HALACARIDAE, ACARI - CiteSeerX

Stygologia 1 (3) 1985, E. J. Brill, Leiden

T H E HALACARID FAUNA (HALACARIDAE, ACARI) O F BERMUDA'S CAVES BY ILSE BARTSCH Biologische Anstalt Helgoland, Notkestr. 31, 2 Hamburg 52, Federal German Republic

THOMAS M. ILIFFE Bermuda Biological Station, Ferry Reach 1-15, Bermuda SUMMARY Nine species of halacarid mites (Halacaridae, Acari) are here reported from inland marine caves on Bermuda. Five of these are new species, e.g. Agauopsis bennudensis, A. littoralis, Copidognathus bmnudcnsis, C, subtmaneus, and C. longispinus, while two species, Copidognathus floridensis and Sirnognathusfuscus, are new records for Bermuda. Probably none of these halacarids are true cavernicolous forms. INTRODUCTION

The isolated mid-ocean islands of Bermuda have over 150 known limestone caves, many of which contain tidal, sea level pools and extensive submarine passages. A faunal survey of these marine caves was started in 1978 with the help of Professor Boris Sket of the University of Ljubljana, Yugoslavia. These investigations have revealed the presence of a rich and diverse invertebrate fauna including an unexpectedly high number of new species (Sket & Iliffe, 1980). Species described so far include Atlantasellus cavernicolus, an isopod representing a new family (Sket, 1979); Miostephos leamingtonensis, a new calanoid copepod (Yeatman, 1980); Apseudes bermudeus, a new hermaphroditic tanaidacean (Bacescu, 1980); Somersiella sterreri and Typhlatya iliffei, two new species of caridean shrimp (Hart & Manning, 1981); Mesonerillaprospera, a new archiannelid polychaete (Sterrer & Iliffe, 1982); and Bermudalana aruboides, from a new genus of cirolanid isopods (Bowman & Iliffe, 1983). We here report on 9 species of halacarid mites collected from Bermuda caves, including 5 new species and 2 new records for Bermuda (table I). HABITAT

The Bermuda islands consist of a volcanic sea mount of mid-ocean origin completely capped with eolian and marine Pleistocene and Recent limestone (Land et al., 1967; Mackenzie & Vacher, 1975). Bermuda's limestone caves

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Halacaridae in caves of Bermuda with accompanying salinity and tide data. The percent tide range and tide lag time are stated in reference to tides measured in the open ocean at Bermuda.

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Cave name

Halacarid species

Grenadier Pool Green Bay Cave

Arhodeoporus perlucidus Agauopsis bemudensis Copidognathus bemudensis Arhodeoporus perlucidus Arhodeoporus perlucidus Arhodeoporus perlucidus Agauopsis littoralis Copidognathus benudensis Copidognathus floridensis Copidognathus longispinus Arhodeoporus perlucidus Agaue nationalis Simognathus fuscus Arhodeoporus perlucidus Copidognathus subteraneus Simognathus fuscus

Deep Blue Cave Myrtle Bank Cave Walsingham Cave

Palm Cave Emerald Sink

Surface 1M Percent Tide salinity salinity tide range lag time (OIOO) (OIOO) (%) (minutes) 21.5 28.9 64 61 20.3 27.9 22 151 27.2 32.2 18.9

35.3 33.4 32.6

61

59

63

53

26.3

35.8

55

57

26.4

33.6

41

95

were probably formed during glacial low stands of Pleistocene sea level and were later flooded by sea water as post-glacial sea levels rose (Bretz, 1960; Palmer et al., 1977; Iliffe, 1981). Partial collapse of ceiling rock into deeper solutional voids gave rise to the fissure entrances and collapse chambers characteristic of Bermuda's caves. Diving explorations in the caves have revealed the existence of integrated networks of phreatic passages at depths averaging 16 to 18 m below present sea level (Iliffe, 1980). Most of Bermuda's caves are located around the perimeter of Harrington Sound, a 4.8 km2, almost totally enclosed inshore sea water body. Approximately 50% of the tidal exchange of Harrington Sound is through cave connections with the North Lagoon, Castle Harbour of South Shore (Morris et al., 1977). Those caves with moderate to strong tidal currents passing through them have profuse growths of sponges and other encrusting organisms almost completely covering the walls. This is in striking contrast to those far inland caves with little or no net tidal exchange which are relatively barren except for strict troglobitic species with requirements modest enough to survive in such an environment. The inland cave pools of Bermuda are composed of a several metres deep surface layer of brackish water with 3 to 30°/oo salinity overlying full salinity (35-36OIoo) waters (table I). Anomalous increases of water temperature with depth for pools remote from the sea has been attributed as a possible extension

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of the natural geothermal gradient observed in underlying basalts (Iliffe et al., 1983). Considering Bermuda's present position as the northern-most coral reef ecosystem in the Atlantic Ocean, warmer cave waters could have served to protect certain temperature sensitive species when Pleistocene glaciation lowered sea surface temperatures. Tides in cave pools are delayed over those in the open sea with tide ranges being similarly reduced. MATERIALS AND METHODS

All specimens were collected from deeper portions of the underwater caves by divers. Cave diving equipment and techniques met standards set by the Cave Diving Section of the U.S. National Speleological Society. A hand-held fine mesh dip net was often used to skim the upper few centimeters of silty sediments on the floor of the cave. Alternately, a collapsible plastic bottle was used to suck up animals from the surface of the sediments. O n occasion, attached organisms such as sponges or hydroids were removed from the cave in plastic bags and later examined for associated fauna. A map of the locations of caves from which halacarids were collected is shown in fig. 1. Holotypes of the new species described here have been deposited in the Zoologisches Institut und Zoologisches Museum, Hamburg, FRG. DESCRIPTION O F SPECIES

Arhodeoporus perlucidus Bartsch, 1983 Material. Ca. 35 specimens, adults and juveniles, from Grenadier Pool, Deep Blue Cave, Myrtle Bank Cave, Walsingham Cave, Palm Cave, and Emerald Sink (all in Hamilton Parish), leg. T . Iliffe.

