22970). — MUSORSTOM 6: stn DW 487, Ride des Loyauté, 21°23.3’S, 167°46.4’E, 500 m, 23.02.1989: 1 (MNHN EcOs 22971). — SMIB4: stn DW 58, 22°59.6’S, 167°24.2’E, 480-560 m, 09.03.1989: 1 (MNHN EcOs 22467).

New Zealand. Challenger: stn 170a, Kermadec Islands, 29°45’S, 178°11’W, 1171 m, 14.07.1874, paratype: 1 (BMNH 1882.12.23.183). Philippines. Challenger: stn 205, west of Luzon Is, 16°42’N, 119°22’E, 1953 m, 13.11.1874, holotype: 1 (BMNH 1882.12.23.186). Australia. BSS: stn 34DN, Eastern Bass Strait, 55 km NE of Babel Island, Tasmania, 39°38.2’S, 148°49.2’E, 695 m, 27.03.1979, identified by O’Hara (1990) as O. incisa: 1 (MoV F52775). — K7/73: stn 5, Bass Strait, south of Point Hicks, 38°24.5’S, 149°25.5’E, 823 m, 21.11.1973, identified by Baker & Devaney (1981) as O. incisa: 6 (MoV F45361). — SLOPE: stn 32, South of Point Hicks, 38°21.9’S, 149°20’E, 1000 m, 23.07.1986: 24 (MoV F80848). — SLOPE: stn 68, 63 km S of Point Hicks, 38°22.66’S, 149°18.41’E, 1073-1169 m, 25.10.1988: 47 (MoV F80851). — SS01/97: stn 40, 82.6 km SSE of SE Cape, ‘‘J1’’ seamount, 44°14.4’S, 147°21.6’E, 1200-1450 m, 27.01.1997: 3 (MoV F82033).

OTHER MATERIAL EXAMINED. — Ophioplinthaca incisa (Lyman, 1883): West Indies, off Santa Cruz Island, 1078 m, syntypes: 3 (MCZ 4079).

DESCRIPTION. — (New Caledonian material). Disc up to 15 mm d.d., radial shields 1/3-1/4 d.d., roughly triangular, 2-2.5 times as long as wide, with a sharp or rounded proximal angle, contiguous distally. Disc granules conical, cylindrical to capitate, finely rugose or rarely with a few longer thorns, 0.3-0.4 mm high. Oral shields cruciform, with a pointed lobe proximally, rounded lateral angles and an enlarged rounded lobe distally that can be grooved or sunken. The oral shields vary in shape from longer than wide to wider than long depending on the size of the distal lobe. Adoral plates 3 times as wide as long, meeting fully within. Jaw as long as or longer than wide, with 1-3 apical and 3-5 oral papillae, pointed to square-shaped. Dorsal arm plates bell-shaped, with a convex to wavy distal edge and a rounded obtuse angle proximally, a little wider than long, separate after the third segment. Ventral arm plates triangular and just contiguous on basal plates becoming trapezoid and separate distally, twice as wide as long. Up to 8 arm spines, uppermost 2-3 segments long, thorny, hollow. Tentacle scales 2-3 on the first pore, then 1, erect, curved inwards, twice as long as wide with a pointed to rounded tip. DISTRIBUTION. — Philippines (1953 m), Indonesia (930-1595 m), New Caledonia (480-1475 m), Kermadec Is (1116-1171 m), ?New Zealand (640-1169 m), SE Australia (640-2003 m).

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OPHIUROIDS FROM

NEW CALEDONIA

REMARKS. — The New Caledonian specimens were initially identified as O. pulchra Koehler, 1904 and despite their clear separation in the key in this paper, it can be difficult to distinguish O. pulchra from O. plicata. Many features are highly variable and it is difficult to separate the species on the oral armature, arm plates, arm spines, and radial shields. In fact the only unequivocal difference between the two species appears to be the shape of the disc spines, which are spherical to capitate in O. pulchra and conical, cylindrical or clavate in O. plicata. However, even this character is variable. Koehler (1922a) synonymised O. pulchra with O. mitis Koehler, 1904 despite the large difference in the size of the disc stumps in the respective type specimens (Fig. 18C, D). There is also much morphological variation in the type series of O. plicata, particularly in the shape of the disc stumps (Fig. 18G), the position of the radial shields, and the shape of the dorsal arm plates. The holotype (Challenger station 205) has conical smooth disc stumps, the paratypes from station 170 have squat cylindrical stumps, with a truncate or rounded apex, and the paratypes from station 214 have elongate spines with small thorns along their length and a rounded tip. The radial shields range from being separate in the holotype, to contiguous for more than half their length (stn 214). The dorsal arm plates are widened on the holotype, and bell-shaped on most of the smaller animals. However, none of the New Caledonian specimens have the capitate granules illustrated by Koehler (1904, 1922a), and on (at least) the MNHN syntype the arm spines are solid, so for the time being the two species are regarded as distinct. The relationships of O. pulchra are further discussed under that species below. The unique holotype of O. vicina (9 mm d.d.) falls within the range of variation in the O. plicata type series and is considered a synonym. The disc stumps are conical to cylindrical (0.5 mm high) with a few minute thorns near the tip; the radial shields, 1/4 mm d.d., are broadly contiguous distally; and the dorsal arm plates are bell-shaped, just separate. There are five bluntly pointed arm spines, covered in fine thorns, and four oral papillae, sometimes one can be in a suboral position. The specimens reported by Litvinova (1981) as O. vicina from the Marcus-Necker Seamounts in the NW Pacific are more likely to belong to O. defensor judging from the large disc stumps and contiguous radial shields (see O. pulchra below). O’Hara (1990) commented that the specimens identified as O. incisa from southeast Australia are very similar to O. plicata. The large number of specimens now available show a continuous range of variation indicative of a single species throughout the Tasman Sea. The type specimens of O. incisa from the West Indies are also very similar, however, we hesitate from fully synonymising this species until the range of morphological variation from this region is better documented. The specimens recorded as O. pulchra from north of New Zealand (McKnight 1975, 1993) and eastern Australia (Rowe & Gates 1995) are also probably this species.

Ophioplinthaca rudis (Koehler, 1897) Fig. 9A-C Ophiomitra rudis Koehler, 1897: 358-360, pl. 9 (74-75). Ophiomitra rudis ¢ Koehler 1899: 65-67, pl. 7 (58-59). Ophioplinthaca rudis ¢ Koehler 1904: 132; 1922a: 142-147, pl. 24 (1-6), 96 (1). — Clark, H.L. 1939: 46-47. — Clark, A.M. 1977: 141. — Guille 1981: 425. — Imaoka et al. 1990: 79, fig. 38. Ophiomitra cardiomorpha Clark, H.L., 1911: 179-180, fig. 81. Ophioplinthaca cardiomorpha ¢ Clark, H.L. 1915: 210. — Matsumoto 1917: 130-131.

TYPE MATERIAL. — Lectotype: ZSI 8581/6 (designated herein). TYPE LOCALITY. — India, Bay of Bengal, 1450 m. MATERIAL EXAMINED. — Indonesia. Siboga: stn 212, off southern Sulawesi, west of Salayar Island, 5°54.5’S, 120°19.2’E, 462 m, 26.09.1899, identified by Koehler (1904): 2 (ZMA Ech O 6820).

India. Investigator: stn 54, Bay of Bengal, 12°21.5’N, 92°3.5’E, 1450 m, 13.04.1889, lectotype: 1 (ZSI 8581/6). New Caledonia. BIOCAL: stn CP 30, Ride de Norfolk, 23°9.65’S, 166°40.85’E, 1140 m, 29.08.1985: 4 (MNHN EcOs

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22476). — BIOCAL: stn CP 57, Ride de Norfolk, 23°43.3’S, 166°58.1’E, 1490-1620 m, 01.09.1985: 9 (MNHN EcOs 22477). — BIOCAL: stn CP 61, Ride de Norfolk, 24°11.7’S, 167°31.8’E, 1070 m, 02.09.1985: 5 (MNHN EcOs 22475). — BIOCAL: stn DW 70, Ride de Norfolk, 23°24.7’S, 167°53.65’E, 965 m, 04.09.1985: 1 (MNHN EcOs 22470). — BIOCAL: stn CP 74, Ride de Norfolk, 22°14.06’S, 167°29.01’E, 1300-1475 m, 04.09.1985: 1 (MNHN EcOs 22474). — BIOCAL: stn CP 75, Ride de Norfolk,

22°18.65’S, 167°23.3’E, 825-860 m, 04.09.1985: 3 (MNHN EcOs 22473). — MUSORSTOM 5: stn CP 323, 21°18.52’S, 157°57.62’E, 970 m, 14.10.1986: 1 (MNHN EcOs 22471). — MUSORSTOM 5: stn CP 324, 21°15.01’S, 157°51.33’E, 970 m, 14.10.1986: 3 (MNHN EcOs 22472). Philippines. MUSORSTOM 1: stn CP 49, W of Lubang Island, 13°49’N, 120°0’E, 750-925 m, 25.03.1976, identified by Guille (1981): 4 (MNHN EcOs 20382).

DESCRIPTION. — (New Caledonian material). Disc up to 13 mm d.d., arms longer than 6 d.d.. Radial shields 1-2 times as long as wide (even on the same specimen), up to 1/3 d.d. in length, rounded triangular, attenuated proximally, separate and parallel, or contiguous distally and proximally divergent. Disc spines needle-like, long and slender, up to 1.3 mm in length, smooth to finely serrate, often smaller and conical near the disc margin. Oral shields pentagonal, with an obtuse proximal angle, and a truncate distal lobe, as wide or slightly wider than long, often grooved distally. Adoral shields 3 times as wide as long. Jaw as wide as long, bearing 1 apical and 5-6 lateral oral papillae in a single row, apical papillae largest, distal one flattened and adpressed. Dorsal arm plates 2 times as wide as long, widest distally, appearing granular towards the distal margin, contiguous or just separate. Ventral arm plates 2 times as wide as long, with a widened convex thickened distal border, widely separate. Up to 5 arm spines, uppermost 6 segments in length, widely separated by the dorsal arm plates, with fine thorns. One bottle-shaped to pointed tentacle scale, pointing laterodistally, half as long as the ventral arm plate. DISTRIBUTION. — Natal (780-1200 m), Zanzibar (786-1463 m), Gulf of Aden (1270 m), India (1311-1450 m), Philippines (165-1417 m), Indonesia (239-1886 m), Eastern Australia (920-1200 m), New Caledonia (825-1620 m). REMARKS. — The New Caledonian material is similar to the 14 mm d.d. type of Ophioplinthaca rudis in the ZSI (here designated as the lectotype) and Koehler’s (1897) description. The form of the long slender spines is very characteristic of this species. There can be some variation in the density and form of the spinelets, from almost smooth to finely serrate. Nevertheless, they never have the irregularly thorny spines characteristic of the new species O. amezianeae. There is another specimen in the BMNH labelled as a ‘‘type’’ (BMNH 98.7.11.17). But it has relatively short stumps, two times as high as wide, with an indented to slightly thorny head, and small radial shields, 1/6 d.d in length, and is perhaps referable to O. globata. We present here notes on other Indo-Pacific species of Ophioplinthaca.

Ophioplinthaca monitor Koehler, 1930 Fig. 18I Ophioplinthaca monitor Koehler, 1930: 88-90, pl. 8 (4-5). Ophioplinthaca victor Koehler, 1930: 90-92, pl. 8 (8-10) [new synonymy].

TYPE MATERIAL. — Syntypes: ZMUC(2). TYPE LOCALITY. — Indonesia, Kei Is, 290 m. MATERIAL EXAMINED. — Indonesia. MPE Kei Is: stn 58, 5°29’S, 132°37’E, 290 m, 12.05.1922, syntypes of O. victor: 7 (ZMUC); syntypes: 2 (ZMUC).

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NEW CALEDONIA

DISTRIBUTION. — Indonesia (290 m). REMARKS. — Surprisingly, Koehler (1930) did not compare the types of O. monitor and O. victor, particularly as they were collected from the same station. However, they share all important taxonomic characters. Ophioplinthaca monitor is characterised by the large, separate, triangular to oblong radial shields and bowl-shaped disc stumps with an expanded apex covered in sharp thorns (Fig. 18I). The disc spines are closest in form to O. citata, however, that species has narrow parallel radial shields. The disc spines of O. globata, O. manillae and O. papillosa are generally divided at the apex into three rays which are bifurcated or thorny at the tips.

Ophioplinthaca pulchra Koehler, 1904 Fig. 18C Ophioplinthaca pulchra Koehler, 1904: 125-127, pl. 27 (5-8). Ophioplinthaca pulchra ¢ Koehler 1922a: 140-142, pl. 30 (1-7), 94 (5); 1930: 83-84. — Guille 1981: 424-425. Ophioplinthaca mitis Koehler, 1904: 127-129, pl. 25 (1-3).

TYPE MATERIAL. — Syntypes: ZMA E2449-E2452, MNHN EcOs 20380, MCZ 3506. TYPE LOCALITY. — Indonesia, 304-522 m. MATERIAL EXAMINED. — Indonesia. Siboga expedition, Île de la Sonde, syntype: 1 (MNHN EcOs 20380). — Siboga: stn 253, Kapulauan Kai (Kei Islands), 5°48.2’S, 132°13’E, 304 m, 10.12.1899, syntypes of O. mitis: 8 (ZMA E2448). OTHER MATERIAL EXAMINED. — Ophioplinthaca defensor Koehler, 1930: MPE Kei Is: stn 59, Indonesia, 5°28’S, 132°36’E, 385 m, 12.05.1922, holotype: 1 (ZMUC). Ophioplinthaca miranda Koehler, 1904: Siboga: stn 267, Indonesia, Kapulauan Kai (Kei

Islands), 5°54’S, 132°56.7’E, 984 m, syntypes: 2 (ZMA E2446). Ophioplinthaca weberi (Koehler, 1904): Siboga: stn 297, Indonesia, West Timor, east of Roti, 10°39’S, 123°40’E, 520 m, 27.01.1900, holotype: 1 (ZMA E2434).

DISTRIBUTION. — Philippines (353-925 m), Indonesia (38-732 m). REMARKS. — This species is characterised by its relatively large radial shields, up to 1/3 mm d.d., contiguous distally, and spherical to capitate disc stumps (up to 0.5 mm in diameter). Koehler (1904) originally described specimens with comparatively small disc stumps as O. mitis, later synonymising this species with O. pulchra after examining a range of specimens from the Philippines (Koehler 1922a). McKnight (1975, 1993) and Rowe & Gates (1995) do not supply any morphological details about their animals, from north of New Zealand and off eastern Australia respectively, which are probably O. plicata (see above). Several other species of Ophioplinthaca also have spherical granules. Ophioplinthaca tylota H.L. Clark, 1939 is similar except it has some disc granules in the form of bowls (Fig. 18E) (although these have the appearance of granules that have been split horizontally, they are not an obvious artefact of collection) and others that are elongated into clubs (Fig. 18F). The holotype and only known specimen of O. defensor Koehler, 1930 also has the appearance of an aberrant O. pulchra, but differs in having massive, contiguous radial shields, almost 1/2 d.d., and relatively short arm spines, up to 1.5 segments in length. It has large cylindrical to spherical disc granules 0.6-0.8 mm high and 0.5 mm in diameter (Fig. 18H). Ophioplinthaca defensor Koehler, 1930 is quite similar to O. weberi (Koehler, 1904) and possibly synonymous. The unique type of Ophioplinthaca weberi has no disc granules of any kind, broadly contiguous dorsal arm plates and relatively small tentacle scales, but these are not particularly reliable characters in this genus. The larger (12 mm d.d.) syntype of O. miranda Koehler, 1930 is a bizarre animal with very stout upper arm spines (Fig. 18B) that have the appearance of elongate disc stumps and short stout tapering arms. The disc stumps are large (1 mm

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diameter) and capitate (Fig. 18B), and radial shields are 2/5 d.d. in length, contiguous distally. There are only three oral papillae, the outermost thickened. The arms on the smaller syntype (7 mm d.d.) are not as obviously tapered. It does have similar arm spines proximally, but distally they are slender and reach three segments in length. Only two small disc granules are present, only 0.4 mm in diameter. Without more material, it is difficult to ascertain the limits of these nominal species.

Genus OPHIOMITRELLA Verrill, 1899 Ophiomitrella Verrill, 1899a: 39, 43. Ophiomitrella ¢ Paterson 1985: 61-62.

Type species: Ophiacantha laevipellis Lyman, 1883. OTHER MATERIAL EXAMINED. — Ophiacantha languida (Koehler, 1904): Siboga: stn 74, Indonesia, Makassar Strait, west of Makassar, 5°3.5’S, 119°0’E, 450 m, 08.06.1899, holotype: 1 (ZMA E2420). Ophiacantha severa Koehler, 1922a: MPE Kei Is: stn 56, Indonesia, 5°30.3’S, 132°51’E, 345 m, 10.05.1922, identified by Koehler (1930): 6 (ZMUC). Ophiomitrella barbara Koehler, 1904: Siboga: stn 254, Indonesia, Kapulauan Kai (Kei Islands), 5°40’S, 132°26’E, 310 m, 10.12.1899, holotype: 1 (ZMA E2419). Ophio-

mitrella mutata Koehler, 1904: Siboga: stn 251, Indonesia, Kapulauan Kai (Kei Islands), 5°28.4’S, 132°0.2’E, 204 m, 08.12.1899, syntype: 1 (ZMA E2422). — Siboga: stn 253, Indonesia, Kapulauan Kai (Kei Islands), 5°48.2’S, 132°13’E, 304 m, 10.12.1899, syntypes: 2 (ZMA E2423). Ophiomitrella sagittata Koehler, 1922: MPE Kei Is: stn 8, Indonesia, 5°39’S, 132°26’E, 300 m, 05.04.1922, identified by Koehler (1930): 1 (ZMUC).

REMARKS. — Ophiomitrella was originally created by Verrill (1899a) for the species Ophiacantha laevipellis Lyman, 1883 from the West Indies. Diagnostic features included the presence of disc granules that do not obscure the underlying plates, small separate radial shields that are ‘‘largely’’ uncovered, arm spines that meet above the dorsal midline, one apical jaw papilla and wide adoral shields that do not separate the oral shields from the lateral arm plates. It was separated from Ophiacantha, which had the disc and most of the radial shields ‘‘wholly’’ covered in spines or granules. Numerous other species were rapidly added to the genus from the Atlantic, Indo-Pacific and Southern Oceans. The inclusion of these species subtly changed the definition of the genus, so that by 1927, Mortensen defined the genus as having short, thick disc stumps or granules that do not conceal the plates, radial shields large and distinct, tentacle pores small and inconspicuous, one tentacle scale and simple papilliform oral papillae. Thus the radial shield character state had changed from small, separate and partly covered by disc plates to being large and distinct. Paterson (1985) took this one step further by including Ophiomitrella in the Ophioplinthacinae which is characterised by radial shields that are fully integrated into the armature of the disc, in comparison with the Ophiacanthinae (e.g. Ophiacantha sensu stricto) where the bar-like radial shields are mostly covered in disc plates with only the distal tip exposed. We have not examined any specimens of O. laevipellis, however, the shape of the radial shields in Lyman’s (1883) figures of the type are very similar to those we have seen in many species of Ophiacantha, i.e. they appear to represent only the distal ‘‘pear-shaped’’ section of a larger bar-like ossicle that is mostly obscured by the disc plates. In this case O. laevipellis would belong in the Ophiacanthinae, closely related to (if not synonymous with) Ophiacantha. On the other hand the radial shields may be genuinely small and integrated into the disc in which case the species belongs in the Ophioplinthacinae. Confirmation is required from dissection of O. laevipellis material. Regardless of the outcome of this examination, it appears unlikely that many of the species currently assigned to Ophiomitrella with large naked radial shields are congeneric with O. laevipellis. The species assigned to Ophiomitrella in the central Indo-Pacific appear to form several different groups. The first group has large rounded radial shields, often contiguous, relatively large disc plates, stout disc granules or stumps, short stout arms and arm spines. These species are typically epizoic on cnidarians. This group contains Ophioripa marginata Koehler, 1922a, O. nugator Koehler, 1922a, Ophiolebes tylota H.L. Clark, 1911 and O. pachybracta H.L. Clark, 1911 all from the Bering Sea (at least some of these species are likely to be synonymous), Ophioripa conferta Koehler, 1922b from the

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Southern Ocean and the Tasman Sea, possibly Ophiactis clavigera Ljungman, 1865 from the North Atlantic, and several new species described below. Matsumoto (1917) established the genus Ophiosemnotes for O. tylota and Koehler (1922a) Ophioripa for O. marginata, O. nugator and O. conferta. Ophiosemnotes was later synonymised with Ophiophthalmus by Fell (1961) and Ophioripa with Ophiomitrella by Madsen (1967). While this group appears well defined, intermediates exist between these species and O. laevipellis, such as O. ingrata Koehler, 1901 from the Southern Ocean with relatively small radial shields. Until a systematic revision of all relevant species occurs, we will continue to use the genus Ophiomitrella for these species. The second group includes O. polyacantha (H.L. Clark, 1911) and O. stellifera Matsumoto, 1917 with medium-sized radial shields, one-sixth to one-tenth the disc diameter, that are integrated into the armature of the disc, and stellate disc spines with a slender stalk and a ring of apical thorns. Perhaps related to these species are O. mutata (Fig. 18R), O. subjecta and O. sagittata with robust trilobed disc stumps, and O. barbata Koehler, 1904 with disc stumps with irregular thorny tips (Fig. 18P, discussed under O. stellifera below). However these four nominal species have relatively small visible radial shields and their relationship to Ophiacantha needs to be investigated. The third group has species with medium to large radial shields and small granules, including O. granulosa (Lyman, 1878a), O. tenuis Koehler, 1904 (with synonym O. ikedai Murakami, 1944), and another possible synonym ‘‘Ophiophthalmus’’ suspectus Koehler, 1922a. The distinction between Ophiomitrella and ‘‘Ophiophthalmus’’ is unclear (Paterson 1985). Koehler (1922a) considered it a mixed assemblage of species, with only some of the included species having the wide contiguous dorsal arm plates and few-relatively short arm spines characteristic of the type species, O. cataleimmoida (H.L. Clark, 1911). Paterson (1985) has pointed out that the name ‘‘Ophiophthalmus’’ is a junior homonym of a reptile. Given the invalid status of the name ‘‘Ophiophthalmus’’ and the unclear distinction between these genera and Ophiomitrella (see Paterson 1985), O. granulosa, O. tenuis and O. suspectus have been provisionally retained in Ophiomitrella. The disc of Ophiomitrella tenuis can be covered in skin that obscures the underlying plates (Fig. 18S). This is a diagnostic characteristic of the genus Ophiosemnotes Matsumoto, 1917, although confusingly, judging from their type descriptions, most of the species included in that genus appear to have visible disc plates. The other species included in Ophiosemnotes and ‘‘Ophiophthalmus’’ occur predominately in the north Pacific and lie outside the scope of this work. The last group is a heterogeneous assemblage of species that have been referred to Ophiomitrella but are better placed into other genera. Ophiomitrella fidelis Koehler, 1930 from SE Australia and O. funebris Koehler, 1930 from the Indo-Pacific have long bar-like radial shields and can be assigned to Ophiacantha sensu stricto (O’Hara 1990, this paper). Ophiomitrella exilis Koehler, 1922a has long adoral shields that separate the oral shields from the lateral arm plates. It also can be referred to Ophiacantha and it is very similar to O. moniliformis (=O. renekoehleri) as noted by Koehler, 1922a. Ophiomitrella nominata Koehler, 1930 is referable to Ophiocamax (see below). Ophiomitrella lineata Koehler, 1930 is a synonym of Ophiomitra leucorhabdota (H.L. Clark, 1911) (see below). Ophiomitrella languida Koehler, 1904 from Indonesia appears to have small, widely separate, radial shields. We have not dissected the unique type specimen to determine whether these plates represent only the distal tip of longer radial shields. Koehler (1904) describes the 7 mm specimen as having the unusual combination of granules on the dorsal surface of the disc and small thorny spines marginally and ventrally. However, we could not find any granules when we examined the type. Instead only large circular spine bases are visible. Either the granules have subsequently fallen off or Koehler misinterpreted the spine bases as granules. Regardless of which interpretation is correct, the spiniform marginal and ventral spines (0.1-0.15 mm long) are not typical of other Ophiomitrella species and we consider it better placed in Ophiacantha as placed by H.L. Clark (1915). The status of Ophiacantha severa (Koehler, 1922a), referred to Ophiomitrella by Koehler (1930), is unclear. The holotype was described as having robust disc spines with an apical ring of six thorns. The single paratype, and material from Indonesia later described by Koehler (1930), have much longer disc spines, with thorns present along their length. Possibly two species are present. All specimens are described as having relatively small radial shields. On the material from Indonesia we have examined, it is only the distal portion of the plate that is visible. Until more material is available we consider that this species also is better placed in Ophiacantha.

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Ophiomitrella conferta (Koehler, 1922) Figs 10F-H, 18N-O Ophioripa conferta Koehler, 1922b: 19-20, pl. 85 (9-13). Ophioripa conferta ¢ Rowe & Pawson 1977: 350. Ophiomitrella falklandica Mortensen, 1936: 256-259, fig. 8c-d, pl. 7 (5). Ophiomitrella conferta ¢ Madsen 1967: 127. — McKnight 1984: 144. — O’Hara 1990: 299-300, figs 2c-d, f-g.

