Lithodes longispina Sakai, 1971

Wang, Teng-Wei, Ahyong, Shane T. & Chan, Tin-Yam, 2016, First records of Lithodes longispina Sakai, 1971 (Crustacea: Decapoda: Anomura: Lithodidae) from southwestern Taiwan, including a site in the vicinity of a cold seep, Zootaxa 4066 (2), pp. 173-176 : 173-176

Lithodes longispina Sakai, 1971

( Figs. 1–2 )

Lithodes longispina T. Sakai, 1971: 11 , 33, pl. 9–11, figs. 2a', b'; 1976: 694, fig. 377, pl. 241.— K. Sakai, 1987: 19 –21, fig. 1, pl. 1, 2a– b.— Macpherson, 1990: fig. 1b; 1991: figs. 1b, 2c–d.— Ikeda, 1998: 48, pl. 67.

Taiwanese material examined. TAIWAN 2006, stn PCP344, 22°15.95'N, 120°0.11'E, 995–1073 m, 0 8 March 2006, 1 male (cl 20.0 mm, pcl 11.0 mm, cw 9.0 mm), NTOU A01414.— TAIWAN 2008, stn PCP445, 22°17.10'N, 120°0.17'E, 982–999 m, 14 July 2008, 1 male (cl 34.0 mm, pcl 22.0 mm, cw 20.0 mm), NTOU A01419.—Cold seep project cruise 2015, stn CST 2, 22°05.19'N, 119°48.30'E, 1360–1669 m, 30 May 2015: 1 ovigerous female (cl 163.5 mm, pcl 110.9 mm, cw 100.5 mm), NTOU A01420 .

Comparative material examined. Japan, SW of Jogashima, Sagami Bay, crab pot, 800–850 m, December 1983, 1 male (cl 163.1 mm, pcl 104.7 mm, cw 94.4 mm), NTOU A01424 .

Diagnosis. Carapace dorsal surface with long, slender spines, length reduced in large adults; gastric region with 4 upright spines, anterior pair longer than half length of hepatic spine, posterior pair half length of hepatic spine or shorter; cardiac and intestinal regions each with 2 long upright spines; branchial surface with 2 dorsal spines, anterior spine in adults considerably longer than posterior spine. Branchial margins with 2 primary, latero-dorsally directed spines positioned at level between pereiopods 2 and 3, and pereiopods 3 and 4, respectively; margin between posterior primary branchial spine and intestinal spine with no more than 5 short protrusions or spines. Adult rostrum half pcl or longer; proximal half strongly upraised by 30–45°. Abdominal somite 2 comprising 3 separate plates in adults. Antennal peduncle article 2 with slender outer spine reaching beyond midlength of article 4. Chelipeds unequal; palms generally smooth, with low tubercles on dorsal surface. Ambulatory legs spinose; surface between major spines smooth or with very few, scattered spines. Pereiopod 4 merus slightly shorter than to slightly longer than pcl (0.9–1.1), length less than 7 times height; propodus length about 12 times height; dactylus half length of propodus, flexor margin smooth, without corneous spines.

Coloration. Generally deep orange-red overall. Cornea dark brown.

Remarks. Lithodes longispina has been accorded a wide distribution outside of Japan including Australia, New Zealand, and the central Pacific ( Midway Island) but recent studies indicate a much more limited range for the species. Ahyong (2010) showed that the New Zealand and Australian records of L. longispina were referable to several other species, primarily L. aotearoa Ahyong, 2010 , L. australiensis Ahyong, 2010 , and L. richeri Macpherson, 1990 . Takeda's (1974) Midway Island record does not appear to be L. longispina . Takeda (1974: pl. 1, fig. 1) shows the pereiopod 2–4 meri to be distinctly longer than the carapace; his record could be referable to L. paulayi Macpherson & Chan, 2008 , described from Guam. Thus, until now, L. longispina was known with certainty only from Japan. Three species of Lithodes are now known from Taiwan: L. turritus , L. formosae and L. longispina , each of which has long spines on the carapace and walking legs persisting into at least the early adult stage. Lithodes longispina is distinguished from L. formosae and L. turritus by carapace ornamentation. Lithodes longispina and L. formosae have a distinctly upraised rostrum, which in L. turritus , is almost horizontal. Lithodes longispina can be distinguished from L. formosae by having one instead of two long dorsal branchial spines in adults (posterior dorsal branchial spine very short or obsolete), and lacking a row of small corneous spines on the flexor margins of the walking legs (Ahyong et al. 2010).