Length of idiosoma in females 295-316pm, in males 285-335pm, in deutonymphs 220-303 pm, in protonymphs 186-230 pm, and in a larva 127 P".m. Arhodeoporw perlucidus is related to the European species A . gracilipes and A . minor. A. perlucidus is distinguished from A . gracilipes by the longer rostrum - in A . perlucidus extending almost to the end of the second palpal segment (P-2), in A . gracilipes just to the middle of P-2 - and from A. minor by the broader plates and the larger porose areolae. Distribution. Arhodeoporus perlucidus is known from the Caribbean area and Bermuda (Bartsch, 1983). Agauopsis bermudensis n. sp. Material. 1 female (holotype), Green Bay Cave, Hamilton Parish, 18.XI.1981, collected at 14 m depth by a fine mesh dip net with scuba from silt on the floor of the Green Bay Passage just past the Rat Trap, leg. T . Iliffe; 1 male, Grenadier Pool, Hamilton Parish, 21.XI.1981, collected at 6 m depth by fine mesh dip net with scuba from bottom silt, leg. T . Iliffe.

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Fig. 1. Locations of Bermuda Caves from which halacarid species were collected: 1 , Grenadier Pool; 2, Green Bay Cave; 3, Deep Blue Cave; 4, Myrtle Bank Cave; 5, Walsingham Cave; 6, Palm Cave; 7 , Emerald Sink.

Female: Length of idiosoma 442pm. In the female, the following measurements were obtained (in pm).

Idiosoma Anterodorsal plate Ocular plate Posterodorsal plate Anterior epimeral plate Genitoanal plate Genital opening Gnathosoma Rostrum

Length 442 158 100 221 125 185 90 135 65

Width 285 142 65 172 285 162 32

Raised porose areolae on dorsal plates (fig. 2); outside these areas, surface of integument covered with many shallow pores. Anterodorsal plate (AD) with a short frontal spine. Base of frontal spine knob-like. O n 2 ridges, surface of integument pierced by many fine canaliculi, while in deeper integumental layers, alveoli are present (cf. fig. 5). Ocular plates (OC) slightly pointed medially and

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Figs. 2-14. Agauopsis benudensis n sp. 2, idiosoma, dorsal view, Q ; 3, idiosoma, ventral view, Q (broken lines indicate porose areolae); 4, genitoanal plate, 0 ; 5, portion of left posterodorsal plate at level of d-4, Q ; 6, portion of right anterior epimeral plate anterior to third ventral seta, Q ; 7, tip of rostrum, dorsal view, 0 ; 8, gnathosoma, lateral view, Q ; 9, leg I, medial view, Q ; 10, leg 11, medial view, Q ; 11, leg IV, medial view, Q ; 12, palp, 0 ; 13, tarsus I, lateral view, Q (medial pararnbulacral setae and claw omitted); 14, tarsus 11, medial view, Q. 2-6, 8-13: scale division = 50 ym; 7: scale division = 10 ym.

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distally. Two corneae on ocular field; medial to corneae, a slightly raised porose area present. Posterodorsal plate (PD) elongate; ornamented as in the AD. The 2 longitudinal porose costae convergent posteriorly, thus U-shaped. Only 4 pairs of dorsal setae present; these setae small. First pair of dorsal setae (d-1) on AD, at anterior end of the costae; d-2 inserted within striated integument between AD and OC; d-3 on lateral margin of the PD at level of insertion of leg 111; d-4 close to porose costae at level of leg IV. Adanal setae standing close together at the end of the PD. Integument of epimeral plates with shallow pores and groups of deeper, canalicular ones (fig. 6). Areolae with canaliculi elaborate, well demarcated both dorsally and ventrally (figs. 2, 3). On dorsal and marginal portion of epimeral plates, areolae circular or ovate; on ventral portions, ribbon-like. Anterior epimeral plate wide, with 3 pairs of long setae. Posterior epimeral plate with 1 dorsal and 3 ventral setae. Genital opening (GO) large. Distance to anterior margin of genitoanal plate (GA) less than length of GO. Only 2 pairs of perigenital setae and a single subgenital seta - on the left genital sclerite - seen. Gnathosoma small. Base of gnathosoma ventrally pierced by canaliculi (fig. 8). First pair of long maxillary setae inserted on base of gnathosoma, second pair near end of rostrum. Three pairs of minute setae at tip of rostrum (fig. 7). Rostra1 sulcus extending posteriad beyond second pair of maxillary setae. Palps short, hardly reaching beyond rostrum. Second papal segment (P-2) with a dorsal bristle, P-3 with a denticulate dorsomedial spine, and P-4 with 2 basal setae and a minute distal one (fig. 12). First leg strong, with characteristic stout spines (fig. 9). O n telofemur I, 1 ventromedial and 2 ventral spines; on genu 1, 1 ventromedial and 1 ventral spine; on tibia I, 2 ventromedial and 1 ventral spine; and on tarsus I, 1 ventromedial one. Spines distally denticulate. O n the following legs on telofemora and on genua, no stout spines present. O n tibia I1 insert 2 pectinate spinelets (fig. 10) and on tibiae I11 and IV, 2 slender pointed bristles (fig. 11). Integument on telofemora finely porose. Dorsomedially on telofemora I and 11, a reticulation discernible, formed by slightly raised fine cuticular bars. No cuticular spines present. O n tarsus I, beside the medial spine, 2 ventral and 3 dorsal setae present, 1 solenidion and 1 famulus, both in dorsolateral position, and at tip of tarsus, doublet eupathid parambulacral setae (fig. 13). O n tarsus I1 stand 3 dorsal setae, 1 ventral seta, 1 medial parambulacral seta and 1 solenidion, hidden behind the medial membrane of claw fossa (fig. 14). On tarsi I11 and IV, beside the 3 dorsal setae, only 1 parambulacral seta inserted on the medial flank. Lateral claws on tarsus I small, smooth, neither comb nor accessory tooth seen. Lateral claws on the following legs longer than on leg I, provided with a comb with fine teeth. Medial claw on leg I strong, bidentate. Median claws on the following legs without dents, only basal portion of claw present.

