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Zootaxa 1464: 1–43 (2007) www.mapress.com / zootaxa/

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Tanaidacea (Crustacea: Peracarida) from Japan. II. Tanaidomorpha from the East China Sea, the West Pacific Ocean and the Nansei Islands KIM LARSEN1 & MICHITAKA SHIMOMURA2 Department of Natural History, Kitakyushu Museum of Natural History & Human History, 2-4-1, Higashida, Yahatahigashi-ku. Kitakyushu 805-0071, Japan. E-mail: [email protected] [email protected]

Table of contents Abstract ...............................................................................................................................................................................2 Introduction .........................................................................................................................................................................2 Materials and methods ........................................................................................................................................................3 Systematics.......................................................................................................................................................................... 4 Suborder Tanaidomorpha ....................................................................................................................................................4 Family Colletteidae Larsen & Wilson, 2002 .......................................................................................................................4 Genus Tumidochelia Knight, Larsen & Heard, 2003 .......................................................................................................... 4 Tumidochelia knighti n. sp........................................................................................................................................... 4 Tumidochelia uncinata (Hansen, 1913) new comb.......................................................................................................7 Tumidochelia dentifera (G.O. Sars, 1896) new comb. ................................................................................................. 8 Key to the species of Tumidochelia, females ......................................................................................................................9 Family Leptocheliidae Lang, 1973 ..................................................................................................................................... 9 Subfamily Heterotanaidinae Larsen & Wilson, 2002 ......................................................................................................... 9 Genus Mesotanais Dollfus, 1897 ........................................................................................................................................ 9 Mesotanais birdi n. sp.................................................................................................................................................. 9 Key to the species of Mesotanais, females ....................................................................................................................... 13 Family Leptognathiidae Sieg, 1973 .................................................................................................................................. 14 Key to the genera of Leptognathiidae ...............................................................................................................................14 Genus Leptognathia G.O. Sars, 1882 ................................................................................................................................ 14 Leptognathia bamberi n. sp. ......................................................................................................................................15 Key to the Leptognathia sensu stricto ...............................................................................................................................19 Biarticulata n. gen. .....................................................................................................................................................19 Forcipatia n. gen. .......................................................................................................................................................19 Family Nototanaidae Sieg, 1973 ....................................................................................................................................... 20 Genus Typhlotanais G. O. Sars, 1882................................................................................................................................ 20 Typhlotanais magdalensis n. sp. ................................................................................................................................20 Typhlotanais ohtsukae n. sp. ......................................................................................................................................24 Family Tanaellidae Larsen and Wilson, 2002 ...................................................................................................................28 Genus Tanaella Norman & Stebbing, 1886 ...................................................................................................................... 28 Tanaella kommritzia n. sp. .........................................................................................................................................28 Family incerta sedis ...........................................................................................................................................................32 Genus Chauliopleona Dojiri & Sieg, 1997 .......................................................................................................................32 Chauliopleona hansknechti n. sp............................................................................................................................... 33 Chauliopleona dentata Dojiri & Sieg, 1997 ..............................................................................................................38 Additional species .............................................................................................................................................................41 Acknowledgements ...........................................................................................................................................................41 Literature cited ..................................................................................................................................................................42 Accepted by J. Svavarsson: 5 Mar. 2007; published: 3 May 2007

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Abstract The Japanese shallow water fauna of tanaidomorphan Tanaidacea are examined. Seven new species Tumidochelia knighti, Mesotanais birdi, Leptognathia bamberi, Typhlotanais magdalensis, Typhlotanais ohtsukae, Tanaella kommritzia and Chauliopleona hansknechti are described. Chauliopleona dentata Dojiri & Sieg, 1997, from the type locality (California) is re-described. Leptognathia dentifera and L. unicinata are transferred to Tumidochelia. The genus Leptognathia is redefined and a number of species removed from the genus. The new leptognathid genera Biarticulata and Forcipatia are erected. A key to the Tumidochelia, Mesotanais, Leptognathia sensus stricto, and Forcipatia is given. Key words: Tanaidacea, Tanaidomorpha, Biarticulata, Forcipatia, Tumidochelia, Mesotanais, Leptognathia, Typhlotanais, Tanaella, Chauliopleona, Japanese fauna

Introduction This is the second of a series of systematical papers on the Tanaidacea from Japanese waters. This study reports on the species within the suborder Tanaidomorpha from the East China Sea, the West Pacific Ocean, and the Nansei Islands. For an overview of the previous literature published on the Tanaidacea from Japan, see Larsen & Shimomura (2006). Most systematic studies on the Tanaidacea from Japan have focused on the suborder Apseudomorpha. The much more abundant suborder Tanaidomorpha has been largely ignored, probably due to their smaller size and the design of the sampling gear employed at the time which were not suitable for smaller benthic invertebrates. There are some exceptions to this rule; Kudinova-Pasternak (1966, 1984) described a large number of deep-sea Tanaidomorpha, although most are from the deep sea surrounding Japanese territorial waters. Also Shiino (1951) and Ishimaru (1985) have recorded or described a few tanaidomorphan species. A list of species recorded from Japan or its surrounding deep sea, is given in table 1. TABLE 1. Tanaidomorpha recorded from Japanese waters or surrounding deep sea. Species

Authority

Reference

Locality/Habitat

Anarthruopsis longus

Kudinova-Pasternak, 1984


Sea of Japan, 200–1130 m.

Anatanais normani

(Richardson, 1905)

Shiino, 1951

South coast of Honshu, West Pacific ocean, intertidal, on algae, sponges, acidians and barnacles.


North West Pacific, 2193–4895 m.

Biarticulata tuberculata (Hansen, 1913) Chauliopleona hansknechti

Larsen & Shimomura This study

West Pacific Ocean, 260–278 m.

Leptochelia itoi

Ishimaru, 1985

Ishimaru, 1985

South coast of Honshu, Pacific Ocean, 1–4 m. Sand

Leptochelia dubia**

Krøyer, 1842

This study; Shiino, 1952; Seto Inland Sea, littoral, on algae and Ishimaru, 1985 sponges. North coast of Hokkaido, Sea (as Leptochelia savigney) of Japan,

Leptognathia birsteini (Not Leptognathia)



Leptognathia bamberi


Osumi Strait, 223–367m.

Metatanais cylindricus

Shiino, 1952

Seto Inland Sea, littoral, on algae and sponges

Shiino, 1952


to be continued.

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LARSEN & SHIMOMURA

TABLE 1 (continued). Species

Authority

Reference

Locality/Habitat

Mesotanais birdi


West Pacific Ocean 186–169 m.

Paratyphlotanais japonicus




Pseudotanais vitjazi




Sinelobus stanfordi

Richardson, 1901

Miyadi, 1938; Shiino, 1951 Southern Kurile Islands, fresh water lakes South coast of Honshu, West Pacific Ocean, intertidal, on algae, sponges, acidians and barnacles.

Tanaella kommritzia


Tanais dulongii

(Audouin, 1826)

Shiino, 1951 (as Tanais South coast of Honshu, West Pacific, cavolinii) intertidal, on algae, sponges, acidians and barnacles.

Tanaopsis curtus



Tumidochelia knighti


East China Sea 654–635 m.

Typhlotanais angularis



North West Pacific, 6065 m.

Typhlotanais compactus Kudinova-Pasternak, 1966



Typhlotanais grandis

Hansen, 1913


Circum polar, 1265–6135 m.

Typhlotanais rectus



Central and North West Pacific, 3610– 7370 m.

Typhlotanais setosus



North Pacific, 4895–6051 m.

Typhlotanais simplex




West Pacific Ocean, East China Sea, 169–654m.


Typhlotanais magdalen- Larsen & Shimomura This study sis

West Pacific Ocean, Osumi Strait, 169– 367 m.

Typhlotanais ohtsukae

Osumi Strait, 367–254 m


** The Leptochelia dubia/savigney complex and synonymy problems are still unresolved (Heard et al. 2004) and many specimens referred to this species complex are probably separate different species.

Materials and methods The type materials are deposited in the Kitakyushu Museum of Natural History & Human History, Japan. Most of the material was collected by Professor S. Ohtsuka and party during the annual cruises of the TR/ V Toyoshio-maru, Hiroshima University and R/V Tansei-maru, University of Tokyo. Terminology follows Larsen (2003). Abbreviations are as follows: KMNH (Kitakyushu Museum of Natural History and Human History); ZMUC (Zoological Museum, University of Copenhagen); NHMO (Natural History Museum of Oslo); SBMNH (Santa Barbara Museum of Natural History); NHMLAC (Natural History Museum of Los Angeles County, ZMH (Zoological Museum Hamburg). TANAIDACEA FROM JAPAN

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Systematics Suborder Tanaidomorpha Family Colletteidae Larsen & Wilson, 2002 Genus Tumidochelia Knight, Larsen & Heard, 2003 Diagnosis. Female (modified from Knight et al. 2003). Body elongate. Antennule article 1 shorter than rest of antennule, article 2 almost as long as article 1. Antenna with five or six articles, article 3 with or without fusion line. Mandible molar pointed but not quite as much as in Leptognathia, with small apical spines. Cheliped with inflated “shield-like” expansion of the inner distal side of the carpus. Pereopod 1 carpus shorter than merus Pereopods 1–3, propodus longer than dactylus and unguis combined. Pereopods 4–6, propodus longer, or as long as dactylus and unguis combined. Pleopods small but present. Uropod bearing spiniform distal process on inner margin of basal article; endopod and exopod each with 2 articles. Male. Listed as ‘unknown’ by Knight et al. (2003) but one male is reported by Hansen (1913:84, pl.VIII, 4f–i) belonging to L. uncinata (transferred to Tumidochelia below). This male is of the ‘swimming male’ type with no functional mouthparts, reduced pereon, and multiarticulated antennule with multiple aesthetacs, but differing from the leptognathid male by a biarticulated uropodal exopod. It is not certain that his male belongs to Tumidochelia as other species (leptognathids) were found in the same sample. Type species. Tumidochelia randyi Knight, Larsen & Heard, 2003 by monotypy. Gender. Feminine. Remarks. With the finding of the new species, described below, and the transfer of Leptognathia unicinata Hansen, 1913 and L. dentifera G.O. Sars, 1896 there can be no doubt as to the validity of the genus Tumidochelia. There is, however, some doubts as to the family designation of the genus. While currently placed in the family Colletteidae the genus is probably better placed in the Leptognathiidae but this transfer will have to await a comprehensive phylogenetic analysis. The basis for this statement is the pointed nature of the mandibular molar.

