Rimicaris variabilis ( Komai & Tsuchida, 2015 )

Komai, Tomoyuki, Menot, Lenaick & Segonzac, Michel, 2016, New records of caridean shrimp (Crustacea: Decapoda) from hydrothermally influenced fields off Futuna Island, Southwest Pacific, with description of a new species assigned to the genus Alvinocaridinides Komai & Chan, 2010 (Alvinocarididae), Zootaxa 4098 (2), pp. 298-310 : 307-308

Rimicaris variabilis ( Komai & Tsuchida, 2015)

Chorocaris variabilis Komai & Segonzac, 2015: 12 , figs 6–10 (type locality: South Su site, Manus Basin). Rimicaris variabilis .— Vereshchaka et al. 2015: 21, figs 4–6.

Material examined. DS “Nautile”, dive 1776, Kulo Lasi, Futuna, 14°55.0466’S, 177°14.9152’W, 1478 m, 12 September 2010, slurp gun, bottle 2, 3 males (cl 4.8–7.2 mm), 1 female (cl 8.1 mm), 11 ovigerous females (cl 6.0– 7.6 mm), MNHN-IU-2011-5030; dive 1777, same site, 14°56.5574’S, 177°15.0001’W, 1477 m, 13 September 2010, slurp gun, bottle 4, 1 female (cl 5.4 mm), 3 ovigerous females (cl 5.3–5.9 mm), MNHN-IU-2011-5015; dive 1778, same site, 14°55.177’S, 177°14.9559’W, 1477 m, 15 September 2010, slurp gun, bottle 3, 6 ovigerous females (cl 5.6–8.5 mm), MNHN-IU-2011-5037.

Distribution. Previously known from hydrothermal vents on three locations in the Southwest Pacific, viz., Manus Basin, North Fiji Basin and off Vanuatu, at depths of 1305–2480 m (Komai & Tsuchida 2005).

Remarks. Vereshchaka et al. (2015) confirmed the non-monophyly of Chorocaris Martin & Hessler (1990) on the basis of separate phylogenetic analyses based on morphological and molecular data, and finally synonymized the genus with Rimicaris . Consequently, the six species once assigned to Chorocaris , viz., C. chacei (Williams & Rona, 1990) , C. parva Komai & Tsuchida, 2015 , C. paulexa Martin & Shank, 2005 , C. susannae ( Komai, Gierre & Segonzac, 2007) , C. vandoverae Martin & Hessler, 1990 , and C. variabilis , have been all transferred to Rimicaris .

The present material morphologically closely agrees with the type series of R. variabilis . Partial fragments of the mitochondrial COI gene (600 bp; GenBank accession numbers KT948642 , KT948643 , KT948644 ) from the three Futuna specimens are completely consistent with each other (100%). On the other hand, the K2P genetic divergences between those three specimens from Kulo Lasi and four specimens of Rimicaris variabilis used by Komai & Tsuchida (2005) (DNA Data Bank of Japan accession numbers AB772279 , AB772280 , AB772281 , AB772283 ; 600 bp are available for comparison) range from 1.6–3.7% (mean 2.8%), suggesting that the Kulo Lasi specimens belong to the same species.

Rimicaris variabilis was the dominant species among the swarms of alvinocaridid shrimps observed and sampled in the vicinity of active chimneys in the caldera.