TYPE MATERIAL. — Syntypes: AM J3579(7), MNHN EcOs 20388. TYPE LOCALITY. — Australia, Tasmania, off Maria Island, 2340 m. MATERIAL EXAMINED. — New Caledonia. SMIB4: stn DW 58, 22°59.6’S, 167°24.2’E, 480-560 m, 09.03.1989: 9 (MNHN EcOs 22438). — SMIB4: stn DW 60, 23°0.1’S, 167°21.6’E, 535 m, 10.03.1989: 2 (MNHN EcOs 22437). — SMIB4: stn DW 62, 23°0.4’S, 167°21.8’E, 540 m, 10.03.1989: 1 (MNHN EcOs 22439). — SMIB4: stn DW 63, 22°58.7’S, 167°21.1’E, 520 m, 10.03.1989: 2 (MNHN EcOs 22436). Australia. BSS: stn 34 DN, Eastern Bass Strait, 55 km NE of

Babel Island, Tasmania, 39°38.2’S, 148°49.2’E, 695 m, 27.03.1979: 4 (MoV F52685). — BSS: stn 37 DN, Eastern Bass Strait, 87 km ENE of North Point, Flinders Island, 39°28.2’S, 148°52.4’E, 841 m, 29.03.1979: 1 (MoV F52684). — K7/73: stn 7, Bass Strait, south of Point Hicks, 38°17.3’S, 149°25’E, 640 m, 21.11.1973: 6 (MoV F52683). — AAE expedition, off Maria Is, 42°48’S, 148°40.75’E, 2340 m, 13.12.1912, syntype: 1 (MNHN EcOs 20388); syntypes: 7 (AM J3579).

DESCRIPTION. — (New Caledonian material). Disc 5 to 10 mm d.d., arms frequently curled under the disc, epizoic. Disc round, bearing coarse thick overlapping plates, 5-6 from centre to margin, 3 from the centre to the proximal edge of the radial shield. Some plates with 1-2 stout stumps, 0.2-0.25 mm high, 0.15-0.2 mm diameter, capitate to club-shaped with a short round pedicel expanding to a spherical or truncate head, microscopically roughened, particularly near the apex. Radial shields 1/4-1/8 d.d., round to rounded triangular, attenuated proximally, just separate or contiguous. Oral shields wider than long, with an obtuse proximal angle, rounded lateral angles, and a pronounced distal lobe. Adoral shields 3 times as wide as long, contiguous or slightly separate interradially, sausage-shaped, with a slightly concave proximal edge. Jaw narrow, a little longer than wide, bearing elongate, cylindrical, bluntly pointed oral papillae, 2-3 times as long as wide, subequal. Dorsal arm plates roughly fan-shaped, with a rounded proximal angle and a convex to centrally-produced thickened distal margin, just separated. Ventral arm plates wider than long with a very obtuse proximal angle or a straight proximal edge, with a wide convex distal margin, just contiguous basally, distally quite separate. Lateral arm plate with a low ridge bearing up to 6 arm spines, not hollow, upper spine longest, 1.5 segments in length, cylindrical, tapering to a blunt point, granular but without obvious thorns; lower spines with irregular thorns near the base, thorns ventrally directed on distal spines but not hook-like. A single tentacle scale, oval to spiniform, half the length of the ventral arm plate. One specimen has 6 arms. DISTRIBUTION. — SE Australia (640-2340 m); Macquarie Island (741 m), Falkland Islands (79-463 m), off Enderby Land, Antarctica (193-603 m), New Caledonia (480-560 m). REMARKS. — Material identified as O. conferta is very variable and possibly represents more than one species. The syntypes differ from the New Caledonian material by having elongated club-shaped stumps (0.8 mm high, 0.25 mm wide, Fig. 18O), ventral arm plates with a straight or slightly notched distal edge, thicker arm spines which almost meet dorsally on basal segments, and widely separated dorsal arm plates. Other southeast Australian specimens have smaller disc stumps, up to 0.3 mm high (O’Hara 1990). Specimens from the Falkland Islands (originally described as O. falklandica) and off Antarctica have relatively short stout arm spines (Mortensen 1936; Madsen 1967; O’Hara 1990). Although, overlapping morphological variation was the basis for synonymising O. falklandica and O. conferta by O’Hara (1990), it is equally plausible that each population represents a different species, given the fragmented nature of its preferred habitat

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FIG. 10. A-E, Ophiomitrella parviglobosa n. sp. holotype MNHN EcOs 22443; A, dorsal aspect; B, ventral aspect; C, disc granules; D, arm spines; E, tentacle scales; F-H, Ophiomitrella conferta MNHN EcOs 22437; F, dorsal aspect; G, ventral aspect; H, disc granules; I-M, Ophiomitrella mensa n. sp.; I-L, holotype MNHN EcOs 22446; I, dorsal aspect; J, ventral aspect; K, dorsal arm; L, disc granule; M, paratype MNHN EcOs 22807 dorsal aspect; N-Q, Ophiomitrella polyacantha MNHN EcOs 22440; N, dorsal aspect; O, ventral aspect; P, disc spinelets; Q, tentacle scales. SEM images, scale bars in mm . FIG. 10. A-E, Ophiomitrella parviglobosa n. sp. holotype MNHN EcOs 22443 ; A, vue dorsale ; B, vue ventrale ; C, granules discaux ; D, épines des bras ; E, écailles des tentacules ; F-H, Ophiomitrella conferta MNHN EcOs 22437 ; F, vue dorsale ; G, vue ventrale ; H, granules discaux ; I-M, Ophiomitrella mensa n. sp. ; I-L, holotype MNHN EcOs 22446 ; I, vue dorsale ; J, vue ventrale ; K, vue dorsale des bras ; L, granules discaux ; M, paratype MNHN EcOs 22807 vue dorsale ; N-Q, Ophiomitrella polyacantha MNHN EcOs 22440 ; N, vue dorsale ; O, vue ventrale ; P, spinules discales ; Q, écailles des tentacules. Images MEB, échelles en mm .

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(cnidarians growing on rocky seamounts) and limited dispersal capability (brooding live young). The New Caledonian seamount specimens may also represent a distinct species, although molecular evidence is possibly required to resolve the issue. Unfortunately, the New Caledonian specimens are dry and have not been dissected to see if brooded young are present in the bursae.

Ophiomitrella granulosa (Lyman, 1878) n. comb. Fig. 11L-N Ophiacantha granulosa Lyman, 1878a: 138, pl. 8(206-208). Ophiacantha granulosa ¢ Lyman 1882: 183, pl. 14(7-9). ?Ophiacantha granulosa ¢ Clark, H.L. 1911: 215. TYPE MATERIAL. — Holotype and paratype, BMNH 1882.12.23.217. Paratypes: MCZ 1949(3). TYPE LOCALITY. — Philippines, off Zamboanga, 152-189 m. MATERIAL EXAMINED. — New Caledonia. BATHUS 3: stn CP 833, Ride de Norfolk, 23°2.75’S, 166°58.23’E, 441-444 m, 30.11.1993: 1 (MNHN EcOs 22816). — MUSORSTOM 6: stn DW 391, Ride des Loyauté, 20°47.35’S, 167°5.7’E, 390 m, 13.02.1989: 6 (MNHN EcOs 22810); 1 (MNHN EcOs 22430). — MUSORSTOM 6: stn DW 428, Ride des Loyauté, 20°23.54’S, 166°12.57’E, 420 m, 17.02.1989: 1 (MNHN EcOs 22811). — MUSORSTOM 6:

stn CP 464, Ride des Loyauté, 21°2.3’S, 167°31.6’E, 430 m, 21.02.1989: 1 (MNHN EcOs 22804); 1 (MNHN EcOs 22429). Philippines. Challenger: stn 201, off Samboanga (Zamboanga), 7°3’N, 121°48’E, 152-189 m, 26.10.1874, identified by Lyman (1882): 3 (BMNH 1956.10.2.27); holotype and paratypes: 2 (BMNH 1882.12.23.217).

DESCRIPTION. — (New Caledonian material) Disc 2-9 mm d.d., arms over 9 times d.d. long. Disc circular and flat, covered with small imbricating plates, typically 0.2-0.3 mm wide, 16 plates from centre to margin on 6 mm d.d. specimen; lateral margin rounded; many disc plates bearing a small spherical to dome-shaped granule, microscopically thorny, 0.1 mm diameter, granules not obscuring limits of plates. Radial shields roughly triangular with rounded angles, slightly longer than wide, 1/7 times d.d., separated by 1-3 rows of disc plates, slightly convergent proximally. Ventral disc surface tumid, covered in similar plates to the dorsal surface, a few plates bearing granules. Oral shields 1.5-2 times as wide as long, almost elliptical with obtuse proximal and distal angles. Adoral shields lying proximal to the oral shield, almost as large as the oral shield, quadrilateral, with almost straight proximal and distal sides, meeting broadly within, but separated without by the first ventral arm plate. Jaw slightly wider than long, with a single elongate club-shaped apical papilla, 2.5 times as high as wide. Three elongate oral papillae on each jaw side, 2-2.5 times as high as wide, bluntly pointed, separate, pointing at right angles to the oral plate. Arms robust, not particularly noded. Dorsal arm plates fan-shaped with an acute proximal angle, straight divergent lateral sides, and a convex distal edge, overlapping for the first 2-3 segments then just contiguous, becoming separate distally. Ventral arm plates longer than wide, proximal edge just overlapped by the distal edge of the previous plate, lateral sides convex, slightly indented around the pores, distal edge convex. Up to 9 arm spines basally, most appear macroscopically smooth but actually covered in minute thorns, cylindrical, tapering to a sharp point, hollow, upper spines longest, to 3.5 segments long, lowest spines shortest, up to 1 segment in length, some with notable thorns near the base. One oval to elliptical tentacle scale, twice as long as wide, 1/4 the length of the ventral arm plate. Colour (dry) arms with either a dark longitudinal stripe that extends onto the disc between the radial shields, or a series of dark dots along the arm including several between and proximal to the radial shields; disc tan, or with a greenish tinge, often with yellow flecking near the margin. DISTRIBUTION. — Japan (97-192 m), Philippines (152-189 m), New Caledonia (383-500 m).

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FIG. 11. A-D, Ophiomitrella tenuis MNHN EcOs 22451; A, dorsal aspect, B, ventral aspect, C, dorsal arm plates; D, disc granules; E-G, Ophiomitrella stellifera MNHN EcOs 22444; E, dorsal aspect; F, ventral aspect; G, disc spinelets; H-K, Ophiomitra leucorhabdota MNHN EcOs 22435; H, dorsal view showing longitudinal line on arm; I, dorsal aspect; J, ventral aspect; K, disc spinelets; L-N, Ophiomitrella granulosa MNHN EcOs 22429; L, dorsal aspect; M, ventral aspect; N, disc granules. SEM images except H, scale bars in mm. FIG. 11. A-D, Ophiomitrella tenuis MNHN EcOs 22451 ; A, vue dorsale ; B, vue ventrale ; C, plaques dorsales des bras ; D, granules discaux ; E-G, Ophiomitrella stellifera MNHN EcOs 22444 ; E, vue dorsale ; F, vue ventrale ; G, spinules discales ; H-K, Ophiomitra leucorhabdota MNHN EcOs 22435 ; H, vue dorsale montrant les lignes longitudinales sur les bras ; I, vue dorsale ; J, vue ventrale ; K, spinules discales ; L-N, Ophiomitrella granulosa MNHN EcOs 22429 ; L, vue dorsale ; M, vue ventrale ; N, granules discaux (N). Images MEB sauf H, échelles en mm.

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REMARKS. — The type material of O. granulosa, although comparatively large (7 and 9 mm d.d.), is very similar to the new material from New Caledonia. The specimens have faded, but the characteristic dark dots are still evident on the arms and disc. The ventral disc surface is fully covered with thin plates and granules. This similar species O. tenuis (Koehler, 1904) differs in having a definite edge to the dorsal disc surface and a constricted ventral disc surface that is often completely without scales. The dark longitudinal stripe sometimes extending along the dorsal arm plates of this species is reminiscent of Ophiomitra dives, however, that species clearly differs in having a cluster of papillae at the apex of each jaw and larger disc granules, to 0.5 mm in diameter.

Ophiomitrella mensa n. sp. Figs 10I-M, 18M TYPE MATERIAL. — Holotype: MNHN EcOs 22446. Paratypes: MNHN EcOs 22807, 22802, 22813, 22814, 22808, 22445, 22448, 22447. TYPE LOCALITY. — New Caledonia, 20°49.46’S, 167°9.11’E, 570 m. MATERIAL EXAMINED. — New Caledonia. BIOCAL: stn CP 67, Ride de Norfolk, 24°55.44’S, 168°21.55’E, 500-510 m, 03.09.1985, holotype: 1 (MNHN EcOs 22446); paratype on SEM stub: 1 (MNHN EcOs 22807); paratypes: 3 (MNHN EcOs 22802). — BIOCAL: stn CP 75, Ride de Norfolk, 22°18.65’S, 167°23.3’E, 825-860 m, 04.09.1985, paratypes: 9 (MNHN EcOs 22445). — BIOCAL: stn CP 109, Ride de Norfolk, 22°10’S, 167°15.2’E, 495515 m, 09.09.1985, paratype: 1 (MNHN EcOs 22448). — CHALCAL 2: stn DW 73, Ride de Norfolk, 24°39.9’S, 168°38.1’E, 573 m,

29.10.1986, paratypes: 13 (MNHN EcOs 22447). — MUSORSTOM 6: stn DW 394, Ride des Loyauté, 20°49.46’S, 167°9.11’E, 570 m, 13.02.1989, paratype: 1 (MNHN EcOs 22813). — MUSORSTOM 6: stn DW 444, Ride des Loyauté, 20°54.32’S, 167°17.82’E, 300 m, 19.02.1989, paratype: 1 (MNHN EcOs 22814). — MUSORSTOM 6: stn DW 483, Ride des Loyauté, 21°19.8’S, 167°47.8’E, 600 m, 23.02.1989, paratypes: 23 (MNHN EcOs 22808).

DESCRIPTION. — (Holotype). Disc irregular, 4.7 mm d.d., arms 4-5 times d.d, capable of being twisted distally, epizoic. Disc covered in large imbricating plates, 0.4-0.6 mm wide, 8-11 plates from the centre of the disc to the margin; radial shields quadrilateral, slightly attenuated proximally, 3-4 times as long as wide, contiguous for most of their length, 1/6 in length. Some disc plates bearing stout table-shaped stumps with a cylindrical pedicel and an expanded flat-topped to slightly convex, circular to polygonal apex, with a granular surface, 0.2-0.25 mm high and wide. Ventral interradial surface covered in smaller plates with small conical to cylindrical stumps. Oral shields pentagonal, the distal edge truncate or slightly notched in the centre, forming 3 sides, the proximal edge with an obtuse angle, and the lateral angles acute, two times as wide as long. Adoral shields as large or larger than the orals, 2 times as wide as long, contiguous interradially but widely separated radially by the first ventral arm plate, lying proximal to the oral shield and not separating the oral shield from the lateral arm plates, roughly trapezoid with a narrower distal than proximal edge, the proximal edge can be slightly concave, beaded surface. Jaw as wide as long, bearing 1 large clavate apical and 3 smaller conical to leaf-shaped oral papillae, inner ones pointed, outer papillae slightly widened. First dorsal arm plate short and wide, adjoining disc, succeeding plates fan-shaped, slightly wider than long, with an obtuse proximal angle, straight proximolateral sides and a convex distal margin, just separated by the lateral arm plates. First ventral arm plate roughly trapezoid, with a short distal edge, diverging lateral sides, and a truncate to convex proximal edge, longer than wide, just contiguous with the second plate. Second and third plates as wide as long, with a right angle proximally, straight proximolateral sides, slightly concave around the pore, and a convex distal edge, narrowly separate or just contiguous. Succeeding plates longer, with an almost hemispherical distal edge that is slightly uplifted from the underlying lateral plates, some plates with a slightly produced centre to the distal edge, others quite concave on each side

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around the pore. Lateral arm plates meet dorsally and ventrally, with a low flange bearing the arm spines, ridges separated from each other by their own width. Up to 8 arm spines basally, thereafter 5, uppermost almost cylindrical with a blunt point, 1-1.5 segments in length basally, without notable thorns; lower spines slightly flattened, spatulate, no more than one segment in length, terminally spiniferous, distally lowest spine with some ventrally-directed thorns but not true hooks. A single tentacle scale over each pore, oval or slightly enlarged and roughened distally, twice as long as wide, 1/3 as long as the ventral arm segment. Colour (dry) pinkish-white. (Paratype variations). Disc often pentagonal, some specimens (CHALCAL DW 73) with large radial shields to 1/5 disc diameter, others with radial shields that are completely separate, disc stumps range from 0.15-0.3 mm diameter, oral shields are sometimes produced distally, as wide as long, uppermost arm spines can be up to 3 segments in length, and occasionally 2 tentacle scales on basal pores, tentacle scale can be rounded, only just longer than wide. Several animals were found clinging epizoically to a cnidarian. DISTRIBUTION. — New Caledonia (300-860 m). REMARKS. — This new species is similar to a group of epizoic Ophiomitrella species with large robust disc stumps, sometimes placed in the genus Ophioripa Koehler, 1922a. Within this group, it is distinguished by the long parallel contiguous radial shields and the flat-topped disc stumps. ETYMOLOGY. — Mensa (Latin, feminine) = table, in reference to the flat-topped disc spines.

Ophiomitrella parviglobosa n. sp. Figs 10A-E, 18L TYPE MATERIAL. — Holotype: MNHN EcOs 22443. Paratypes: MNHN EcOs 22803, 22442. TYPE LOCALITY. — New Caledonia, 24°55.44’S, 168°21.55’E, 500-510 m. MATERIAL EXAMINED. — New Caledonia. BIOCAL: stn CP 67, Ride de Norfolk, 24°55.44’S, 168°21.55’E, 500-510 m, 03.09.1985, holotype: 1 (MNHN EcOs 22443); paratypes: 6

(MNHN EcOs 22803). — SMIB4: stn DW 39, 24°56.2’S, 168°21.5’E, 525-560 m, 07.03.1989, paratype: 1 (MNHN EcOs 22442).

DESCRIPTION. — (Holotype). Disc 4.0 mm d.d., arms broken, remaining pieces 3 times d.d. in length, not moniliform. Disc covered in large imbricating plates, 0.4-0.5 mm wide, seven plates from the centre of the disc to the margin; radial shields triangular to circular, 1/9 times d.d, separated by 1-2 disc plates. Disc plates bearing 1-8 spherical granules, 0.12-0.16 mm in diameter, scattered all over the disc and around the distal ends of the radial shields. Slightly smaller plates and spines on the small ventral disc surface. Oral shields triangular to rhombic, 2 times as wide as long, with an obtuse proximal angle and a distal edge that is rounded or with an obtuse angle or lobe in the centre. Adoral shields 2 times as wide as long, meeting interradially, not separating the oral shields from the first lateral arm plate. Jaw as wide as long, bearing 1 large apical and 4 smaller oral papillae on each side. Inner oral papilla pointed, middle 2 papillae squarish or with a rounded tip, outer papilla small, sometimes adpressed. First dorsal arm plate wide and short, succeeding plates fan- to bell-shaped, slightly wider than long, almost as wide as the arm, with an acute proximal angle, straight to slightly concave proximolateral sides, and a convex distal edge, not contiguous. First ventral arm plate rectangular, 1.5 times as long as wide. Second plate contiguous with the first, slightly wider than long, broadly triangular with a small straight proximal margin, straight proximolateral sides and a convex to

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FIG. 12. A-E, Ophiocamax vitrea MNHN EcOs 22384; A, dorsal aspect; B, ventral aspect; C, disc spines; D, spiny ventral arm plates and tentacle scales with opening for tube foot; E, arm spine; F-J, Ophiocamax nominata MNHN EcOs 22373; F, dorsal aspect; G, ventral arm plates and multiple tentacle scales; H, ventral aspect; I, spiny dorsal arm plates; J, disc spines; K-N, Ophiocopa spatula MNHN EcOs 22400; K, dorsal aspect; L, ventral aspect; M, arm spine and spine articulations; N, disc granules. SEM images, scale bars in mm. FIG. 12. A-E, Ophiocamax vitrea MNHN EcOs 22384 ; A, vue dorsale ; B, vue ventrale ; C, épines discales ; D, plaques ventrales des bras spinuleuses et écailles des tentacules avec une ouverture pour le tube pédieux ; E, épines des bras ; F-J, Ophiocamax nominata MNHN EcOs 22373 ; F, vue dorsale ; G, plaques ventrales des bras et multiples écailles des tentacules ; H, vue ventrale ; I, plaques dorsales épineuses des bras ; J, épines discales ; K-N, Ophiocopa spatula MNHN EcOs 22400 ; K, vue dorsale ; L, vue ventrale ; M, épines des bras et articulations des épines ; N, granules discaux. Images MEB, échelles en mm.

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slightly-lobed distal margin. Succeeding plates almost 2 times as wide as long, just separated from neighbouring plates, broadly triangular with an obtuse proximal angle, straight to slightly concave proximolateral sides and a slightly convex distal edge. Lateral arm plates almost meeting above and below the arm. Five, basally 6 arm spines, short, stout, with a slightly enlarged base and rounded tip, minute thorns scattered around the upper 2/3 of the spine, uppermost spines longest, as long as a segment, lowest spines slightly shorter, thinner, distally more thorny but not hook-shaped. Tentacle scale single, oval, 2 times as long as wide and 1/2 the length of the ventral arm plate, completely covering the small pore. Colour (dry) white. (Paratypes variations). The largest paratype (MNHN EcOs 22442) 4.5. mm d.d., with long robust arms, 5 times d.d. in length. This specimen differs from the holotype in having smaller, more widely spaced, radial shields, 1/11 d.d.; bell-shaped dorsal arm plates with a rounded proximal edge and concave proximolateral sides; and ventral arm plates that are just contiguous for the first 4 segments. Other specimens have only 3 rather than 4 oral papillae. DISTRIBUTION. — New Caledonia (500-560 m). REMARKS. — This species is closely related to species placed by Koehler (1922a and 1922b) in the genus Ophioripa: O. nugator, O. marginata and O. conferta, as well as O. mensa n. sp. It shares with these species the large disc plates, large radial shields, stout arms and robust minutely-thorned arm spines and disc stumps. It differs from those species most clearly in having relatively small spherical disc granules and wide, broadly triangular, ventral arm plates. The spherical disc granules are reminiscent of O. ingrata Koehler, 1908 from the South Atlantic. But that species has slightly smaller granules (0.12-0.14 mm), narrow ventral arm plates and contiguous radial shields. O. globifera (Koehler, 1896) from the eastern Atlantic has small circular disc granules and relatively wide ventral arm plates. However, the granules differ in being conical rather than spherical, the ventral arm plates are pentagonal rather than triangular, and the arm spines are longer, up to two segments in length (Paterson 1985). ‘‘Ophiophthalmus’’ cataleimmoida (H.L. Clark, 1911) has several granules per disc plate and rounded to triangular radial shields, however, it also has longer arm spines (3 segments in length) and smaller disc granules. Many other species of Ophiomitrella are viviparous. The type material is dry and has not been dissected. ETYMOLOGY. — Parva (Latin, feminine) = small and globosa (Latin, feminine) = spherical, in reference to the shape of the disc spines.

Ophiomitrella polyacantha (H.L. Clark, 1911) Fig. 10N-Q Ophiomitra polyacantha Clark, H.L., 1911: 187-188, fig. 86. Ophiomitrella polyacantha ¢ Matsumoto 1917: 106.

TYPE MATERIAL. — Holotype: USNM 25631. Paratypes: USNM 25631, MCZ 3233. TYPE LOCALITY. — Japan, Kyushu Is, Osumi Strait, Sata Misaki, 188 m. MATERIAL EXAMINED. — Indonesia. MPE Kei Is: stn 63, 5°32’S, 132°36.4’E, 250 m, 16.05.1922, identified by Koehler (1930) as O. stellifera: 2 (ZMUC). Japan. Albatross: stn 4936, Kyushu Is, Osumi Strait, Sata Misaki, 30°54.7’N, 130°37.5’E, 188 m, 16.08.1906, holotype: 1 (USNM 25631). New Caledonia. BIOCAL: stn DW 37, Ride de Norfolk, 22°59.99’S, 167°15.65’E, 350 m, 30.08.1985: 1 (MNHN EcOs

22441). — BIOCAL: stn CP 105, Bassin des Loyauté, 21°30.71’S, 166°21.72’E, 330-335 m, 08.09.1985: 3 (MNHN EcOs 22440). — MUSORSTOM 6: stn DW 391, Ride des Loyauté, 20°47.35’S, 167°5.7’E, 390 m, 13.02.1989: 15 (MNHN EcOs 22955). — MUSORSTOM 6: stn DW 393, Ride des Loyauté, 20°48.29’S, 167°9.54’E, 420 m, 13.02.1989: 4 (MNHN EcOs 22956). — MUSORSTOM 6: stn DW 398, Ride des Loyauté, 20°47.19’S, 167°5.65’E, 370 m, 13.02.1989: 2 (MNHN EcOs 22957).