Tumidochelia knighti n. sp. (Figs 1 and 2) Material examined. Holotype, non-ovigerous female (KMNH IvR 700.166), Station 8, 26°26.63’N, 127°33.04’E, 654–635 m, sand, Northwest of Cape Zanpa, Okinawa, 27 May 2006. Paratype, 1 non-ovigerous female (KMNH IvR 700.167), dissected, same locality. Diagnosis. Female. Pereonites 2 and 3 longer than wide, pereonite 2 longest. Pleotelson shorter than combined length of three pleonites. Antenna with five articles, article 3 longer than other articles, without fusion line. Mandibular molar tapering abruptly, with one anterior spine at apex. Male. Unknown. Etymology. The species is named after Ms. Julianne Knight who described the genus Tumidochelia. Description (body of holotype, appendages of dissected paratype). FEMALE. Body (Fig. 1A, B). Body length 3.6 mm. Sub-cylindrical, elongate, approximately 9.5 times longer than wide. Cephalothorax. Longer than wide (l/w 1.5) with no pronounced spines or setae. Pereonites. Pereonites 1 and 6 wider than long. Other pereonites longer than wide, pereonites 2 longest. Pleonites. All wider than long, subequal, bearing pleopods.


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FIGURE 1. Tumidochelia knighti n. sp. A, holotype, female, dorsal view; B, same lateral view, scale bar = 0.4 mm. C, antennule; D, antenna; E, labrum; F, right mandible; f, same, other side; G, left mandible; H. labium; I, maxillule; J, maxilla; K, maxilliped; L, pleopod; M, uropod. Scale bars = 0.2 mm. TANAIDACEA FROM JAPAN


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FIGURE 2. Tumidochelia knighti n. sp. A, cheliped; B, pereopod 1; C, pereopod 2; D, pereopod 3; E, pereopod 4; F, pereopod 5; G, pereopod 6. Scale bar = 0.2 mm.

Pleotelson. Shorter than combined length of three pleonites. Antennule (Fig. 1C). With four articles. Stout at base tapering distally, almost as long as carapace. Article 1 with one simple distal seta and three subdistal setulated setae; article 2 approximately 0.80 times as long as article 1, with two simple distal setae; article 3 approximately 0.3 times length of article 2, with one simple distal seta; article 4 narrowing distally, approximately twice length of article 3, with six simple distal setae. Antenna (Fig. 1D). With five articles. Approximately 0.7 times as long as antennule. Article 1 wider than other articles, with dorsodistal process and one distal seta; article 2 band-shaped, with one distal seta, Article 3 longer than other articles, without fusion line, with one distal seta; article 4 with two simple distal setae; article 6 approximately 0.25 length of article 5, with three simple distal setae. Mouthparts. Relatively small (mandibular body less than 0.1 mm), considering size of entire animal, mouthparts are very small. Labrum (Fig. 1E) apex pointed, apparently naked. Mandibles (Fig. 1F, f1, G) molar of intermediate width, tapering abruptly, anterior spine at apex. Left mandible (Fig. 1G) incisor narrow, with three distal denticles; lacinia mobilis blunt. Right mandible (Fig. 1F, f1) incisor with two rows of several acute denticles. Labium (Fig. 1H) with one pair of lobes, with small acute process at outer corners. Maxillule (Fig. 1I) endite with seven terminal spiniform setae of which two are setulose; palp not recovered. Maxilla (Fig. 1J) narrow and fairly large (half as long as maxillule endite). Maxilliped (Fig. 1K) endites with blunt dis-


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tal process, fairly wide (almost as wide as basis). Basis fused. Palp article 1 naked; article 2 with two inner setae; article 3 with three inner setae; article 4 with four setae. Epignath not recovered. Cheliped (Fig. 2A). Attached to cephalothorax by a large sclerite. Basis naked, narrow in posterior part, approximately as long as carpus. Merus with two ventral setae. Carpus widening distally, with two small dorsal setae and one simple ventrodistal seta, ventrodistal part inflated, extending distally past propodus articulation. Propodus shorter than basis, with two simple ventral setae mid-length, and three small distal setae proximal to fixed finger. Fixed finger displaying two spines and three setae on inner margin. Dactylus large, with one dorsoproximal seta. Pereopod 1 (Fig. 2B). Longer than other pereopods. Coxa with one seta. Basis robust without seta. Ischium with one simple distal seta; merus widening distally, longer than carpus, with two ventrodistal setae. Carpus rectangular, half as long as propodus, with two spiniform distal setae. Propodus elongate, longer than merus, with one spiniform ventro-subdistal seta, ventral margin with row of small spines and dorsal spine. Dactylus and unguis approximately 0.4 times length of propodus, dactylus with distal spine at unguis insertion. Unguis as long as dactylus. Pereopod 2 (Fig. 2C). As pereopod 1 except: smaller; coxa naked; merus shorter; carpus with two spiniform and two simple distal setae; dactylus with only one spine. Pereopod 3 (Fig. 2D). As pereopod 2 except: dactylus smooth. Pereopod 4 (Fig. 2E). As pereopod 2 except: propodus with three spiniform distal setae; dactylus (including unguis) as long as propodus, with ventral serration; unguis less than 0.3 times as long as dactylus. Pereopod 5 (Fig. 2F). As pereopod 4 except: basis without seta; dactylus with notches extending the full length of posterior margin. Pereopod 6 (Fig. 2G). As pereopod 4 except: propodus, with four distal setae. Pleopods (Fig. 1L). Basal article smooth. Endopod rectangular, with numerous simple distal setae. Exopod rectangular, with one robust proximal seta, and numerous simple distal setae. Uropods (Fig. 1M). Biramous, basal article naked, with dorsomedial spiniform process. Endopod with two subequal articles; article 1 with two simple distal setae; article 2 with four simple distal setae. Exopod only reaching just beyond midlength of first endopod article, with two subequal articles; article 1, with one simple distal seta; article 2 with two simple distal setae. Remarks. Tumidochelia knighti can be separated from T. unicinata by the long pereonites 2 and 3 and the pleotelson being shorter than combined length of three pleonites. From T. randyi the new species can be discriminated by the short pleotelson and the antenna article 3 longer than other articles being without fusion line. The structure of the mandibular molar also shows a difference in the abrupt tapering and fewer apical spines. Tumidochelia knighti strongly resembles T. dentifera G.O. Sars (1896) but can be separated by the lack of fusion line and a shorter uropodal exopod. Also the geographical distribution would be unlikely for one species. The antenna consists of five articles in T. knighti while T. randyi is described as having six (Knight et al. 2003). However, there is some uncertainty about the condition of T. randyi as no complete antenna was recovered (Knight et al. 2003:500); also the presence/absence of a fusion line can confuse the issue as some workers might count the pseudoarticulation as a real articulation.

Tumidochelia uncinata (Hansen, 1913) new comb. Leptognathia uncinata Hansen, 1913

Material. Holotype, non-ovigerous female, (ZMUC CRU-8518), Davis Strait, Ingolf Sta. 36, 61°50’N, 56°21’W, 2702 m. Paratype, 1 juvenile (ZMUC CRU-9275), Ingolf Sta. 103, 66°23’N, 8°52’W, 1090 m.

TANAIDACEA FROM JAPAN


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Remarks. Leptognathia unicinata is transferred to Tumidochelia due to the special structure of the cheliped carpal shield and the biramous uropod with a spiniform process on the basal article. It also conforms to the other diagnostic characters: antennule article 1 shorter than rest of antennule, article 2 almost as long as article 1, and the pereopod 1 carpus shorter than merus.

Tumidochelia dentifera (G.O. Sars, 1896) new comb. (Fig. 3) Leptognathia dentifera G.O. Sars, 1896

Material. Syntypes, 8 non-ovigerous females, 1 ovigerous female, (NHMO F15188), Christiania Fjord (Olso Fjord) 113–188 m. Supplementary description (appendages of dissected paratype). FEMALE. Mouthparts. Labrum apex curved and setose (Fig. 3A). Right Mandible (Fig. 3B) incisor with three acute denticles. Labium (Fig. 3C) with one pair of lobes, without process at outer corners. Maxillule (Fig. 3D) endite with eight terminal spiniform setae of which two are setulose; palp not recovered. Maxilla (Fig. 3E) narrow and fairly large (half as long as maxillule endite). Maxilliped (Fig. 3F) endites with blunt distal process, fairly wide (almost as wide as basis). Basis fused. Palp article 1 naked; article 2 with two inner setae; article 3 with three inner setae; article 4 with four setae.

FIGURE 3. Tumidochelia dentifera G.O. Sars, 1896, syntype, female. A, labrum; B, right mandible; C, labium; D, maxillule; E, maxilla; F, maxilliped; G, cheliped. Scale bars = 0.2 mm.


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Cheliped (Fig. 3G). Attachment via large sclerite. Basis naked, narrow in posterior part, approximately as long as carpus. Merus with one ventral seta. Carpus widening distally, with small dorsodistal seta and one simple ventrodistal seta, ventrodistal part inflated, extending distally past propodus articulation. Propodus shorter than basis, with two simple ventral setae mid-length, and three small distal setae proximal to dactylus. Fixed finger displaying two spines and three setae on inner margin. Dactylus naked. Remarks. Tumidochelia dentifera is very close to T. knighti, but apart from the large distance between the type localities, the obvious fusion line on the antenna article 3 and the longer uropodal exopod of T. dentifera is sufficient to discriminate between these species. As with the species above L. dentifera is here transferred to Tumidochelia due to the biramous uropod with a spiniform process on the basal article; the short antennule article 1 and long article 2. The cheliped carpal shield is not described (G.O. Sars 1896:30) and the illustration (G.O. Sars 1896:p.142, pl1) is not clear regarding this character. However, examination of the syntypes confirms the presence of this character (Fig. 3G) in all specimens and we suspect that Sars illustrated the inner side of the cheliped, thus obscuring this character.

Key to the species of Tumidochelia, females 1. Pleotelson longer than last three pleonites................................................................................................... 2 Pleotelson shorter than last three pleonites ................................................................................................. 3 2. Pereonites of subequal length and width. Antenna article 3 without fusion line............................. T. randyi Pereonite 2 longer than other pereonites. Antenna article 3 with clear fusion line .................... T. uncinata 3 Antenna article 3 with clear fusion line. Uropodal exopod almost reaching the end of first endopod article ..................................................................................................................................................... T. dentifera Antenna article 3 without fusion line. Uropodal exopod barely reaching beyond midlength of first endopod article ....................................................................................................................................... T. knighti

Family Leptocheliidae Lang, 1973 Subfamily Heterotanaidinae Larsen & Wilson, 2002 Genus Mesotanais Dollfus, 1897 Type species. Mesotanais dubius Dollfus, 1897 (by monotypy). Gender. Masculine.

