Alvinocaris komaii Zelnio and Hourdez, 2009: 55 New records of Alvinocarididae (Crustacea: Decapoda: Caridea) from the southwestern Pacific hydrothermal vents, with descriptions of one new genus and three new species Komai, Tomoyuki Tsuchida, Shinji Journal of Natural History 2015 2015-02-28 49 29 1789 1824 9CNTM Zelnio and Hourdez, 2009 Zelnio and Hourdez 2009 [433,950,514,538] Malacostraca Alvinocarididae Alvinocaris GBIF Animalia Decapoda 28 1817 Arthropoda species komaii 9CNTM Zelnio and Hourdez, 2009: 55 Zelnio and Hourdez 55 2009 [212,774,577,602] Malacostraca Alvinocarididae Alvinocaris GBIF Animalia Decapoda 28 1817 Arthropoda species komaii    Material examined  Non-type. Lau Basin.  BIOLAU, BL 08, site Vailili, 23°13 ʹS, 176°38 ʹW,  1740 m,  18 May 1989, slurp gun, 1 male(cl 12.2 mm),  MNHN; BL 10, same site,  22 May 1989, 1 female(cl 15.2 mm), CBM-ZC 11,956.  North Fiji Basin. STARMER  II, RV  Kaiyo, dive 19, site  White Lady, 18°50 ʹS, 173°29 ʹE,  2750 m,  July 1989, 1 female(cl 14.6 mm),  MNHN.  Vanuatu. RV  Sonne, SO229-061-N202, Nifoneavent field, 18°07.735 ʹS, 169° 31.018 ʹE,  1871 m,  19 July 2013, 1 female(cl 19.5 mm), CBM-ZC 12,483.   Supplemental description Rostrum ( Figure 15A–C) slender, terminating acutely, reaching or overreaching distal margin of first segment of antennular peduncle; dorsal margin sharply carinate, armed with row of teeth becoming larger posteriorly and extending beyond midlength of carapace (five postrostral teeth present); ventral ridge well developed, armed with one or more teeth; lateral carina conspicuous. Carapace ( Figure 15A, B) with distinct postrostral carina extending beyond midlength; dorsal margin of carapace in lateral view gently arcuate, with peak at posteriormost tooth of dorsal rostral series; no longitudinal depression on either side of midline even in spawning females; antennal tooth acuminate; pterygostomial tooth strong, acuminate; anterior part of branchial region not strongly inflated; dorsal organ absent. Third pleomere ( Figure 15D) armed with one or more denticles posteroventrally on pleuron; fourth pleuron armed with sharp posteroventral tooth and additional denticles or teeth on posterolateral and/or ventral margins; fifth pleuron with posteroventral tooth and additional teeth on posterolateral margin. Telson ( Figure 15E) with dorsolateral spines in linear row; posterior margin distinctly bilobed, with row of spines ( Figure 15F). Eyes fused, though distinct median notch present; anterior surface rounded, unarmed ( Figure 15C). Antennular stylocerite slender, narrowly separated from first peduncular segment ( Figure 15C). Antenna not forming operculate structure; antennal scale with sharp distolateral tooth clearly separated from lamella; no transverse suture extending mesially from base of distolateral tooth ( Figure 15C). First maxilliped without rudimentary bud of exopod. Third maxilliped with two or more slender spines at ventrodistal margin of antepenultimate segment ( Figure 15G). First pereopod with short grooming setae on flexor surface of palm; carpus with well-developed grooming apparatus consisting of patch of short setae and one or two spinules proximal to setal patch. Second pereopod ( Figure 15H) with one spine on ischium. Third to fifth pereopods increasing in length posteriorly; dactyli each with seven or eight accessory spinules arranged in two longitudinal rows on flexor surface ( Figure 15I); meri of third and fourth pereopods each with one to three spines on lateral faces, that of fifth pereopod unarmed; ischia of third and fourth pereopods each with one or two spines, that of fifth pereopod unarmed. No strap-like epipods on third maxilliped or first to fourth pereopods. Endopod of male first pleopod not bilobed distally, with three stiff setae distomesially; lateral margin with six or seven stiff setae in distal 0.3. Appendix interna of fourth pleopods without terminal cluster of coupling hooks. Uropodal exopod with one spine just mesial to base of posterolateral tooth; protopod sharply pointed posterolaterally.    Distribution Lau Basin ( Zelnio and Hourdez 2009; this study), 1740–2700 mdepths; North FijiBasin, 2750 mdepth (new record); and Vanuatu, Nifonea vent field, 1871 mdepth (new record).    Remarks The present specimens are consistent with the original description of  Alvinocaris komaiiin every diagnostic aspect. Molecular phylogenetic analysis based on 600 bp of the mitochondrial COI nucleotide by Zelnio and Hourdez (2009)suggested that  A. komaiiwas clustered with the  Opaepele/  Chorocaris/  Rimicarisclade, although the bootstrap support was very low (39.7%). As described previously by Zelnio and Hourdez (2009),  A. komaiidiffers from other species of  Alvinocarisin the accessory spinules on the dactyli of the third to fifth pereopods arranged in two or more rows and the unarmed anterior face of each eye. These characters, and the molecular analysis presented herein support the closer relationship of the species to a group including  Alvinocaridinides,  Chorocaris, Opaepele,  Shinkaicarisand  Rimicaris. Furthermore,  A. komaiihas two unique characters within the family, namely, the distinctly bilobed posterior margin of the telson and the multiple spines on the ventrodistal margin of the antepenultimate segment of the third maxilliped. Future study may potentially warrant the establishment of a separate genus for  A. komaii.  