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DESCRIPTION. — (New Caledonian material) Disc 4-6.5 mm d.d, arms at least 8 times d.d.; disc covered in circular imbricating plates bearing stellate stumps; stumps with a stout pedicel, terminating in 5-7 (usually 6) long blunt webbed thorns directed almost perpendicular to the pedicel, up to 0.2 mm high and wide, becoming smaller and less stellate marginally and ventrally; radial shields large, triangular to oblong, longer than wide, separate, 1/6 d.d. in length, free of spines. Oral shields as wide as long, broadly rhomboid, with an acute proximal and rounded to lobed distal angle; adoral shields short and thick, not extending around the oral shield, jaw as wide as long, oral plates slightly tumid near the apex, with 5-7 oral papillae, 1-2 in the apical position, inner papillae spiniform, outer two slightly larger and more rounded. Dorsal arm plates small rhombic, as wide as long, with a curved or pointed distal apex, widely separate; ventral arm plates wider than long, just contiguous basally then separate, with a rounded distal margin and an obtuse proximal angle; up to 11 arm spines basally, where they meet dorsally, dorsal spines longest, up to 6 segments in length, smooth, solid, middle spines sparsely thorny, ventral spines short, thin and relatively smooth; 1 tentacle scale (very rarely 2 on a basal pore), almost as long as a ventral arm plate, basal scales wide and oval, distal scales attenuate and pointed, with a thorny tip. DISTRIBUTION. — Japan (188 m), Indonesia (250 m), New Caledonia (330-420 m). REMARKS. — This species can be distinguished from the closely related O. stellifera by the stellate disc stumps with a ring of long webbed thorns lying almost perpendicular to the pedicel, the large radial shields, large tentacle scale, almost contiguous basal ventral arm plates, and the presence of five or more oral papillae. These are the first records since the type description, and include two specimens from Indonesia misidentified by Koehler (1930) as O. stellifera.

Ophiomitrella stellifera Matsumoto, 1917 Fig. 11E-G Ophiomitrella stellifera Matsumoto, 1917: 103-105, fig. 27. Ophiomitrella stellifera ¢ Koehler 1930: 71-72. — Murakami 1942: 2. — Irimura 1982: 24-25, fig. 14, pl. 6 (4).

TYPE MATERIAL. — Syntypes: ?CSITU(3) (not seen). TYPE LOCALITY. — Japan, Izu, Inatori. MATERIAL EXAMINED. — Indonesia. MPE Kei Is: stn 56, 5°30.3’S, 132°51’E, 345 m, 10.05.1922, identified by Koehler (1930): 1 (ZMUC). — MPE Kei Is: stn 59, 5°28’S, 132°36’E, 385 m, 12.05.1922, identified by Koehler (1930): 3 (ZMUC). — MPE Kei Is: stn 63, 5°32’S, 132°36.4’E, 250 m, 16.05.1922, identified by Koehler (1930): 1 (ZMUC). — MPE Kei Is: stn 67, Java Sea, Sunda Strait, 5°48’S, 106°12’E, 38 m, 27.07.1922, identified by Koehler (1930): 1 (ZMUC).

New Caledonia. BIOCAL: stn DW 46, Ride de Norfolk, 22°53.05’S, 167°17.08’E, 570-610 m, 30.08.1985: 1 (MNHN EcOs 22444). — MUSORSTOM 6: stn DW 410, Ride des Loyauté, 20°38.05’S, 167°6.65’E, 490 m, 15.02.1989: 1 (MNHN EcOs 22959).

OTHER MATERIAL EXAMINED. — Ophiomitrella barbara Koehler, 1904: Siboga: stn 254, Indonesia, Kapulauan Kai (Kei Islands), 5°40’S, 132°26’E, 310 m, 10.12.1899, holotype: 1 (ZMA E2419). Ophiomitrella mutata Koehler, 1904: Siboga: stn 251, Indonesia, Kapulauan Kai (Kei Islands), 5°28.4’S, 132°0.2’E, 204 m,

08.12.1899, syntype: 1 (ZMA E2422). — Siboga: stn 253, Indonesia, Kapulauan Kai (Kei Islands), 5°48.2’S, 132°13’E, 304 m, 10.12.1899, syntypes: 2 (ZMA E2423). Ophiomitrella sagittata Koehler, 1922a: MPE Kei Is: stn 8, Indonesia, 5°39’S, 132°26’E, 300 m, 05.04.1922, identified by Koehler (1930): 1 (ZMUC).

DESCRIPTION. — (New Caledonian specimen) Disc 3.3-5.5 mm d.d., arms broken but at least 4 times the d.d. in length; disc covered in small circular plates, many bearing a single thorny spine, spines stellate with a columnar pedicel and typically 6 divergent pointed terminal thorns formed by a bifurcation of three primary thorns (sometimes the three primary thorns can have more than 2 terminal thorns), up to 0.15 mm high, only a few small spines present ventrally; radial

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shields small, as wide as to wider than long, widely separate, approximately 1/10 d.d. in length, mostly naked or bearing a few disc spines. Oral shields wider than long, with a pointed proximal angle, concave proximolateral sides, rounded lateral angles and a slightly convex distal margin; adoral shields short and wide, not extending around oral shields, jaw as wide as long, bearing 1 large apical and 4 smaller oral papillae, the outermost a little larger than the rest. Dorsal arm plates small, triangular, widely separate; ventral arm plates wider than long, with a relatively straight distal edge and obtuse proximal angle, separate; up to 7 arm spines, hollow, uppermost spine longest, up to 2.5 segments in length, relatively smooth, lower spines thorny, tip with recurved terminal thorns, hook-like distally; 1 small conical tentacle scale, 2/3 the length of the ventral arm plate. Colour (dry) white. DISTRIBUTION. — Japan (200-700 m), Indonesia (38-385 m), New Caledonia (490-610 m). REMARKS. — This species can be distinguished from the sympatric O. polyacantha by subtle differences in the disc spines, which terminate in 6 divergent thorns formed from the bifurcation of 3 primary rays, the small radial shields, separate ventral arm plates with relatively small tentacle scales, and the shorter arm spines. One specimen (MNHN EcOs 22959) was epizoic on a worm tube. There are several other Indo-Pacific Ophiomitrella species that bear some resemblance to O. stellifera. Ophiomitrella subjecta Koehler, 1922a also has small radial shields, disc spines with three main terminal branches and thorny tips, short arm spines, four oral papillae, and oral shields with an elongate pointed proximal angle and concave proximolateral sides. However, the disc spines are much stouter than on O. stellifera, the terminal branches are widened and end in several irregular thorns (see Koehler 1922a, pl. 94(4)); some disc spines are almost capitate. Ophiomitrella mutata Koehler, 1904 (Fig. 18R) and O. sagittata Koehler, 1922a are similar to O. subjecta except they have fewer, smaller thorns on the trilobed disc spines. They differ from each other in trivial ways and are probably synonymous. The disc spines of O. barbara Koehler, 1904 (Fig. 18P) are similar to O. subjecta, however, the unique type specimen has very short attenuated arms, barely 2 times d.d., that coil near the tip, and the oral shields are almost rhomboid in shape, the proximo-lateral sides are almost straight. The radial shields in all these species are very small and the visible portion may only represent the dorsal tip of larger ossicles, in which case they should be referred to Ophiacantha (see Paterson 1985). As with many other Indo-Pacific ophiacanthids, more specimens are required to resolve these relationships.

Ophiomitrella tenuis (Koehler, 1904) Figs 11A-D, 18S Ophiacantha tenuis Koehler, 1904: 102-103, pl. 16(5-7). Ophiomitrella tenuis ¢ Koehler 1930: 72. Ophiomitrella ikedai Murakami, 1944: 249-250, fig. 12 [new synonymy].

TYPE MATERIAL. — Syntypes: ZMA E2262(16), MNHN EcOs 20408(1), MCZ 3513(3). TYPE LOCALITY. — Indonesia, Kei Is, 304 m. MATERIAL EXAMINED. — Indonesia. MPE Kei Is: stn 45, 5°48.5’S, 132°14’E, 270 m, 01.05.1922, identified by Koehler (1930): 4 (ZMUC). — Siboga: stn 253, Kapulauan Kai (Kei Islands), 5°48.2’S, 132°13’E, 304 m, 10.12.1899, syntype: 1 (MNHN EcOs 20408); syntypes: 16 (ZMA E2262). New Caledonia. BIOCAL: stn DW 37, Ride de Norfolk, 22°59.99’S, 167°15.65’E, 350 m, 30.08.1985: 4 (MNHN EcOs

22451). — CHALCAL 2: stn DW 82, Ride de Norfolk, 23°13.68’S, 168°4.27’E, 304 m, 31.10.1986: 1 (MNHN EcOs 22449). — MUSORSTOM 5: stn DW 338, 19°51.6’S, 158°40.4’E, 540-580 m, 15.10.1986: 8 (MNHN EcOs 22450). — MUSORSTOM 6: stn DW 478, Ride des Loyauté, 21°8.96’S, 167°54.28’E, 400 m, 22.02.1989: 3 (MNHN EcOs 22951).

OTHER MATERIAL EXAMINED. — Ophiomitrella suspectus (Koehler, 1922a): Albatross expedition, Philippines, unknown locality and date, holotype: 1 (USNM 41164).

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DESCRIPTION. — (New Caledonian material). Disc 4-5.5. mm d.d., arms almost 7 times d.d., curved but not coiled at the tip. Disc pentagonal, disc plates can be obscured by thin skin over much of the disc, bearing small spherical to cylindrical granules, typically 0.15 mm high, smaller near margin, minutely thorny; radial shields triangular to pentagonal, with a pointed proximal angle and flat to concave distal margin, separate, up to 1/8 d.d. in length, free of granules. Ventrolateral surface of disc often contracted, mostly naked, without plates or granules except some small plates near the oral shields, sharply demarcated from the dorsal disc surface. Oral shields wider than long, rhomboid or with a rounded distal margin; adoral shields long and narrow but not separating oral shield from the arm plates, jaw shape variable, from wider than long to longer than wide, bearing 1 apical and 3, rarely 4, oral papillae, inner papillae long and spiniform, outer papillae slightly widened with a round tip, occasionally a supplemental small distal papilla on the adoral shields. Dorsal arm plates fan-shaped with a convex distal margin, separate; thin lateral plates with naked area between segments; ventral arm plates wider than long, with a raised convex distal margin and an obtuse proximal angle, striated near margin; up to 10 arm spines basally, meeting dorsally, uppermost 5 segments in length, microscopically roughened, sometimes lower spines with some thorns near base; 1 tentacle scale, oval, of variable size ranging from 1/2 to as long as the ventral arm plate, rarely two on basal pores. Colour (dry) white with a few spots of dark or light brown on dorsal disc and arm surfaces, naked ventral disc surface brown, arms can be banded. DISTRIBUTION. — Ryukyu Is, Indonesia (270-304 m), New Caledonia (255-580 m). REMARKS. — There is some variation in the size of the radial shields and tentacle scales within the current material, including within the type specimens of O. tenuis: the radial shields vary in length from 1/8 to 1/12 the diameter of the disc, and the tentacle scales vary from 1/2 to the length of the ventral arm plate, ranging from spiniform to oval in shape. The skin on the disc can vary in thickness, sometimes obscuring the underlying plates. These differences are not consistent across specimens and are considered to represent intraspecific variation. Ophiomitrella ikedai Murakami, 1944 from Japan appears from the description and figures to be synonymous with O. tenuis. The tentacle scales appear slightly smaller than the New Caledonian material but that may be an artefact of the illustrations. Other characters are identical, most notably the restricted ventral disc surface, arm plates, arm spines, disc plates, disc granules and jaw. Murakami’s type specimens are presumed lost (S. Irimura pers comm). Ophiomitrella granulosa is also very similar, but differs in having a rounded edge to the dorsal disc surface and a fully plated ventral disc surface that usually also bears some granules. The holotype of ‘‘Ophiophthalmus’’ suspectus Koehler, 1922a is also very similar to O. tenuis. It differs in having larger quadrangular radial shields that are parallel and contiguous for almost all their length. The specimen however, is in poor condition and the shape and position of the radial shields may be an artefact of preservation, with the shields of each pair pressed together and the skin removed. In this case O. suspectus is likely to be a synonym of O. tenuis. The only other specimens referred to O. suspectus are by McKnight (1975, 1993) from the Tasman Sea, who gives no details about his animals.

Genus OPHIOMITRA Lyman, 1869 Type species: Ophiomitra valida Lyman, 1869 (designated by Verrill, 1899a).

Ophiomitra leucorhabdota (H.L. Clark, 1911) Fig. 11H-K Ophiacantha leucorhabdota Clark, H.L., 1911: 221-222, fig. 102. Ophiophthalmus leucorhabdota ¢ Matsumoto 1917: 109.

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Ophiomitra leucorhabdota ¢ Koehler 1922a: 123. Ophiomitrella lineata Koehler, 1930: 76-78, pl. 7 (6-8) [new synonymy]. Ophiophthalmus honestus Koehler, 1930: 80-83, pl. 8 (1-3) [new synonymy]. Ophiophtalmus honestus ¢ Guille 1981: 424, pl. 1 (8-9).

TYPE MATERIAL. — Holotype: USNM 25655. TYPE LOCALITY. — Japan, Kyushu Island, Osumi Strait, Sata Misaki, 188-278 m. MATERIAL EXAMINED. — Indonesia. Siboga: stn 253, Kapulauan Kai (Kei Islands), 5°48.2’S, 132°13’E, 304 m, 10.12.1899: 1 (ZMA). — MPE Kei Is: stn 46, 5°47.3’S, 132°13’E, 300 m, 02.05.1922, holotype of O. lineata: 1 (MNHN EcOs 20365); syntypes of O. honestus: 2 (ZMUC). — MPE Kei Is: stn 59, 5°28’S, 132°36’E, 385 m, 12.05.1922, syntype of O. honestus: 1 (ZMUC). Japan. Albatross: stn 4934, Kyushu Island, Osumi Strait, Sata Misaki, 30°58.5’N, 130°32’E, 188-278 m, 16.08.1906, holotype: 1 (USNM 25655). New Caledonia. BIOCAL: stn DW 37, Ride de Norfolk, 22°59.99’S, 167°15.65’E, 350 m, 30.08.1985: 12 (MNHN EcOs 22435). — CHALCAL 2: stn DW 82, Ride de Norfolk, 23°13.68’S, 168°4.27’E, 304 m, 31.10.1986: 1 (MNHN EcOs 22431). — MUSORSTOM 5: stn DW 305, 22°9.27’S, 159°24.42’E, 430-440 m, 12.10.1986: 1 (MNHN EcOs 22433). — MUSORSTOM 5: stn CP 332, 20°17.44’S, 158°48.86’E, 400 m, 15.10.1986: 2 (MNHN EcOs 22434). — MUSORSTOM 6: stn DW 391, Ride des Loyauté,

20°47.35’S, 167°5.7’E, 390 m, 13.02.1989: 2 (MNHN EcOs 22937). — MUSORSTOM 6: stn DW 398, Ride des Loyauté, 20°47.19’S, 167°5.65’E, 370 m, 13.02.1989: 1 (MNHN EcOs 22938). — MUSORSTOM 6: stn DW 406, Ride des Loyauté, 20°40.6’S, 167°6.8’E, 373 m, 15.02.1989: 8 (MNHN EcOs 22939). — MUSORSTOM 6: stn CP 408, Ride des Loyauté, 20°41.1’S, 167°7.45’E, 380 m, 15.02.1989: 1 (MNHN EcOs 22940). — MUSORSTOM 6: stn DW 478, Ride des Loyauté, 21°8.96’S, 167°54.28’E, 400 m, 22.02.1989: 1 (MNHN EcOs 22941). — MUSORSTOM 6: stn DW 482, Ride des Loyauté, 21°21.5’S, 167°46.8’E, 375 m, 23.02.1989: 1 (MNHN EcOs 22942). — SMIB4: stn DW 69, 22°55.8’S, 167°14.3’E, 395-405 m, 10.03.1989: 1 (MNHN EcOs 22432). Philippines. MUSORSTOM 1: stn CP 32, NE of Lubang Island, 14°2’N, 120°18’E, 184-193 m, 23.03.1976, identified by Guille (1981) as Ophiophtalmus honestus: 2 (MNHN EcOs 20374).

OTHER MATERIAL EXAMINED. — Ophiomitra dives Koehler, 1922a: USNM: stn 5543, Philippines, Tagolo Light, 8°47.25’N, 123°35’E, 296 m, 20.08.1909, holotype: 1 (USNM Eo1042). — GBRE: stn 15, NE Australia, Cooks Passage, 0.5 mi outside, 14°32’S, 145°34’E, 390 m, 07.03.1929, identified by Clark, H.L.

(1932): 1 (BMNH 1932.4.28.66). Ophiomitra integra Koehler, 1897: Investigator: stn 56, Indian Ocean, Between North and South Sentinel Island, Andaman Islands, 12°’N, 92°’E, 409-446 m, 24.04.1889, holotype: 1 (ZSI 5172/7).

DESCRIPTION. — (New Caledonian material) Disc 5 to 15 mm d.d., covered in disc stumps that obscure the underlying plates, stumps 0.15-0.25 mm high, stumps in centre of disc cylindrical with 6-8 small terminal thorns, marginal stumps conical with rough tip, continue around radial shields and onto the ventral disc surface to the oral shields. Radial shields large, 1/5 d.d., broadly triangular with rounded angles, separate or just contiguous distally. Oral shields variable, ranging from rhombic with an acute distal angle to wider than long with a rounded or lobed distal angle; adoral shields long but not extending around the oral shield; 1-3 small spiniform papillae at the jaw apex and 4-5 on each jaw side, outer papillae rounded and widened. Dorsal arm plates broadly in contact, with a strongly convex distal margin and acute lateral angles, wider than long on large animals; ventral arm plates just in contact or narrowly separate, wider than long, with a convex distal and slightly concave proximal margin; up to 8 arm spines basally, uppermost 5 segments in length, smooth, cylindrical, solid, pointed, lowermost spines slightly flattened, distally becoming serrated or hook-like; tentacle scales large oval-shaped or truncate, as long as the ventral arm plate, 2-3 on basal pores thereafter one. Colour (dry): disc brown with white markings on the radial shields and white disc granules, a darker stripe between the radial shields, arms brown with a broad white longitudinal line distally, arm spines white. DISTRIBUTION. — Indonesia (50-385 m), Japan (188-278 m), Lord Howe Ridge (419-425 m), New Caledonia (304-440 m), Philippines (183-193 m). REMARKS. — This species is immediately recognisable from the porcelain-like appearance and distinctive colour pattern. The white longitudinal stripe along the arms is distinctive even in bleached specimens. Koehler (1930) did not compare

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either O. honestus or O. lineata with O. leucorhabdota, placing these species in two different genera. The description of O. honestus states that there is only one papilla in the apical position of the jaw, however, as Koehler’s own photograph indicates (pl. 8, Fig. 3), there can be one or two depending on the jaw. The unique holotype of O. lineata, although small (5 mm d.d.), already has five oral papillae with one or two in the apical position. On both species the distinctive colour pattern of O. leucorhabdota is clearly evident, particularly the broad longitudinal white stripe along the arms. Juvenile specimens differ somewhat having elongated dorsal arm plates and the disc spines appear relatively large compared to the size of the disc. The holotype of O. lineata was found at the same station (Kei Is stn 46) as syntypes of O. honestus. The placement of specimens of O. leucorhabdota in four different genera, emphasises the ill-defined nature of many genera in the Ophioplinthacinae as noted by Paterson (1985). This species is retained in Ophiomitra as suggested by Koehler (1922a) on the basis that it has several apical oral papillae. However, it is far from clear that Ophiomitra is a monophyletic taxon. Another species referable to Ophiomitra in the Indo-Pacific is O. dives Koehler, 1922a known from the Philippines and off the Great Barrier Reef (H.L. Clark 1932). This species shares the porcelain-like nature of the plates, but differs in having much larger adoral shields, separate dorsal arm plates, larger spherical to capitate disc granules (0.5 mm diameter) and a single longitudinal black stripe along the dorsal arm surface. Ophiomitra integra Koehler, 1897 from the Andaman Islands was transferred by H.L. Clark (1915) to Ophioplinthaca without comment. However, Koehler’s description and figures do not show the interradial disc incisions characteristic of that genus and, although the figures are very diagrammatic, it appears to be similar to O. leucorhabdota. Unfortunately, the holotype and only known specimen of this species has almost completely disintegrated. Koehler does not mention the colour of his animal, and its status remains in doubt until more material from the Bay of Bengal is obtained. Juvenile specimens of O. leucorhabdota have relatively long thorns on the disc stumps and approach those on Ophiomitrella polyacantha in shape. Ophiomitrella polyacantha can be distinguished by the larger serrated arm spines and separate dorsal arm plates.

Genus OPHIOTHAMNUS Lyman, 1869 Type species: Ophiothamnus vicarius Lyman, 1869.

Ophiothamnus biocal n. sp. Fig. 13A-E TYPE MATERIAL. — Holotype: MNHN EcOs 22483. Paratypes: MNHN EcOs 22480, 22482(3), 22815(4), 22805(200), 22481(10). TYPE LOCALITY. — New Caledonia, 22°53.05’S, 167°17.08’E, 570-610 m. MATERIAL EXAMINED. — New Caledonia. BIOCAL: stn DW 46, Ride de Norfolk, 22°53.05’S, 167°17.08’E, 570-610 m, 30.08.1985, holotype: 1 (MNHN EcOs 22483). — BIOCAL: stn DW 33, Ride de Norfolk, 23°9.71’S, 167°10.27’E, 675 m, 29.08.1985, paratype: 1 (MNHN EcOs 22480). — BIOCAL: stn DW 44, Ride de Norfolk, 22°47.3’S, 167°14.3’E, 440-450 m,

30.08.1985, paratypes: 3 (MNHN EcOs 22482). — BIOCAL: stn DW 46, Ride de Norfolk, 22°53.05’S, 167°17.08’E, 570-610 m, 30.08.1985, paratypes on SEM stub: 4 (MNHN EcOs 22815); paratypes: 200 (MNHN EcOs 22805). — BIOCAL: stn DW 51, Ride de Norfolk, 23°5.27’S, 167°44.95’E, 680-700 m, 31.08.1985, paratypes: 10 (MNHN EcOs 22481).

OTHER MATERIAL EXAMINED. — Ophiothamnus affinis Ljungman, 1872: Princess Alice: stn 806, off Madeira Is, 1473 m, syntypes of Ophioplinthaca occlusa: 2 (MNHN EcOs 20385). — Josephine expedition, 38°10’N, 9°25’W, 1438 m, holotype: 1 (SMNH Type1450). Ophiothamnus otho A.H. Clark, 1949: Albatross: stn 4096,

Hawaii, Maui Is, Pailolo Channel, Nakalele Point, 21°9.5’N, 56°5’W, 497-523 m, 22.07.1902, holotype: 1 (USNM E6898). Ophiothamnus vicarius Lyman, 1869: Gulf Stream expedition, 608 m: 1 (SMNH Utl. Oph 135). — Pourtales expedition, syntypes: 2 (MNHN EcOs 345).

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FIG. 13. A-E, Ophiothamnus biocal n. sp. holotype MNHN EcOs 22483; A, dorsal aspect; B, dorsal arm; C, ventral aspect; D, ventral arm; E, arm spine articulation; F-I, Ophiurothamnus eleaumei n. sp. holotype MNHN EcOs 22512; F, dorsal aspect; G, disc spine; H, ventral aspect; I, ventral disc plates. SEM images except F, H, I, scale bars in mm. FIG. 13. A-E, Ophiothamnus biocal n. sp. holotype MNHN EcOs 22483 ; A, vue dorsale ; B, vue dorsale des bras ; C, vue ventrale ; D, vue ventrale des bras ; E, articulation des épines des bras ; F-I, Ophiurothamnus eleaumei n. sp. holotype MNHN EcOs 22512 ; F, vue dorsale ; G, épine discale ; H, vue ventrale ; I, plaques discales ventrales. Images MEB sauf F, H, I, échelles en mm.

DESCRIPTION. — (Holotype). Disc 1.7 mm d.d., strongly lobed radially, interradius deeply incised, radial lobes dominated by the pair of large radial shields, 1/3 d.d. long, contiguous over much of their length, which extend onto the lateral disc surface; disc plates restricted to some circular overlapping plates in the disc centre and 3-4 rows of small imbricating plates forming the ventral surface of the disc. Central disc plates bearing long sharp spines, up to 0.4 mm long. Oral plates rounded triangular, much smaller than adoral shields. Adoral shields large, extending beyond and around the oral shield, meeting interradially, but separated radially by the first ventral arm plate. One papilla on jaw apex, much larger than the inner lateral oral papillae, with a bluntly rounded tip; 1-4 small rounded inner oral papillae, outer papilla operculiform, twice as wide as high, closing the distal oral slit. Arms 13 times d.d., strongly moniliform, dorsal arm plates

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triangular with a straight or slightly convex distal margin, widely separate. First ventral arm plate pentagonal, slightly longer than wide, with sides adjoining the lateral arm plates, adoral shields and distal oral papillae. Succeeding plates wider than long basally, distal margin slightly raised, concave in the centre, widely separate. Up to 9 arm spines basally, which meet dorsally on the first 4 segments, uppermost spine longest, 4 segments in length, slender, smooth or with some tiny thorns near the tip, hollow. One spiniform tentacle scale, 3/4 the length of the ventral arm plate. Colour (dry) white. (Paratypes) — Many specimens are missing the disc which is evidently easily lost. One paratype possibly regenerating the disc, differs by having a circular disc, with no interradial incisions, covered in small plates; the radial shields are small and contiguous, up to 1/6 d.d. Other paratypes have a notched (heart-shaped) papilla at the apex of each jaw. Oral shield shape can vary from diamond-shaped, to rounded triangular or droplet-shaped. Some specimens have smaller disc spines on the interradial plates. DISTRIBUTION. — New Caledonia (440-700 m). REMARKS. — Although the species assigned to Ophiothamnus form a distinct group, the limits of the species are unclear. The main characters used to distinguish the species include the shape and size of the oral shields, radial shields, disc plates and spines. However, these characters vary considerably in the present material, and in samples of the South African species, O. remotus Lyman, 1878a (see Mortensen 1933b). Moreover, the disc is easily lost, and animals with regenerating discs appear very different, with less incised interradii, smaller disc plates and radial shields (Mortensen 1933b). Yet the depth of the interradial incision is one of the characters separating the two Atlantic species, O. affinis (Ljungman, 1872) and O. vicarius Lyman, 1869 (see Paterson 1985: 73). Nevertheless, the New Caledonian material does not fit comfortably in any of the previously known species. It is perhaps closest to O. affinis, which is also strongly lobed with relatively long disc spines, but this species has numerous small disc plates. The type species O. vicarius is possibly synonymous with O. affinis except that it has more numerous arm spines (up to 12 basally) and a less constricted disc. The type description of O. venustus from Japan (3 mm d.d.) indicates that it is not as strongly lobed, has many more disc plates with smaller spines and longer tentacle scales. Koehler’s (1922a) 2.5 mm d.d. specimen of O. venustus from the Philippines appears, from the published photographs, to differ slightly in having denticulate arm spines. Ophiothamnus habrotata (H.L. Clark, 1911) also from Japan has both long and short disc spines. Ophiothamnus otho A.H. Clark, 1949 from Hawaii has a circular disc, divergent radial shields, small disc plates and spines, a tiny oral shield and deeply notched ventral arm plates. Ophiothamnus longibrachius H.L. Clark, 1939 from 1046 m off the Maldives is known from only one imperfect specimen that lacks the dorsal disc. The oral structure is typical. However, it does have relatively long arms (20 times d.d.). Some specimens of O. remotus are similar in many respects, although this species has much larger adoral shields. Lyman (1882: 286) doubtfully reported ‘‘young’’ specimens from Challenger stn 168 off the North Island of New Zealand in 2046 m. Given the geographic locality, these specimens could belong to the new species, but unfortunately we have not examined this material and Lyman supplied no morphological details. Ophiothamnus species frequently aggregate. Over 200 specimens were collected from one station at New Caledonia (BIOCAL DW 46), and similar numbers have been reported for O. remotus and O. affinis (Mortensen 1933b; Paterson 1985). ETYMOLOGY. — Named after the BIOCAL expedition that collected the material (noun in apposition).