Mesotanais birdi n. sp. (Figs 4 and 5) Material examined. Holotype, non-ovigerous female (KMNH IvR 700.168), Station KG-2, 34°58.192’– 34°58.398’N, 140°05.188’–140°05.115’E, 200–169 m, muddy sand, Off Boso Peninsula, 17 November 2003. Paratypes, 1 non-ovigerous female (dissected) (KMNH IvR 700.169), same data; 1 non-ovigerous female (KMNH IvR 700.170), same data. Diagnosis. Female. Antennule shorter than carapace, with long (almost as long as antennule) setae. Pereopod 5 with long robust setulated basal seta. Uropodal exopod shorter than first endopod article. Etymology. This species is named in honor of Dr. G. Bird, the world’s leading authority on tanaidomorphan crustaceans. TANAIDACEA FROM JAPAN


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Description (body of holotype, appendages of dissected paratype). FEMALE. Body (Fig. 4A). Body length 2.2 mm. Nine times as long as broad. Cephalothorax. Shorter than combined length of pereonites 1 and 2. Eye-lobes present, no visual pigmentation. Pereonites. Pereonites 1 and 6 wider than long. Pereonites 2–5 longer than wide. Pleon. Very short (only 15% of total body length). Pleonites all with pleopods. Last pleonite larger than others. Pleotelson. Longer than combined length of last two pleonites. Antennule (Fig. 4B). Shorter than cephalothorax. With three articles; article 1 longer than rest of antennule combined, with several small proximal setae of which at least one is setulated, with one setulated and one simple medial setae, with two simple and one setulated distal setae; article 2 one-third as long as of article 1, with two simple and one setulated distal setae; article 3 about half length of article 1, with seven simple distal setae of varying length (some almost as long as antennule). Antenna (Fig. 4C). Three-quarters length of antennule. With five articles; article 1 longer than article 4, with one spiniform dorsal setae; article 2 shorter than article 1, with one dorsodistal spine; article 3 longer than other articles, with one simple medial seta three long simple and 2 short setulated distal; article 4 slightly longer than half of article 3, with two distal seta; article 5 minute, with five setae. Mouthparts. Labrum (Fig. 4D) smoothly curved, setose. Mandibles (Fig. 4E–G) molar broad and twisted relative to incisor, longer than incisor. Left mandible (Fig. 4E) lacinia mobilis larger than incisor, with several distal denticles on distal margin; incisor with tapering apex with denticles. Right mandible (Fig. 4F, G) incisor with bifurcate apex and serration on dorsal margin. Labium (Fig. 4H) consisting of two pairs of setose lobes. Maxillule (Fig. 4I) with nine spiniform terminal setae, several distal setules on both margins of endite shaft; palp (Fig. 4J) shorter than endite and with two distal setae. Maxilla (Fig. 4K) elongated and featureless. Maxilliped (Fig. 4L) endites narrower than basis, with three flat, short setae and one simple seta. Basis with two long seta at palp insertion. Palp article 1 naked with pointed process on outer margin; article 2 with four inner setae; article 3 with five–six inner setae; article 4 with five–six setae. Epignath not recovered. Cheliped (Fig. 4M). Basis shorter than carpus, naked, attached via anterior sclerite. Merus with one ventral seta. Carpus shorter than propodus including fixed finger, with three ventral and two dorsal setae. Propodus elongated and with two setae at dactylus insertion. Fixed finger with two ventral setae and three setae on inner margin and with pointed denticles on cutting edge. Dactylus as long as fixed finger, with two dorsal setae. Pereopod 1 (Fig. 5A). Almost twice as long as pereopods 2–6. Coxa with one seta. Basis longer than three following articles combined, with one simple and one setulate seta. Ischium naked. Merus as long as carpus, with one dorsosubdistal seta. Carpus half as long as propodus, with three simple distal setae. Propodus longer than half of basis, with three simple subdistal setae and small dorsal spine. Dactylus and unguis combined longer than propodus and not fused. Unguis marginally shorter than dactylus. Pereopod 2 (Fig. 5B). As pereopod 1 except: somewhat shorter; basis with one simple seta; ischium with one ventral seta; merus widening distally, with two distal setae; carpus three-quarters length of propodus, with one simple and one minute distal spiniform setae; propodus shorter than merus and carpus combined, with two simple and one minute spiniform subdistal setae, apparent without dorsal spine; dactylus and unguis shorter than propodus, not fused; dactylus naked. Pereopod 3 (Fig. 5C). As pereopod 2 except: merus naked; propodus with two subdistal setae and dorsal spine. Pereopod 4 (Fig. 5D). Without coxa. Basis marginally thicker than on pereopods 1–3, naked. Ischium naked. Merus as long as carpus, with one small spiniform ventral seta. Carpus with one simple and two small spiniform distal setae. Propodus shorter than combined length of merus and carpus, with one small ventral


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spiniform seta and three dorsodistal rigid setae. Dactylus and unguis fused to a slender claw, shorter than propodus.

FIGURE 4. Mesotanais birdi n. sp. A, holotype, female, lateral view, scale bar = 0.5 mm; B, antennule; C, antenna; D, labrum; E, left mandible; F, right mandible, incisor; G, same, molar; H. labium; I, maxillule; J, same, palp; K, maxilla; L, maxilliped; M, cheliped. Scale bars = 0.2 mm.



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FIGURE 5. Mesotanais birdi n. sp. A, pereopod 1; B, pereopod 2; C, pereopod 3; D, pereopod 4; E, pereopod 5; F, pereopod 6; G, pleopod; H, uropod. Scale bar = 0.2 mm.


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Pereopod 5 (Fig. 5E). As pereopod 4 except: basis with one large circumplumose ventral seta; carpus with one simple seta. Pereopod 6 (Fig. 5F). As pereopod 5 except: basis with two small setulated setae. Ischium with one seta; merus with two small spiniform setae; carpus with one simple and two small spiniform; propodus with two small ventral spiniform setae and four stout dorsodistal setae Pleopods (Fig. 5G). Well developed. Basal article with one plumose seta. Exopod with nine outer and one inner plumose setae. Endopod with 12 outer plumose setae, gap between proximal seta and other setae. Uropods (Fig. 5H). Biramous, more than half as long as pleon. Basal article naked. Exopod biarticulated, shorter than first endopod article; article 1 with one distal seta, article 2 with two distal setae. Endopod with four articles, with 0–4 distal setae. Remarks. This new species can be separated from all other species of Mesotanais by the short antennule, by the strange long setulated basal seta of pereopod 5, and by the uropodal exopod shorter than first endopod article. In other respects Mesotanais birdi is identical to M. longisetosus Sieg & Heard, 1988 and even shares the long antennular setae character. The dorsal spiniform seta on antenna article 2 seems to have fused into a real spine and no articulation could be observed. This species has a four-articulated uropodal endopod, like that of M. styxis Larsen, Błażewicz-Paszkowycz & Cunha, 2006 but this character is likely ontogentically dependant (Masunari 1983; Bird & Bamber 2000). The antenna is diagnosed with six articles, but the new species described above has only five. This is a reoccurring conflict within many tanaidomorphan taxa, and probably reflects an inherent bias from dissection. It appears as though the antenna is attached to the head via a small pedestal (as in amphipods); this may be interpreted as the first article although it is fused to the head. After dissection it is often no longer possible to decide if there is an articulation or not.

Key to the species of Mesotanais, females 1. Antennae with long terminal setae (about ? total length of antennae or longer) ........................................ 2 Antennae with short terminal setae (about ? total length of antennae)....................................................... 4 2. Pereopod 5 basis with long setulated ventral setae. Uropod exopod shorter than first endopod article........ ............................................................................................................................................ Mesotanais birdi Pereopod 5 basis without long setulated ventral setae. Uropod exopod longer than first endopod article 3 3. . Pereopod 1 carpus with several short distal setae and one longer seta almost reaching half the propodus. Pereopods 4–6 merus with two small spiniform setae............................................ Mesotanais longisetosus Pereopod 1 carpus with several short distal setae only. Pereopods 4–6 merus with one small spiniform and one simple setae .............................................................................................................. Mesotanais dubius 4. Antennule as long as cephalothorax and pereonite 1. Maxilleped basis with three flat setae ....................... ........................................................................................................................................... Mesotanais styxis Antennule as long as cephalothorax. Maxilleped basis with two flat setae................................................. 5 5. Chelipeds slender (carpus longer than propodus inclusive fixed finger). Labium ... lateral corners without spiniform setae ........................................................................................................... Mesotanais elongatus Chelipeds robust (carpus as long as propodus inclusive fixed finger). Labium lateral corners without spiniform setae ................................................................................................................... Mesotanais vadicola



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Family Leptognathiidae Sieg, 1973 Diagnosis. (Modified from Larsen 2005) . Female. Medium body calcification. No plates in carapace. Eyes and eye-lobes absent. Pereon with six free pereonites. Pereonite 1 not reduced. Pleon with five free pleonites, as wide as pereon, no articulated setae on pleonites. Antennule with four articles. Antenna with 5–6 articles, article 3 without spiniform setae dorsally. Molar process of mandible pointed. Labium with one pair of lobes, medial spiniform setae absent. Maxillipedal bases fused, endites not fused, narrower than basis, without setose or serrated antero-lateral corners, flat setae, or denticles. Cheliped slender and attached via sclerite, fixed finger and dactylus elongated or simple. Marsupium consisting of four pairs of oostegites. Pereopod coxae present or absent on pereopods 1–3, but always absent on pereopods 4–6, dactylus and unguis not fused. Pleopods well developed or absent. Uropodal endopod with two articles, exopod with one or two articles. Male (terminal male): body significantly shorter than female. Pereonites less, pleonites more developed than in female. Antennule with more than seven articles, densely packed with aesthetascs. Mouthparts reduced. Cheliped not enlarged. Pleopods well developed.