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STYGOLOGIA (3) 1985

Male: Length of idiosoma 440 ym. Similar to female except for the genital region. Genital opening large. Distance to anterior margin of genitoanal plate hardly larger than length of GO. Perigenital setae arranged in a dense ring around the GO, 2 additional setae in anterior portion of the GA (fig. 4). Remarks. Agauopsis bermudensis is similar to A. ornata (Lohmann, 1893), a species found off Bermuda and the Cape Verde Islands (Lohmann, 1893), in the Caribbean region (unpublished data) and on the Galapagos Islands (Bartsch, 1977b). In A. ornata, the length of the idiosoma is 270-360ym (Lohmann, 1893; Bartsch, 1977b), the 2 longitudinal costae on the posterodorsal plate are not contiguous posteriorly, they are well separated from a transverse porose bar at the distal margin of the plate; the porose areas on the ventral plates are small and narrow; in the males, the distance from the genital opening to the anterior margin of the genitoanal plate corresponds to almost 3 times the length of GO; the legs have cuticular spines. Thus, A. bermudensis is easily distinguished from A. ornata by the larger size of idiosoma, the outline of the porose areolae on both dorsal and ventral plates, the large GO in males, and the lack of cuticular spines or lamellae on the legs. Elaborate porose areas on ventral and dorsal plates characteristic in A. ornata and A. bermudensis are also present in A. bacescui Konnerth-Ionescu, 1977, found off Tanzania (Konnerth-Ionescu, 1977), and in 2 species collected in Philippine waters (unpublished). '

Agauopsis littoralis n. sp. Material. 1 male (holotype), Walshingham Cave, Hamilton Parish, 18.11.1982, collected from 6 to 8 m depths in main pool at cave entrance with scuba using a suction bottle, leg. T. Iliffe.

Male: Length of idiosoma 335 ym. In the male, the following measurements were obtained (in ym). Idiosoma Anterodorsal plate Ocular plate Posterodorsal plate Anterior epimeral plate Genitoanal plate Genital opening Gnathosoma Rostrum

Length 335 118 77 182 137 120 39 127 63

Width 239 102 70 125 230 122 25 65 20

Anterodorsal plate (AD) with a small frontal spine. In posterior portion of AD elevated ridges, arranged like an "H". Within these ridges, deep canaliculi piercing the integumental layers. Outside the ridges, a slight paneling and small pores present. First pair of gland pores inserted near anterior end

STYGOLOGZA (3) 1985

307

of the "H". Anterolateral portion of ocular plates (OC) raised; here 2 distinct corneae, a porose area and a gland pore present. At end of the raised portion just ~osteriorto the gland pore, a pore canaliculus seen. Posterodorsal plate (PD) with 2 elevated, longitudinal ridges, converging posteriorly but not meeting (fig. 15). Dorsal setae minute. First pair of dorsal setae (d-1) inserted on the AD, near anterior ends of the H-shaped costae; d-2, d-3, and d-4 within striated integument, d-2 between AD and OC, d-3 between the O C , and d-4 between O C and PD; d-5 on PD, lateral to the 2 costae. Adanal setae stand at end of the PD. Red-brown pigment is found beneath the AD near the anterior spine and beneath the O C between the corneae. All ventral plates finely porose; when focused on deeper integumental layers, a reticulation is discernible. O n the large anterior epimeral plate insert 3 pairs of slender setae. Claparcde organs end with a small slit at surface of the plate between first and second epimera. O n posterior epimeral plate, 3 ventral and 1 dorsal seta present. Genitoanal plate (GA) short. Genital opening (GO) in the middle of the plate. Distance from G O to anterior margin of GA equals length of GO. The 36 perigenital setae arranged in 2 rings densely around the GO; 2 additional setae insert in anterior portion of the plate (fig. 16). At the genital slit stand 9 small spines on the genital sclerites (fig. 19). Integument on base of gnathosoma pierced by canaliculi. Rostrum as long as base of gnathosoma. One pair of long maxillary setae insert on base of gnathosoma, 1 near the end of the rostrum (fig. 17); at tip of rostrum, 3 pairs of minute rostra1 setae present. Palpi slightly bent, thus unfavorable for measurement. O n second palpal segrnet (P-2) stands 1 dorsal seta; on P-3, a strong medial, denticulate spine; and on P-4, 2 basal setae (fig. 18). Integument of legs pierced by canaliculi, these especially prominent on telofemora and tibiae (fig. 25). Leg I stronger than the following legs. O n telofemur I insert 2 ventral and 2 ventromedial spines; on genu I, 1 ventral and 1 ventromedial one; on tibia I, 1 ventral and 2 ventromedial; and on tarsus I , 1 ventromedial spine. The spines are stout, slightly denticulate. O n the following legs, spines are found on the tibiae, but these spines are less stout, flattened, bipectinate. Beside the spine on tarsus I, there are 3 dorsal setae, 2 ventral setae, doublet eupathidia on both sides of the ambulacrum and, in dorsolateral position, a solenidion and a famulus (fig. 23). O n tarsus 11, the solenidion is hidden behind the medial membrane of claw fossa (fig. 24). O n tip of tarsus I1 insert medially a minute spine, laterally a single, eupathid seta. O n tip of tarsus I11 and IV, only 1 ventral spine-like parambulacral seta is found. Of the 3 dorsal setae on tarsus IV, the 2 distal ones are slightly plumose (fig. 25). The lateral claws on tarsus I are smaller than those on the following legs. An accessory tooth is present, but no comb. Between the lateral claws, there is a stout bidentate median claw. The lateral claws on the following legs are slender, provided with long claw combs with many fine teeth. The median claw is only a small sclerite with no dents.