Genus OPHIUROTHAMNUS Matsumoto, 1917 Ophiurothamnus Matsumoto, 1917: 129-130. Ophiurothamnus ¢ Koehler 1922a: 102-104. Ophiocyclus Clark, H.L., 1939: 41 [new synonymy].

Type species: Ophiomitra dicycla H.L. Clark, 1911.

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DIAGNOSIS. — Disc covered in coarse plates that are similar in size to the radial shields, no radial lobes to the disc, 1-2 large circular plates dominate each ventromarginal interradius of the disc. Some species with disc granules or spines. Arms inserted ventrolaterally so that the disc is raised wedge-like over their base. Arms short, moniliform, dorso-ventrally flexible and typically curved under the disc to grasp corals or sponges. Adoral shields short and thick, not separating the oral shield from the lateral arm plates. Dorsal arm plates small, widely separate; ventral arm plates short but wide, separate. Arm spines almost meeting above the arm basally, smooth or lower spines sometimes thorny, lowest arm spine can be hook-like. One tentacle scale, sometimes up to three on first segment. Epizoic. REMARKS. — The above diagnosis differs slightly from that of Matsumoto (1917) and Koehler (1922a) in order to incorporate the new material from New Caledonia (see below). The radial shields are not always contiguous for their whole length radially but may be separated by one to two plates, the disc is not always circular but may be slightly indented radially or interradially, and there can be more than one tentacle scale on basal pores. Nevertheless, the presence of large plates on the ventral disc interradii and the pie-shaped disc that rises above the arms are distinct synapomorphies for the genus. Examination of the type material of Ophiocyclus clausa (Lyman, 1878a), the type species of Ophiocyclus, indicates that it is a senior synonym of Ophiurothamnus stultus (Koehler, 1904) (see below). Consequently, Ophiocyclus becomes a junior synonym of Ophiurothamnus. Matsumoto (1917) established the genus Ophiurothamnus for ophiacanthid species that had previously been included in the genus Ophiothamnus which he restricted to species with large adoral shields that separate the oral shields from the lateral arm plates. Ophiocyclus was established for Ophiomoeris clausa by H.L. Clark (1939) to differentiate it from other species in the hemieuryalid genus Ophiomoeris that have lobed discs and small disc plates in the ventral interradii. Neither Lyman (1878a), Koehler (1904) nor Fell (1960) recognised O. clausa to be an ophiacanthid, Fell (1960) suggesting that it was the young of another hemieuryalid genus Amphigyptis Nielsen, 1932. This confusion has arisen from the similarity between epizoic species in the Hemieuryalidae and Ophiacanthidae. A revision of the Hemieuryalidae and Ophiacanthidae are beyond the scope of this work, however, it is clear that the two families are not clearly differentiated. The Hemieuryalidae is defined by the heavily armoured internal skeleton, the ability of the arms to coil ventrally, and the lack of articular pegs on the arm vertebrae (Matsumoto 1917; Fell 1960). However, these characters have only been examined in three species (Matsumoto 1917) and it is not clear to us whether the Hemieuryalidae are monophyletic or an artefact of convergent evolution resulting from the adoption of an epizoic habit.

Ophiurothamnus clausa (Lyman, 1878) Fig. 14A-I Ophioceramis (?) clausa Lyman, 1878a: 124, pl. 6 (161-163). Ophioceramis (?) clausa ¢ Lyman 1882: 26, pl. 11 (4-6). Ophiomoeris clausa ¢ Koehler 1904: 17. — Clark, H.L. 1915: 190. Ophiothamnus stultus Koehler, 1904: 141-142, pl. 25 (9, 10), 26 (1) [new synonymy]. Ophiurothamnus stultus ¢ Matsumoto 1917: 130. — Koehler 1922a: 104-105, pl. 22 (1-4). — McKnight 1975: 70; 1993: 187. Ophiocyclus clausa ¢ Clark, H.L. 1939: 41. Ophiurothamnus musortomae Guille, 1981: 427, fig. 1g-j, pl. 3 (20-21) [new synonymy].

TYPE MATERIAL. — Holotype: BMNH 1882.12.23.459. Paratype: MCZ 260. TYPE LOCALITY. — Kermadec Is, 1171 m. MATERIAL EXAMINED. — Indonesia. Siboga: stn 45, Flores Sea, south of Pelokang, 7°24’S, 118°15.2’E, 794 m, 06.04.1899, syn-

type of O. stultus: 1 (ZMA E2469). — Siboga: stn 178, Seram Sea, 2°40’S, 128°37.5’E, 835 m, 02.09.1899, syntypes of O. stultus: 2

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(ZMA E2470). — Siboga: stn 211, off southern Sulawesi, east of Salayar Island, 5°40.7’S, 120°45.5’E, 1158 m, 25.09.1899, syntypes of O. stultus: 2 (ZMA E2471). East Timor. Siboga: stn 284, south of Lore, 8°43.1’S, 127°16.7’E, 828 m, 18.01.1900, syntypes of O. stultus: 3 (ZMA E2472). New Caledonia. BIOCAL: stn CP 30, Ride de Norfolk, 23°9.65’S, 166°40.85’E, 1140 m, 29.08.1985: 1 (MNHN EcOs 22529). — BIOCAL: stn DW 33, Ride de Norfolk, 23°9.71’S, 167°10.27’E, 675 m, 29.08.1985: 1 (MNHN EcOs 22528). — BIOCAL: stn DW 46, Ride de Norfolk, 22°53.05’S, 167°17.08’E, 570-610 m, 30.08.1985: 5 (MNHN EcOs 22517). — BIOCAL: stn DW 51, Ride de Norfolk, 23°5.27’S, 167°44.95’E, 680-700 m, 31.08.1985: 18 (MNHN EcOs 22516). — BIOCAL: stn CP 52, Ride de Norfolk, 23°5.79’S, 167°46.54’E, 540-600 m, 31.08.1985: 1 (MNHN EcOs 22515). — BIOCAL: stn CP 54, Ride de Norfolk, 23°10.3’S, 167°42.98’E, 950-1000 m, 01.09.1985: 1 (MNHN EcOs 22521). — BIOCAL: stn CP 57, Ride de Norfolk, 23°43.3’S, 166°58.1’E, 1490-1620 m, 01.09.1985: 1 (MNHN EcOs 22525). — BIOCAL: stn CP 61, Ride de Norfolk, 24°11.7’S, 167°31.8’E, 1070 m, 02.09.1985: 8 (MNHN EcOs 22519). — BIOCAL: stn CP 62, Ride de Norfolk, 24°19.06’S, 167°48.65’E, 1395-1410 m, 02.09.1985: 1 (MNHN EcOs 22524). — BIOCAL: stn CP 69, Ride

de Norfolk, 23°51.38’S, 167°58.68’E, 1220-1225 m, 03.09.1985: 1 (MNHN EcOs 22514). — BIOCAL: stn DW 70, Ride de Norfolk, 23°24.7’S, 167°53.65’E, 965 m, 04.09.1985: 3 (MNHN EcOs 22523). — BIOCAL: stn CP 72, Ride de Norfolk, 22°9’S, 167°33.2’E, 2100-2110 m, 04.09.1985: 1 (MNHN EcOs 22526). — BIOCAL: stn CP 74, Ride de Norfolk, 22°14.06’S, 167°29.01’E, 1300-1475 m, 04.09.1985: 2 (MNHN EcOs 22513). — BIOCAL: stn CP 75, Ride de Norfolk, 22°18.65’S, 167°23.3’E, 825-860 m, 04.09.1985: 5 (MNHN EcOs 22518). — BIOCAL: stn DW 80, Bassin des Loyauté, 20°31.69’S, 166°48.35’E, 900-980 m, 05.09.1985: 1 (MNHN EcOs 22530). — MUSORSTOM 5: stn CP 324, 21°15.01’S, 157°51.33’E, 970 m, 14.10.1986: 2 (MNHN EcOs 22531). — SMIB4: stn DW 58, 22°59.6’S, 167°24.2’E, 480-560 m, 09.03.1989: 1 (MNHN EcOs 22527). — SMIB4: stn DW 59, 22°28’S, 167°22.5’E, 650 m, 10.03.1989: 2 (MNHN EcOs 22522). New Zealand. Challenger: stn 170a, Kermadec Islands, 29°45’S, 178°11’W, 1171 m, 14.07.1874, holotype: 1 (BMNH 1882.12.23.459). Philippines. MUSORSTOM 1: stn CP 54, NW of Lubang Island, 13°54’N, 119°58’E, 975-1075 m, 26.03.1976, holotype of O. musorstomae: 1 (MNHN EcOs 22520).

DESCRIPTION. — (New Caledonian material) 2.5-7.0 mm d.d., disc round and high with a sharply defined dorso-lateral margin, sometimes depressed in the centre. Disc plates range from being arranged in a regular pattern, with 3-4 plates between the centre of the disc and the interradial margin, to being numerous, overlapping and irregularly arranged. A single wide plate may be present at the dorsal interradial margin. Disc plates can be rounded, polygonal or lobed. The plate surface varies from being smooth to being covered in small rugosities, plates near the centre of the disc can bear small, spherical to conical, minutely-thorny granules, 0.07-0.20 mm high. The radial shields vary from being longer than wide and divergent, even separate, to rounded and broadly contiguous, 1/4-1/6 d.d. in length. Each ventral interradius is dominated by a large plate, sometimes split into two or more pieces, ranging in size from being half to totally covering the ventral interradial disc. Additional ventral disc plates may be present near the oral shield. Oral shields are typically 3 times wider than long, with a pointed proximal angle, rounded lateral lobes and a straight, concave or depressed distal margin. Adoral shields are as large as the oral shield, 1.5 times as wide as long, trapezoid, not curving around the lateral lobes of the oral shield. The jaw is slightly wider than long, bearing an apical and three oral papillae on each side, the papillae are pointed, angular and minutely thorny. The apical papilla is largest, the inner 2 oral papillae are small and pointed and the outer papilla widened. The outer papilla is opposed by a small adpressed oral tentacle scale. Arms moniliform, can coil around their cnidarian host. The vertebrae are elongated with an hour-glass like articulation, almost streptospondylous in shape. Dorsal arm plates are as wide as long, fan-shaped with a convex distal margin, separate, sometimes with small rugosities (on specimens with rugose disc plates). Ventral arm plates are twice as wide as long, separate even at the arm base. Arm spines number 6-7 on basal segments, uppermost spines are slender and pointed, 2.5 segments in length, almost meeting dorsally, lowermost spines vary from being smooth and rounded, to thin and pointed, to irregular and thorny. Distally there are 4 spines, uppermost longest, lowermost slightly curved with prominent thorns along one side. One small tentacle scale, 1/2 the length of the ventral arm plate. Colour (dry) pale, sometimes with a grey disc. DISTRIBUTION. — Indonesia (794-1158 m), New Caledonia (480-2110 m), Kermadec Islands (1171 m), New Zealand (716-1705 m), Philippines (975-1266 m), SE Australia (900-1700 m).

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FIG. 14. A-G, Ophiurothamnus clausa MNHN EcOs 22519; A, dorsal aspect; B, disc granules; C, ventral aspect; D, hook-shaped arm spines; E,F, vertebra; E, proximal face; F, distal face; G, dorsal view; H-J, O. clausa MNHN EcOs 22523; H, dorsal aspect; I, ventral aspect; J, hook-shaped arm spine. SEM images, scale bars in mm. FIG. 14. A-G, Ophiurothamnus clausa MNHN EcOs 22519 ; A, vue dorsale ; B, granules discaux ; C, vue ventrale ; D, épines des bras en crochets ; E, F, vertèbre ; E, face proximale ; F, face distale ; G, vue dorsale ; H-J, O. clausa MNHN EcOs 22523 ; H, vue dorsale ; I, vue ventrale ; J, épines des bras en crochets. Images MEB, échelles en mm.

REMARKS. — As detailed in the description, this material is very variable, particularly regarding characters of the disc, arm spines and oral shields. In particular the variation in disc covering is very striking, ranging from smooth naked plates, to smooth plates with granules (Fig. 13C), to plates (including dorsal arm plates) covered with rugosities (Fig. 13G). However, these character states are not correlated with other variable characters such as the number and shape of disc plates, the shape and position of the radial shields, the shape of the arm spines, or the size of the animal. Nor do the characters separate into distinct geographic or bathymetric groups. Specimens with and without granules are present at stations BIOCAL CP 51 and CP 74. Specimens with and without rugosities are present at station BIOCAL CP 70. The disc was missing from a specimen from station BIOCAL CP 46, others have irregularly-shaped radial shields (rarely only a single shield is present instead of a pair) suggesting that this species may be able to shed and regrow the disc producing different plate configurations as has been found in amphiurids. In summary, the material may represent a single variable species or

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a sympatric species-complex. However, there is not enough evidence to divide the material into separate species at this stage. The nominal species O. clausa, O. stultus, O. musortomae and possibly O. discycla (H.L. Clark, 1911) fall within the range of variation of the New Caledonian material. The syntypes of O. stultus have smooth disc plates. Two specimens from station Siboga 178 have spherical granules. The number of disc plates between the centrodorsal and the interradial margin varies between four and seven. The holotype of O. clausa has rectangular contiguous radial shields and relatively few disc plates (2-3 from the disc centre to the interradial margin) covered in rugosities. The large ventral disc plate is split into two plates on one interradius and there are some smaller plates near the oral shield. This is very similar to the specimens from BIOCAL CP 70 and CP 54. A specimen identified by Lyman (1882) from Challenger station 171 proved upon examination to be an Ophioplinthaca, possibly O. plicata. The second specimen from station 171, which resides in MCZ, has not been examined. Guille (1981) differentiated O. musorstomae from other species in the genus by the presence of two large plates on the interradial disc surface and the sunken distal edge of the oral shield. Examination of the unique holotype showed that the shape and size of the large plate is variable. On two interradii it is entire, while it is split on the other three. Other specimens in the present material also have occasional split plates and often have depressed oral shields. Ophiurothamnus discycla, known only from two type specimens (5.5. mm d.d.) from Japan (808-812 m), has numerous irregular disc plates and what appear from the figure to be long contiguous radial shields (although they are described as being ‘‘short and wide’’ in the description). It appears to differ in having a relatively small ventral interradial disc plate and relatively long arm spines. There are three other species in the genus. Ophiurothamnus excavatus Koehler, 1922a, known only from the two Philippine type specimens, has small smooth disc plates bearing a few elongated granules in the centre of the disc and around the margin. Ophiurothamnus laevis (Lütken & Mortensen, 1899) known from the Galapagos Islands (holotype 4 mm d.d.) is described as having very large radial shields, to 1/3 d.d., a few central granules, depressed interradial disc margins, three arm spines and a pair of large ventral disc plates. Finally, O. exigua (Lyman 1878b), described from four specimens (holotype 2.5 mm d.d.) from the tropical west Atlantic (446-744 m), also has large radial shields, relatively few disc plates, six arm spines, a pair of relatively small ventral interradial disc plates, and elongated thorny disc spines. Without more specimens it is difficult to assess the value of these characters for separating species. The range of variation makes a morphological analysis problematic. Molecular evidence may be required to separate species.

Ophiurothamnus eleaumei n. sp. Fig. 13F-I TYPE MATERIAL. — Holotype: MNHN EcOs 22512. TYPE LOCALITY. — New Caledonia, 22°9’S, 167°33.2’E, 2100-2110 m. MATERIAL EXAMINED. — New Caledonia. BIOCAL: stn CP 72, Ride de Norfolk, 22°9’S, 167°33.2’E, 2100-2110 m, 04.09.1985, holotype: 1 (MNHN EcOs 22512).

DESCRIPTION. — (Holotype) Disc 7.5 mm d.d.; arms greater than 40 mm in length, twisted, dorsoventrally flexible. Disc pentagonal, slightly indented radially and interradially, slightly sunken centrally, covered with small imbricating plates, 0.25-0.40 m wide. Radial shields small rectangular, two times as long as wide, 1/8 d.d., separated by two enlarged disc plates. Spines cover the central and interradial disc surfaces, absent from radial shields and surrounding plates, spines 2 times as high as wide, cylindrical with 6-7 short divergent thorns covering or ringing the apex, up to 0.2 mm high. Ventral disc surface covered in large plates, variable, some interradii with 2 large circular plates, others with up to 7 smaller plates, no spines.

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Oral shields wider than long with a convex to truncate distal margin, rounded lateral angles, converging proximal point. Adoral shields short, not extending past oral shields, contiguous radially. Oral plates rounded, longer than wide, slightly sunken near the radial tip of the adoral shields. One apical and 4 oral papillae on each jaw side, apical papilla longest, tapering to a blunt point, inner 3 oral papillae narrow and pointed, with sharp or blunt tip, sometimes slightly curved towards the jaw apex, outer papilla widened, arising from a supplementary plate distal to the oral plate, functioning as an oral tentacle scale. Arms moniliform, dorsal arm plates along the distal edge of each node, small, widely separate, fan-shaped with a convex distal border and an obtuse proximal angle. First ventral arm plate 2 times as wide as long, with a rounded distal and angular proximal margin, second plate just touching centrally, roughly-trapezoid, widest distally, with a slightly indented distal edge and almost truncate proximal edge with a small central point. Succeeding plates separate, slightly larger, 2-3 times as wide as long. Distal plates as wide as long, roughly pentagonal with a rounded distal margin, proximally convergent lateral margins and a straight proximal margin. Up to 9 arm spines basally, almost meeting along the dorsal midline, cylindrical, translucent, hollow, distal spines with thorns, uppermost longest to 2.25 segments or 4 mm long, lower spines shorter and thicker, lowermost 1.5 segments long, distal lowermost spine curved back in a hook-like fashion. One rounded tentacle scale, 1/2 to 2/3 times as long as the ventral arm plate, 2 times as long as wide, thorny at the apex, 2-3 scales on some proximal pores. Colour (dry) tan, slightly darker around the oral shields and near the mouth. DISTRIBUTION. — New Caledonia (2100 m). REMARKS. — Although the radial shields are separated radially by two disc plates, the presence of large interradial plates on the ventral disc surface, the raised pie-shaped disc, the curled moniliform arms and wide ventral arm plates indicate that this species belongs in the genus Ophiurothamnus. Although there is only one specimen, it is clearly differentiated from the other species in the genus by the presence of widely spaced radial shields. Ophiurothamnus clausa differs in having disc granules rather than spines, contiguous or slightly separate radial shields, and more robust arms and solid relatively smooth arm spines. Ophiurothamnus excavatus Koehler, 1922a has similar moniliform arms, oral/adoral plates and disc spines, however, the two type specimens (3.5-5.5 mm d.d.) have disc stumps that are relatively more robust with shorter terminal thorns, fewer arm spines, only five basally which do not meet across the dorsal midline, and contiguous radial shields. The extra plate distal to the true oral plate is similar to Ophiogema punctata Koehler, 1922a, but that species has an ophiacanthin-type disc covered in sharp disc spines. ETYMOLOGY. — Named after Marc Eleaume of the Muséum national d’Histoire naturelle.

Genus OPHIOCOPA Lyman, 1883 Type species: Ophiocopa spatula Lyman, 1883.

Ophiocopa spatula Lyman, 1883 Fig. 12K-N Ophiocopa spatula Lyman, 1883: 266-267, pl. 7 (95-98). Ophiactis parata Koehler, 1904: 97-98, pl. 24 (3-4) [new synonymy]. Ophiocopa singularis Koehler, 1922a: 98-100, pl. 21 (4,8-9) [new synonymy]. Ophiocopa parata ¢ Clark, A.M. 1970: 74.

TYPE MATERIAL. — Holotype: ZMUC.

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TYPE LOCALITY. — Papua New Guinea, Admiralty Is, off Nares Harbour, 279 m. MATERIAL EXAMINED. — Indonesia. Siboga: stn 156, Irian Jaya, eastern Halmahera Sea, east of Gag Is., 0°29.2’S, 130°5.3’E, 469 m, 15.08.1899, syntypes of O. parata: 2 (ZMA E2364). New Caledonia. BIOCAL: stn DW 70, Ride de Norfolk, 23°24.7’S, 167°53.65’E, 965 m, 04.09.1985: 8 (MNHN EcOs 22398). — BIOCAL: stn CP 75, Ride de Norfolk, 22°18.65’S, 167°23.3’E, 825-860 m, 04.09.1985: 1 (MNHN EcOs 22399). — MUSORSTOM 6: stn DW 391, Ride des Loyauté, 20°47.35’S, 167°5.7’E, 390 m, 13.02.1989: 4 (MNHN EcOs 22915). — MUSORSTOM 6: stn DW 398, Ride des Loyauté, 20°47.19’S, 167°5.65’E, 370 m, 13.02.1989: 1 (MNHN EcOs 22916). — MUSORSTOM 6: stn DW 406, Ride des Loyauté, 20°40.6’S, 167°6.8’E, 373 m, 15.02.1989: 4 (MNHN EcOs 22917). —

MUSORSTOM 6: stn DW 460, Ride des Loyauté, 21°1.72’S, 167°31.45’E, 420 m, 20.02.1989: 1 (MNHN EcOs 22918). — MUSORSTOM 6: stn CP 464, Ride des Loyauté, 21°2.3’S, 167°31.6’E, 430 m, 21.02.1989: 2 (MNHN EcOs 22919); 5 (MNHN EcOs 22400). — MUSORSTOM 6: stn DW 479, Ride des Loyauté, 21°9.13’S, 167°54.95’E, 310 m, 22.02.1989: 2 (MNHN EcOs 22920). — MUSORSTOM 6: stn DW 487, Ride des Loyauté, 21°23.3’S, 167°46.4’E, 500 m, 23.02.1989: 2 (MNHN EcOs 22921). Papua New Guinea. Challenger: stn 219, Admiralty Is, off Nares Harbour, 1°50’S, 146°39.6’E, 279 m, 10.03.1875, syntype: 1 (ZMUC).

DESCRIPTION. — Disc up to 9 mm d.d., round, covered in thin circular plates, 0.5-1.0 diameter near centre, smaller near margin. Radial shields as wide as long, quadrangular to round, 1/8 d.d., broadly contiguous. Disc stumps present particularly near disc margin, several per plate, spherical, 0.10-0.15 mm high, microscopically perforated. Oral shields almost cruciform, with an acute proximal angle and lobed distal and lateral angles, as wide as long. Adoral shields long and thin, can extend distally around oral shield. Jaw as wide as long, 1 small blunt apical papilla and 5-6 oral papillae, the outer one enlarged, 3 times as wide and high. Arms short and tapered, 3-4 times d.d.. Dorsal arm plates wider than long, bell-shaped, convex distal margin which is often glassy, contiguous. Ventral arm plates wider than long, curved distal margin, just in contact with succeeding plate. Arm spines 4-6, flattened, with a bluntly rounded tip, middle and sometimes the upper spines widened distally with a finely serrate tip, sometimes curved, thorny on juveniles, as long as 2 arm segments, distal ventralmost spine serrate and curved. One large oval tentacle scale, 2/3 as long as the ventral arm plate, 2 scales on basal arm segments. Colour (dry) grey mottled disc with brown arms, lightly banded. DISTRIBUTION. — Philippines (340-686 m), Indonesia (469 m), Papua New Guinea (279 m), New Caledonia (310-965 m). REMARKS. — Examination of type material of O. spatula, O. parata and Koehler’s (1922a) photographs of O. singularis indicate that only one species is involved. The material of all three species is very similar. Koehler (1922a) distinguished O. singularis from O. spatula by the difference in locality (Philippines compared with the ‘‘Caribbean’’), the fewer tentacle scales (one compared to two) and the narrower upper arm spines. Koehler, however, was misled about the type locality of O. spatula by Lyman’s (1883) inclusion of his new species in a paper on the Blake ophiuroids from the Caribbean. The unique type of O. spatula was actually collected from Challenger stn 219 off Papua New Guinea. This specimen could not be located with the other Challenger types in the BMNH. However, there is a 8.5 mm d.d. specimen labelled ‘‘cotype’’ in the ZMUC which is possibly the holotype, mistakenly sent from Harvard along with other exchange material early in the twentieth century. This specimen differs slightly from Lyman’s (1883) description in having two tentacle scales on the first pores and then variably 1-2 on subsequent arm segments, not two scales on all pores as shown in his figures. This is exactly the situation in O. singularis. The upper arm spines of this specimen are broader at the tip than on the other material to hand. However, given the similarity of all other features, including the microstructure of the plates and spines, this can be attributed to individual variation. The two type specimens of Ophiactis parata from Indonesia are identical to O. singularis, as predicted by A.M. Clark (1970). Thus Ophiocopa is a monotypic genus restricted to the central Indo-Pacific. This taxon is characterised by the large disc plates, contiguous roughly-circular radial shields, disc granules restricted to the margin, widened distal oral papillae, spatulate arm spines and large oval tentacle scales. The dorsal disc surface is similar to species of ‘‘Ophiophthalmus’’ while the ventral surface is reminiscent of Ophiolimna.