Key to the genera of Leptognathiidae 1. Uropodal exopod with biarticlulated .............................................................................Biarticulata n. gen. Uropodal exopod with uniarticlulated ......................................................................................................... 2 2. Cheliped propodus enlarged; dactylus longer than fixed finger ...................................... Forcipatia n. gen. Cheliped propodus not enlarged; dactylus as long as fixed finger ................ Leptognathia G.O. Sars, 1882

Genus Leptognathia G.O. Sars, 1882 Gender. Feminine. Type species. Tanais breviremis Lilljeborg, 1864. Diagnosis. Female. Cheliped fixed finger and dactylus simple. Uropodal exopod with one article. Remarks. Although a full scale revision of the Leptognathia is not within the scope of this study, a few changes are justified here. The genus Leptognathia is generally considered paraphyletic- rather than a monophyletic taxon (Sieg 1986a; Larsen 2005) and is often treated as a repository for ‘unidentifiable’ and poorly described deep-sea tanaidomorphans. According to Anderson et al. (2006) the genus Leptognathia currently contain 39 morphologically heterogeneous species of which most are very poorly described. Bird and Holdich (1984) initiated the first serious attempt of a solution by removing and organizing a number of leptognathid species into separate genera. Sieg (1986b), by redescribing the type species L. breviremis Lilljeborg, 1864, provided a much needed platform for a continuation of this effort, by giving a reference point to a more precise diagnosis to the Leptognathiidae. A more restrictive diagnosis of the Leptognathiidae was given by Larsen & Wilson (2002) and of Leptognathia by Larsen (2005), but a number of problems still plagues this genus. One of these problems is a large number of poorly described species, of which many do not correspond to the narrower definition of Leptognathia sensu Larsen. In order to identify the Leptognathia species described below, several of these non-Leptognathia sensu stricto species were identified and are here removed from the Leptognathia, although final genus designation for many species will have to await a more detailed revision. The following species are removed from Leptognathia as they posses a biarticulated uropodal exopod: Leptognathia arctophylax (Norman & Stebbing, 1886); L. distincta Kudinova-Pasternak, 1981; L. elegans


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Kudinova-Pasternak, 1965; L. greveae Kudinova-Pasternak, 1976; L. mironovi Kudinova-Pasternak, 1981; L. parabranchiata Kudinova-Pasternak, 1977*; L. paraelegans Kudinova-Pasternak, 1970; L. tuberculata Hansen, 1913 and L. voeringi (G.O. Sars, 1877), A new leptognathidean genus Biarticulata is here erected to accommodate these species. L. tuberculata may not belong to the Leptognathiidae at all as the structure of the molar is unknown. Another new leptognathidean genus Forcipatia is erected to receive L. rotundicauda Kudinova-Pasternak, 1970; Leptognathia longimanus Larsen, 2005; and L. sp G. (currently undescribed, G. Bird, pers. comm.). Leptognathia angustocephala Kudinova-Pasternak, 1975a; L. birsteini Kudinova-Pasternak, 1965; L. lineate Shiino, 1978; linearis (Hansen, 1913); L. microcephala Kudinova-Pasternak, 1977*; and L. zenkevitchi Kudinova-Pasternak, 1970 are completely removed from the family Leptognathiidae as they have broad mandibular molars. Also removed from the family is L. profunda Hansen, 1913, which have a spiniform exopodal process and probably belongs to Araphura Bird & Holdich, 1984. Leptognathia vinogradovae Kudinova-Pasternak, 1970; L. indivisa (Hansen, 1913) and L. paramanca Lang, 1958, which have uniramous uropods, are also removed from the family. Furthermore, L. dentifera G.O. Sars, 1896 and L. uncinata Hansen, 1913 both possess a biarticulated uropodal exopod and a spiniform process on the uropodal basal articles as well as a cheliped carpal shield, and are here transferred to Tumidochelia (see above). These removals reduced the number of species in the Leptognathia to eight verified species: L. bamberi n. sp; L. breviremis Lilljeborg, 1864; L. breviremoides Sieg, 1986b; L. glandiceps Shiino, 1978; L. gyreae Larsen, 2005; L. longa (Kudinova-Pasternak, 1982); L. manca G.O. Sars, 1882; and L. vitjazi (Kudinova-Pasternak, 1982) and nine species inceta sedis, which may belong to Leptognathia but were the molar structures are not known: L. langi Kudinova-Pasternak, 1970; L. zezinae Kudinova-Pasternak, 1973; L. acanthifera Hansen, 1913; L. crassa Hansen, 1913; L. tenella Hansen, 1913; L. ventralis Hansen, 1913; L. abyssorum (Dollfus, 1897); L. luykeni Vanhöffen, 1914; L. vanhoeffeni Gutu, 1972.

Leptognathia bamberi n. sp. (Figs 6 and 7) Material examined. Holotype, non-ovigerous female (KMNH IvR 700.171), Station 12, 31°14.28’N, 131°32.68’E, 367–254 m, shell sand, East of Cape Toi, Miyazaki, 29 May 2006. Paratype, 1 female (KMNH IvR 700.172) (dissected), Station 2, 31°11.45’N, 131°28.78’E, 223 m, shell sand, East of Cape Toi, Miyazaki, 23 May 2006. Diagnosis. Female. Mandibular molars sharply decrease in width midlength. Pereopod 4–6 meral and carpal spiniform setae short (less than 20 % of article length). Uropods shorter than pleotelson, endopod articles subequal, exopod uniarticulated and shorter than first endopod article. Etymology. The species is named in honor of Dr. R. Bamber, tanaidacean expert. Description (body of holotype, appendages of dissected paratype). FEMALE. Body (Fig. 6A, B). Body length 1.2 mm. Dorso-ventrally flattened, 6.25 times as long as broad. Cephalothorax. Marginally longer than combined length of pereonites 1 and 2. Eyes absent but weak traces of eye-lobes persist. Pereonites. All wider than long. Pleon. About 0.25 times as long as total body length. All pleonites subequal; bearing small pleopods. Pleotelson longer than combined length of three pleonites.



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FIGURE 6. Leptognathia bamberi n. sp. A, holotype, female, dorsal view; B, same, lateral view; C, antennule; D, antenna, scale bar = 0.2 mm; E, pleopod. Scale bar = 0.5 mm.


LARSEN & SHIMOMURA

FIGURE 7. Leptognathia bamberi n. sp. A, labrum; B, left mandible; C, right mandible; D, labium; E, maxillule; F, maxilla; G, maxilliped; H, cheliped; I, pereopod 1; J, pereopod 2; K, pereopod 3; L, pereopod 4; M, pereopod 5; N, pereopod 6; O, uropod. Scale bar = 0.1 mm.



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Antennule (Fig. 6C). As long as cephalothorax. Article 1 as long as rest of antennule combined, with one simple and three short setulated setae. Article 2 shorter than half the length of article 1, with two simple distal setae. Article 3, longer than half of article 2, with two simple distal setae. Article 4 as long as article 2, with four long and one tiny simple distal setae. Antenna (Fig. 6D). 0.8 times as long as antennule. Article 1 naked, wider than other articles. Article 2 longer than article 3, with one dorsal seta. Article 3 longer than article 1, with one dorsal seta. Article 4 longer than other articles and with medial fusion line, with three simple distal setae. Article 5 shorter than article 2, with one simple distal seta. Article 6 minute, with four distal setae. Mouthparts. Labrum (Fig. 7A) smoothly curved, rounded. Mandibles molar S-shaped, pointed and longer than incisor. Left mandible (Fig. 7C) lacinia mobilis as long as incisor and with pointed apex; incisor as lacinia mobilis. Right mandible (Fig. 7B) incisor pointing outwards, broad and with many small tubercles. Labium (Fig. 7D) with two lobes, naked. Maxillule (Fig. 7E) short, endite with eight distal spiniform setae; palp with two terminal setae. Maxilla (Fig. 7F) ovoid, without features. Maxilliped (Fig. 7G) basis with one seta at palp insertion. Endites as wide as basis, with one inner distal seta. Palp article 1 naked; article 2 with two setae on inner margin; article 3 with three setae on inner margin; article 4 with three setae on inner margin and one on outer margin. Epignath not recovered. Cheliped (Fig. 7H). Basis shorter than carpus, divided unequally by sclerite, naked. Merus with one ventral seta. Carpus shorter than propodus including fixed finger, with one ventral and two dorsal setae. Propodus with two setae between dactylus and fixed finger. Fixed finger with two ventral setae and three on inner margin, with few small distal denticles on inner margin. Dactylus as long as fixed finger. Pereopod 1 (Fig. 7I). Longer than other pereopods. Coxa with one seta. Basis longer than three succeeding articles combined, with one dorsomedial setulated seta. Ischium with one ventral seta. Merus as long as carpus, widening distally, naked. Carpus longer than half the length propodus, with one dorsodistal seta. Propodus longer than half the length of basis, with one ventral and one dorsodistal seta and dorsal spine. Dactylus and unguis shorter than propodus and not fused. Unguis longer than dactylus. Pereopod 2 (Fig. 7J). As pereopod 1 except: merus with one small spiniform ventral seta; carpus with two small distal spinifom setae. Pereopod 3 (Fig. 7K). As pereopod 2 except: basis with additional long ventrodistal plumose seta; propodus without dorsal seta. Pereopod 4 (Fig. 7L). Coxa partly fused with somite. Basis marginally thicker than in pereopods 1–3, with one dorsomedial setulate seta. Ischium with one ventral seta. Merus with two spiniform setae. Carpus with one simple and two spiniform distal setae. Propodus ventral margin with two spiniform distal setae, dorsally with one seta and spine. Dactylus and unguis shorter than propodus. Unguis shorter than dactylus. Pereopod 5 (Fig. 7M). As pereopod 4 except: basis with ventromedial setulated seta (broken in illustration); propodus with two spiniform distal setae on both margins. Pereopod 6 (Fig. 7N). As pereopod 5 except: basis with both ventral and dorsal setulated setae; carpus with three distal spiniform and one simple setae. Pleopods (Fig. 6E). Small but well developed, both rami with gap between proximal and other setae. Endopod with ten plumose setae. Exopod with seven plumose setae. Uropods (Fig. 7O). Including basal article almost half as long as pleotelson. Basal article with one seta. Endopod with two articles of subequal length; article 1 with two distal setae; article 2 with five distal setae. Exopod longer than half of first endopod article, with one simple distal seta. Remarks. This species is the only species of Leptognathia sensu stricto recorded from the Pacific. It can be separated from L. gyreae, L. manca, L. breviremis, and L. glandiceps by the short uropods (shorter than pleotelson) and from L. vitjazi, L. longa, and L. breviremoides by the presence of an obvious fusion line on antenna article 3 and by its short spiniform carpal setae on pereopods 4–6.


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Key to the Leptognathia sensu stricto 1. Uropods longer than pleotelson .................................................................................................................. 2 Uropods shorter than pleotelson .................................................................................................................. 5 2. Exopod reaching about one quarter the length of first endopod article ......................................... L. gyreae Exopod reaching about one half the length of first endopod article or longer ............................................ 3 3. Pereonites 3 and 4 longer than wide. Pereopod 1 merus and carpus with long robust setae, reaching near the end of carpus and propodus respectively .................................................................................. L. manca Pereonites wider than long. Pereopod 1 merus and carpus robust setae reaching about midway on carpus and propodus respectively .......................................................................................................................... 4 4. Exopod reaching about half the length of first endopod article. Pleotelson apex smoothly rounded ........... .................................................................................................................................................. L. breviremis Exopod reaching almost to the end of first endopod article. Pleotelson apex pointed .............L. glandiceps 5. Antenna article 3 with fusion line.................................................................................................L. bamberi Antenna article 3 without fusion.................................................................................................................. 6 6. Exopod reaching about half the length of first endopod article ..................................................... L. vitjazi Exopod reaching 80–100% of first endopod article .................................................................................... 7 7. Cephalothorax shorter than combined length of pereonites 1–3. Exopod reaching to the end of first endopod article ......................................................................................................................... L. breviremoides Cephalothorax longer than combined length of pereonites 1–3. Exopod not reaching to the end of first endopod article................................................................................................................................. L. longa

Biarticulata n. gen. Diagnosis. Female. Cheliped fixed finger and dactylus simple. Uropodal exopod with two articles. Etymology. The genus is named for the presence of a biarticulated uropodal exopod. Remarks. The new leptognathidean genus Biarticulata is here erected to accommodate the species listed below. It is freely admitted that the phylogenetic evidence for erection of this genus is weak, as it is dependant on only one character (which is probably homoplastic). However, as a working taxon, this organization seems to work. Most of the species in this genus are too poorly described to construct a key. Furthermore, all the slides of the species described by Kudinova-Pasternak have been lost (Dr. M. Błażewicz-Paszkowycz, pers. comm.). This unfortunate fact is severely obstructing any attempts to revise the Leptognathia complex. This genus currently composes of: Leptognathia arctophylax (Norman & Stebbing, 1886); L. distincta Kudinova-Pasternak, 1981; L. elegans Kudinova-Pasternak, 1965; L. greveae Kudinova-Pasternak, 1976; L. mironovi Kudinova-Pasternak, 1981; L. parabranchiata Kudinova-Pasternak, 1977*; L. paraelegans Kudinova-Pasternak, 1970; L. tuberculata(?) Hansen, 1913 and L. voeringi (G.O. Sars, 1877).

