CRUSTACEAN RESEARCH, NO. 36:1-14, 2007 1 New species of Munidopsis (Decapoda: Anomura: Galatheidae) from hydro thermal vent in Okinawa Trough and cold seep in Sagami Bay Sherine Sonia Cubelio, Shinji Tsuchida and Seiichi Watanabe Abstract— Three new species of ferent types of hydrothermal vent fields have galatheid crabs, Munidopsis ryukyuen- been found in the two major oceanic areas to sis n. sp. and Munidopsis longispinosa the south of the main archipelago, namely, n. sp., both associated with hydro ther­ the Izu- Ogasawara Island Arc and the mal vents in the Hatoma Knoll, East Okinawa Trough in the East China Sea China Sea, and Munidopsis naginata n. (Ishibashi & Urabe, 1995; Kimura et aL, sp. associated with hydrothermal vents 1988). Five active vent sites, such as Dai-Yon in the Hatoma Knoll and cold seep in Yonaguni, Minami-Ensei and Hatoma Knolls Sagami Bay are described and illustrat­ (Fig. 1), Iheya Ridge and Izena Calderon ed. Their affinities to closely related have been located in Okinawa Trough species are discussed. The records of (Hashimoto et aL, 1995). In Hatoma Knoll, Munidopsis species associated with Munidopsis are abundant along with the hydrothermal vents in the West Pacific other galatheid crab, Shinkaia crosnieri Ocean are increased to seven. The habi­ Baba & Williams, 1998, deepsea mussels, tat of the new species is briefly Bathymodiolus platifrons; provannid gas­ described. Distributional patterns of tropods, Provanna glabra and alvinocaridid vent associated Munidopsis in the West shrimps, Alvinocaris longirostris (see Pacific is briefly discussed. Introduction 40°N Since the first discovery of hydrothermal vents on the Galapagos Rift in 1977 (Corliss et aL, 1979), numerous biological communi­ ties endemic to such chemosynthetic envi­ ronments have been reported (Desbruyeres et aL, 1982; Hessler & Lonsdale, 1991 Tunnicliffe, 1991; Ohta & Laubier, 1987 30°N Hashimoto et aL, 1989; Paul et aL, 1984 Embley et aL, 1990) and galatheid crabs of the genus Munidopsis (Anomura: Galatheidae) are found to be common species in such environments (Williams, 1988; Williams & Van Dover, 1983; Williams 20°N & Baba, 1989; Baba & de Saint Laurent, 120°E 130°E 140°E 1992; Baba, 1995, 2005; Macpherson & Segonzac, 2005; Martin & Haney, 2005; Fig.l. Locality map of Hatoma Knoll and Sagami Bay from where the specimens have been collect­ Desbruyeres et aL, 2006). Around Japan, dif- ed. 2 S. S. CUBELIO ETAL. Kojima,2002). The National Science Museum, Tokyo Munidopsis currently comprises more (NSMT) and JAMSTEC. Abbreviations used than 200 species worldwide with nine report­ in the text include: PI, first pereopod (che- ed only from active hydrothermal vent fields liped); P2-4, second to fourth pereopod (first (Williams, 1988; Williams & Van Dover, to third walking legs); P5, fifth pereopod. 1983; Williams & Baba, 1989; Baba & de Saint Laurent, 1992; Baba, 1995, 2005; Macpherson & Segonzac, 2005; Osawa et al, Taxonomy 2006; Schnabel & Bruce, 2006; Desbruyeres et al., 2006). So far, four species of Order Decapoda Munidopsis have been described from the Superfamily Galatheoidea Samouelle, 1819 West Pacific hydrothermal vents such as M. Family Galatheidae Samouelle, 1819 marianica Williams & Baba, 1989 from Genus Munidopsis Whiteaves, 1874 Mariana Back Arc Basin, M. starmer Baba & Munidopsis ryukyuensis, new species de Saint Laurent, 1992 and M. sonne Baba, (Figs. 3a, 4) 1995 from North Fiji Back Arc Basin and M Material examined. —Holotype: oviger- lauensis Baba & de Saint Laurent, 1992 from ous female, 17.37mm (NSMT-Cr 16867), Lau and North Fiji Back Arc Basins. In the Hatoma Knoll, Okinawa Trough, ROV Hyper- East Pacific, three species occur in vent Dolphin, dive HD # 399, 24° 51.48' N 123° fields, namely, M. alvisca Williams, 1988, M. 50.51' E, 1480m, 26 April 2005. lentigo Williams & Van Dover, 1983 (Martin Paratypes: 3F, 18.36mm, 15.33mm, & Haney, 2005; Desbruyeres et al., 2006), 16.94mm; 2M, 17.06mm (infected with rhizo- and Munidopsis sp. near M. recta Baba, 2005 cephalan parasite), 11.02mm (JAMSTEC (the material reported by Van Dover et al 059255- 059259), ROV Hyper-Dolphin, dive (1985) under M. subsquamosa Henderson, HD # 400, 24° 51.48' N 123° 50.51' E, 1885; see Baba (2005) and Macpherson & 1480m, 26 April 2005; IF ovigerous 18.44mm Baba in Desbruyeres et al., 2006)). In the (JAMSTEC 027965), 24° 51. 48' N 123° Mid-Atlantic Ridge, two species, M. 50.51' E, 1454m, Shinkai 2000, dive 2K # acutispina Benedict, 1902 and M. exuta 1183; 2F, 21.20mm, 16.41mm (NSMT-Cr Macpherson & Segonzac, 2005 are found. 16868, NSMT-Cr 16869), Shinkai 2000, dive Here we describe two new species of 2K # 1183, 24° 51.20'N 123° 50.29' E, Munidopsis found around the hydrothermal 1454m, 20 May 2000; IM, 18.82 mm vent site in Hatoma Knoll, Okinawa Trough, (NSMT-Cr 16870), Shinkai 2000, dive 2K # East China Sea and a third species associat­ 1185, 24° 51. 