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OPHIUROIDS FROM

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Genus OPHIOCAMAX Lyman, 1878 Type species: Ophiocamax vitrea Lyman, 1878a.

Ophiocamax nominata (Koehler, 1930) n. comb. Fig. 12F-J Ophiomitrella nominata Koehler, 1930: 78-80, pl. 7 (2-3).

TYPE MATERIAL. — Holotype: ZMUC. TYPE LOCALITY. — Indonesia, Kei Is, 385 m. MATERIAL EXAMINED. — Indonesia. MPE Kei Is: stn 59, 5°28’S, 132°36’E, 385 m, 12.05.1922, holotype: 1 (ZMUC). New Caledonia. BIOCAL: stn DW 51, Ride de Norfolk, 23°5.27’S, 167°44.95’E, 680-700 m, 31.08.1985: 2 (MNHN EcOs 22373).

DESCRIPTION. — (New Caledonian specimen). Disc 7-9 mm d.d., arms broken but at least 5 times d.d. Disc covered in coarse rounded plates, with 7 plates between the centrodorsal and the radial shields, bearing 1-2 spines (mostly broken off) with a stout circular pedicel, a wreath of short, sometimes bifurcating, thorns at mid height and 3-5 terminal thorns, up to 0.55 mm high; radial shields small, 1/10 d.d. in length, twice as wide as long, broadly contiguous. Oral shields longer than wide, with an acute proximal angle, and a long distal lobe, covered in tiny thorns proximally and sometimes disc spines along distal margin; adoral shields short and thick. Jaw as wide as long, bearing a cluster of spiniform papillae at the apex and another cluster of oral papillae on each jaw side, inner papillae spiniform, outer ones stout and thorny. Dorsal arm plates wider than long, widest near distal margin, with convex to lobed distal margin, acute lateral and obtuse proximal angles, covered in small thorns, widely separate; ventral arm plates 3 times as wide as long, with convex distal and proximal sides and elongated lateral angles, thorny, separate; up to 6 arm spines basally, upper and lower spines short and thorny, third spine longest, up to 4 segments in length, covered in thorns; a cluster of 3-5 thorny tentacle scales on basal pores, standing vertically around the pore, pore can continue through an enlarged scale. DISTRIBUTION. — Indonesia (385 m), New Caledonia (680-700 m). REMARKS. — This species can be distinguished from other Ophiocamax species by the short wide radial shields and the form of the disc spines which are relatively stout, as wide as high, with two tiers of thorns, one circling the spine at mid height and one at the apex. It was a surprise to find that the New Caledonian material was conspecific with the unique type of Ophiomitrella nominata. While the photograph of the dorsal side of this specimen given by Koehler [1930, pl. 7 (2)] is accurate, the ventral photograph [pl. 7 (3)] looks nothing like the holotype and clearly is another species, possibly an Ophiomitrella or Ophioplinthaca. This mistake is compounded as Koehler appears to have based his text description on the photograph not the specimen. Thus the description and figures are a hybrid based on the dorsal surface of the O. nominata holotype and the ventral surface of an unknown animal. Nevertheless the species is recognisable from the description and figures of the dorsal surface and, under the rules of the ICZN, the species name O. nominata is valid. The 5 mm d.d. holotype of O. nominata is damaged; almost all the disc spines and many of the arm spines and tentacle scales have been broken off. The remaining spines and scales are similar to the New Caledonian material; the jaw has the characteristic long oral shield, wide adoral shields, and clustered oral papillae that are elongated and thorny distally. The dorsal arm plates and oral shields are thorny. The ventral arm plates are very wide and separate, the lateral angles being extended into elongated wings that can curve slightly distally.

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Ophiocamax vitrea Lyman, 1878 Fig. 12A-E Ophiocamax vitrea Lyman, 1878a: 156, pl. 8 (218-221), 9 (242-244). Ophiocamax vitrea ¢ Lyman 1882: 210-211, pl. 14 (10-12). Ophiocamax fasciculata ¢ Koehler 1897: 360-361; 1899: 67 [Non Ophiocamax fasciculata Lyman, 1883]. Ophiocamax rugosa Koehler, 1904: 139-141, pl. 26 (4-7). — Koehler 1922a: 147-151, pl. 27 (5-8), 28 (1-6), 29 (1-6), 94 (8); 1930: 92-93. — Murakami 1944: 251. — McKnight 1975: 69-70. — Guille 1981: 423-424. — Rowe 1989: 287. — Liao & Clark A.M. 1995: 178, fig. 80. — Irimura & Kubodera 1998: 139 [new synonymy]. Ophiocamax polyploca Clark, H.L., 1911: 193-195, fig. 90. Ophiocamax plesiotaxis Clark, H.L., 1915: 213-214, pl. 3 (9-10) [new synonymy]. ?Ophiocamax rugosa ¢ McKnight 1993: 174, 187.

TYPE MATERIAL. — Holotype: BMNH 1882.12.23.63. Paratype: MCZ 2096, BMNH. TYPE LOCALITY. — Papua New Guinea, Admiralty Is, off Nares Harbour, 279 m. MATERIAL EXAMINED. — Indonesia. MPE Kei Is: stn 41, 5°28.6’S, 132°28’E, 245 m, 25.04.1922, identified by Koehler (1930) as Ophiocamax rugosa: 1 (ZMUC). — Challenger: stn 192, Ki (Kei) Is, 5°42’S, 132°25’E, 239 m, 26.09.1874, types: 2 (BMNH 1882.12.23.65). New Caledonia. BIOCAL: stn DW 36, Ride de Norfolk, 23°8.64’S, 167°10.99’E, 650 m, 29.08.1985: 2 (MNHN EcOs 22394). — BIOCAL: stn DW 37, Ride de Norfolk, 22°59.99’S, 167°15.65’E, 350 m, 30.08.1985: 16 (MNHN EcOs 22392). — BIOCAL: stn DW 39, Ride de Norfolk, 22°55.06’S, 167°22.84’E, 650 m, 30.08.1985: 1 (MNHN EcOs 22375). — BIOCAL: stn DW 44, Ride de Norfolk, 22°47.3’S, 167°14.3’E, 440-450 m, 30.08.1985: 1 (MNHN EcOs 22396). — BIOCAL: stn DW 51, Ride de Norfolk, 23°5.27’S, 167°44.95’E, 680-700 m, 31.08.1985: 2 (MNHN EcOs 22377). — BIOCAL: stn CP 105, Bassin des Loyauté, 21°30.71’S, 166°21.72’E, 330-335 m, 08.09.1985: 19 (MNHN EcOs 22384). — BIOCAL: stn CP 109, Ride de Norfolk, 22°10’S, 167°15.2’E, 495-515 m, 09.09.1985: 10 (MNHN EcOs 22393). — CHALCAL 1: stn CP 8, Îles Chesterfield, 19°43.8’S, 158°35.25’E, 348 m, 19.07.1984: 13 (MNHN EcOs 22385). — CHALCAL 1: stn DC 32, Îles Chesterfield, 19°43.22’S, 158°33.19’E, 230 m, 19.07.1984: 2 (MNHN EcOs 22374). — CHALCAL 2: stn DW 82, Ride de Norfolk, 23°13.68’S, 168°4.27’E, 304 m, 31.10.1986: 3 (MNHN EcOs 22378). — MUSORSTOM 5: stn DW 328, 20°22.8’S, 158°43.6’E, 340-355 m, 15.10.1986: 1 (MNHN EcOs 22381). — MUSORSTOM 5: stn DW 340, 19°48.5’S, 158°40.9’E, 675-680 m, 16.10.1986: 2 (MNHN EcOs 22386). — MUSORSTOM 5: stn DC 362, 19°52.9’S, 158°40’E, 410 m, 19.10.1986: 1 (MNHN EcOs 22391). — MUSORSTOM 5: stn DC 376, 19°51.1’S, 158°29.8’E, 280 m, 20.10.1986: 2 (MNHN EcOs 22376). — MUSORSTOM 5: stn DC 378, 19°53.74’S, 158°38.3’E, 355 m, 20.10.1986: 4 (MNHN EcOs 22390). — MUSORSTOM 5: stn DC 380, 19°37.7’S, 158°43.9’E, 555-570 m, 21.10.1986: 1 (MNHN EcOs 22380). — MUSORSTOM 6: stn DW 391, Ride des Loyauté, 20°47.35’S, 167°5.7’E, 390 m, 13.02.1989: 1 (MNHN EcOs 22397); 2 (MNHN EcOs 22894). — MUSORSTOM 6: stn DW 392, Ride des Loyauté,

20°47.32’S, 167°4.6’E, 340 m, 13.02.1989: 2 (MNHN EcOs 22895). — MUSORSTOM 6: stn DW 393, Ride des Loyauté, 20°48.29’S, 167°9.54’E, 420 m, 13.02.1989: 1 (MNHN EcOs 22896). — MUSORSTOM 6: stn DW 398, Ride des Loyauté, 20°47.19’S, 167°5.65’E, 370 m, 13.02.1989: 8 (MNHN EcOs 22897). — MUSORSTOM 6: stn DW 399, Ride des Loyauté, 20°41.8’S, 167°0.2’E, 282 m, 14.02.1989: 2 (MNHN EcOs 22898). — MUSORSTOM 6: stn DW 406, Ride des Loyauté, 20°40.6’S, 167°6.8’E, 373 m, 15.02.1989: 34 (MNHN EcOs 22899). — MUSORSTOM 6: stn DW 407, Ride des Loyauté, 20°40.7’S, 167°6.6’E, 360 m, 15.02.1989: 4 (MNHN EcOs 22900). — MUSORSTOM 6: stn CP 409, Ride des Loyauté, 20°41.05’S, 167°7.25’E, 385 m, 15.02.1989: 2 (MNHN EcOs 22901). — MUSORSTOM 6: stn CP 419, Ride des Loyauté, 20°41.65’S, 167°3.7’E, 283 m, 16.02.1989: 7 (MNHN EcOs 22902). — MUSORSTOM 6: stn DW 446, Ride des Loyauté, 20°54.33’S, 167°18.59’E, 360 m, 19.02.1989: 1 (MNHN EcOs 22903). — MUSORSTOM 6: stn CP 454, Ride des Loyauté, 21°0.6’S, 167°26.5’E, 260 m, 20.02.1989: 5 (MNHN EcOs 22904). — MUSORSTOM 6: stn CP 455, Ride des Loyauté, 21°0.65’S, 167°26.08’E, 260 m, 20.02.1989: 8 (MNHN EcOs 22905). — MUSORSTOM 6: stn DW 456, Ride des Loyauté, 21°0.71’S, 167°26.35’E, 240 m, 20.02.1989: 7 (MNHN EcOs 22906). — MUSORSTOM 6: stn DW 457, Ride des Loyauté, 21°0.42’S, 167°28.71’E, 353 m, 20.02.1989: 5 (MNHN EcOs 22907). — MUSORSTOM 6: stn DW 472, Ride des Loyauté, 21°8.6’S, 167°54.7’E, 300 m, 22.02.1989: 2 (MNHN EcOs 22908). — MUSORSTOM 6: stn DW 480, Ride des Loyauté, 21°8.5’S, 167°55.98’E, 380 m, 22.02.1989: 1 (MNHN EcOs 22909). — MUSORSTOM 6: stn CB 481, Ride des Loyauté, 21°21.85’S, 167°50.3’E, 300 m, 23.02.1989: 1 (MNHN EcOs 22910). — SMIB4: stn DW 58, 22°59.6’S, 167°24.2’E, 480-560 m, 09.03.1989: 1 (MNHN EcOs 22388). — SMIB4: stn DW 60, 23°0.1’S, 167°21.6’E, 535 m, 10.03.1989: 7 (MNHN EcOs 22383). — SMIB4: stn DW 61, 22°59.9’S, 167°22.3’E, 520-550 m, 10.03.1989: 1 (MNHN EcOs 22382). — SMIB4: stn DW 62, 23°0.4’S, 167°21.8’E, 540 m, 10.03.1989: 4 (MNHN EcOs

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22395). — SMIB4: stn DW 65, 22°55.3’S, 167°14.5’E, 400-420 m, 10.03.1989: 1 (MNHN EcOs 22389). — SMIB4: stn DW 69, 22°55.8’S, 167°14.3’E, 395-405 m, 10.03.1989: 5 (MNHN EcOs 22387). Philippines. Albatross expedition, unknown locality and date, identified by Koehler (1922a) as Ophiocamax rugosa: 1 (MNHN EcOs 20355). — MUSORSTOM 1: stn CP 35, NE of Lubang

OPHIUROIDS FROM

NEW CALEDONIA

Island, 13°59’N, 120°18’E, 186-187 m, 23.03.1976, identified by Guille (1981) as Ophiocamax rugosa: 1 (MNHN EcOs 20304). — Challenger expedition, Cebu, types: 2 (BMNH 1882.12.23.143); type: 1 (ZMUC). Papua New Guinea. Challenger: stn 219, Admiralty Is, off Nares Harbour, 1°50’S, 146°39.6’E, 279 m, 10.03.1875, holotype: 1 (BMNH 1882.12.23.63).

DESCRIPTION. — (New Caledonian material) Disc up to 20 mm d.d., dominated by the large, triangular, contiguous to just separate, radial shields, usually 1/3 d.d. in length; smaller plates in the centre and interradially; disc spines numerous, sometimes on radial shields, polymorphic, ranging from slender spinelets, with a circle of thorns at mid-length and a few terminal thorns (typically 0.5 mm high), to smooth or thorny conical granules (0.20-0.35 mm high), to long thorny spines (1.52.5 mm high). Oral shields small relative to the adoral shields, variable in shape ranging from wider than long to longer than wide, but generally with a sharp proximal angle, rounded lateral angles and a convex to lobed distal margin, often bearing long thorny spines; adoral shields short and wide; jaw wider than long bearing numerous smooth spiniform papillae, generally in a cluster at the jaw apex and around the oral tentacle pore. Dorsal arm plates wider than long, contiguous or separate, 2-3 times as wide as long, with elongated lateral projections, thorny surface; lateral arm plates armed with numerous sharp slender thorns; ventral arm plates up to 3 times wider than long, swollen at the centre of the distal margin, separate; up to 10 arm spines, rough to denticulate, longest 2-6 segments in length; a cluster of 3-4 elongate smooth tentacle scales projecting upward around basal pores, 1 scale distally, often thorny, sometimes pore continues through scale. DISTRIBUTION. — Andaman Is (241-465 m), Japan (135-1350 m), Ryukyu Is, Southern China (101-472 m), Malay Peninsula (186-213 m), Philippines (82-510 m), Indonesia (90-520 m), Papua New Guinea (279-279 m), New Caledonia (230-700 m), Tasman Sea (412-521 m). REMARKS. — This is a very polymorphic species; there is considerable variation in the shape and size of the radial shields, disc spines, arm plates, arm spines, tentacle scales, and oral shields which is detailed in the description above. Some of the variation is size based, for example on younger animals ( 6.5 m (broken at tip), curled (but not coiled) under the disc. Disc slightly lobed over the arms, margin with short incisions in many interradii, radial lobes dominated by the large radial shields, 1/4 d.d. in length, broadly rectangular, 3 times as long as wide, contiguous for most of their length, centre of disc and interradial margin covered in coarse overlapping plates, about 6 plates from the centre of the disc to the interradial margin, irregularly placed, primary plates a little larger than the others, 1 row of plates between the radial shields and the interradial incisions. Wide genital slit, genital scale present. Ventral disc surface with a few overlapping thin plates. Oral shields twice as wide as long, rhombic, with obtuse proximal and distal angles and acute lateral angles. Adoral shields sub-rectangular, twice as wide as long, do not separate the oral shields from the lateral arm plates. Jaw longer than wide, bearing 1 apical and 2, sometimes 3, oral papillae; apical papilla bullet-shaped, pointed, inner oral papilla slightly smaller, thinner, spiniform, 3 times as long as wide, outer papilla widened, triangular in shape, as wide as high, highest along the proximal margin, occasionally replaced by 2 spiniform papillae. Two oral tentacles are present along the jaw side within the slit. Teeth are pointed. Arms only slightly noded. Vertebrae with large curved aboral flanges, a complex universal articulation point and two peltate ventral processes. Dorsal arm plates fan-shaped, with a blunt proximal angle, straight lateral sides and a convex distal margin, separate. First ventral arm plate trapeziform to pentagonal, with a straight distal edge, proximally divergent lateral sides and either a convex or angled proximal margin; next 3 plates roughly triangular, with a proximal angle and a convex distal edge, as wide as long, just contiguous with neighbouring plates; succeeding plates becoming rectangular

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OPHIUROIDS FROM

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FIG. 15. A-D, Ophiomyces delata MNHN EcOs 22453; A, dorsal aspect; B, ventral aspect; C, ventral arm plates; D, dorsal arm plates; E-L, Ophiohamus nanus n. sp. holotype MNHN EcOs 22371; E, dorsal aspect; F, ventral aspect; G, jaw; H, arm spines; I, J, vertebra; I, distal face; J, proximal face; K, arm spine articulation; L, hook-shaped arm spine. SEM images, scale bars in mm. FIG. 15. A-D, Ophiomyces delata MNHN EcOs 22453 ; A, vue dorsale ; B, vue ventrale ; C, plaques ventrales des bras ; D, plaques dorsales des bras ; E-L, Ophiohamus nanus n. sp. holotype MNHN EcOs 22371 ; E, vue dorsale ; F, vue ventrale ; G, mâchoires ; H, épines des bras ; I, J, vertèbre ; I, face distale ; J, face proximale ; K, articulation des épines des bras ; L, épines des bras en crochets. Images MEB, échelles en mm.

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with straight lateral and distal sides and a convex to obtusely angled proximal side, 2 times as wide as long, separate. Lateral arm plates meeting above and, after the first few segments, below the arm, with a low distal ridge bearing 4 (distally 3) arm spines, restricted to the lateral side of the arm. Upper 3 spines bluntly pointed, slightly flattened, almost 1 segment in length, denticulate along the edge; lowest spine slightly smaller, hook-shaped with a swollen base and a proximally-curved terminal thorn, sometimes bearing a small secondary tooth mid-way along the hook, terminal thorn becomes more pronounced on distal spines. The arm spine articulation points have 2 curved ridges on each side, but are not comma-shaped. Tentacle pore small, completely covered by 1 oval tentacle scale, 1/2 the length of a proximal ventral arm plate. Colour (dry) dirty white. (Paratypes) Up to 3 mm d.d., arms up to at least 15 mm in length, similar in most respects to holotype. On some paratypes, the disc plates are more regularly arranged, sometimes with one or two low mounds on the larger plates, on others (possibly regenerating the disc) the plates are very irregular, one radial shield of each pair can be much larger than the other, or displaced to one side, and the interradial disc incision is sometimes absent. The disc is missing from one specimen. On some specimens, the lateral arm plates do not meet above and below the arm but are separated by a small decalcified area. Colour (dry) ranges from brown to white. DISTRIBUTION. — New Caledonia (210-420 m). REMARKS. — This species is being referred to the Ophiacanthidae on the basis of the oral frame and papillae. Within this family it appears best placed in the subfamily Ophioplinthacinae because of the large radial shields that are integrated into the disc plating, the relatively small oral shields and tentacle pores, and the position of the oral tentacles within the jaw slit. Within this subfamily it appears to require a new genus. It shares characters with Ophioplinthaca, Ophiodictys and Ophiothamnus including the large radial shields and the tendency to form indentations in the interradial disc margin. These interradial incisions can be less marked in small specimens. The new species differs from these genera by having relatively few arm spines that are restricted to the lateral side of the arm and hook-like lower arm spines. The first two genera also have a series of spiniform oral papillae, lacking the widened distalmost one characteristic of O. nanus. Ophiodictys also differs in having a series of hooks instead of the uppermost arm spines. The hooks on Ophiodictys differ from those on O. nanus in having a conspicuous row of secondary teeth. Ophiodictys is also known from relatively few specimens, the type specimens of O. pectorale (Lyman, 1878a) and its synonym O. uncinatus Koehler, 1922a (see A.M. Clark 1970) from the Philippines. Ophiothamnus also has elongated, often contiguous radial shields and operculiform distal oral papillae. However, it has reduced oral shields surrounded by enlarged adoral shields and pointed, sometimes finely serrated arm spines but never hooks. Other genera within the Ophioplinthacinae lack interradial incisions, including Microphiura Mortensen, 1911 which lacks genital slits, Ophiurothamnus with an enlarged disc plate on the ventral interradius, Ophiomitrella and Ophiophthalmus with conspicuous disc granulation, and Ophiomitra and Ophiocamax with numerous oral and apical papillae. The new species also bears some resemblance to epizoic Hemieuryalidae species, such as Ophiomoeris obstricta, which differs in having a lobe-like disc, wide ventral arm plates and straight arm spines. This family has been separated from the Ophiacanthidae on the shape of the vertebrae, which supposedly have simple saddle-shaped articulations in the Hemieuryalidae, allowing the animal to coil its arms, and ball-and-socket joints in the Ophiacanthidae. However, the shape of the vertebrae differs widely between genera of the Ophiacanthidae and is in part related to the habit of each species (Litvinova 1994). Not all hemieuryalid species can coil their arms. The vertebrae of the new species have complex articulations. The new species also shows characters typical of an epizoic habit, the slender arms that can curl ventrally, the hook-like arm spines used to grip the host, and the irregular plating on the disc. Similar species in other subfamilies or families include Ophioparva blochi Guille, 1982 from Kerguelen, which has no dorsal disc granules and 3 arm spines that are curved and almost hook-like distally. However, this species has narrow radial shields reminiscent of the Ophiacanthinae, block-like oral papillae and a minute tentacle scale. Amphicyclis Mortensen, 1933a which lives on the spines of sea-urchins

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OPHIUROIDS FROM

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has hook-shaped arm spines, but with Amphipholis-like mouth parts, and belongs in the Amphiuridae Ljungman, 1867. Ophiothela in the Ophiotrichidae is another genus with diminutive epizoic species with hooked arm spines. It differs in having a cluster of apical and no oral papillae on each jaw. ETYMOLOGY. — Nanus (Latin, masculine) = dwarf, in reference to the small size of the animal.

Subfamily OPHIOHELINAE Perrier, 1985 Genus OPHIOMYCES Lyman, 1869 Type species: Ophiomyces fructectosus Lyman, 1869 (designated by Clark H.L., 1915).

Ophiomyces delata Koehler, 1904 Fig. 15A-D Ophiomyces delata Koehler, 1904: 100-101, pl. 17 (9), 18 (1-2). Ophiomyces delata ¢ Koehler 1922a: 41-42, pl. 22 (11-12), 96 (13); 1930: 57. — Clark, H.L. 1939: 55-56. — Baker 1979: 36, fig. 5d.

TYPE MATERIAL. — Syntype: ZMA E2043 (whereabouts of other 2 syntypes unknown). TYPE LOCALITY. — Philippines, Sulu archipelago. MATERIAL EXAMINED. — New Caledonia. BERYX 11: stn CP 21, Kaimon maru seamount, 24°45.03’S, 168°6.8’E, 430-450 m, 17.10.1992: 1 (MNHN EcOs 22453). — BIOCAL: stn CP 13, Bassin des Loyauté, 20°18.55’S, 167°17.65’E, 3690 m, 13.08.1985: 1 (MNHN EcOs 5601). — BIOCAL: stn DW 44, Ride de Norfolk, 22°47.3’S, 167°14.3’E, 440-450 m, 30.08.1985: 1 (MNHN EcOs 22452). — BIOCAL: stn DW 77, Ride de Norfolk, 22°15.32’S, 167°15.4’E, 440 m, 05.09.1985: 2 (MNHN EcOs

5600). — BIOCAL: stn KG 103, Bassin des Loyauté, 21°29.15’S, 166°19.97’E, 630 m, 08.09.1985: 2 (MNHN EcOs 22454). — MUSORSTOM 5: stn DW 306, 22°7.66’S, 159°21.4’E, 375-415 m, 12.10.1986: 1 (MNHN EcOs 22455). — MUSORSTOM 5: stn DC 380, 19°37.7’S, 158°43.9’E, 555-570 m, 21.10.1986: 1 (MNHN EcOs 22456). Australia. DM: stn 1255, South of Norfolk Island, 29°46.6’S, 168°58.9’E, 500 m, 01.01.1976: 8 (MoV F52777).