Forcipatia n. gen. Diagnosis. Female. Cheliped fixed finger and dactylus elongated. Uropodal exopod uniarticulated. Etymology. The genus is named for the shape of the chela; elongated and of similar shape to the cheliped in Pseudotanais. Remarks. Leptognathia rotundicauda Kudinova-Pasternak, 1970, L. longimanus Larsen, 2005, and L. sp G. (currently undescribed, Dr. G. Bird, pers. comm.), are removed from Leptognathia to the new genus due to the special features of the chela. In all other respects this genus is identical to Leptognathia. TANAIDACEA FROM JAPAN


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1. Uropods longer than pleotelson ............................................................................................ F. rotundicauda Uropods shorter than pleotelson ............................................................................................. F. longimanus

Family Nototanaidae Sieg, 1973 Genus Typhlotanais G. O. Sars, 1882 Gender: Masculine. Type species: Tanais aequiremis Lilljeborg, 1864. Remarks. Larsen et al. 2006 stated that the Typhlotanais had to be split into several genus level taxa. The species described below, possibly belongs to new taxa currently under description (Dr. M. Błażewicz-Paszkowycz, in prep.). Placement within the Typhlotanais should be considered temporary only.

Typhlotanais magdalensis n. sp. (Figs 8–10) Material examined. Holotype, non-ovigerous female, (KMNH IvR 700.173), Station 12, 31°14.28’N, 131°32.68’E, 367–254 m, shell sand, East of Cape Toi, Miyazaki, 29 May 2006. Paratypes, 1 non-ovigerous female (KMNH IvR 700.174) (dissected), same locality; 7 non-ovigerous females (KMNH IvR 700.175– 700.181), same data; 3 non-ovigerous females (KMNH IvR 700.182–700.184), Station 2, 31°11.45’N, 131°28.78’E, 223 m, shell sand, east of Cape Toi, Miyazaki, 23 May 2006; 1 non-ovigerous female (KMNH IvR 700.185), Station KG-2, 17 November 2003, 34°58.192’–34°58.398’N, 140°05.188’–140°05.115’E, 186–169 m, muddy sand, off Boso Peninsula; 1 non-ovigerous female, (KMNH IvR 700.186), Station 3, 31°18.80’N, 131°28.00’E, 101 m, shell sand, East of Cape Toi, Miyazaki, 20 May 2003. Diagnosis. Female. Pereonite 1 lateral shield progressing anteriorly beyond posterior margin of cephalothorax. Lateral shield weak on posterior pereonites. Antennule article 3 with apical spiniform process. Chelipeds basis not reaching edge of pereonite 1. Chela shorter than carpus. Pereopod 4–6 unguis serrated but not bifurcate. Uropods longer than pleotelson; endopod and exopod uniarticulated, exopod only half as long as endopod. Etymology. Named in the honour of the Typhlotanais specialist Dr. Magdalena Błażewicz-Paszkowycz. Description (body of holotype, appendages of dissected paratype). FEMALE. Body (Fig. 8A). Body length 3.3 mm. Cylindrical, about 9 times as long as broad. Cephalothorax. Shorter than combined length of pereonites 1 and 2. Eye-lobes absent. Pereonites. Pereonites 1 and 6 wider than long. Pereonite 2 as wide as long. Pereonite 3–5 longer than wide. Pereonite 1 lateral shield progressing anteriorly beyond posterior margin of cephalothorax, with ventral hyposphera. Succeeding pereonites with lateral shield receding in a posterior direction, to the level of disappearing. Pleon. Marginally wider than pereon, short (including pleotelson about 15% of total body length). All pleonites subequal, carrying pleopods, weak lateral shield. Pleotelson longer than combined length of two pleonites. Antennule (Fig. 9A). Shorter than cephalothorax. Article 1 longer than rest of antennule, with several simple and setulated setae. Article 2 less than 0.25 times as long as article 1, with three simple distal setae. Article 3 more than twice as long as article 2, with apical spiniform process, two simple setae, one setulated seta and one aesthetasc.


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Antenna (Fig. 9B). Almost as long as antennule. Article 1 not broader than following articles, naked. Article 2 longer than article 3, with one seta. Article 3 longer than article 1, with one minute dorsal seta. Article 4 longer than other articles, with two simple and four setulated distal setae. Article 5 longer than article 3, with two distal setae. Article 6 minute, with three distal setae. Mouthparts. Labrum (Fig. 9C) flat and with several setules. Mandibles (Fig. 9D, E) molar broad and longer than incisor, with terminal ring of denticles, and small proximal spines. Left mandible (Fig. 9D) lacinia mobilis and longer than incisor, with four denticles; incisor broad, with two denticles. Right mandible (Fig. 9E) incisor divided into two equal parts. Labium (Fig. 9F) with inner and outer processes, both with setules. Maxillule (Fig. 9G) endite with seven distal spiniform setae, palp shorter than endite, with two terminal setae. Maxilla (Fig. 9H) ovoid and featureless. Maxilliped (Fig. 9I) basis with one seta at palp insertion. Endites with inner processes and one seta, almost as wide as basis. Palp article 1 naked; article 2 with one outer and three inner setae; article 3 with three inner setae; article 4 with one outer and five inner setae; all inner palp setae setulose. Epignath (Fig. 9J) longer than maxillule endite, with inner notches.

FIGURE 8. Typhlotanais magdalensis n. sp. A, holotype, female, lateral view. Scale bar = 0.5 mm.



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FIGURE 9. Typhlotanais magdalensis n. sp. A, antennule; B, antenna; C, labrum; D, left mandible; E, right mandible; F, labium; G, maxillule; H, maxilla; I, maxilliped; J, epignath. Scale bars = 0.2 mm.

Cheliped (Fig. 10G). Basis divided unequally by small sclerite attached to the proximal part of basis, shorter than carpus. Merus with one ventral seta. Carpus longer and wider than propodus including fixed finger, with two ventral and two small dorsal setae. Propodus with one seta at dactylus insertion. Fixed finger


LARSEN & SHIMOMURA

with two ventral setae and three setae and one small denticle on cutting edge. Dactylus marginally longer than fixed finger. Pereopod 1 (Fig. 10A). Coxa naked. Basis longer than three succeeding articles combined, with several small simple and one setulate setae. Ischium with one seta. Merus as long as carpus, widening distally, with two distal setae. Carpus three-quarters length of propodus, with four distal setae. Propodus shorter than half of basis, with three simple and one robust distal setae. Dactylus and unguis shorter than propodus, not fused into a claw. Dactylus shorter than unguis.

FIGURE 10. Typhlotanais magdalensis n. sp. A, pereopod 1; B, pereopod 2; C, pereopod 3; D, pereopod 4; E, pereopod 5; F, pereopod 6; G, cheliped; H, pleopod; I, uropods. Scale bars = 0.2 mm.

Pereopod 2 (Fig. 10B). As pereopod 1 except: merus with few small spines and four distal setae; carpus half as long as propodus, with few small spines and one tubercule; propodus with four distal setae. Pereopod 3 (Fig. 10C). As pereopod 2 except: merus with several small spines and two distal setae. Pereopod 4 (Fig. 10D). Coxa not present. Basis twice as wide as on pereopods 1–3, with two small simple TANAIDACEA FROM JAPAN


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and two setulose setae. Ischium with two setae. Merus with two spiniform serrated distal setae and many small spines. Carpus with one simple dorsodistal seta, clinging apparatus surrounded by small spines. Propodus with two ventrodistal spiniform serrated setae, one dorsoproximal setulated seta, one dorsodistal robust seta and dorsal spine. Dactylus and unguis shorter than propodus and incompletely fused into an elongate claw. Unguis with serrated apex, much shorter than dactylus. Pereopod 5 (Fig. 10E). As pereopod 4 except: carpus with two spiniform serrated setae. Pereopod 6 (Fig. 10F). As pereopod 5 except: propodus with three dorsodistal setae. Pleopods (Fig. 10H). Well developed and held in together in a cone. Basal article naked. Exopod with one outer and many inner plumose setae. Endopod with many inner plumose setae, gap between proximal seta and other setae. Uropods (Fig. 10I). Basal article less than half as long as exopod, naked. Endopod uniarticulated but traces of fusion line can be observed, longer than pleotelson; with two simple and one pinnate medial setae, seven simple and one setulate distal setae. Exopod uniarticulated, only half as long as endopod, with two small medial setae, one short simple and one long thick distal setae. Remarks. This species belongs to a group of typhlotanaid species which might be raised to genus level in the near future (Dr. M. Błażewicz-Paszkowycz, in prep.). This group includes: T. angularis Kudinova-Pasternak, 1966, T. elegans Kudinova-Pasternak, 1977*, T. grandis Hansen, 1913, T. longisetosus Kudinova-Pasternak 1990, T. parangularis Kudinova-Pasternak, 1975b, T. rotundirostris Lang, 1970, and two new species currently under description (Dr. M. Błażewicz-Paszkowycz, in prep.). Typhlotanais magdalensis differs from these species by the uniarticulated uropods, and apart from T. parangularis, by the short uropodal exopod. It is differentiated from T. parangularis, by the short uropodal basal article. Because of the currently undergoing revision of the typhlotanaids, no key is given here.