Figure 15.  Alvinocaris komaiiZelnio and Hourdez,, 2009. (A, C, D, G–I) Male (carapace length 12.2 mm), MNHN (rostrum damaged); (B, E, F) female (carapace length 14.6 mm), MNHN. (A) Carapace and cephalic appendages, lateral view; (B) carapace, lateral view; (C) anterior part of carapace and cephalic appendages, dorsal view; (D) posterior part of pleon, lateral view (posterior part of telson broken off); (E) telson, dorsal view; (F) posterior part of telson, dorsal view; (G) distal part of antepenultimate segment of left third maxilliped, lateral view; (H) left second pereopod, lateral view; (I) same, dactylus and distal part of propodus, flexor view. Scale bars: 5 mm for A, B, D; 2 mm for C, E, H; 0.5 mm for G, I, J.   Genetic divergence of the two new species of  Chorocaris The ML tree inferred from partial COI sequences (460 bp) for 18 identified species (including the two new species referred to  Chorocaris) and two unidentified species of the Alvinocarididaeis shown in Figure 16. At present, COI sequences are not  Figure 16. Molecular tree of the Alvinocarididaebased on partial cytochrome c oxidase subunit I (COI) sequences (460 bp), constructed by the maximum likelihood (ML) method.  Lebbeus laurentae Wicksten, 2010(registered as  L. carinatusin GenBank) used as an outgroup. Bootstrap values greater than 70% are given for branches with 500 replicate sampling in the sequence of ML, maximum parsimony (MP) and neighbour-joining (NJ). Note that  Mirocaris keldyshi Vereshchaka, 1997is a junior synonym of  Mirocaris fortunata( Martin and Christiansen, 1995). available for the following 13 formally described species:  Alvinocaridinides formosa Komai and Chan, 2010,  Alvinocaris alexander Ahyong, 2009,  Alvinocaris brevitelsonis Kikuchi and Hashimoto, 2000,  Alvinocaris methanophila Komai, Shank and Van Dover, 2005,  Alvinocaris niwa Webber, 2004,  Alvinocaris williamsi Shank and Martin, 2003,  Chorocaris paulexa,  Chorocaris susannae,  Manuscaris acuminatus gen. et sp. nov.,  Mirocaris indica Komai et al. (2006),  Nautilocaris saintlaurentae Komai and Segonzac, 2004,  Rimicaris kairei Watabe and Hashimoto, 2002, and  Shinkaicaris luerokolos( Kikuchi and Hashimoto, 2000). The two new species of  Chorocarisare clustered in a clade consisting of  C. chacei,  C. vandoverae, Opepele  loihi,  Rimicaris exoculataand  Rimicaris hybisaewith relatively high bootstrap support (88%, 93% and 100% in ML, MP and NJ, respectively) ( Figure 16). The relationship among these species could not be fully resolved, because some inner branches have weak bootstrap support (less than 70%; e.g. the position of  C. parva sp. nov.,  C. vandoveraeand  C. variabilis sp. nov.). The monophyly of  Chorocarisis not supported, with the two  Rimicarisspecies and  O. loihisubordinated within  Chorocaris. Interspecific divergence among these seven species is summarized in Table 1. The minimum divergence is seen between  C. variabilis sp. nov.and  C. parva sp. nov.(5.5– 6.7%), whereas the maximum divergence is seen between  C. variabilis sp. nov.and  O. loihi(11.0–11.5%). Previous studies on decapod crustaceans [e.g. Jones and Macpherson 2007(Anomura: Munidopsidae:  Munidopsis); Cabezas et al. 2009(Anomura: Munididae:  Munidaand allied genera); Tsoi et al. 2011(Achelata: Palinuridae:  Linuparus); Chang et al. 2014(Astacidea: Nephropidae:  Thaumastocheles)] have shown that COI divergence of more than 10% is indicative of species level differentiation, although lower divergence (> 4.0%) could also be of specific significance [(e.g. Davie et al. 2010(Brachyura: Micytlidae: Mictylis); Yang et al. 2010( Caridea: Pandalidae:  Heterocarpus)]. Together with the morphological evidence, we consider that full species status is warranted for the two new taxa described in this study. Four specimens of  C. variabilis sp. nov.(three from the Manus Basin and one from the North FijiBasin) are clustered with well-supported bootstrap value (93%, 96% and 100% in ML, MP and NJ, respectively). The intraspecific divergence in the four specimens is 0.3–1.8 %, and there is little doubt that they belong to the same species. 2848385314 1989-05-18 BIOLAU Vailili 1740 -23.216667 1256 -176.63333 28 1817 BL 08 1 1 2848385303 1989-05-22 MNHN Fiji North Basin. 28 1817 BL 10 1 1 2848385311 1989-07 II, RV Kaiyo & White Lady Fiji 2750 -18.833334 1273 173.48334 28 1817 1 1 2848385304 2013-07-19 MNHN, RV Sonne, SO & Nifonea Vanuatu 1871 -18.128916 Vanuatu 1 169.51697 28 1817 1 1