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STYGOLOGZA (3) 1985

Figs. 15-25. Agauopsis littoralis n. sp., 0'. 15, idiosoma, dorsal view; 16, idiosoma, ventral view; 17, gnathosoma, ventral view; 18, gnathosoma, dorsal view; 19, genital region; 20, leg I, medial view; 21, leg 11, medial view; 22, leg 111, medial view; 23, tarsus I, lateral view; 24, tibia and tarsus I, medial view; 25, tibia and tarsus IV, medial view. Each scale division = 50 pm.

STYGOLOGZA (3) 1985

Female: Not seen.

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Remarks. Agauopsis littoralis belongs to the brevipalpus group and is most similar to A. brevipalpus. A unique character in A. littoralis is 3 spines on tibiae I11 and IV. The note in Chichkoff (1907) mentioning 3 spines on tibiae I11 and IV for A. brevipalpus could never be verified. O n telofemur I, a variability in the number of spines is known (cf. MacQuitty, 1983), but the number of spines on the tibiae appears to be constant. More than 50 specimens of species in the brevipalpus group were examined, in none 3 spines were found. In A. littoralis, all 4 posterior legs are armored with 3 spines each; thus the number of spines obviously is constant in this species. Other distinguishing characters in A. littoralis are the smaller size of idiosoma and the smaller number of perigential setae in the male. The species now known to belong to the brevipalpus group are listed with notes to characteristics and geographical distribution: A. brevipalpus brevipalpus (Trouessart, 1889). Length of idiosoma in females 416-530 pm, in males 321(?)-477 pm (Trouessart, 1889; Lohmann, 1893; Viets, 1939140; Newell, 1947; Bartsch, 1975; Morselli & Mari, 1982). Anterodorsal plate with a small blunt spine. Four ventral spines on telofemur I. Known from Black Sea, Mediterranean, northwest and northeast Atlantic Ocean, off northern Brazil, off Sydney Australia (cf. Viets, 1956) and Gulf of Bengal (Rao & Ganapati, 1968). A . brevipalpus ponticus (Chichkoff, 1907). Length of idiosoma 528-750 (?) pm (Chichkoff, 1907; Viets, 1928). A small blunt spine on anterodorsal plate. Four ventral spines on telofemur I. Known from the Black Sea, Mediterranean, and northeast Atlantic Ocean (Viets, 1939140, 1956; Benard, 1962). A. borealis Newell, 1947. Length of idiosoma in females 471-530 pm, in males 432-490 pm (Newell, 1947; Bartsch, 1979b). Anterodorsal plate with a rounded tip but no spine. Four ventral spines on telofemur I. Known from the east coast of the U.S. (Bartsch, 1982). A. filirostris MacQuitty, 1983. Length of idiosoma in females 633-708 pm, in males 577-618 pm (MacQuitty, 1983). Frontal margin of anterodorsal plate tridentate. Rostrum slender, 3 ventral spines on telofemur I. Known from southern California (MacQuitty, 1983). A. newelli Krantz, 1973. Length of idiosoma in females 63 1-735 pm, in males 595-630 pm (Krantz, 1973). Anterodorsal plate with a rounded tip but no spine. Rostrum very short, eminently shorter than base of capitulum. Three ventral spines on telofemur I. Known from Oregon (Krantz, 1973). A. tricuspis Benard, 1962. Length of idiosoma in females 473-487 pm, in males 398-483 pm (Krantz, 1970; unpublished data from northern France). Small, blunt spine on anterodorsal plate. Five small, blunt spines on telofemur I. Known from the Mediterranean and northern France (Benard, 1962; Krantz, 1970; Bartsch, 1976, 1978179).

Copidognathus floridensis Newell, 1947 Material. 1 female, Walsingham Cave, Hamilton Parish, 18.11.1982, collected from 6 to 8 m depths in main pool at cave entrance with scuba using a suction bottle, leg. T. Iliffe.

The characters of this female agree well with those of C. angustusfloridensis described in Newel1 (1947). Though undoubtedly closely related to C.angustus, C.floridensis ought to be raised to specific rank. C.jloridensis is easily separated from C. angustus by the smaller lamellae on the legs. Distribution. Copidognathus jloridensis is recorded from Florida (Newell, 1947).