Typhlotanais ohtsukae n. sp. (Figs 11–13) Holotype, non-ovigerous female (KMNH IvR 700.187), Station 12, 31°14.28’N, 131°32.68’E, 367–254 m, shell sand, East of Cape Miyazaki, 29 May 2006. Paratypes, 1 non-ovigerous female (KMNH IvR 700.188)(dissected), same locality; 1 ovigerous, 1 non-ovigerous females, 1 male, (KMNH IvR 700.189– 700.190), same data. Diagnosis. Female. Lateral shield prominent on posterior pereonites. Antennule article 3 without apical spiniform process. Chelipeds basis not reaching edge of pereonite 1, with a wide groove at the cheliped insertion. Chela shorter than carpus. Pereopod 4–6 unguis serrated but not bifurcate. Uropods longer than pleotelson; endopod and exopod biarticulated, exopod more than half as long as endopod. Etymology. This species is named after Professor S. Ohtsuka, Hiroshima University, who collected this material during the yearly Toyoshio-maru cruises. Description (body of holotype, appendages of dissected paratype). FEMALE. Body (Fig. 11A). Body length 1.6 mm Cylindrical, about 7 times as long as broad. Cephalothorax. Longer than combined length of pereonites 1 and 2. Eye-lobes absent. Pereonites. Pereonites 1, 2 and 6 wider than long. Pereonite 3 as wide as long. Pereonites 4–5 longer than wide. Pereonite 1 lateral shield not reaching beyond posterior margin of Cephalothorax. Lateral shield present on all pereonites and pleonites. Pleon. Not wider than pereon, short (including pleotelson about 22% of total body length). All pleonites subequal, carrying pleopods. Pleotelson longer than combined length of two pleonites. Antennule (Fig. 11B). Longer than cephalothorax. Article 1 longer than rest of antennule, with several


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simple and setulated setae. Article 2 less than 0.25 times as long as article 1, with three simple distal setae. Article 3 more than twice as long as article 2, with five simple setae and one aesthetasc.

FIGURE 11. Typhlotanais ohtsukae n. sp. A, holotype, female, lateral view, scale bar = 0.5 mm. B, antennule; C, antenna; D, labrum; E, left mandible, incisor; F, same, molar; G, right mandible; H, labium; I, maxillule; J, maxilla; K, maxilliped; L, epignath. Scale bars 0.2 = mm.



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FIGURE 12. Typhlotanais ohtsukae n. sp. A, cheliped; B, pereopod 1; C, pereopod 2; D, pereopod 3; E, pereopod 4; F, pereopod 5; G, pereopod 6; H, pleopod; I, Telson and uropods. Scale bars = 0.2 mm.

Antenna (Fig. 11C). About 0.8 times as long as antennule. Article 1 broader than following articles, with one seta and small setules; article 2 longer than half of article 1, with two small setae. Article 3 longer than other articles, with three simple and two setulose distal setae. Article 4 twice as long as article 2, with one distal seta. Article 6 minute, with two distal setae and one aesthetasc.


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Mouthparts. Labrum (Fig. 11D) with setulate apex. Mandibles (Fig. 11E-G) molar broad, with terminal ring of blunt denticles. Left mandible (Fig. 11G) lacinia mobilis longer than incisor, without denticles; incisor broad, with four outer denticles. Right mandible (Fig. 11E, F) incisor simple, with inner denticles. Labium (Fig. 12H) without outer processes, with pointed, setulated apex. Maxillule (Fig. 11I) endite with eight distal spiniform setae, palp shorter than endite, with two terminal setae. Maxilla (Fig. 11J) ovoid and featureless. Maxilliped (Fig. 11K) basis with one seta at palp insertion. Endites with inner processes and one seta, almost as wide as basis. Palp article 1 naked; article 2 with one outer and three inner setae; article 3 with three inner setae; article 4 with one outer and five inner setae; all inner palp setae setulose. Epignath (Fig.11L) shorter than maxillule endite. Cheliped (Fig. 12A). Basis divided unequally by small sclerite attached to the proximal part of basis, shorter than carpus, with one dorsomedial seta. Merus with one ventral seta. Carpus as long as propodus including fixed finger and only slightly wider, with two ventral and two small dorsal setae. Propodus with one seta at dactylus insertion. Fixed finger with two ventral setae and three on inner margin, with one small denticle on inner margin. Dactylus as long as fixed finger. Pereopod 1 (Fig. 12B). Coxa naked. Basis longer than three succeeding articles combined, with three small simple setae. Ischium with one seta. Merus as long as carpus, with one distal seta. Carpus three-quarters length of propodus, with four distal setae. Propodus longer than half of basis, with three subdistal setae. Dactylus and unguis shorter than propodus, not fused into a claw. Dactylus shorter than unguis. Pereopod 2 (Fig. 12C). As pereopod 1 except: coxa with one seta. Merus with two distal setae. Carpus half as long as propodus, with two setae and one tubercle. Propodus with three distal setae. Pereopod 3 (Fig. 12D). As pereopod 2 except: coxa naked; carpus with four distal setae; propodus with ventrodistal spiniform seta and serrated dorsal margin. Pereopod 4 (Fig. 12E). Coxa not present. Basis twice as wide as on pereopods 1–3, naked. Ischium with two setae. Merus with one spiniform distal seta and many small spines. Carpus with one spiniform distal seta, clinging apparatus surrounded by small spines. Propodus with two ventrodistal spiniform setae, one dorsoproximal setulated seta, one dorsodistal robust seta and dorsal spine. Dactylus and unguis shorter than propodus and incompletely fused into an elongate claw. Unguis much shorter than dactylus. Pereopod 5 (Fig. 12F). As pereopod 4. Pereopod 6 (Fig. 12G). As pereopod 4 except: basis with one seta; propodus with three dorsodistal setae. Pleopod (Fig. 12H). Basal article naked. Exopod with one outer and many inner plumose setae. Endopod with many inner plumose setae, small gap between proximal seta and other setae. Uropods (Fig.12I). Basal article more than half as long as exopod, naked. Endopod biarticulated, longer than pleotelson; with one or two simple and one pinnate medial setae, with four to five simple and one setulate distal setae. Exopod biarticulated, longer than half as long as endopod, first article with one small seta, distal article with one short simple and one long thick distal setae. MALE (Fig. 13A) Body. Laterally compressed, almost amphipod-like. Pereonites. Reduced. Pleonites. Enlarged. Pleotelson. Narrow and tapering into a pointed apex. Antennule. With seven articles; articles 3, 4 and 5 densely covered with aesthetascs (many more than illustrated). Mouthparts. Without functional mouthparts. Pereopods. Much slimmer and less armored than those of female. Pleopods. Better developed than in female. Remarks. This species shares a number of characters with Peraeospinosus adipatus (Tzareva, 1982), notably the microsetae on the antenna. Typhlotanais ohtsukae differ, however, in the biarticulated uropods, the pereopod 2 and 3 carpal process and in the presence of a small clinging apperatus on pereopods 4–6. TANAIDACEA FROM JAPAN


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The status of P. adipatus is somewhat confused. When Sieg (1986a) erected the genus Peraeospinosus, he included P. adipatus. During her revision of the genus, Błażewicz-Paszkowycz (2006) removed P. adipatus from the genus but did not assign another position of this species. Typhlotanais ohtsukae cannot be included into the Peraeospinosus as is currently diagnosed (BłażewiczPaszkowycz 2006) because it does not display the row of minute setae on the dorsal margin of the cheliped carpus; the epignath is not sharply tipped or bifurcated; the distal seta on propodus of pereopods 4 and 5 is not longer than unguis; and the uropods are not uniarticulated. It is possible that an intermediate genus, consisting of T. ohtsukae and P. adipatus could possibly be justified, but because the typhlotanaids are currently undergoing revision, no such action is taken here. The male corresponds to the male described by Sieg (1986a:95) for P. adipatus and is thus referred to T. ohtsukae as it was found in the same sample. However, as with all ‘swimming males’, only with a molecular analysis can conspecificity be confirmed (Larsen 2001).

FIGURE 13. Typhlotanais ohtsukae n. sp. A, male, lateral view, scale bar = 0.5 mm.

Family Tanaellidae Larsen and Wilson, 2002 Genus Tanaella Norman & Stebbing, 1886 Gender: Female. Type species: Tanaella unguicillata Norman & Stebbing, 1886

Tanaella kommritzia n. sp. (Figs 14–16) Material examined. Holotype, non-ovigerous female (KMNH IvR 700.192), Station TS-4, 15 November 2003, 35°11.409’–35°11.460’, 140°52.629’–140°53.441’E, off Boso Penisula, 444–574 m, muddy sand. Paratypes, 1 non-ovigerous female (KMNH IvR 700.193)(dissected), same locality; 2 non-ovigerous females (KMNH IvR 700.194, 700.195), same locality; 1 non-ovigerous female (KMNH IvR 700.196), Station 8,


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26°26.63’N, 127°33.04’E, Northwest of Cape Zanpa, Okinawa, 654–635 m, sand, 27 May 2006; 2 nonovigerous females (KMNH IvR 700.197, 700.198), Station KG-2, 17 November 2003, 34°58.192’– 34°58.398’N, 140°05.188’–140°05.115’E, off Boso Peninsula, muddy sand, 186–169 m. Diagnosis. Female. Antennule article 2 half the length of article 1. Cheliped fixed finger with pronounced serration. Cheliped dactylus without depression and processes. Uropods stout and long (longer than combined length of pleotelson and two pleonites), particularly the basal article (longer than pleotelson). Etymology. Named after the tanaidacean expert Dr. J. Gurrero-Kommritz, Zoological Museum Hamburg. Description (body of holotype, appendages of dissected paratype). FEMALE. Body (Figs. 14A, 15A). Body length 3.2 mm. Cylindrical, nine times longer than broad. Cephalothorax. As long as combined length of pereonites 1 and 2. Pereonites. Wider than long. Pereonite 1 shorter than pereonites 5. Pereonite 2 and 3 subequal. Pereonite 4 and 5 subequal, shorter than pereonites 2 and 3. Pereonite 6 shorter than other pereonites. Pleon. All pleonites subequal and with pleopods. Pleotelson shorter than combined length of three pleonites. Antennule (Fig. 14B). With five articles. Longer than cephalothorax. Article 1 marginally shorter than rest of antennule, with one simple and two setulose distal setae. Article 2 half the length of article 1, with one simple subdistal seta. Article 3 half as long as article 4, with one simple subdistal seta. Article 4 length half of article 2, with six simple distal setae and one aesthetasc. Article 5 minute and obscured by ring of distal setae on article 4. Antenna (Fig. 14C). With six articles and fusion line, 0.8 times as long as antennule. Article 1 not broader than following articles, naked. Article 2 longer than article 1, with one simple dorsodistal seta. Article 3 shorter than article 2, with one dorsodistal seta. Article 4 with clear fusion line, longer than other articles, with two simple and three setulated distal setae. Article 5 longer than article 2, with two distal setae. Article 5 minute, with four distal setae and one aesthetasc. Mouthparts. Labrum (Fig. 14D) almost square, naked. Left mandible (Fig. 14E) lacinia mobilis broad, bifurcate, incisor broad with four denticles. Right mandible (Fig. 14F) incisor square, with proximal spine. Labium (Fig. 14G) simple M-shaped. Maxillule (Fig. 14H) endite with eight distal spiniform setulose setae. Maxilla (not recovered). Maxilliped (Fig. 15B) endites with weak process on distal margin and no setae, outer corners with weak serration. Basis only marginally wider than endites. Palp article 1 with one outer seta. Article 2 with three inner setae of which one is bipinnate. Article 3 with four inner setae of which two are setulated. Article 4 with four bipinnate and one simple distal setae. Epignath (Fig. 14I) slender, naked. Cheliped (Fig. 15C). Basis divided equally by sclerite, shorter than carpus. Merus triangular with one seta. Carpus shorter than propodus, with two ventral and two dorsal seta. Propodus with one seta between fixed finger and dactylus, fixed finger with pronounced serration (at least seven acute spines), with two ventral setae and three on inner margin. Dactylus with one small spiniform seta on inner margin. Pereopod 1 (Fig. 16A). Coxa with one seta. Basis longer than three succeeding articles together, with one dorsoproximal setulated seta. Ischium with one ventral seta. Merus longer than carpus, widening distally and with one spiniform ventral seta. Carpus half as long as propodus, rectangular, with ventrodistal spiniform seta and one long dorsodistal spiniform seta. Propodus longer than half of basis, ventral margin smooth, with one spiniform ventrodistal spiniform seta and dorsodistal spine. Dactylus and unguis combined shorter than propodus. Pereopod 2 (Fig. 16B). As pereopod 1 except: basis naked; carpus with two dissimilar spiniform ventrodistal seta, one long spiniform dorsodistal seta and one modified seta one serrated distal setae; dactylus with small seta at unguis insertion.