DESCRIPTION. — (New Caledonian material). Disc 1-6 mm d.d., elongate, sac-like; arms bent back dorsally, at least 4.5 times d.d. in length; disc covered in long thin sharp spines; radial shields apparently absent. Oral frame obscured by the spatulate oral papillae that lie flattened in a distal direction, in 2 rows on either side of the jaw, outer papillae longest and widened on one side at the tip. Dorsal arm plates small, with a rounded distal margin, separate; ventral arm plates axe-head shaped, widest distally, and curved laterally around the large open pore, just separate basally. Up to 15 short, pointed arm spines, uppermost short, middle spines longest, 2 segments in length; 3 tentacle scales around basal pores, 1 large rounded scale arising from the ventral arm plate covering the distal side of the pore, another of approximately the same size arising from the lateral arm plate extending transversely over the proximal part of the pore, and a small outer scale (often broken off) arising from the lateral arm plate next to the arm spines lies beneath the larger proximal scale, distal segments with 1 elongate scale arising from the lateral arm plate. Juveniles (1-2 mm d.d.) with fewer shorter disc spines, thinner oral papillae, 2 tentacle scales, and on average only 5 arm spines. DISTRIBUTION. — Zanzibar (640 m), Philippines (450 m), Indonesia (210-4239 m), New Caledonia (375-3690 m), Tasman Sea (500 m).

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FIG. 16. A-G, Ophiomoeris obstricta SMNH-29248; A, dorsal aspect; B, ventral aspect; C, ventral arm plates; D, dorsal arm plates; E, F, vertebra; E, proximal face; F, distal face; G, dorsal view; H-J, Ophiomoeris nodosa MNHN EcOs 22532; H, dorsal aspect; I, ventral aspect; J, ventral arm plates. SEM images, scale bars in mm. FIG. 16. A-G, Ophiomoeris obstricta SMNH-29248 ; A, vue dorsale ; B, vue ventral ; C, plaques ventrales des bras ; D, plaques dorsales des bras ; E, F, vertèbre ; E, face proximale ; F, face distale ; G, vue dorsale ; H-J, Ophiomoeris nodosa MNHN EcOs 22532 ; H, vue dorsale ; I, vue ventrale ; J, plaques ventrales des bras. Images MEB, échelles en mm.

REMARKS. — The New Caledonian material differs slightly from the Tasman Sea material figured by Baker (1979). On that specimen, the inner scale on the lateral arm plate is comparatively small, even on distal segments where it is the sole remaining scale. Ophiomyces grandis Lyman, 1879 known from south-eastern Australia as well as the Atlantic, has spiniform proximal oral papillae and up to 5 tentacle scales, 3 on the ventral plate and 2 on the lateral plate (O’Hara 1990). Ophiomyces spathifer Lyman, 1879 from Japan, with no disc spines and one tentacle scale, was transferred to Ophiotholia by Litvinova (1992).

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OPHIUROIDS FROM

NEW CALEDONIA

Family HEMIEURYALIDAE Verrill, 1899 Subfamily OPHIOCHONDRINAE Verrill, 1899

Genus OPHIOMOERIS Koehler, 1904 Ophiomoeris Koehler, 1904: 16-17. Ophiomoeris ¢ Koehler 1922a: 41. — Clark, H.L. 1939: 41. Ophiogyptis Koehler, 1905: 121 [new synonymy]. Ophiurases Clark, H.L., 1911: 250. Type species: Ophiomoeris spinosa Koehler, 1904 = O. obstricta (Lyman, 1878) — see below. REMARKS. — This synonymy is discussed below under the species Ophiomoeris nodosa.

Ophiomoeris nodosa Koehler, 1905 n. comb. Fig. 16H-J Ophiogyptis nodosa Koehler, 1905: 121-122, pl. 12 (11-14). Ophiogyptis nodosa ¢ Koehler 1922a: 40-41, pl. 6 (5-6); 1930: 56-57. — Guille 1981: 423. — Rowe 1989: 286. Ophiomoeris pentagona Murakami, 1944: 252-254, fig. 13.

TYPE MATERIAL. — Syntypes: ZMA E2408(2), E2409(2). TYPE LOCALITY. — Indonesia, Kepulauan Solor and Kei Is, 90-113 m. MATERIAL EXAMINED. — Indonesia. MPE Kei Is expedition, Amboina, 93 m, 13.03.1922, identified by Koehler (1930): 3 (ZMUC). — MPE Kei Is: stn 24, 5°37’S, 132°56’E, 100 m, 15.04.1922, identified by Koehler (1930): 1 (ZMUC). — MPE Kei Is: stn 55, 5°33’S, 132°51.5’E, 353 m, 10.05.1922, identified by Koehler (1930): 1 (ZMUC).

New Caledonia. SMIB4: stn DW 57, 23°21’S, 168°21’E, 210 m, 09.03.1989: 1 (MNHN EcOs 22532). Philippines. MPE: stn 140327, off Jolo, 15 mi west, 465 m, 27.03.1914, identified by Koehler (1930): 1 (ZMUC). — MUSORSTOM 1: stn CP 18, NE of Lubang Island, 13°56’N, 120°16’E, 150-159 m, 21.03.1976, identified by Guille (1981): 7 (MNHN EcOs 20203).

DESCRIPTION. — (New Caledonian material) Disc 3.5 mm d.d. five-lobed with deep interradial incisions, covered in thick overlapping plates, centrodorsal large and conspicuous with lobed margin, surrounded by several rows of small irregular plates, 2 large plates separating each pair of radial shields, inner one largest, outer one sloped downward to meet the dorsal surface of the arm, small spherical granules present along the inner edge of the radial shields and across the base of the arm, 0.13 mm high, 0.15 mm diameter. Radial shields forming the outer border of the five disc lobes, triangular with a rounded proximal angle, straight lateral sides and a convex distal side. Oral shields 2 times as wide as long, rhombic with blunt rounded angles proximally, distally and laterally. Adoral shields twice as wide as long, larger than the oral shields but do not separate the oral shield from the lateral arm plate. Jaw slightly longer than wide, bearing 1 apical and 3 oral papillae, the outer oral papilla is slightly enlarged. Dorsal arm plates fan-shaped or cordiform (heart-shaped) 1.5 times wider than long, widely separate. Ventral arm plates 2 times as wide as long on basal segments, fragmented into several pieces from the third segment. A decalcified furrow exists between the lateral arm plates ventrally. Six short arm spines, less than a segment in length; minute tentacle scales may be present proximally. Colour (dry): arms with purple transverse bands, 2 segments in length.

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DISTRIBUTION. — Bonin Islands, Philippines (35-465 m), Indonesia (73-353 m), New Caledonia (210 m), Norfolk Island Ridge, Tasman Sea. REMARKS. — There are some differences between the New Caledonian specimen and the other material examined from the Philippines and Indonesia. The largest specimen (6 mm d.d.) from the Philippines has some interradial disc plates present between the radial shields, granules are present on the distal edge of most large plates, there are up to seven arm spines and the tentacle scale is more obvious than on small specimens. The ventral furrow between the lateral arm plates can support a series of small plates, creating a line of fragmented plates as shown diagrammatically by Koehler (1905). Guille (1981) provisionally synonymised O. pentagona with O. nodosa on the basis of the fragmented ventral arm plates. The two species are very similar in most respects. The type figure (Murakami 1944, fig. 13a) does show radial shields that are contiguous distally, however, the text explicitly states that they are separated by disc plates. The radial shields are separate on all specimens examined for this study. The presence of fragmented ventral arm plates on specimens of Ophiomoeris obstricta (see above) removes the character that distinguished Ophiogyptis and Ophiomoeris and the two genera are synonymised herein. Ophiomoeris nodosa can be distinguished from O. obstricta by the consistently separate radial shields, the larger disc granules, the greater degree of fragmentation of ventral arm plates, and the purple coloured bands across the arms.

Ophiomoeris obstricta (Lyman, 1878) Fig. 16A-G Ophioceramis (?) obstricta Lyman, 1878a: 124-125, pl. 6 (164-166). Ophioceramis (?) obstricta ¢ Lyman 1882: 26-27, pl. 11 (1-3). Ophiomoeris obstricta ¢ Koehler 1904: 17; 1922a: 38-39, pl. 5 (3-4); 1930: 55. — Matsumoto 1915: 65; 1917: 140. Ophiomoeris spinosa Koehler, 1904: 17-18, pl. 4 (1-3). — Koehler 1922a: 40; 1930: 55-56 [new synonymy]. Ophiurases obstrictus ¢ Clark, H.L. 1911: 250-252, fig. 122. Ophiomoeris projecta Matsumoto, 1915: 65. — Matsumoto 1917: 141-143, fig. 35. — McKnight 1975: 70; 1993: 174, 187 [new synonymy]. — Imaoka et al. 1991: 124, fig. 47. Ophiomoeris parva Clark, H.L., 1939: 39-41, figs 4-5 [new synonymy]. Ophiomoeris inflata Clark, A.H., 1949: 15-17, fig. 5a-b [new synonymy].

TYPE MATERIAL. — Holotype: BMNH 1882.12.23.443. Paratype: MCZ 265. TYPE LOCALITY. — Indonesia, Kei Is, 239 m. MATERIAL EXAMINED. — Indonesia. MPE Kei Is: stn 8, 5°39’S, 132°26’E, 300 m, 05.04.1922, identified by Koehler (1930) as O. spinosa: 1 (ZMUC). — MPE Kei Is: stn 12, 5°30’S, 132°35’E, 325 m, 09.04.1922, identified by Koehler (1930): 1 (ZMUC). — MPE Kei Is: stn 24, 5°37’S, 132°56’E, 100 m, 15.04.1922, identified by Koehler (1930): 1 (ZMUC). — MPE Kei Is: stn 41, 5°28.6’S, 132°28’E, 245 m, 25.04.1922, identified by Koehler (1930): 3 (ZMUC). — MPE Kei Is: stn 43, 5°30’S, 132°45’E, 35 m, 27.04.1922, identified by Koehler (1930): 3 (ZMUC). — MPE Kei Is: stn 44, 5°39’E, 132°23’S, 268 m, 30.04.1922, identified by Koehler (1930) as O. spinosa: 1 (ZMUC). — MPE Kei Is: stn 45, 5°48.5’S, 132°14’E, 270 m, 01.05.1922, identified by Koehler (1930): 3 (ZMUC); identified by Koehler (1930) as O. spinosa: 1 (ZMUC). — MPE Kei Is: stn 46, 5°47.3’S, 132°13’E, 300 m, 02.05.1922, identified by Koehler (1930) as O. spinosa: 1 (ZMUC); identified by Koehler (1930): 1 (ZMUC). — MPE Kei Is: stn 48,

5°40.2’S, 132°21’E, 263 m, 03.05.1922, identified by Koehler (1930) as O. spinosa: 1 (ZMUC). — MPE Kei Is: stn 50, 5°34’S, 132°25.7’E, 233 m, 04.05.1922, identified by Koehler (1930) as O. spinosa: 3 (ZMUC). — MPE Kei Is: stn 53, 5°36’S, 132°55’E, 85 m, 09.05.2022, identified by Koehler (1930): 2 (ZMUC). — MPE Kei Is: stn 58, 5°29’S, 132°37’E, 290 m, 12.05.1922, identified by Koehler (1930) as O. spinosa: 3 (ZMUC); identified by Koehler (1930): 3 (ZMUC). — Challenger: stn 192, Ki (Kei) Is, 5°42’S, 132°25’E, 239 m, 26.09.1874, holotype: 1 (BMNH 1882.12.23.443). — Siboga expedition, Île de la Sonde, syntype of O. spinosa: 1 (MNHN EcOs 20204). Indian Ocean. John Murray expedition: stn 157, Maldives Is, 229 m, paratype of O. parva: 1 (ZMUC). New Caledonia. BATHUS 3: stn CP 833, Ride de Norfolk, 23°2.75’S, 166°58.23’E, 441-444 m, 30.11.1993: 3 (MNHN EcOs 23014). — BIOCAL: stn DW 08, Bassin des Loyauté, 20°34.35’S,

DEEP-WATER

OPHIUROIDS FROM

NEW CALEDONIA

FIG. 17. Disc and arm spines of Indo-Pacific species of Ophiacantha and Ophiotreta (unless stated the figure refers to disc spines). A, Ophiacantha duplex holotype ZSI 6005/7; B, lowermost arm spine, ZMA E6168; C, O. audax holotype, ZMA E2328; D, O. clandestina syntype, ZMA E2331; E, lowermost arm spine; F, O. vorax syntype, NMHN EcOs 20353; G, O. benigna, ZMC; H, O. legata holotype, USNM 41373; I, O. dallasii syntype, BMNH 1880.1.3.1217; J, O. ’’ameleta’’, BMNH 1948.5.26.16; K, O. hospes holotype, ZMC; L, O. indica holotype, SMNH Type-1403; M, Ophiotreta nefasta holotype, ZMC; N, O. larissae paratype, ZMC; O, O. stimulea (left fig.) holotype, BMNH 1882.12.23.36, (three right figs) syntype of O. gratiosa, BMNH 1898. 7.11.13; P, O. valenciennesi holotype, BMNH 1882.12.23.456; Q, O. imperita holotype, ZMA E2344; R, O. matura syntype, ZMA E2349; S, O. eximia syntypes, ZMA E2339. FIG. 17. Épines du disque et des bras des espèces de l’Indo-Pacifique Ophiacantha et Ophiotreta (sans précisions, les figures font référence aux épines discales). A, Ophiacantha duplex holotype ZSI 6005/7 ; B, épines des bras les plus basses, ZMA E6168 ; C, O. audax holotype, ZMA E2328 ; D, O. clandestina syntype, ZMA E2331 ; E, épines des bras les plus basses ; F, O. vorax syntype, NMHN EcOs 20353 ; G, O. benigna, ZMC ; H, O. legata holotype, USNM 41373 ; I, O. dallasii syntype, BMNH 1880.1.3.1217 ; J, O. ’’ameleta’’, BMNH 1948.5.26.16 ; K, O. hospes holotype, ZMC ; L, O. indica holotype, SMNH Type-1403 ; M, Ophiotreta nefasta holotype, ZMC ; N, O. larissae paratype, ZMC ; O, O. stimulea (figure de gauche) holotype, BMNH 1882.12.23.36, (trois figures de droite) syntype de O. gratiosa, BMNH 1898. 7.11.13 ; P, O. valenciennesi holotype, BMNH 1882.12.23.456 ; Q, O. imperita holotype, ZMA E2344 ; R, O. matura syntype, ZMA E2349 ; S, O. eximia syntypes, ZMA E2339.

166°53.9’E, 435 m, 12.08.1985: 3 (MNHN EcOs 22543). — BIOCAL: stn DW 33, Ride de Norfolk, 23°9.71’S, 167°10.27’E, 675 m, 29.08.1985: 3 (MNHN EcOs 22535). — BIOCAL: stn DW 36, Ride de Norfolk, 23°8.64’S, 167°10.99’E, 650 m, 29.08.1985: 1 (MNHN EcOs 22542). — BIOCAL: stn DW 44, Ride de Norfolk, 22°47.3’S, 167°14.3’E, 440-450 m, 30.08.1985: 1 (MNHN EcOs 22541). — BIOCAL: stn DW 46, Ride de Norfolk, 22°53.05’S, 167°17.08’E, 570-610 m, 30.08.1985: 11 (MNHN EcOs 22538). — BIOCAL: stn DW 51, Ride de Norfolk, 23°5.27’S, 167°44.95’E, 680-700 m, 31.08.1985: 3 (MNHN EcOs 22534). — BIOCAL: stn CP 52, Ride de Norfolk, 23°5.79’S, 167°46.54’E, 540-600 m,

31.08.1985: 2 (MNHN EcOs 22630). — BIOCAL: stn DW 77, Ride de Norfolk, 22°15.32’S, 167°15.4’E, 440 m, 05.09.1985: 1 (MNHN EcOs 22546). — BIOCAL: stn CP 108, Ride de Norfolk, 22°2.55’S, 167°5.68’E, 335 m, 09.09.1985: 3 (MNHN EcOs 22548). — BIOCAL: stn CP 109, Ride de Norfolk, 22°10’S, 167°15.2’E, 495-515 m, 09.09.1985: 1 (MNHN EcOs 22545). — CHALCAL 2: stn DW 75, Ride de Norfolk, 24°39.31’S, 168°39.67’E, 600 m, 29.10.1986: 2 (MNHN EcOs 22536). — MUSORSTOM 5: stn DW 272, 24°40.91’S, 159°43’E, 500-540 m, 09.10.1986: 10 (MNHN EcOs 22549). — MUSORSTOM 5: stn DW 277, 24°10.6’S, 159°34.9’E, 270 m, 10.10.1986: 1 (MNHN

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EcOs 22554). — MUSORSTOM 5: stn DW 300, 22°48.27’S, 159°23.94’E, 450 m, 11.10.1986: 1 (MNHN EcOs 22553). — MUSORSTOM 5: stn DW 333, 20°16.61’S, 158°49.02’E, 410-425 m, 15.10.1986: 1 (MNHN EcOs 22552). — MUSORSTOM 6: stn DW 398, Ride des Loyauté, 20°47.19’S, 167°5.65’E, 370 m, 13.02.1989: 1 (MNHN EcOs 23016). — MUSORSTOM 6: stn DW 406, Ride des Loyauté, 20°40.6’S, 167°6.8’E, 373 m, 15.02.1989: 1 (MNHN EcOs 23017). — MUSORSTOM 6: stn DW 407, Ride des Loyauté, 20°40.7’S, 167°6.6’E, 360 m, 15.02.1989: 1 (MNHN EcOs 23018). — MUSORSTOM 6: stn CP 409, Ride des Loyauté, 20°41.05’S, 167°7.25’E, 385 m, 15.02.1989: 1 (MNHN EcOs 23019). — MUSORSTOM 6: stn DW 420, Ride des Loyauté, 20°29.3’S, 166°43.3’E, 590 m, 16.02.1989: 2 (MNHN EcOs 22544). — MUSORSTOM 6: stn DW 428, Ride des Loyauté,

20°23.54’S, 166°12.57’E, 420 m, 17.02.1989: 1 (MNHN EcOs 23012). — MUSORSTOM 6: stn DW 471, Ride des Loyauté, 21°8’S, 167°54.1’E, 460 m, 22.02.1989: 1 (MNHN EcOs 23021). — MUSORSTOM 6: stn DW 472, Ride des Loyauté, 21°8.6’S, 167°54.7’E, 300 m, 22.02.1989: 1 (MNHN EcOs 22547). — SMIB4: stn DW 55, 23°21.4’S, 168°4.5’E, 260 m, 09.03.1989: 1 (MNHN EcOs 22550). — SMIB4: stn DW 58, 22°59.6’S, 167°24.2’E, 480-560 m, 09.03.1989: 11 (MNHN EcOs 22551). — SMIB4: stn DW 59, 22°28’S, 167°22.5’E, 650 m, 10.03.1989: 1 (MNHN EcOs 22539). — SMIB4: stn DW 61, 22°59.9’S, 167°22.3’E, 520-550 m, 10.03.1989: 1 (MNHN EcOs 22537). — SMIB4: stn DW 62, 23°0.4’S, 167°21.8’E, 540 m, 10.03.1989: 2 (MNHN EcOs 22533). — SMIB4: stn DW 64, 22°55.3’S, 167°16.4’E, 455-460 m, 10.03.1989: 1 (MNHN EcOs 22540).

OTHER MATERIAL EXAMINED. — Ophiomoeris tenera (Koehler, 1897): Investigator: stn 177, Indian Ocean, Laccadive Sea, 13°47.8’N, 73°7’E, 1184 m, 05.05.1894, paralectotype: 1 (ZSI

4720/7). — Investigator expedition, Indian Ocean, Andaman Islands, 492 m, lectotype: 1 (ZSI E1237/1).

DESCRIPTION. — (New Caledonian material). Disc 2-5.5 mm d.d., forming 5 heart-shaped lobes over the base of each arm, separated by an interradial incision. The lobes are dominated by large elongate radial shields, forming the outer margin of each lobe, typically 1/3 d.d. in length, 2-3 times as long as wide, varying from being contiguous for most of their length to completely separate, typically contiguous distally and separated proximally by 1-3 radial plates, rarely contiguous proximally and separated distally by one or more incipient dorsal arm plates (MNHN EcOs 22554, 5.5 mm d.d.). The centre of the disc often sunken, covered with a large centrodorsal plate and one (specimens < 4.5 mm d.d.) or more rings of smaller polygonal radial and interradial plates, disc plates occasionally irregular with no centrodorsal. Conical to spherical granules can occur along the inner borders (and rarely the outer distal borders) of the radial shields. Oral shields fan-shaped with a pointed proximal angle and a convex (rarely pointed or notched) distal margin, 1.5-2 times as wide as long. Adoral shields twice as wide as long, do not separate oral shield from first ventral arm plate. Jaw as wide as long, bearing 1 apical and 3 oral papillae, oral papillae vary from being pointed and separate to rectangular and almost contiguous. Arms frequently curled under the disc, arms relatively thin in small specimens with dorsal arm plates covering the width of the arm, broader in larger specimens, wider than the dorsal arm plates. Vertebrae elongated, small relative to the lateral arm plates, articulation hour-glass shaped. Dorsal arm plates fan-shaped to cordiform, 1-2 times as wide as long, with a distal edge that can be convex, straight or notched, always separate. Ventral arm plates much wider than long on basal plates, becoming reduced distally, can be fragmented into several pieces from the second segment, rarely absent, always separate. Four to 7 arm spines proximally, vary from thick and squat, half the length of a segment, to thin and sharp, typically as long as a segment, rarely up to 3 segments in length on small animals, smooth or spiniferous at the tip. One minute tentacle scale evident on larger specimens. Colour (dry): grey, white or brown, often banded distally, one specimen (MUSORSTOM 6 DW 471) with a longitudinal dark stripe along the arms, that bifurcates on the disc, following the inner margin of each pair of radial shields. DISTRIBUTION. — Maldives Is (229 m), Japan (120-558 m), Philippines (439 m), Indonesia (35-522-?1901 m), New Caledonia (260-700 m), north of New Zealand (480-841-?1171 m), Hawaii (722-726 m). REMARKS. — The limits of the nominal species within the genus Ophiomoeris are very ill-defined. Seven species have been referred to this genus from the Indo-Pacific. One species, O. clausa (Lyman, 1878a), is herein transferred to the genus Ophiurothamnus in the Ophiacanthidae (see above). One additional species O. nodosa is transferred here from Ophiogyptis (see below). The other six species are very similar, and at least several appear to be synonymous. Part of the problem has arisen from the poor quality of the illustrations accompanying the type descriptions of O. obstricta and O. spinosa (see H.L. Clark 1911, 1939). Most of the species have been described from relatively few specimens.

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The extensive material available from around New Caledonia and Indonesia shows a considerable amount of morphological variation, some of which is size-related. The dorsal disc covering varies considerably, as does the shape of the arm plates and the number and shape of arm spines (see description above). In particular, the number of disc plates appears to increase with age, specimens larger than 4-5 mm d.d. can have numerous disc plates in several rings around the centrodorsal plate. Disc granules are only present in 14% of animals, but when they are present they can occur in the same sample as individuals with no granules (e.g. MNHN EcOs 22549). There is morphological variation within the type series of O. obstricta. The holotype (4 mm d.d.) has a series of plates separating the radial shields, wide dorsal arm plates with a straight distal edge, wide ventral arm plates and blunt arm spines, whereas paratypes, also from station 192 and deposited in the MCZ, have relatively few disc plates, cordiform (heart-shaped) dorsal arm plates, reduced ventral arm plates and pointed arm spines (H.L. Clark 1911). The specimens recorded by Lyman (1882) from station 170, off the Kermadec Is, are not present in the BMNH or major collections in the United States (Downey 1969) and their identity cannot be confirmed. Koehler (1904) separated O. spinosa, the type species described from Indonesia, from O. obstricta by the cordiform dorsal arm plates, longer arm spines and more numerous disc plates. In the New Caledonian material there is no relationship between the presence of cordiform dorsal arm plates and the pattern of disc plates. Koehler (1904) recorded the size of the type series as ranging up to 7 mm d.d., which may explain the number of disc plates. H.L. Clark (1939) records that (presumably smaller) paratypes in the Museum of Comparative Zoology had relatively few disc plates. Examination of a large number of specimens from the Kei Islands identified by Koehler (1930), showed that the larger specimens (up to 7 mm d.d.) were labelled O. spinosa and the smaller specimens O. obstricta. The few equal-sized specimens were very similar. Again the arm spine length varies from short to relatively long, and a few specimens possessed disc granules. One syntype of O. spinosa was collected from a station (Siboga 119, 1901 m) that is much deeper than all the other Siboga material (to 522 m) and requires confirmation. The holotype of O. projecta from Japan (4 mm d.d.) was described as having relatively few disc plates, with only one radial plate separating the proximal ends of the radial shields. Granules occur in a row along the inner edge of the radial shield with a few along the distal edge as well. The specimens in the type series of O. parva, from the Maldives Islands, are small (2-3 mm d.d.) and many of the features used to distinguish this species are juvenile characters, including the relatively thin arms, 5-6 arm spines, the uppermost to 3 segments in length, and the relatively small ventral arm plates. The diamond-shaped oral shields are similar to specimens figured by H.L. Clark (1911) (as O. obstricta) and Matsumoto (1917) (as O. projecta). There are no disc granules. A. H. Clark (1949) did not attempt to distinguish O. inflata from Hawaii from any other species. There appear to be no characters that can be used to distinguish the small holotype (3 mm d.d.) from O. obstricta. Finally, O. tenera Koehler, 1897 from the Andaman Sea, was differentiated from O. obstricta by the arrangement of disc plates, the shape of the arm plates and the three arm spines. However, examination of the syntypes (the specimen ZSI E1237/1, 5.7 mm d.d., is here designated as the lectotype) showed that they possess up to 5 arm spines basally (typically 3 in mid arm) and ventral arm plates that are similar in shape to the O. obstricta figured here. The description of the disc covering is generally consistent with larger New Caledonian specimens, however, the arrangement of the radial shields is unusual in that they are wider apart distally and convergent proximally. This occurred in several New Caledonian specimens (MUSORSTOM 5 DW 277, MUSORSTOM 6 DW 428, DW 489), the former with six arm spines. Koehler (1992a) recorded two additional smaller specimens from the Philippines, however he gave no morphological details. The status of this species will have to await the collection of additional material. In summary, there appears to be little reason to differentiate the nominal species of Ophiomoeris, and with the exception of O. nodosa and possibly O. tenera, all are here regarded as synonymous. The result is an Indo-West Pacific taxon that occurs epizoically on soft corals or sponges from the Maldives to Hawaii in tropical (to 35°latitude) bathyal waters. However, whether this result is a single species or a species-complex is not determined. The range of morphological variation may be indicative of a suite of cryptic species which require resolution by a future molecular analysis.