Copidognathus bermudensis n. sp. Material. 1 female (holotype), Walsingham Cave, Hamilton Parish, 18.11.1982, collected from 6 to 8 m depths in main pool at cave entrance with scuba using a suction bottle, leg. T. 11iffe; 1 male, Green Bay Cave, Hamilton Parish, 3.111.1982, collected with scuba at 16 m depth from hydroids attached to guide line in the Rat Trap, leg. T. Iliffe.

Female: Length of idiosoma 306 pm. In the female, the following measurements were obtained (in pm) Idiosoma Anterodorsal plate Ocular plate Posterodorsal plate Anterior epimeral plate Genitoanal plate Genital opening

Length 306 90 91 208 115 147 64

Width 171 75 48 104 156 100 37

Idiosoma slender. Dorsal plates coarsely sculptured with large, shallow pores and rosette pores within raised areas. Rosette pores with large ostiae and alveoli and delicate canaliculi. Three circular, porose cones on anterodorsal plate (AD), 1 on a rounded projection in the anterior end of the AD, and 2 in the middle of the plate. O n the posterior margin of the plate, 2 lamellar projections present (fig. 27), ornamented with coarse pores as on the other portions of the plate. First pair of gland pores not seen, obviously they are obscured by the 2 median porose areolae. Ocular plates (OC) large, wide in their anterior ends, ending bluntly at level of leg 111. Two large corneae in anterior portion of the plate; medial to the corneae, a raised area with ca. 11 rosette pores present. Beneath this area, there is brown pigment. Gland pores lateral to the corneae at margin of plate hardly discernible. Posterodorsal plate (PD) slender. Two longitudinal costae, conspicuously raised posteriorly. First pair of dorsal setae (d-1) on AD at anterior end of paired porose cones, d-2 at anteromedian corners of the OC, d-3, d-4, and d-5 on the PD, lateral to the longitudinal costae (fig. 27).

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Figs. 26-33. Copidognathus benudensis n. sp. 26, pathosoma, ventral view, 0 ; 27, idiosoma, dorsal view, Q ; 28, idiosoma, ventral view, Q ; 29, genitoanal plate, 0 ; 30, palp, Q ; 31, leg IV, medial view, Q ; 32, leg I, lateral view, Q ; 33, leg 11, lateral view, Q . Each scale division = 50 i.Lm.

O n ventral plates, marginally coarse pores and areolae with rosette pores; ventrally, integument finely porose with delicate canaliculi. Epimeral process I large, slightly pointed; epimeral process I1 wide. Pores of Clapar2de organ circular. Ventral setae long, slender. Genital opening (GO) large; distance to anterior margin of genitoanal plate (GA) slightly less than length of GO. Three pairs of perigenital setae, the second pair inserted near the lateral margin of the GA. In the anterior end of the GO, a pair of minute subgenital setae present. Ovipositor surpassing the G O for 113 of the G O (fig. 28). Gnathosoma slender. Rostrum evidently longer than base of gnathosoma, reaching beyond second palpal segment (P-2) (fig. 26). Palps slender. P-4 conspicuously longer than P-2 (fig. 30).

Legs long. All telofemora markedly sculptured with coarse pores (figs. 31-33). Small ventromedial lamellae on telofemora I and 11, no lamellae on telofemora I11 and IV. Trochanters I11 and IV each with a lamellar distal spine. Leg chaetotaxy equals the one in C. jloridensis. Male: Similar to the female except for the genital region. G O smaller than in the female. Distance to anterior margin of GA longer than length of G O (fig. 29). In the only male available, 23 perigenital setae arranged ring-like around the GO. Four pairs of subgenital setae standing on the genital sclerites near the genital slit. Remarks. Characters in these 2 specimens are: AD with 3 conical porose areas and lamellar projections posteriorly; PD with 2 longitudinal costae, markedly raised in their distal portions; d-2 inserted on the OC; ventral portion of the ventral plates pierced by delicate canaliculi; second pair of perigenital setae in females inserted near the lateral margin of the GA; gnathosoma slender, rostrum longer than base of gnathosoma, P-4 longer than P-2; legs slender, telofemora coarsely sculptured; the 2 ventral setae on tibia IV both slender and smooth; tarsi I11 and IV both with 4 dorsal setae; ventrolateral lamellae on telofemora I and 11 small, on telofemora I11 and IV absent. The 2 specimens are closely related and very similar to C.jloridensis but differ from the latter by: more slender idiosoma; lamellar processes at distal margin of AD; narrow but prominently raised costae on PD; second pair of perigenital setae in female inserted near the lateral margin of GA. A similar arrangement of the perigenital setae in females is known from C. peregrinus Bartsch, 1977, a species related to C. jloridensis. But C. peregrinus is not as slender as C. bermudensis; the lamellar processes at distal margin of AD are lacking; the costae on PD are wider, but less raised; the telofemora are shorter than in C. bermudensis. In Bermudian waters, another slender, similar-looking species is known, Copidognathus hartwigi Bartsch, 1979. But in C. hartwigi there are no lamellar processes on the posterior margin of the AD; the second pair of dorsal setae insert within the striated integument between AD and O C ; the longitudinal costae on the PD are not conspicuously raised; the second pair of perigenital setae insert near the GO; on tibia IV, the ventromedial seta is bipectinate, just as the one on tibia 111; on tarsus IV, there are only 3 dorsal setae present.

Copidognathus subterraneus n. sp. Material. 1 male (holotype), Emerald Sink, Hamilton Parish, 17.1.1982, collected at 11 m depth in the west pool by a fine mesh dip net with scuba from bottom silt, leg. T. Iliffe.

Male: Length of idiosoma 310 pm. In the male, the following measurements were obtained (in pm).