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FIGURE 14. Tanaella kommritzia n. sp. A, holotype, female, lateral view, scale bar = 0.5 mm. B, antennule; C, antenna; D, labrum; E, left mandible; F, right mandible; G, labium; H, maxillule; I, epignath; J, pleopod; K, uropod. Scale bars = 0.2 mm.

Pereopod 3 (Fig. 16C). As pereopod 2 except: coxa naked; merus with one spiniform ventral seta and one simple seta; dactylus naked. Pereopod 4 (Fig. 16D). Without coxa. Basis slightly wider than on pereopod 1–3, with two setulated seta. Ischium with two setae. Merus with two spiniform ventrodistal setae, about as long as carpus. Carpus with one small modified seta and four spiniform distal setae. Propodus with three spiniform distal setae and dorsal spine. Dactylus and unguis not fused, longer than propodus. Dactylus with two parallel rows of small setules.


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FIGURE 15. Tanaella kommritzia n. sp. A, paratype, dorsal view, scale bar = 0.5 mm. B, maxilliped; C, cheliped. Scale bar = 0.2 mm.

Pereopod 5 (Fig. 16E). As pereopod 4 except: carpus with three spiniform distal setae; propodus with two spiniform distal setae, dorsal spine, and dorsomedial setulose seta. Pereopod 6 (Fig. 16F). As pereopod 4 except: basis naked; propodus with four spiniform setae and paired dorsal spines. Pleopods (Fig. 14J). Well developed. Peduncle rhomboid. Exopod with 14 plumose setae and basal seta, gap between basal seta and others. Endopod with eight plumose setae. Uropods (Fig. 14K). Basal article as long as endopod, with two simple distal setae near exopod process. Exopod completely reduced to a small process. Endopod with one simple and one setulose medial setae, distally with four long and two short simple setae and one setulate seta. Remarks. Tanaella kommritzia is easily recognized from other Tanaella by the long powerful uropods (particularly the basal article) being longer than combined length of pleotelson and two pleonites. Tanaella was recently revised (Larsen & Heard 2004) but new species appear in all major deep-sea surveys. This genus is cosmopolitan and is probably present in all habitats over 100 meters depth. A key to the genus is given by Gurrero-Kommritz & Błażewicz-Paszkowycz (2004).



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FIGURE 16. Tanaella kommritzia n. sp A, pereopod 1; B, pereopod 2; C, pereopod 3; D, pereopod 4; E, pereopod 5; F, pereopod 6. Scale bar = 0.2 mm.

Family incerta sedis Genus Chauliopleona Dojiri & Sieg, 1997 Leptognathia group a, subdivision a Hansen, 1913 Chauliopleona Dojiri & Sieg, 1997


LARSEN & SHIMOMURA

Diagnosis. Female (Modified from Larsen 2005). Eyes and eye-lobes absent. Pleon short (including pleotelson only 0.2 times total body length). Pleonite 5 with conspicuous, posterior-directed spine, reaching under the pleotelson. Antennule with four articles. Antenna with five–seven articles (occasionally with fusion line). Mandibular molar pointed. Maxillule with seven–nine spiniform terminal setae, some of which are often setulose. Maxilla elongate and often with distal setules. Carapace almost completely surrounding the cephalothorax and including the ventral part of the cheliped attachment point. Cheliped attached via lateral sclerite. Pereopods 1–3 with coxa. Pereopod 1 merus with one long, spiniform seta reaching carpus. Pereopods 4–6 without coxa; dactylus and unguis not fused into a claw, propodus often serrated, dactylus with two parallel rows of spinules. Pleopods present and biramous, albeit often reduced. Uropod biramous, both endo- and exopod bi-articulate; exopod shorter than first endopod article. Male: antennule with five articles. Type species: Chauliopleona dentata Dojiri & Sieg, 1997. Gender: Feminine. Remarks. Most diagnostic characters appear stable at this time. The characters separating the species include: (1) antennule length/width ratio, (2) length of cheliped carpus relative to that of propodus including fixed finger, (3) dactylus denticulations, and (4) pereopod 1 armament. The number of antennal articles is a dubious character, owing to the frequent presence of a fusion line and to the difficulties in determining whether the small proximal ‘article’ is really an article, or part of the cephalothorax itself, or muscle-tissue torn out from the cephalothorax during dissection. This genus is easily recognizable by the ventral, posteriorly directed spine on pleonite 5 that protrudes under the pleotelson. A key to the genus is given by GuerreroKommritz (2005). Larsen & Wilson (2002) excluded Chauliopleona from their phylogenetic analysis of the Paratanaoidea owing to the poor description and definition of the genus (Dojiri & Sieg, 1997). Although no phylogenetic analyses have been conducted in this study, it is likely that this genus belong to the Leptognathiidae.

Chauliopleona hansknechti n. sp. (Figs 17–19) Material examined. Holotype, non-ovigerous female (KMNH IvR 700.199), Station KG-3, 17 November 2003, 34°57.931’– 34°58.168’N, 140°06.572’–140°06.486’E, 278–260 m. Paratype, 1 male (KMNH IvR 700.200)(dissected), same locality. Diagnosis. Male. Antennule with five articles. Functional mouthparts present. Maxilliped basis without long setae. Etymology. Named after another tanaidacean expert Mr. T. Hansknecht, Senior consultant at ‘Barry A. Vittor and Associates Inc., Alabama. Description (body of holotype, appendages of dissected paratype). MALE. Body (Fig. 17A). Body length 4.4 mm. Elongate, about 10 times as long as wide. Carapace. Shorter than pereonites 1 and 2 combined. Eyes and eye-lobes absent. Pereonites. Pereonites 2 and 3 longer than wide. Pereonite 4 as wide as long. Pereonites 1, 5 and 6 wider than long. Pereonites 1, 5 and 6 wider than long. Pereonites longer than dorsal shield and exposing margins of weakly calcified areas between the individual pereonites. Pleon. Short (including pleotelson 25% total body length). All pleonites subequal, with small posterior protuberance. Pleonite 5 with ventral posteriorly-directed spine not protruding beyond pleotelson apex. Pleotelson longer than the lengths of two free pleonites combined, apex rounded, and covered by a dorsal plate.



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Antennule (Fig. 18A). With 5 articles, shorter than carapace. Article 1 shorter than rest of antennule, with one simple and one setulose distal setae. Article 2 shorter than half of article 1, with one simple and two setulated distal setae. Article 3 shorter than article 2, with two simple distal setae. Article 4 shorter than other articles, naked. Articles 5 about as long as article 2, with three distal setae and one aesthetasc.

FIGURE 17. Chauliopleona hansknechti n. sp. A, male, lateral view; B, female, dorsal view; C, same, lateral view. Scale bar = 0.5 mm.


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FIGURE 18. Chauliopleona hansknechti n. sp. male. A, antennule; B, antenna; C, labrum; D, left mandible; E, right mandible; F, labium; G, maxillule; H, same, palp; I, maxilla; J, maxilliped; K, epignath; L, pleopod; M, uropod. Scale bar mouthparts = 0.2 mm, other appendages scale bar = 0.5 mm.



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FIGURE 19. Chauliopleona hansknechti n. sp, male. A, cheliped; B, pereopod 1; C, pereopod 2; D, pereopod 3; E, pereopod 4; F, pereopod 5; G, pereopod 6. Scale bar = 0.5 mm.

Antenna (Fig. 18B). 0.75 times as long as antennule. Article 1 wider than following articles, with one small distal seta. Article 2 shorter than article 1, with one distal seta. Article 3 longer than other articles, with clear fusion line and five simple and one setulose distal setae. Article 4 longer than article 1, with one distal seta. Article 5 smallest, with three simple distal setae and one aesthetasc.


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Mouthparts. Labrum (Fig. 18C) with finely setose apex. Mandibular molar process tapering and longer than incisor, with small distal spines. Left mandible (Fig. 18D) lacinia mobilis longer than incisor; incisor blunt, with three denticles. Right mandible (Fig. 18E) incisor bifurcate. Labium (Fig. 18F) consists of one pair of setose lobes, with small spine on anterolateral corners. Maxillule (Fig. 18G) endite with nine apical spiniform setae of which at least three are serrated; palp with two distal setae. Maxilla (Fig. 18H) remarkably large, wider at basis, with finely setose anterior distal margin. Maxilliped (Fig. 18I) basis naked. Endites with two blunt inner and one spiniform outer processes, with two small simple setae, almost as wide as basis. Palp article 1 naked; article 2 asymmetric, with three pinnate setae on inner margin and one larger simple seta on outer margin; article 3 with four pinnate setae on inner margin; article 4 only 0.5 times as wide as article 3, with five distal pinnate setae. Epignath (Fig. 18J) slender and naked, terminal seta absent. Cheliped (Fig. 19A). Basis unequally divided by prominent sclerite, as long as carpus. Merus triangular, with one ventromedial seta. Carpus as long as propodus (including fixed finger), with two ventromedial setae, one small dorsal seta at each end, small proximal setules. Propodus robust and with high dorsal crest. Fixed finger with two setae ventrally and three on inner margin, with only weak denticulation on inner margin. Dactylus as long as fixed finger, naked. Pereopod 1 (Fig. 19B). Coxa with one seta. Basis longer than the three succeeding articles combined, with one tiny simple seta. Ischium with one seta. Merus as long as carpus, widening distally and with one long spiniform and one small simple distal setae. Carpus more than half as long as propodus, with two long spiniform distal setae and one simple seta. Propodus more than half as long as basis, with one spiniform and one small simple distal setae, distal setules and dorsal spine, with small ventral scales. Dactylus and unguis not fused, combined as long as propodus. Pereopod 2 (Fig. 19C). As pereopod 1 except: carpus with three spiniform and one simple distal setae and a row of small spines. Pereopod 3 (Fig. 19D). As pereopod 2 except; coxa naked. Pereopod 4 (Fig. 19E). No visible coxa. Basis stouter than those of pereopods 1–3, with two setulated ventral setae. Ischium with two setae. Merus with two spiniform setae. Carpus with three spiniform and one simple distal setae. Propodus with three spiniform distal setae. Dactylus and unguis combined as long as propodus, with rows of small ventral spines. Unguis less than half as long as dactylus. Pereopod 5 (Fig. 19F). As pereopod 4. Pereopod 6 (Fig. 19G). As pereopod 4 except: basis with only one setulated seta; propodus with five spiniform distal setae and dorsal spine. Pleopods (Fig. 18L). All pairs subequal. Endopod with two circumplumose proximal setae separated by wide gap and 16 plumose setae. Exopod with two circumplumose distal setae and 12 plumose setae. Uropod (Fig. 18M). Longer than pleotelson. Basal article short (as long as exopod), naked. Endopod with two articles; article 1 with one setulated and one simple distal setae; article 2 slightly longer than article 1, with one setulated, three long and one short simple distal setae. Exopod with two articles, shorter than first endopod article; article 1 naked; article 2 with two unequal setae distally. FEMALE (not dissected) (Fig. 17B, C) Body. Less than 8 times as long as wide. Pereonite 2 in female as long as wide. Remarks. This species is morphologically very close to Chauliopleona dentata, re-described below, but can be separated by the lack of long setae on the maxilliped basis. The male specimen was found in the same sample as a female which did not completely correspond in the proportions of the pereonites. Despite the female being less elongated, it is unlikely that the only two specimens of Chauliopleona collected from Japan (from the same sample) should belong to two different species. Despite these uncertainties, this male is described here since it is the first male of the genus to be properly described.