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FIG. 18. Disc and arm spines of Indo-Pacific species of Ophioplinthaca and Ophiomitrella (unless stated the figure refers to disc spines). A, B, Ophioplinthaca miranda lectotype, ZMA E2446; B, uppermost and lowermost arm spines; C, O. pulchra syntype, MNHN EcOs 20380; D, O. mitis syntype, ZMA E2948; E, O. tylota holotype, BMNH 1948.5.26.43; F, marginal disc spine; G, O. plicata holotype, BMNH 1882.12.23.186 (two left figs), NMHN EcOs 22468 (right fig.); H, O. defensor holotype, ZMC; I, O. monitor holotype, ZMC; J, O. papillosa holotype, BMNH 1948.5.26.38; K, O. laudator holotype, ZMC; L, Ophiomitrella parviglobosa holotype, MNHN EcOs 22443; M, O. mensa holotype, MNHN EcOs 22446; N, Ophiomitrella conferta, NMHN EcOs 22439; O, syntype, MNHN EcOs 20388; P, O. barbara holotype, ZMA E2419; Q, O. nudextrema holotype, BMNH 1948.5.26.32; R, O. mutata syntype, ZMA E2423; S, O. tenuis, MNHN EcOs 22451. FIG. 18. Épines des disques et bras des espèces de l’Indo-Pacifique Ophioplinthaca et Ophiomitrella (sans précisions, les figures font référence aux épines discales). A, B, Ophioplinthaca miranda lectotype, ZMA E2446; B, épines les plus hautes et les plus basses des bras ; C, O. pulchra syntype, MNHN EcOs 20380; D, O. mitis syntype, ZMA E2948 ; E, O. tylota holotype, BMNH 1948.5.26.43 ; F, épines marginales du disque ; G, O. plicata holotype, BMNH 1882.12.23.186 (deux figures de gauche), NMHN EcOs 22468 (figure de droite) ; H, O. defensor holotype, ZMC ; I, O. monitor holotype, ZMC ; J, O. papillosa holotype, BMNH 1948.5.26.38 ; K, O. laudator holotype, ZMC ; L, Ophiomitrella parviglobosa holotype, MNHN EcOs 22443 ; M, O. mensa holotype, MNHN EcOs 22446 ; N, Ophiomitrella conferta, NMHN EcOs 22439 ; O, syntype, MNHN EcOs 20388 ; P, O. barbara holotype, ZMA E2419 ; Q, O. nudextrema holotype, BMNH 1948.5.26.32 ; R, O. mutata syntype, ZMA E2423 ; S, O. tenuis, MNHN EcOs 22451.

KEY TO ALL GENERA AND TROPICAL INDO-WEST PACIFIC SPECIES OF OPHIACANTHIDAE This key includes all the known extant genera of the Ophiacanthidae as well as all species reported from the tropical Indo-West Pacific between Africa and Hawaii. For the purposes of this key, this region is defined to be between 30°N and 30°S, and thus does not include the largely temperate fauna of Japan and the Northern Pacific, southern Australia and New Zealand, and South Africa. Subfamilial classification follows Paterson (1985). Of the genera listed by Fell (1960) but not included here, Ophioblenna is now considered to belong to the Ophiomyxidae Ljungman, 1867 (Hendler et al. 1995), Amphipsila to the Ophiocomidae Ljungman, 1867 (H.L. Clark, 1915) and Ophiambix to the Ophiuridae Lyman, 1865 (Paterson 1985). Genera and species marked with an asterisk (*) have not been examined, and their characters have been

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derived from published information. This key is based on adult character states. Juveniles often differ considerably from adults therefore this key must be used with caution if the ontogenetic stage of the animal is not known. [Notes: 1 There are some genera that are intermediate between the subfamilies as defined by Paterson (1985). Ophiotreta (Ophiacanthinae) has small tentacle pores but elongate jaws covered by numerous spiniform oral papillae confluent with spatulate oral tentacle scales. Ophiolimna (Ophiotominae) is similar but has squarish oral papillae and a flange like oral tentacle scale that completely covers the oral pore; 2 Although the two species of Ophiacanthella, O. troscheli (Lyman, 1878a) from the Atlantic and O. acontophora (H. L. Clark, 1911) from Japan, contradict the diagnosis of the Ophiacanthinae in having naked radial shields, their form and position, and the nature of the disc plates generally, are reminiscent of the subfamily; 3 Many of the species referred to Ophiolebes do not have the thick skin covering the disc and arm plates that is present in the type species, O. scorteus Lyman, 1878a from the Southern ocean. In particular, the many species described from the Northern Pacific by H. L. Clark (1911) and Matsumoto (1915) appear to have disc plating characteristic of many Ophiomitrella (=Ophioripa) species. A review of these species is outside the geographical scope of this work; 4 Some specimens of Ophiacantha severa have enlarged spatulate distal oral papillae; however, there are only 3 oral papillae on each jaw side; 5 The type series of O. severa as described by Koehler (1922a) appears to contain specimens with two forms of disc spines. The holotype has disc stumps that widen at the tip to support a crown of thorns and appears related to O. funebris. The only paratype, and Koehler’s (1930) specimens, have elongate thorny disc spines (see couplet 26); 6 Examination of the holotype and only known specimen of O. languida suggests that the disc ‘‘granules’’ are possibly the base of large disc spines that have broken off. More material is required to resolve this issue; 7 The species O. audax Koehler, 1904, O. clandestina Koehler, 1905 and O. suspecta Koehler, 1905 are all very similar to O. duplex and possibly synonymous. They differ slightly in the form of the disc spinelets and arm spines (see text, Fig. 17A-E). O. pacata and O. prionota are also similar in many ways. The absence of the thorny disc spinelets on the two holotypes of these species may be an accident of preservation or intraspecific variation; 8 The exposed radial shields are not like other Ophiacantha species, and possibly this species is better placed in Ophiomitrella; 9 O. rosea is included in the key on the basis of records from off Southern Japan (Irimura et al. 1995). Although it has been recorded from the southern Tasman Sea (33-52°S), it has not been collected from elsewhere in the tropical Indo-Pacific and may have an anti-tropical distribution; 10 This southern Australian species is included on the basis of specimens from northern New South Wales (29°S) in the Australian Museum, Sydney; 11 See note 5; 12 The syntypes of Ophiacantha pentagona include two species: one with serrated arm spines and another undescribed species with smooth arm spines (see text). Another closely related species is Ophiacantha baccata Mortensen, 1933b from South Africa which appears to differ only in its smaller size and by having relatively coarse plating with larger beading; 13 The relationship between these three closely related abyssal species requires further investigation. Ophiacantha bathybia is included in this key on the basis of specimens reported from south of Japan by Irimura et al. (1995); 14 This largely temperate Australian species has been recorded on the Western Australian coast as far north as Broome (17°S) (Baker & Devaney 1981). Although O. clavigera keys out here with other species having trifid spinelets, it also shares many characters with other diminutive southern Australian species such as O. alternata with which it has been confused; 15 Anamphiura valida was transferred to Amphilimna by Thomas (1975), although A.M. Clark & Courtman-Stock (1976) note that the upper arm spines under the disc on the available specimens are modified into a flange but not fused with the lower spiniform arm spines, and retained the species with doubt in the Amphiuridae. A similar species with tall sparse disc spines is Sinophiura multispina (Koehler, 1922a). Although superficially very like Amphilimna, Liao (1983) transferred this species to the Ophiuridae on the basis of internal and ontogenetic characters. It can be distinguished externally from A. valida by the shape of the oral shield (longer than wide) and the more numerous arm spines (9 compared to 6); 16 Fell (1961) speculates that the only species of Ophiodaces, O. inanis Koehler, 1922b is a juvenile of an Ophiosparte species, possibly O. gigas Koehler, 1922b. Fell’s (1960) listing of Ophiodaces as a synonym of Ophiodictys is clearly a mistake; 17 The holotype of Ophiacantha megatreta has no disc. Matsumoto (1917) describes additional material as having dense disc spines, placing the species in Ophiopora, considered by H. L. Clark (1915) to be a synonym of Ophiotoma. Irimura et al. (1995) however, list this species (from as far south as 29°N) as an Ophiotrema, possibly on the basis that their material had tentacle scales on the arms. A redescription of this species is required; 18 This distinction may not hold true for the Atlantic

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species of Ophiotrema, in which case Ophioprium is likely to be a junior synonym of Ophiotrema; 19 O. weberi was placed by Koehler (1904) in a new genus Ophiomytis, which is here considered a synonym of Ophioplinthaca (see text). The massive radial shields, cluster of apical oral papillae and the tiny tentacle scales are similar to O. defensor and the lack of disc granules may be an artefact of collection. Ophioplinthaca crassa was mistakenly reported to be without disc granules (see below); 20 The unique type specimen of O. crassa from off Zanzibar was reported to be without disc granules, however, re-examination of the unique specimen revealed a few bluntly pointed granules on the disc plates. Apart from the disc granules, it differs from O. tylota in having fewer disc plates; 21 The range of disc spine shapes described for this species is considerable. Possibly more than one species is involved, in which case O. manillae can be used for those forms with complicated bifurcated trifid stumps; 22 The nature of the plates for O. integra and the Atlantic species of Ophiomitra is unknown; 23 O. integra was referred by H. L. Clark (1915) to Ophioplinthaca without comment. However, the type description and figures do not mention an interradial incision and the figures recall Ophiomitra leucorhabdota. Unfortunately the unique type has disintegrated and Koehler did not describe the colour of his specimen; 24 Ophiomitrella sagittata Koehler, 1922a is probably a synonym; 25 Ophiacantha nudextrema is here treated as an Ophiomitrella, as the holotype has large exposed triangular radial shields. Within Ophiomitrella the presence of stout trifid disc stumps that bear terminal thorns appears to align it to the O. mutata/O. subjecta group of species; 26 The generic name Ophiophthalmus is preoccupied (see Paterson 1985); 27 The unique holotype of Ophiomitrella suspectus is in poor condition and the shape and position of the radial shields may be an artefact of disc contraction. It is otherwise very similar to O. granulosa and possibly synonymous.] 1. Jaw as long as broad; tentacle pores not enlarged, usually fully covered by tentacle scale. . . . . . . . . 21 — Jaw longer than broad; large tentacle pores, usually only partially covered by tentacle scales. . . . . . 3 2. Disc covered in small thin plates or skin; radial shields long and bar-like, only the distal section (if any) exposed, plates or skin covering the proximal section (except Ophiacanthella) . . . . . . . Ophiacanthinae 4 — Disc with well developed plates; radial shields can be long, rounded or triangular but not substantially covered proximally by disc plates; disc sometimes incised inter-radially . . . . . . . . Ophioplinthacinae 73 3. Disc flat, fragile, often torn in preserved specimens; arms extend laterally, sinuous; jaw edge supports a single row of oral papillae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiotominae 47 — Disc high and pointed; arms often erect, raised dorsally above the disc (at least in preserved specimens); usually several rows of modified oral papillae covering the jaw; specialised parasol-shaped structures can be present on distal arm segments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiohelinae 113 OPHIACANTHINAE 4. Radial shields elongate, contiguous, parallel, mostly exposed (Western Atlantic, Northern Pacific) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiacanthella 2 — Radial shields mostly covered by thin disc plates or skin, only small distal section exposed. . . . . . . 5 5. Disc and often arms covered in a thick skin obscuring the plates (Southern and Atlantic Oceans, possibly Northern Pacific). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiolebes 3 — Disc and arms covered by readily observable plates in a thin skin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 6. Distal oral papillae carried on a supplementary oral plate; dorsal arm plates bearing sharp spines similar to those on the disc; ventral arm plates up to 4 times as wide as long, ventral arm spines curved but not hooked. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiogema punctata Koehler, 1992a* — Not as above; although dorsal arm plates can bear granules similar to those on the disc (e.g. Ophiotreta spp), ventral arm plates can be wider than long (e.g. Ophiacantha pentagona) and ventral spines can be curved (e.g. O. cornuta) but they never occur in combination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 7. Dorsal arm plates wide, broadly in contact............................. Ophialcaea tuberculosa (Lyman, 1878a) — Doral arm plates triangular, fan-shaped or bell-shaped, generally separate . . . . . . . . . . . . . . . . . . . . . . 8 8. Disc with spines or granules; oral papillae spiniform or spatulate. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 — Disc without spines or granules, oral papillae block-like, contiguous (Kerguelen) . . . . . . . Ophioparva

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9. Jaw elongated, longer than wide, generally bearing 5 or more oral papillae on each side, the distal ones (oral tentacle scales) frequently elongated and spatulate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiotreta 10 4 — Jaw as long as wide, 3-4 oral papillae (rarely with supplementary papillae, e.g. O. placida, O. rosea), distal papillae can be enlarged but not spatulate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiacantha 16 10. Disc covered in small hemispherical to conical granules and sometimes spines; arm spines smooth; two tentacle scales throughout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 — Disc covered in thorny spines, sometimes with granules; arm spines smooth or thorny; one tentacle scale on segments in the middle of the arm, sometimes two on basal pores . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 11. Disc covered in granules only (Figs 5A-D, 17P) . . . . . . . . . . . Ophiotreta valenciennesi (Lyman, 1879) — Disc covered in granules and some small spines. . . . . . . . . . Ophiotreta durbanensis Mortensen, 1933b 12. Disc centre covered in tiny slender spines (to 0.25 mm high) with divergent terminal thorns, modified to low conical granules near the disc margin; colour tan with dark spoke-like stripes between each pair of white radial shields (Figs 5E, 17N) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiotreta larissae (Baker, 1979) — Disc covered in elongated spines > 0.5 mm high, rarely with some additional granules . . . . . . . . . 13 13. Disc spines elongated conical shape with small thorns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 — Disc spines very slender with long thorns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 14. Outer oral papillae much larger than the others, spatulate; disc spines with 3-4 conical terminal thorns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiotreta spatulifera Koehler (1922a) — Outer oral papillae can be wider than the others but never spatulate, disc spines 2-6 times as high as wide, covered in thorns (Figs 4A-D, 17O) . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiotreta stimulea (Lyman, 1878a) — Outer oral papillae spiniferous; disc spines elongate with 2-3 terminal thorns, some disc granules present (only known specimen a juvenile) (Fig. 17M) . . . . . . . . . . . . . . . . . . . . . . Ophiotreta nefasta Koehler, 1930 15. Disc spines with small adpressed thorns; arm spines long (to 6 segments long) and thorny; lower arm spines thorny but not hooked-shaped (Figs 4E-G, 17S) . . . . . . . . . . . . Ophiotreta eximia (Koehler, 1904) — Disc spines with irregular erect thorns; arm spines short (to 2.5 segments long) and thorny; lower arm spines curved but not hooked-shaped (Fig. 17Q) . . . . . . . . . . . . . . . . Ophiotreta imperita (Koehler, 1904) — Disc spines with flared terminal thorns; arm spines long (to 5 segments long), upper ones smooth, lower spines distinctly hooked-shaped distally (Figs 4H-L, 17R) . . . . . . . . . Ophiotreta matura (Koehler, 1904) 16. Disc bearing long slender spines, 0.5-1.0 mm long, more than five times as long as wide, sometimes in combination with granules or thorny spinelets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 ¢ Disc plates bearing stumps, granules or spinelets with divergent thorns but never long pointed spines . . 23 17. Disc with spines only . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 — Disc with two types of spines, slender spines and either granules or small thorny spinelets . . . . . . 21 18. Oral shields rhomboid with an acute angle distally, depressed distally; outer oral papillae spatulate, higher than the inner papillae. . . . . . . . . . . . . . . . . . . . . . . . Ophiacantha severa Koehler, 1922a (in part) 5* — Oral shields rounded triangular with a convex distal margin; outer oral papillae leaf or dome-shaped, often wider but not much longer than the inner papillae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 19. Disc spines smooth; oral shields minute, dwarfed by the enlarged adoral shields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiacantha vagans Koehler, 1898 — Disc spines thorny; oral shields larger than adoral shields. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 20. Disc spines with some terminal thorns. . . . . . . . . . . . . . . . . . . . . . Ophiacantha pacata Koehler, 1922a* — Disc spines microscopically roughened . . . . . . . . . . . . . . . . . . . Ophiacantha prionota H.L. Clark, 1911* 21. Disc with both long smooth spines (minutely thorny) and small conical granules; arm spines smooth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 — Disc covered in low granules, with thorny spines around the periphery; arm spines long and slender with small sparse thorns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiacantha languida (Koehler, 1904) 6 — Disc with smooth or thorny spines and some spinelets with usually 3 terminal thorns; upper arm spines smooth, lower ones slightly flattened with long thorns along one or both sides, the lowest spine modified distally into a hook (Fig. 17A-E) (epizoic). . . . . . . . . . . . . . . . . . . . . . . Ophiacantha duplex Koehler, 1897 7

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22. Radial shields totally covered with disc plates and granules; ventral arm plates with a straight to slight convex distal margin; oral shields broadly triangular. . . . . . . . . . . . . Ophiacantha vepratica Lyman, 1878a — Distal section of radial shields exposed, 1/6 the disc diameter in length; ventral arm plates with a very convex distal edge, striated; oral shields diamond-shaped (or with distal section slightly enlarged) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiacantha scutigera Mortensen, 1933b 8 23. Disc covered in stumps, 1-3 times as high as wide, smooth or covered in microscopic thorns. . . 24 — Disc spinelets with 2-12 prominent terminal thorns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 24. Stumps uniformly distributed across the disc; oral shields inverse triangular or bell-shape, with a wide straight proximal margin; larger specimens with numerous oral papillae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiacantha rosea Lyman, 1878 a 9 — Disc granules elongate near the margin; oral shields rhomboid with an obtuse proximal angle; never more than 3 lateral oral papillae; arm spines alternate in number from one segment to the next . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiacantha alternata A.M. Clark, 1966 10 25. Disc spinelets capitate with 6-12 short divergent terminal thorns, sometimes in several rings . . . 26 — Disc spinelets trifid or irregularly multifid, but thorns not arising radially from an expanded apex. 27 26. Disc spines with ‘half a dozen’ terminal thorns, oral shields depressed distally, tentacle scales almost as long as the ventral arm plate . . . . . . . . . . . . . . . . . . . . . . . . Ophiacantha severa Koehler, 1922a (in part) 11* — Disc spines bearing 8-12 thorns, often in two tiers, oral shields flat, tentacle scales 2/3 the length of the ventral arm plate (Fig. 1H-J). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiacantha funebris (Koehler, 1930) 27. Outer distal oral papillae rectangular, twice as wide as high . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 — Outer distal oral papillae spiniform or leaf-shaped, can be larger than inner papillae but typically as high or higher than wide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 28. Arm spines smooth (Fig. 1K-M). . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiacantha levispina Lyman, 1878 — Arm spines thorny (particularly lower ones). . . . . . . . . . . . . . . . . Ophiacantha composita Koehler, 1897 29. Arms conspicuously noded (moniliform), swollen laterally and dorsally around the spine-bearing ridge; disc spinelets typically minute with 2-6 terminal thorns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 — Arms not noded, although some species can have raised spine-bearing ridges laterally . . . . . . . . . . 37 30. Adoral shields with distal extensions that extend around the lateral angle of the oral shields . . . . 31 — Adoral shields not extending distally around the lateral edge of the oral shields . . . . . . . . . . . . . . . . 36 31. Three oral papillae (on each jaw side, in addition to the single apical one) . . . . . . . . . . . . . . . . . . . . 32 — Four oral papillae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 32. Oral shields rhomboid, twice as wide as long, often larger than an adoral shield. . . . . . . . . . . . . . . 33 — Oral shield triangular, as wide as long, smaller than the enlarged adoral shields . . . . . . . . . . . . . . . . 34 33. Disc with a sharp lateral edge, disc spines are thorny granules . . Ophiacantha renekoehleri new name — Disc with a rounded lateral edge, disc spines small thorny granules (Fig. 3F-H) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiacantha richeri n. sp. 34. Disc spinelets trifid; upper arm spines on basal segments outside disc are elongated, more than twice as long as the other spines; tentacle scale minute (Fig. 17I) . . . . . . . . Ophiacantha dallasii Duncan, 1879 — Disc spinelets multifid; upper arm spines longest, but never twice as long as other spines; tentacle scale 2/3 to as long as the ventral arm plate (Fig. 17K) . . . . . . . . . . . . . . . . . . Ophiacantha hospes Koehler, 1930 35. Oral shields grooved at their distal margin; dorsal arm plates almost contiguous on basal segments; more than one tentacle scale on basal pores (Fig. 3A-E) . . . . . . . . . . . . . . . Ophiacantha placida (Koehler, 1904) — Oral shields flat; dorsal arm plates widely separate; only one tentacle scale throughout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiacantha exilis (Koehler, 1922a)* 36. Oral shields rounded triangular, as wide as long (Fig. 2H-K) . . . Ophiacantha serrata Lyman, 1878a — Oral shields diamond-shaped, with obtuse distal and proximal angles, twice as wide as long; adoral shields with a beaded surface (Fig. 2E-G) . . . . . . . . . . . . . . . . . . . Ophiacantha pentagona Koehler, 1897 12 37. Lowest arm spine conspicuously curved; basal tentacle pores with 3 small scales (Fig. 2A-D) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiacantha cornuta Lyman, 1878a — Lowest arm spine can have asymmetrical thorns but are never curved; basal tentacle pores with one scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

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38. Disc with irregularly thorny stumps; adoral shields frequently extend distally around the lateral angles of the oral shield; wide ventral arm plates; minute tentacle scale; large (to 20 mm d.d) abyssal animals (to 5300 m). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 — Disc with trifid or multifid spinelets; adoral plates usually lie proximal to the lateral angles of the oral shields (O. indica can be an exception); tentacle scale small to large. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 39. Ventral arm plates with a concave distal margin; arm spines to 3 segments long . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiacantha bathybia H.L. Clark, 1911 13 — Ventral arm plates with a concave distal margin; arm spines to 2 segments long . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiacantha cosmica Lyman, 1878a — Ventral arm plates with a convex distal margin; arm spines to 2 segments long . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiacantha sociabilis Koehler, 1897 40. Disc spinelets with 2-4 long terminal thorns, diverging at approximately half the length of the spinelet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 — Disc spinelets with 2-6 short terminal thorns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 41. Disc spines with 2-4 webbed terminal thorns, often curving upwards in a single plane like a trident (Fig. 1D-G) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiacantha fuscina n. sp. — Disc spines with 2-3 divergent terminal thorns, not webbed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 42. Disc spines with a smooth pedicel (Fig. 1A-D) . . . . . . . . . . . . . . . Ophiacantha longidens Lyman, 1878 — Disc spines with secondary thorns on pedicel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 43. Oral shield broadly triangular; lowest arm spine with lateral denticulations distally (almost hookshaped); tentacle scale less than half as long as the ventral arm plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiacantha striolata Mortensen, 1933b — Oral shield diamond-shaped; lowest arm spines not denticulate distally; tentacle scale more than half as long as the ventral arm plate (Fig. 17H). . . . . . . . . . . . . . . . . . . . . . . . . . Ophiacantha legata Koehler, 1922a 44. Ventral arm plates twice as wide as long; adoral shields larger than oral shields, conspicuously beaded (Fig. 17G) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiacantha benigna Koehler, 1922a — Ventral arm plates as long as wide; oral shields larger than adoral shields . . . . . . . . . . . . . . . . . . . . . 45 45. Disc spines multifid; tentacle scale almost as long as the ventral arm plate (Fig. 17F) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiacantha vorax Koehler, 1897 — Disc spines predominantly trifid (although sometimes the three primary thorns can bifurcate at the tip); tentacle scale to half as long as the ventral arm plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 46. Disc spines covered in skin, obscuring the terminal thorns (Fig. 17L) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiacantha indica Ljungman, 1867 — Disc spines free of skin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiacantha clavigera Koehler, 1907b 14 OPHIOTOMINAE 47. Oral tentacle pore without scales or covered by an enlarged distal oral papillae. . . . . . . . . . . . . . . . 48 — Oral tentacle pore surrounded by a series of spiniform or spatulate tentacle scales. . . . . . . . . . . . . . 51 48. Three oral papillae, oral tentacle without scales, disc decalcified except for small areas around radial shields with thin imbricating plates, skin with small white granules; tiny tentacle scale on first four arm segments only, replaced distally by a series of short lower arm spines with terminal hooks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophientrema scolopendrica (Lyman, 1883) — Five to six oral papillae, outermost widened and sometimes operculate, covering oral tentacle pore; disc covered in plates bearing granules; oral plates covered in granules; a single oval tentacle scale, completely covering the pore . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiolimna 49 49. Disc plates and granules covering the radial shield (Figs 6K-N) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiolimna antarctica (Lyman, 1879) — Radial shields exposed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 50. Disc spines as high or slightly higher than long; arms not noded; dorsal arm plates rhombic, not raised (Figs 6H-J) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiolimna perfida (Koehler, 1904)