Idiosoma Anterodorsal plate Ocular plate Posterodorsal plate Anterior epimeral plate Genitoanal plate Genital opening Gnathosoma

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Length 310 82 67 214 105 147 29 85

Width 140 72 30 102 115 87 18

Dorsal plates ornamented with a network (fig. 34), each larger area subdivided by small cuticular ribs. Anterodorsal plate (AD) with a small pointed anterior process and A-shaped elevated crista. A pair of small gland pores on lateral margin of the AD, at level of leg I. Ocular plates (OC) distally tapering but not tail-like. Neither corneae nor eye pigment seen in this specimen. At lateral margin of plate, a large gland pore and slightly distal to this, a pore canaliculus present. Posterodorsal plate (PD) slender, with its straight-ending anterior portion reaching beyond insertion of leg 111. The 2 pairs of gland pores situated almost terminal. First pair of small dorsal setae (d-1) standing close together in middle of AD; d-2 inserted within striated integument anterior to OC; d-3, d-4, and d-5 on the PD (fig. 34). Ventral plates ornamented with minute ribs, thus finely porose, moreover a much coarser paneling contoured. Anterior epimeral plate (AE) slender; its posterior, almost quadrangular, portion extending beyond insertion of leg I11 (fig. 35). Epimeral processes inconspicuous. Three pairs of long, slender vental setae on AE. Between epimera I and 11, Clapari.de organ like a four-leaf clover beneath the plate (fig. 37). Posterior epimeral plates with 1 pair of dorsal and 3 pairs of ventral setae. Genital opening small, surrounded by 34 perigenital setae. At margin of genital sclerites, 4 pairs of minute setae present; the 2 proximal and the most distal ones hair-like, the third one spine-like (fig. 36). Base of gnathosoma ornamented as ventral plates. Rostrum almost extending to end of third palpal segment (fig. 39). One pair of long maxillary setae at base of gnathosoma, 1 pair in middle of rostrum, 4 pairs of minute setae at tip of rostrum (fig. 38). Palpi slender. Fourth palpal segment (P-4) almost as long as P-1 plus P-2. O n P-2, 1 seta; on P-4, 3 basal setae and 1 minute distal one. Leg I much stouter than the following ones. O n telofemur I and tibia I, a coarse paneling present, the large panels divided by minute ribs (fig. 41); in deeper integumental layers, fine canaliculi piercing the integument. Telofemur I with a huge, pointed ventrolateral lamella; ventromedial lamella absent. On tibia I, ventromedially, 1 slender and 1 bipectinate bristle; ventrally, 1 slender one; dorsally, 4 setae (fig. 42). Tarsus I with huge lateral membrane of claw fossa (fig. 44). At base of this membrane stands a seta-like solenidion; in the membrane, a canalicular famulus seen. Telofemora and tibiae on the following legs finely paneled. O n tibia 11, ventromedially 2 pectinate; ventrally 1

STYGOLOGZA (3) 1985

Figs. 34-44. Copidognathus subterraneus n. sp., 0'.34, idiosoma, dorsal view; 35, idiosoma, ventral view; 36, genitoanal plate, ventral view; 37, portion of anterior epimeral plate with Claparkde organ; 38, idiosoma, ventral view; 39, gnathosoma, lateral view; 40, leg 111, medial view; 41, leg I, lateral view; 42, leg I, medial view; 43, leg 11, medial view; 44, tarsus I, lateral view. Each scale division = 50 pm.

8

315

STYGOLOGZA (3) 1985

1

slender, smooth seta (fig. 43); on tibiae I11 and IV each ventrally 1 pectinatec and 1 smooth seta. Tarsus I11 with 4 dorsal setae (fig. 40), tarsus IV with 3 dorsal setae. Lateral claws stout. O n tarsus I, a small accessory tooth present but no claw comb. On the following tarsi, claw comb inconspicuous, with only a few small teeth. Between lateral claws, a minute median claw present.

I

Female: Not seen. I

,

Remarks. Copidognathus subterraneus is easily recognized and distinguished from all other known Copidognathus species by the huge ventrolateral lamella on telofemur I. Further characteristics are: slender idiosoma; marked paneling on plates and legs; Claparkde organ enlarged, with an outline of a four-leaf clover. Claparkde organs are present in all Copidognathus species, usually as small tubes ending at the surface of AE with a fine slit or a circular pore. The circular pore is often concealed by minute protruding teeth. Only a few species with enlarged Claparkde organs are known, e.g. Copidognathus tectiporus (Viets, 1935), C . poriferus Bartsch, 1979b, an undescribed species from the Caribbean area and 2 species from Philippine waters (description in preparation). C . tectiporus and C . poriferus are known from brackish water only; in these 2 species, the enlarged Claparkde organs obviously have osmoregulatory functions. The Caribbean and Philippine specimens were collected in shallow water marine habitats; the function of the enlarged Claparsde organs in these species is unknown. Similar ornamentation of dorsal and ventral plates and large gland pores are also found in Copidognathus magniporus Bartsch, 1973. Copidognathus subterraneus might be related to C . magniporus. The prominent, pointed lamella on telofemur I in C . subterraneus is supposed to be of importance in capturing prey.

Copidognathus longispinus n. sp. Material. 1 female (holotype), Walsingharn Cave, Hamilton Parish, 18.11.1982, collected from 6 to 8 rn depths in main pool at cave entrance with scuba using a suction bottle, leg. T. 11iffe.