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Chauliopleona dentata Dojiri & Sieg, 1997 (Figs 20 and 21) Material examined. Paratypes (from California), 2 females, 1 male (SBMNH 144123), Sta. 4C, 33°50.40’N, 118°26.22’W, 76 m. Non-type material, 1 female, 1 male (SBMNH 36937), same locality; 1 female (SBMNH 369416), Sta. 6B, 33°52.27’N, 118°34.12’W, 75 m; 6 females, 3 males, 2 mancas (SBMNH 36418), Sta. R-4-3, 34°43.01’N, 120°47.23’W, 92 m; 5 females (1 dissected), 1 male, 2 mancas (SBMNH 36420), Sta. R-4-1, 34°43.01’N, 120°47.23’W, 92 m; 1 female (ZMH K-40226), Antarctica (doubtful if this specimen is C. dentate) , RV Victor Jensen Station 1270, 54°55.’S, 70°45’W, 135 m. Diagnosis. Maxilliped basis with long seta at palp insertion. Description (body of holotype, appendages of dissected paratype). FEMALE (from California). Body (Fig. 20A, B). Elongate, about 7.5 times as long as wide. Carapace. Marginally shorter than pereonites 1 and 2 combined. Eyes absent. Pereonites. Pereonites wider than long. Pleon. Short (including pleotelson 25% total body length). All pleonites subequal, with small posterior protuberance. Pleonite 5 with ventral posterior-directed spine not protruding beyond pleotelson apex. Pleotelson longer than the lengths of two free pleonites combined, apex rounded, and covered by a dorsal plate. Antennule (Fig. 20C). With 4 articles, shorter than carapace. Article 1 as long as rest of antennule, with one simple and several setulose distal/subdistal setae. Article 2 shorter than half of article 1, with five distal/ subdistal setae. Article 3 shorter than article 2, with 1 simple distal seta. Article 4 about as long as article 2, with five distal setae and one aesthetasc. Antenna (Fig. 20D). 0.75 times as long as antennule. Article 1 wider than following articles. Article 2 shorter than article 1, with one distal seta. Article 3 longer than other articles, with clear fusion line and one setulose setae at fusion line, with five simple and one setulose distal setae. Article 4 longer than article 1, with one distal seta. Article 5 smallest, with four simple distal setae and one aesthetasc. Mouthparts. Labrum (Fig. 20E, e1) with finely setose apex. Mandibular molar process tapering and longer than incisor, with small distal spines. Left mandible (Fig. 20F) lacinia mobilis of the same shape as incisor; incisor blunt, bifurcate. Right mandible (Fig. 20G) incisor bifurcate. Labium (Fig. 20H) consists of one pair of setose lobes, with small spine on anterolateral corners. Maxillule (Fig. 20I) endite with nine distal spiniform setae of which at least four are serrated; palp with two distal setae. Maxilla (Fig. 20J) remarkably large, wider at basis, with few setules at distal margin. Maxilliped (Fig. 20K) basis with long seta at palp insertion. Endites with two blunt inner and one spiniform outer distal processes, with one simple subdistal setae, almost as wide as basis. Palp article 1 naked; article 2 asymmetric, with three setae on inner margin and one larger seta on outer margin; article 3 with four setae on inner margin; article 4 narrower than article 3, with six distal setae. Epignath not recovered. Cheliped (Fig. 21A). Basis unequally divided by prominent sclerite, shorter than carpus, with one distal seta. Merus triangular, with one ventromedial seta. Carpus longer than propodus (including fixed finger), with two ventromedial setae, one small dorsal seta at each end. Propodus robust and with high dorsal crest and row of small setae on inner margin by dactylus insertion. Fixed finger with two setae ventrally and three on inner margin, with only weak denticulation on inner margin. Dactylus as long as fixed finger, with one outer seta, with only very weak dorsal crennulation. Pereopod 1 (Fig. 21B). Coxa with one seta. Basis longer than the three succeeding articles combined, with one setulated dorsal seta. Ischium with one seta. Merus as long as carpus, widening distally and with one long spiniform and one smaller distal setae. Carpus more than half as long as propodus, with two long and one short spiniform distal setae and one simple seta. Propodus more than half as long as basis, with one spiniform ventral and one small simple distal setae and dorsal spine, ventral margin without spinules. Dactylus and unguis not fused, combined as long as propodus.


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FIGURE 20. Chauliopleona dentata Dojiri & Sieg, 1997, female (from type locality). A, dorsal view; B, later view C, antennule; D, antenna; E, labrum, lateral view; E1, same dorsal view; F, left mandible; G, right mandible; H, labium; I, maxillule; J, maxilla; K, maxilliped. Scale bar mouthparts = 0.2. mm, other appendages scale bar = 0.5 mm.



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FIGURE 21. Chauliopleona dentata Dojiri & Sieg, 1997, female (from type locality). A, cheliped; B, pereopod 1; C, pereopod 2; D, pereopod 3; E, pereopod 4; F, pereopod 5; G, pereopod 6; H, pleopod; I, uropod. Scale bar = 0.2 mm.

Pereopod 2 (Fig. 21C). As pereopod 1 except: basis naked; carpus with three spiniform and two simple distal setae; dactylus with small seta.


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Pereopod 3 (Fig. 21D). As pereopod 2 except; basis with additional distal setae; ischium with two setae. Pereopod 4 (Fig. 21E). No visible coxa. Basis stouter than those of pereopods 1–3, naked. Ischium with two setae. Merus with two spiniform setae. Carpus with three spiniform and one simple distal setae. Propodus with three spiniform distal setae. Dactylus and unguis combined as long as propodus, with rows of small ventral spines. Unguis less than half as long as dactylus. Pereopod 5 (Fig. 21F). As pereopod 4 except: basis with two setulated setae. Pereopod 6 (Fig. 21G). As pereopod 4 except: propodus with five spiniform distal setae and dorsal spine. Pleopods (Fig. 21H). All pairs subequal. Basal article wit large circumplumose seta. Exopod with 12 plumose inner setae and one outer seta. Endopod 21 plumose setae. Both rami without gap between proximal seta and other setae. Uropod (Fig. 21I). Longer than pleotelson. Basal article short (shorter than exopod), with one or two setae. Endopod with two articles; article 1 with two setulated distal setae; article 2 as long as article 1, with four long and two short simple distal setae. Exopod with two articles, shorter than first endopod article; article 1 with one long distal seta; article 2 with two unequal setae distally. Remarks. Several problems are currently connected with this species. Chauliopleona dentata sensu stricto is incompletely described (Dojiri & Sieg, 1997:231, pl. 17) and while the redescription by GuerreroKommritz (2005:1180-84) is better, his re-description is based on a specimen collected from the Antarctic. As the type locality of C. dentata is Santa Monica Bay, California, such distribution is unlikely (see Larsen 2005 for review of Tanaidacean distribution patterns). Examination of C. dentata material from the typo locality (from SBMNH material as the extensive material in the NHMLAC could not be located and is presumed lost (G.E. Davis, pers. comm.)), revealed a number of problems with important characters: 1) the dorsal crennulation on the cheliped dactylus is very variably, even between the left and right cheliped, to the point of being absent in some specimens. This character is not unique to C. dentata as it is also found in Chauliopleona paradoxa Guerrero-Kommritz, 2005. 2) The spatulate spinules on the propodus of pereopod 1 are described as being present on females with marsupium only, while attenuated in non-ovigerous females and neuters (Dojiri & Sieg 1997:233). The spatulate spinules, however, are clearly present in the Chauliopleona cf dentata from Antarctica described by Guerrero-Kommritz (2005) but this is from a non-ovigerous female. The specimen dissected from the type locality in this study, was ovigerous but did not display these spinules. 3) The three small setae on the uropodal basal article, mentioned by both Dojiri & Sieg (1997:233, pl. 3.17) and GuerreroKommritz (2005:1180 & 1183, fig. 1g) are also variable (from 1–3) and not diagnostic. Furthermore the long maxilliped basal seta on the material from the type locality, are not present on Chauliopleona dentata from Antarctica. Studies applying molecular techniques (Larsen 2001) have illustrated the problems with sister species, thus it is doubtful whether Guerrero-Kommritz’s re-described female really are C. dentata or morphologically similar but different species.

Additional species Apart from the species described above, a number of additional species were found during this study. New species of Leptochelia is part of a master degree study (Mr. K. Kakui, pers. comm.). Additionally two species of Paratanais, one of Tanaidae, one of Pseudotanais, and one of Agathotanais, were found. These species are all probably new to science, but were found in too few numbers to be treated in this study.

Acknowledgements The senior author was funded by the Japanese Society for Promotion of Sciences. We thank Ms. Julianne Knight for critical reading of earlier versions. Material was provided by Professor S. Ohtsuka of the Takehara TANAIDACEA FROM JAPAN


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Marine station, Hiroshima University, and Professor S. Ohta of the Ocean Research Institute, University of Tokyo. We thank the Captain and crew on the TR/V Toyoshio-maru and R/V Tansei-maru for support during collection. Also thank to Dr. J. Guerrero-Kommritz (ZMH) for checking specimen (K-40226) of Antarctic Chauliopleona for us.

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