129

130


— Disc spines twice as high are broad, with thorny tips in centre of disc; arms noded; dorsal arm plates bell-shaped with raised distal margin (Figs 6A-G) . . . . . . . . . . . . . Ophiolimna placentigera (Lyman, 1880) 51. Jaw with 3 spiniform apical papillae and 2 block-like papillae on each jaw side, oral tentacle bordered by several short scales; no tentacle scales on arms; no bursal slits (Atlantic, Southern Oceans) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiocymbium* — Jaws support a series of spiniform to spatulate oral papillae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 52. Radial shields 3-4 times longer than broad, contiguous, disc notched radially between radial shields, uppermost arm spines much thickened on segments under the disc, often fused . . . . . . . Amphilimna 53 — Not as above . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 53. Inner tentacle scales arising from the ventral arm plate elongate and spine-like . . . . . . . . . . . . . . . . 54 — Inner tentacle scales oval, much smaller than the large oval scale on the lateral arm plate, sometimes absent. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 54. Disc with spines and granules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Amphilimna granulosa Liao, 1989* — Disc with spines only . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 55. To 6 arm spines basally . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Amphilimna cribriformis A.M. Clark, 1974* — To 13 arm spines basally. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Amphilimna polycantha Liao, 1983* 56. Disc with tall sparse spines only . . . . . . . . . . . . . . . . . . . . . . Amphilimna valida (H.L. Clark, 1939) 15 * — Disc with tiny spinules and sometimes granules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 57. Disc with tiny spinelets only . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Amphilimna sinica Liao, 1989* — Disc with tiny spinules and granules. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 58. Most of the radial shields covered with spines and granules. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Amphilimna transacta (Koehler, 1930)* — Radial shields naked. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Amphilimna tanyodes Devaney, 1974* 59. Disc covered in thick skin, embedded plates observable when dry, separate, not imbricating, no spines or granules (Antarctica) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiosparte — Disc covered in thin skin with imbricating plates sometimes bearing spines or granules. . . . . . . . . 60 60. Tentacle scales lacking or rudimentary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 — Tentacle scales present, needle-like or scale-like . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 61. Oral tentacle pore superficial, oral tentacle scales higher in the jaw slit than the oral papillae; small conical tentacle scales present on distal arm segments (Antarctica) . . . . . . . . . . . . . . . . . . . Ophiodaces 16 * — Oral tentacle scales continuous with the oral papillae; tentacle scales rudimentary on basal segments or absent. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiotoma 62 62. Disc covered in skin embedded with small imbricating plates, no granules or spines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiotoma assimilis Koehler, 1904 — Disc densely covered in spines. . . . . . . . . . . . . . . . . . . . . . . Ophiotoma megatreta (H.L. Clark, 1911) 17* 63. Oral and arm tentacle scales needle-like, much longer than wide . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 — Oral and arm tentacle scales scale-like, flattened, oval to spatulate . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 64. Oral tentacle pore very superficial, oral tentacle scales higher in the jaw slit than the oral papillae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiotrema tertium Koehler, 1922a 18 — Oral tentacle scales continuous with the oral papillae (W. Atlantic) . . . . . . . . . . . . . . . . . . Ophioprium* 65. Disc with a few large plates bordered by spiniform granules (Antarctica). . . . . . . . . . . . Glaciacantha* — Disc with numerous small imbricating plates that may or may not bear spines or granules . . . . . . 66 66. Oral tentacle scales similar to oral papillae. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 — Oral tentacle scales elongated, longer than oral papillae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 67. Disc with elongate spines with a thorny tip; arms short, only 2 times the disc diameter; surface of dorsal arm plates granular; arm spines flattened with lateral serrations . . . . . . Ophiodelos insignis Koehler, 1930 — Disc covered in naked plates, no spines or granules; arms long, at least 7 times the disc diameter; arm spines flattened but smooth (Fig. 7H-J) . . . . . . . . . . . . . . . . . . Ophiologimus quadrispinus H.L. Clark, 1925 68. Disc with naked plates or granules; arm spines round in cross section, smooth, 2-4 small tentacle scales arising from both the lateral and ventral arm plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiomedea 69

DEEP-WATER

OPHIUROIDS FROM

NEW CALEDONIA

— Disc with plates bearing elongated hollow spines with truncate or divided tip; arm spines flattened, with a row of sharp thorns along each lateral edge; 1-3 tentacle scales oval and flat, arising from the lateral arm plate only, large, often covering pore . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiopristis 70 69. Disc covered in granules, 2 elongated oral tentacle scales . . . Ophiomedea discrepans Koehler, 1922a — Disc covered in naked scales, 3 elongated oral tentacle scales (Fig. 7K) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiomedea liodisca (H.L. Clark, 1911) 70. Tentacle scales 2-3 throughout the arm (Fig. 7C-G) . . . . . . . . . Ophiopristis dissidens (Koehler, 1905) — Tentacle scales typically 1, sometimes 2 on basal pores . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 71. Tentacle scales lanceolate; oral shields with a prominent distal lobe, without spines along the distal edge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiopristis vestita (Koehler, 1898) — Tentacle scales rounded; oral shields with a rounded distal angle or a slight distal lobe, a series of small spines along the distal edge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 72. Disc spines pointed or with a minutely bifid tip; arm spines minutely thorny . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiopristis luctosa (Koehler, 1904) — Disc spines truncate or with 1-2 irregular thorns; arm spines notably thorny . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiopristis procera (Koehler, 1904) OPHIOPLINTHACINAE 73. Disc margin incised interradially . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 — Disc circular in shape, without interradial incisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 74. Some arm spines modified into hooklets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 — Arm spines smooth or thorny but not modified into hooklets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 75. Upper arm spines replaced by small hooks . . . . . . . . . . . . . . . . . Ophiodictys pectorale (Lyman, 1880)* — Lowest arm spine modified into a hook (Fig. 15E-L) . . . . . . . . . . . . . . . . . . . . Ophiohamus nanus n. sp. 76. Distal oral papillae operculiform, wider than long; oral shields reduced, surrounded laterally by enlarged adoral shields. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiothamnus 77 — Distal oral papillae can be slightly enlarged but not operculiform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 77. Narrow elliptical to diamond-shaped oral shields, more than two times as long as wide, tiny, dwarfed by the large adoral shields. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 — Oral shields as high as wide, rounded triangular, tear-shaped or diamond-shaped. . . . . . . . . . . . . . 79 78. Numerous disc plates, at least 12 from centre to margin; disc spines short, less than 0.1 mm in height; tentacle scales as long as the ventral arm plate . . . . . . . . . . . . . Ophiothamnus venustus Matsumoto, 1915* — Disc plates covered in coarse plates, up to 5 between the centre and margin; disc spines short or long; tentacle scales almost as long as the ventral arm plate in length . Ophiothamnus remotus Lyman, 1878a* — Disc deeply incised, plates restricted to a few in the centre of the disc and 3-4 rows on the ventral disc surface; disc spines to 0.4 mm high; tentacle scales shorter than the ventral arm plate in length (Fig. 13A-E) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiothamnus biocal n. sp. 79. Long arms, more than 20 times the disc diameter . . . Ophiothamnus longibrachius H.L. Clark, 1939* — Short arms, probably as short as 3 times disc diameter. . . . . . . . Ophiothamnus otho A.H. Clark, 1949 80. No disc stumps, spines or granules . . . . . . . . . . . . . . . . . . . . . Ophioplinthaca weberi (Koehler, 1904) 19 — Disc spines predominantly spherical to capitate (spherical with a short stalk) granules, smooth or covered with minute thorns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 — Disc spines predominantly stumps, 1-3 times as high as wide, crowned by short thorns . . . . . . . . 85 — Disc spines predominantly thorny or smooth spines, greater than 3 times as high as wide. . . . . . . 93 81. Radial shields long and narrow, parallel, separated by at least their own width, sunken below the disc plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophioplinthaca bythiaspis (H.L. Clark, 1911) — Radial shields contiguous, at least distally, shape varies from oblong, to rounded to triangular, not sunken, at the same level as disc plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 82. Radial shields massive taking up much of the dorsal disc surface, broadly contiguous (Fig. 18H) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophioplinthaca defensor Koehler, 1930

131

132


— Radial shields rounded triangular, 1/3 to 1/7 the diameter of the disc, separate proximally for at least half their length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 83. Upper arm spines very short and stout, similar to elongated disc granules, less than one segment long (Fig. 18A-B) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophioplinthaca miranda Koehler, 1904 — Upper arm spines slender, thorny, 1.5 to 3 arm segments in length. . . . . . . . . . . . . . . . . . . . . . . . . . . 84 84. In addition to spherical granules, some granules are bowl-shaped, like a spherical granule that has been split in half horizontally, others are elongated into a club shape (Fig. 18E-F) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophioplinthaca tylota H.L. Clark, 1939 — Disc granules bluntly conical . . . . . . . . . . . . . . . . . . . . . . . . . . Ophioplinthaca crassa H.L. Clark, 1939 20 — Disc granules all spherical to capitate (Fig. 18C). . . . . . . . . . . . . Ophioplinthaca pulchra Koehler, 1904 85. Radial shields long and narrow, four times as long as wide, parallel, separated by at least their own width . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 — Radial shields oval to oblong, contiguous at least distally . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 86. Disc with ‘‘numerous elongate granules with a few radiating spinules at the summit’’; ventral and dorsal arm plates separate, distal edge of ventral arm plate not notched . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophioplinthaca athena A.H. Clark, 1949* — Disc with stumps, two times as high as wide, often slightly wider near the truncate apex, thorns projecting vertically at the apex, with some on the upper trunk; ventral and dorsal arm plates contiguous, ventral arm plates notched in the centre of the distal margin (Fig. 9H-J) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophioplinthaca citata Koehler, 1904 87. Oral shields reduced or lacking, replaced by enlarged adoral shields (Fig. 18k) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophioplinthaca laudator Koehler, 1930 — Oral shields as large as adoral plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 88. Radial shields at least twice as long as wide, 1/4 the diameter of the disc . . . . . . . . . . . . . . . . . . . . . 89 — Radial shields as long as or slightly longer than wide, 1/6 the diameter of the disc. . . . . . . . . . . . . . 91 89. Radial shields contiguous for most of their length; disc stumps with 3-6 thorns, not all terminal (Fig. 18J) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophioplinthaca papillosa H.L. Clark, 1939 — Radial shields contiguous for distal half or slightly separate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 90. Disc stumps conical, sometimes with a few terminal thorns (Figs 8M-P, 18G) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophioplinthaca plicata (Lyman, 1878a) — Disc with ‘‘swollen cylindrical stumps with a flaring group of a few spines’’ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophioplinthaca semele (A.H. Clark, 1949)* — Disc stumps narrow at the base, the expanded apex bearing a crown of thorns (Fig. 18I) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophioplinthaca monitor Koehler, 1930 91. Disc stumps club-shaped, thorny (Fig. 8I-L) . . . . . . . . . . . . . . . Ophioplinthaca hastata Koehler, 1922a — Disc ‘‘stumps terminating in a flaring irregular crown of a dozen or so spinules’’ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophioplinthaca clothilde A.H. Clark, 1949* — Disc stumps predominantly trifid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 92. Disc stumps variable, some simply trifid, others with three terminal bifurcating branches, others multifid (Fig. 8D-H). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophioplinthaca globata Koehler, 1922 21 — Disc stumps only, with three terminal bifurcating branches. . . . Ophioplinthaca manillae Guille, 1981 93. Disc with long, slender spines, smooth or with a few minute thorns along their length (Figs 9A-C) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophioplinthaca rudis (Koehler, 1897) — Disc spines with notable irregular thorns along their length, terminating 1-3 sharp points (Figs 9D-G) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophioplinthaca amezianeae n. sp. 94. No dorsal arm plates; one block-like oral papillae on each jaw side; minute oral shields (West Indies) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Microphiura* — Dorsal arm plates; three to numerous lateral oral papillae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

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95. A cluster of oral papillae at each jaw apex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 — A single oral papillae at each jaw apex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99 96. Disc with pointed spines, encircled along their length with one or more wreaths of thorns; dorsal arm plates covered in minute pointed spines; tentacle scales thorny, basal pores usually surrounded by several erect scales . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiocamax 97 — Disc with granules or stumps, often terminally thorny; plates smooth, like porcelain; tentacle scales flat, oval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiomitra 98 22 97. Radial shields large and triangular, to 0.3 times d.d, disc spines fine, with a thorny tip and often encircled by a single row of thorns at mid height (Fig. 12A-E). . . . . . . Ophiocamax vitrea Lyman, 1878a — Radial shields rectangular, twice as wide as long, 0.1 times the disc diameter, disc spines stout, encircled with 2 rows of thorns (Fig. 12F-J). . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiocamax nominata (Koehler, 1930) 98. Disc stumps are rounded granules; dorsal arm plates separate; a longitudinal black stripe along the mid-dorsal arm surface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiomitra dives Koehler, 1922a — Disc stumps cylindrical or conical with a crown of terminal thorns; dorsal arm plates contiguous basally; longitudinal white stripe along the mid-dorsal arm surface, bordered on each side by a dark line (Fig. 11H-K) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiomitra leucorhabdota (H.L. Clark, 1911) — Disc stumps cylindrical with a crown of terminal thorns; dorsal arm plates separate; colour unknown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiomitra integra Koehler, 1897 23 99. Disc thick with an angular edge to the dorsal margin (pie-shaped), 1-2 large circular plates dominating the ventrolateral interradial disc surface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiurothamnus 100 — Disc laterally rounded, ventral disc surface covered in small plates or naked. . . . . . . . . . . . . . . . . . 102 100. Radial shields widely spaced (Fig. 13F-I) . . . . . . . . . . . . . . . . . . . . . . . Ophiurothamnus eleaumei n. sp. — Radial shields contiguous or just separate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 101. Disc covered in naked plates or sometimes with spherical granules near the centre (Fig. 14A-J) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiurothamnus clausa (Lyman, 1878 a) — Disc with elongated granules near the centre of the disc. Ophiurothamnus excavatus Koehler, 1922a* 102. Adoral shields extending around the lateral angle of the oral shields; 5-6 oral papillae, the distal one twice as wide as long; arm spines flattened, upper ones near the arm base often widened at the tip, spatulate (Fig. 12K-N). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiocopa spatula Lyman, 1883 — Adoral shields short, not extending around the lateral edge of the oral shield, 3 spiniform oral papillae on each jaw side; arm spines fine and pointed or blunt and clavate, but not spatulate . . . . . . . . . . . . 103 103. Disc plates bearing spines with divergent apical thorns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 — Disc bearing stout elongated stumps or granules. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 — Disc covered in small spherical granules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110 104. Arms short, measuring less than 2 times the diameter of the disc (Fig. 18P) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiomitrella barbara Koehler, 1904 — Arms more than four times the diameter of the disc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105 105. Disc spines stellate, with long terminal thorns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 — Disc spines trilobed at the tip, each lobe may or may not bear short thorns. . . . . . . . . . . . . . . . . . . 107 106. Disc spines terminate in 5-7 long webbed thorns that radiate perpendicularly from the stalk of the spine (Fig. 10N-Q) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiomitrella polyacantha (H.L. Clark, 1911) — Disc spines with 6 long terminal thorns, typically formed by a bifurcation of three primary thorns (Fig. 11E-G) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiomitrella stellifera Matsumoto, 1917 107. Disc spine lobes without terminal thorns (Fig. 18R) . . . . . . . Ophiomitrella mutata Koehler, 1904 24 — Disc spine lobes terminating in an irregular series of thorns, some spines cylindrical or capitate. 108 108. Disc spines elongated and cylindrical near interradial margin (Fig. 18Q) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiomitrella nudextrema (H.L. Clark, 1939) 25 — Disc spines capitate near interradial margin . . . . . . . . . . . . . . . . Ophiomitrella subjecta Koehler, 1922a*

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109. Disc granules, spherical to club-shaped, large, to 0.8 mm diameter; radial shields contiguous or narrowly separate (Figs 10F-H, 18N-O) . . . . . . . . . . . . . . . . . . . . . Ophiomitrella conferta (Koehler, 1922b) — Disc granules spherical, small, to 0.16 mm diameter; radial shields separate, parallel (Figs 10A-E, 18L) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiomitrella parviglobosa n. sp. — Disc granules slightly tabulate, with a flattened slightly-widened apex; radial shields contiguous (Figs 10I-M, 18M). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiomitrella mensa n. sp. — Disc granules cylindrical, higher than wide, with a crown of thorns at the apex; radial shields just contiguous distally. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiomitrella hamata Mortensen, 1933b* 110. Five thorny arm spines, one arm segment in length; epizoic, arms often curled dorso-ventrally under disc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ‘‘Ophiophthalmus’’ relictus (Koehler, 1904) 26 — Numerous (9-11) smooth arm spines, uppermost spines near the base of the arm more than 3 segments long; habitat unknown. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 111. Ventral and lateral disc surface contracted, naked or with some small plates embedded in skin. 112 — Ventral disc surface with similar disc plates to dorsal surface, bearing small scatted disc granules (Fig. 11 L-N) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiomitrella granulosa (Lyman, 1878a) 112. Radial shields triangular, separate (Figs 11A-D, 18S) . . . . . . . . Ophiomitrella tenuis (Koehler, 1904) — Radial shields quadrilateral, contiguous along their length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiomitrella suspectus (Koehler, 1922a) 27 OPHIOHELINAE 113. Arms with hyaline parasol-shaped hooklets on distal segments . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114 — Arms with arm spines only, no accessory hooklets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115 114. One series of oral papillae along the jaw edge. . . . . . . . . . . . . . . Ophiohelus pellucidus Lyman, 1880* — Several series of oral papillae, flattened, spatulate to comma-shaped . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiotholia spathifer (Lyman, 1879)* 115. Five arms; several series of oral papillae, flattened, spatulate to comma-shaped (Fig. 15A-D) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophiomyces delata Koehler, 1904 — Seven arms; one series of oral papillae along the jaw edge . Ophiothauma heptactis H.L. Clark, 1938*

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DISCUSSION Taxonomic changes The large number of taxonomic revisions contained in this paper (including 37 species-level synonyms, 5 genus-level synonyms, 19 new genus-species combinations, see Table 1) indicates the inadequate prior level of knowledge of Indo-Pacific ophiacanthid and hemieuryalid taxonomy. The lack of access to comparative type material by early researchers impeded a systematic approach, and combined with inadequate type illustrations and the natural morphological variability of many species, frequently has led to the same species being described in several different regions. Detailed illustrations and measurements of the disc spines are essential to the identification of ophiacanthids and yet these were rarely available in early reports. Only Koehler’s (1922a) splendid Philippine monograph provides photographs of disc spines that are adequate enough for identification. Moreover, in many ophiacanthids the disc spines change shape and size during ontogeny, which frequently has lead to misidentification of juvenile specimens. The lack of opportunities to travel to other museums or borrow type material, effectively created three schools of identification for Indo-Pacific ophiacanthids: the Americans (Lyman, H.L. Clark), the French (Koehler, Guille), and the Japanese (Matsumoto, Murakami). Paratypes of many Challenger species were deposited in the USNM or the Museum of Comparative Zoology at Harvard and thus were available to Clark. Koehler retained one or two specimens of many species he described at the University in Lyon where he worked. These specimens were retrieved by Guille many years after Koehler’s death (they were being used in student practical classes!) and deposited in the Muséum national d’Histoire naturelle in Paris. Some of Matsumoto’s type specimens, long thought lost during World War II, have just been rediscovered at the University of Tokyo (Toshihiko Fujita pers. comm.). Nevertheless, we have reservations about creating more wide-ranging morphologically-variable species. Recent population genetic studies of shallow-water echinoderms have revealed that some ‘‘species’’ are in fact complexes of several cryptic species (see O’Hara et al. 2004). Although, nothing is known of molecular variation in deep-sea ophiacanthids, their morphological variability and tendency to live in fragmented habitats (e.g. on arborescent cnidarians on seamounts) indicates a potential for cryptic speciation. The extensive list of synonymies reported in this paper may have to be reassessed in the light of future molecular research. Taxonomic issues requiring further investigation This work also highlights the large number of taxonomic problems that still require resolution within these two families. The distinction between the Ophiacanthidae and the Hemieuryalidae is unclear. Fell (1960) distinguishes these families on the basis of their vertebrae, which supposedly have broad saddle-shaped articulations in the Hemieuryalidae, allowing the arm to roll vertically into tight coils. However, ophiacanthids can also possess saddle-shaped joints (Litvinova 1994), and there is much similarity between hemieuryalid species and small epizoic ophiacanthid species, both of which can coil and twist their arms. For example, specimens of Ophiurothamnus clausa have been referred to both families.

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This review follows Paterson (1985) in dividing the Ophiacanthidae into four subfamilies. This scheme is largely satisfactory from a classification viewpoint (the subfamilies are paraphyletic in the only cladistic analysis — see Smith et al. 1995). However, there are genera that do not fit comfortably into any subfamily, particularly within the Ophiotominae, which may be polyphyletic as currently understood. Ophiotoma, Ophiomedea, Ophiologimus, Ophiopristis, Ophiotrema and Ophioprium are a cohesive group, characterised by numerous spiniform to spatulate oral papillae that are more or less confluent with a ring of oral tentacle scales. But genera like Ophiolimna, Amphilimna, Ophientrema and Ophiocymbium have completely different arrangements of oral papillae and are only included in the Ophiotominae because they have an elongate jaw, which may have evolved independently. The limits of many ophiacanthid genera are obscure (Paterson 1985). The speciose genera, Ophiacantha, Ophioplinthaca and Ophiomitrella are ancient (the first two date back to the Mesozoic, see Jagt 2000) and contain recognizable internal clades. For example, within Ophiacantha, O. bathybia/O. cosmica/O. sociabilis, O. rosea/O. vivipara/O. pentactis/O. nodosa and O. longidens/O. legata/O. fuscina are obvious groups. These groups possibly deserve equal status with recognized genera with more obvious apomorphies, such as Ophiacanthella. Genera such as Ophiomelina, Ophiotreta and Ophiolebes may in turn be paraphyletic with respect to Ophiacantha as it is currently defined. The relationships between Ophiomitrella, Ophioripa, ‘‘Ophiophthalmus’’, Ophiomitra and Ophiocopa also require investigation. The resolution of these problems requires a phylogenetic approach using both quantitative morphological and molecular data. A large size series is necessary to observe the development of skeletal elements and their change of shape and position during ontogeny. Many ophiacanthid genera were described by Verrill (1899a, 1899b) based on species from the West Indies or western Atlantic. A revision of these taxa was outside the scope of this project. At the species-level, there are several complexes that require further attention. This is particularly true within Ophioplinthaca, where every population (or in some cases every specimen) has a slightly different morphology. This has led to a proliferation of species names (in contrast to the equally variable Ophiocamax where much of the variation is assumed to be subspecific). It is going to require many more specimens from across the Indo-Pacific, or a molecular study to resolve species limits in this genus. Other problematic species complexes include the Ophiacantha duplex group, the Ophiacantha pentagona group, the Ophiomitrella mutata/O. subjecta group, the polymorphic Ophiurothamnus clausa, some Ophiotreta species, Ophiothamnus and Ophiopristis in the Ophiacanthidae and Ophiomoeris in the Hemieuryalidae. BIOGEOGRAPHY The ophiacanthid and hemieuryalid fauna of New Caledonia consists almost entirely of tropical Indo-West Pacific species. Of the 48 species reported here from the New Caledonian region, 7 are apparently endemic (all newly described) and 35 have also been reported from Indonesia or the Philippines. The remaining six have been reported from elsewhere in the Pacific (Ophiacantha cornuta from the Norfolk and Kermadec ridges, Ophiolimna placentigera from Fiji and Ophiologimus quadrispinus from Hawaii), one from Japan (Ophiomedea liodisca), one from the southern Tasman Sea (Ophiomitrella conferta) and one is widespread (Ophiolimna antarctica). Of the 132 Indo-Pacific ophiacanthid species listed in the key, just over one third are recorded in this report from the New Caledonian region. One interesting omission is the speciose genus Amphilimna, which in the Indo-Pacific is known from east Africa, China, Philippines, Indonesia and Pitcairn Is. Many of the New Caledonian species shared with Indonesia are also widespread throughout the tropical Indo-Pacific from Africa to Hawaii. In contrast, there is a marked turnover of species between the New Caledonian region (19-25°S) and Tasmania in the south-west Tasman Sea (40-44°S). Only five species (Ophiacantha vepratica, Ophiolimna antarctica, Ophioplinthaca plicata, Ophiomitrella conferta, Ophiurothamnus clausa) appear to be common to the two regions (O’Hara 1998) and most of these have enough morphological variability to suggest that they may consist of suites of cryptic species. The same five species have been reported from New Zealand, in addition to Ophiacantha levispina, O. pentagona and Ophiomoeris obstricta. In summary, there appears to be a single ophiacanthid fauna at upper to middle slope depths (200-2500 m) across the Indo-West Pacific from Africa to Hawaii, with limited east-west differentiation. This fauna grades into distinct temperate

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bathyal faunas near South Africa, China/Japan and Australia/New Zealand, until there is an almost complete changeover of species by 45° latitude in both hemispheres. ACKNOWLEDGEMENTS We would to thank Dr. Nadia Améziane and Marc Eleaume for hosting a three month visit by one of us (Tim O’Hara) to the Muséum national d’Histoire naturelle in Paris from September to December 1999. We also thank Ann Whittall (BMNH), Andrew Cabrinovic (BMNH), Joke Bleeker (ZMA), Claus Nielsen (ZMC) and Ashok Kumar Singh (ZSI) for hosting visits to their institutions, and to Cynthia Ahearn (USNM) for providing specimens. We also wish to thank Marc Eleaume (MNHN) for translating the abstract, Christine Hammar (SMNH) for processing countless rolls of film the reviewers, Bertrand Richer de Forges (IRD) and all the french expeditioners who collected the samples. This project was financially supported by visiting scientist grants from the Muséum national d’Histoire naturelle, Paris, the Naturhistoriska Riksmuseet, Stockholm, and Riksmusei vänner, Stockholm.

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