The two juvenile males collected in 2006 and 2008 were matched to the adult and identified as L. longispina through DNA barcoding (COI 657bp: 99.2–99.7% similarity, GenBank no. KU214586 –214588). Comparison of COI sequences of the Taiwanese specimens with available sequences of Japanese L. longispina in GenBank ( AB476813 –476817) showed 98.7–99.4% similarity.

Morphologically, the Taiwanese specimens agree well with published accounts of L. longispina and a comparative topotypic specimen from Japan. The dorsal spines of the Taiwanese female are proportionally shorter than those of the size-matched male from Japan, but within the expected range of variation. As in other species of Lithodes , the juveniles have considerably longer dorsal spines than adults as figured by Ikeda (1998) for Japanese specimens.

Although all three specimens were collected from off southwestern Taiwan in relatively close proximity, the large female was collected by a French beam trawl ( Tsai et al. 2009) over a cold seep site together with dead shells of the bivalve Calyptogena (Archivesica) aff. nankaiensis Okutani, Kojima & Ashi, 1996 , which is restricted to chemosynthetic habitats ( Okutani et al. 1996; Sasaki et al. 2005). Lithodid crabs have been reported from seep and vent environments ( Martin & Haney 2005) but this is the first record of L. longispina from the vicinity of such habitats. Given that the female L. longispina was trawled, we cannot confirm whether it was living at the cold seep site or on adjacent nonchemosynthetic habitat; further investigations are required. Lithodes longispina is a large predator, so its occurrence at cold seeps, if confirmed, is of ecological importance.

Distribution. Previously known with certainty only from Japan, and now also found in Taiwan; 550–1699 m.

Acknowledgements. Grateful acknowledgements are extended to H. Ikeda of the Hayama Shiosai Museum, Kanagawa, for providing with us a specimen of Lithodes longispina from Japan; E. Krylova of P.P. Shirshov Institute of Oceanology, Moscow, and P. Bouchet of the Muséum national d’Histoire naturelle, Paris, for the identification of the bivalves collected at the cold seep site off southwestern Taiwan; C. H. Yang of the National Taiwan Ocean University for DNA analysis. This work is supported by research grants from the Ministry of Science and Technology, Taiwan, R.O.C. This is a contribution from the Australian Museum Research Institute.

Figures

FIGURE 1. Lithodes longispina Sakai, 1971, off southwestern Taiwan: a, stn CST 2, 1360 – 1669 m, ovigerous female (cl 163.5 mm, pcl 110.9 mm, cw 100.5 mm), NTOU A 01420; b, stn PCP 445, 982 – 999 m, male (cl 34.0 mm, pcl 22.0 mm, cw 20.0 mm), NTOU A 01419; c, stn PCP 344, 995 – 1073 m, male (cl 20.0 mm, pcl 11.0 mm, cw 9.0 mm), NTOU A 01414.

FIGURE 2. Lithodes longispina Sakai, 1971, off southwestern Taiwan, stn CST 2, 1360 – 1669 m, ovigerous female (cl 163.5 mm, pcl 110.9 mm, cw 100.5 mm), NTOU A 01420: a, carapace, dorsal view; b, anterior carapace, right lateral view; c, right antennal peduncle, dorsal view; d, right pereiopod 4; e, dactylus of right pereiopod 4. Scales = 10 mm.