29' N 123° 50.45' E, 1487m, 24 ed both with vents in Hatoma Knoll, May 2000. Okinawa Trough and cold seep in Sagami Additional materials: 3F, 12.18mm, Bay. 13.64mm, 11.65mm, 2M, 10.86mm, 10.36mm (JAMSTEC 027265-69), Shinkai 2000, dive 2K # 1182, 24° 51.48' N 123 50°. 51'E, Materials and Methods 1480m, 19 May 2000; 2M, 9.31mm, 7.45mm The material reported here was collected (JAMSTEC 027270-71), Shinkai 2000, dive by manned submersible Shinkai 2000 and 2K # 1182, 24° 51. 48'N 123° 50. 51'E, ROV Hyper-Dolphin with their support ship 1480m, 19 May 2000. Natsushima of Japan Agency for Marine- Earth Science and Technology (JAMSTEC). Diagnosis. — Carapace, exclusive of ros­ Measurements of specimens, given in mil­ trum, distinctly longer than broad, gastric limeters (mm), indicate the carapace length region with transverse rugae occasionally including the rostrum. Type specimens are feebly tuberculate. Rostrum almost straight deposited in the crustacean collections of horizontal in profile, triangular with fine lat- NEW VENT ASSOCIATED MUNIDOPSIS FROM JAPAN 3 '$-,-- fiT'4 - . ..; . - • ^ :• Fig. 2. ZM-MYW photo of Hatoma Knoll where Munidopsis ryukyuensis n. sp. is seen among the deep-sea mussels (inside photo is the close up view). Fig. 3. a, Munidopsis ryukyuensis n. sp. holotype female, 17.37mm, dorsal; b, Munidopsis longispinosa n. sp. holotype male, 24.36mm, dorsal; c, Munidopsis naginata n. sp. holotype male, 17.44mm, dorsal. 4 S. S. CUBELIO ETAL. eral serrations. Abdomen unarmed. Telson exclusive of spines, somewhat longer than composed of 10 plates. Eyes moderate in broad, distolateral inflation bearing tubular size, well-exposed, smoothly ovate cornea. process often developed into small spines, PI with weakly developed, setose rugosites distolateral spine well developed, distoven- tending to be tuberculate in longitudinal tral margin scalloped, contiguous with small lines, long plumose setose more dense ven­ mesiodorsal spine. Antennal peduncle hav­ trally along distomesial margin of merus. P2- ing segment 1 with flat ventral process end­ 4 relatively long and slender, often weakly ing in acute spine, and much smaller disto­ tuberculate, dactyli setose, stout, ending in lateral spine; segment 2 with short distolat­ short, curved, corneous claw. Epipods eral spine, segment 3 unarmed; and fourth absent from Pl-4. with crenulated scalloped ending. Description. — Carapace, exclusive of Third maxilliped basis with 2 or 3 small rostrum, distinctly longer than broad, mod­ corneous spines in line with crest on ischi­ erately arched transversely, anterior and um, ischium distoventrally with distinct posterior bifurcations of cervical groove dis­ spine, shorter than merus when measured in tinct. Rostrum 0.2 times length of carapace, midlateral line, crista dentata armed with straight horizontal in profile, triangular with finely uniform evenly spaced corneous fine lateral serrations often obscured, bear­ tipped spines. Merus small, often obsoles­ ing distinct dorsal carina merging into ante­ cent spines on flexor margin and a small rior gastric region. Strongly oblique frontal spine at distodorsal corner. Sternite at base margin sweeping to small antennal spine of third maxilliped forming apposed lobe at directly lateral to eyestalk. Gastric region either side of midline, irregularly serrate on moderately dilated, with transverse rugae margin. occasionally feebly tuberculate, often obso­ PI 1.08-1.10 times as long as carapace lescent, with 2 longer anterior rugae consis­ including rostrum, with weakly developed, tent on epigastric region. Anterior branchial setose rugosites in longitudinal lines, long region also with rugae, lateral margin with plumose setose more dense ventrally along small spine. Posterior branchial region with distomesial margin of merus, distal margin interrupted rugae more pronounced than of carpus and mesial margin of palm. those on anterior branchial region, lateral Ischium with small distodorsal spine, merus margin with small anterior spine. with 2 strong spines terminally; mesial, ven­ Pterygostomian flap with obliquely interrupt­ tral and lateral spines small or often obsoles­ ed rugae distinct posteriorly, obsolescent cent. Carpus with well-developed acute anteriorly, ending in rounded margin. mesial spine somewhat proximal to juncture Abdomen unarmed, transverse ridge on with palm; fingers about as long as palm, segments 2 & 3 with spare short stiff setae; straightly fitting to each other on opposable segments 4, 5 and 6 considerably smooth, margin, with minute intermeshing teeth at posteriomost with posteromedian margin tips. almost transverse, posterior margin of later­