Female: Length of idiosoma 353 ym. In the female, the following measurements were obtained (in ym). Idiosorna Anterodorsal plate Ocular plate Posterodorsal plate Anterior epimeral plate Genitoanal plate Genital opening

Length 353 167 103 174 107 157 45

Width 192 136 28 145 185 135 30

3 16

STYGOLOGZA (3) 1985

Anterodorsal plate (AD) with an elevated, elongate gable-like area, anteriorly protruding in form of a long stout spine (fig. 45). Spine markedly sculptured (fig. 48). Lateral portions of the gable-like area with rosette pores, median portion reticulate. AD distally straight-edged. Gland pores at margin of the gablelike area. Ocular plates (OC) oblong, almost quadrangular, in its anterior portion; posterior portion hidden beneath posterodorsal plate. Anterior cornea protruding beyond frontal margin of O C ; posterior cornea small, circular in outline. A pair of gland pores at level of distal cornea, a small pore canaliculus slightly further distal. Medial and lateral to corneae, few scattered rosette pores present. Posterodorsal plate (PD) with its anterior straight-edged portion almost contiguous to the AD. Two elevated, slightly curved longitudinal costae with rosette pores on PD (fig. 49). On median and lateral portions of the PD, integument ornamented by cuticular ribs, thus forming a network. A pair of gland pores at level of trochanters IV, and 1 at posterior end of the plate. Dorsal setae slender; all of equal length. First pair (d-1) on AD within the gablelike area; d-2 on medial margin of OC; d-3, d-4, and d-5 on PD within porose costae. Adanal setae standing on minute papillae at end of the PD. Anterior epimeral plate (AE) and genitoanal plate (GA) fused laterally (fig. 46). Marginal portions of ventral plates with rosette pores, ventral portions with minute pores and pycnotic rosette pores. Trochanters I enclosed laterally and medially by huge processes on the AE. Clapar2de organ ending at surface of the AE with a small slit. Genital opening in distal end of the GA; distance from G O to anterior margin of GA almost 3 times the length of the GO. Ovipositor very long, surpassing the G O for much more than twice the length of the G O (fig. 46). Gnathosoma stout, rostrum short. Base of gnathosoma dorsally coarsely paneled, ventrally integument pierced by many delicate canaliculi. Rostrum short. Epistome strong, as a stout crest extending just beyond the level of the second pair of long maxillary setae (fig. 47). Chaetotaxy of palps as usual in the genus Copidognathus, viz. 1 seta on second palpal segment (P-2), no seta on P-3, 3 basal and a minute delicate distal one on P-4. Legs with huge lamellae. All basifemora with ventral lamellae. Telofemora with large ventrolateral (figs. 50-53), but only narrow ventromedial lamellae. Distal lamellae on tibiae I and I1 large, almost quadrangular; distal lamellae on tibiae I11 and IV smaller. Trochanters I11 and IV dorsally prolonged like a cornet. Lateral membrane of claw fossa on tarsi I and I1 large, medial membrane inconspicuous. Membranes of claw fossae on posterior legs absent. O n tarsus I, laterally and medially doublet, eupathid parambulacral setae (fig. 55); on tarsus I1 on both flanks, an eupathid and a delicate, minute seta (fig. 54). All tarsi with large lateral claws and small, bidentate median claws. O n lateral claws of leg I, only few teeth of claw comb present; on tarsi I1 and 111, long claw combs with many fine teeth; on tarsus IV, only a short claw comb discernible.

(

STYGOLOGZA (3) I985

317

I

Figs. 45-55. Copidognathus longispinus n. sp., Q . 45, idiosoma, dorsal view; 46, idiosoma, ventral view; 47, gnathosoma, ventrolateral view; 48, frontal spine of anterodorsal plate; 49, portion of right posterodorsal plate at level of gland pore; 50, leg I, medial view; 51, leg 11, medial view; 52, leg IV, medial view; 53, leg 111, medial view; 54, tibia and tarsus I, lateral view; 55, tibia and tarsus I, lateral view. Each scale division = 50 pm.

Male: Not seen.

b Remarks. - Copidognathus longispinus belongs to the gibbus group (cf. Newell, 1971; Bartsch, 1977a, and in press). C. longispinus is very similar to C. cristatus Viets, 1936, a species from C u r a ~ a oBut . in C. cristatus, the frontal spine is not pronounced; the porose costae on the PD are not widened at level of gland pore; the lamellae on the legs are conspicuously smaller than in the species found in Bermudian caves. Off the Atlantic coast of South America, another species of the gibbus group is known, viz. C. caulifer (Trouessart, 1899), known from a female collected off Brazil. In C. caulifeer, there is only a short frontal spine; the costae on the AD are narrow; only 2 rosette pores wide; on the PD, the costae are straight, not widened as in the Bermudian species. Copidognathus sinuosus Newell, 1971, found off the Pacific coast of South America, appears to be similar to C. longispinus. But in C. sinuosus, too, the frontal spine is not as prominent and the costae on the dorsal plates are narrower than in C. longispinus.

Agaue nationalis (Lohmann, 1893) Material. 1 deutonymph, Palm Cave, Hamilton Parish, 13 & 16.111.1982, collected from bottom silt at 16 m depth with scuba using a fine mesh dip net, leg. T. Iliffe.

Length of idiosoma 429 p.m. Distribution. Bermuda, Florida, off northeastern Brazil (Viets, 1956), Caribbean area (unpublished data).

Simognathus fuscus Viets, 1936 Material. 1 deutonymph, Emerald Sink, Hamilton Parish, 17.1.1982, collected at 11 m depth in the west pool by a fine mesh dip net with scuba from bottom silt, leg. T. Iliffe; 1 larva, Palm Cave, Hamilton Parish, 13 & 16.111.1982, collected from bottom silt at 16 m depth with scuba using a fine mesh dip net, leg. T. Iliffe.

Length of idiosoma in the deutonymph 313 ym, in the larva 138 ym. No adult specimens were available, but the triangular ocular plates, and the insertion of the ventral spine on the second palpal segment, distal to the cuticular knob indicate these specimens to belong to Simognathusfuscus. Distribution. Simognathusfuscus is known from Bonaire (Viets, 1936). ORIGIN O F THE CAVE HALACARID FAUNA

All the caves from which halacarids were collected have more or less direct connections to open waters and moderate to strong tidal currents flowing through them. In most instances, the halacarids were found on the surface of silty sediments, although in one instance, they were associated with hydroids on cave walls. The areas from which we collected halacarids were in total or almost total darkness.

n a

1 c t

I I

Many of the species found have large corneae and brown eye pigment both beneath the corneae and at the tip of the anterodorsal plate, e.g. Agauopsis bermudensis, A. littoralis, Copidognathus bemudensis, C. longispinus, Agaue nationalis, and Simognathusfiscus. Similar shape of idiosoma, elaborate lamellae, as well as large corneae usually are found in species inhabiting the littoral zone, calcareous encrustrnents, and bushy algae. Thus, most of the species mentioned above are swept into the cave by tidal currents. Arhodeoporus perlucidus is abundant along the shoreline in upper sediment layers, and is not a true cavernicolous form. Copidognathus subterraneus is new to science. It is characterized by very slender idiosoma, lack of eye pigment and corneae. These features are usually found in halacarid species well adapted to interstitial life. Probably none of the halacarid species found are genuine cavernicolous forms. In contrast to the halacarids, other species collected from the caves are strict troglobites. These include the isopods ~aantaselluscauernicolus and Bermudalana aruboides, the shrimps Somersiella sterreri and Typhlatya iliffei, and the archiannelid Mesonerilla prospera. Except for Mesonerilla, troglobiont species have been found only in caves lacking direct tidal exchange with the open sea.

ACKNOWLEDGMENTS This study was supported by National Science Foundation grant BSR-8215672 to T. Iliffe. This paper is Contribution No. 1012 of the Bermuda Biological Station for Research. REFERENCES BACESCU, M., 1980. Apseudes bermudeus n. sp. from caves around Bermuda islands. Acta adriat., 21: 401-407. BARTSCH, I., 1973. Halacaridae (Acari) von der Josephinebank und der Grossen Meteorbank aus dem ijstlichen Nordatlantik, 11. Die Halacaridae aus den Bodengreiferproben. Meteor Forsch Ergebn., (D) 15: 51-78. --, 1975. Beitrag zur Halacariden-Fauna des Eulitorals bei Banyuls-sur-Mer (Mittelmeer) (Halacaridae, Acari). Mitt. hamb. zool. Mus. Inst., 72: 137-155. --, 1976. Erganzungen zur Halacariden-Fauna (Halacaridae, Acari) im Becken von Arcachon. Vie Milieu, (A) 26: 31-46. --, 1977a. Zur oculatus- und gibbus-Gruppe der Gattung Copidognathus (Halacaridae, Acari). Ent. Mitt. 2001. Mus. Hamburg, 6 (97): 1-12. --, 1977b. Interstitielle Fauna von Galapagos, XX. Halacaridae (Acari). Mikrofauna Meeresboden, 65: 1-108. --, 1978179. Verbreitung der Halacaridae (Acari) im Gezeitenbereich der Bretagne-Kuste, eine okologische Analyse, I. Verbreitung der Halacaridae, 11. Quantitative Untersuchungen und Faunenanalyse. Cah. Biol. mar., 19: 363-383; 20: 1-28. --, 1979a. Copidognathus hartwigi n. sp. (Halacaridae, Acari), eine Meeresmilbe neu fur die Fauna der Bermudas. Acarologia, 20: 93-96. --, 1979b. Halacaridae (Acari) von der Atlantikkiiste Nordamerikas. Beschreibung der Arten. Mikrofauna Meeresboden, 79: 1-62. --, 1982. Halacaridae (Acari) von der Atlantikkiiste des borealen Nordamerikas. Okologische und tiergeographische Faunenanalyse. Helgolander Meeresunters., 35: 13-46.

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--, in press. Zur Verbreitung der gibbus-Gruppe (Copidognathus:

--, 1899. Description d'esptces nouvelles d'klalacaridae. Bull. Soc. Ctud. scient. Angers, 29: 209-223. VIETS,K., 1928. Wassermilben aus dem Schwarzen Meer, dem Kaspischen Meer und dem Aral See. Abh. natunu. Ver. Bremen, 27: 47-80. --, 1935. Wassemilben aus Bulgarien. Zool. Anz., 109: 33-39. --, 1936. Zoologische Ergebnisse einer Reise nach Bonaire, Curacao und Amba im Jahre 1930, No. 18. Halacariden aus Westindien. Zool. Jb., (Syst) 67: 389-424. --, 1939140. Meeresmilben aus der Adria (Halacaridae und Hydrachnellae, Acari). Arch. Naturgesch., (n. F.) 8: 516-550; 9: 1-135. --, 1956. Die Milben des Siisswassers und des Meeres. Hydrachnellae et Halacaridae, 111. Katalog der Halacaridae, Meeresmilben: 641-870. (Fischer Verlag, Jena). YEATMAN, H. 1980. Miostephos leamingtonensis, a new species of copepod from Bermuda. J . Tenn. Acad. Sci., 55 (1): 20-21. Received 11 April 1984