A revision of Carcinoplax abyssicola (Miers, 1885) and seven related species of Carcinoplax H. Milne Edwards, 1852, with the description of two new species and an updated key to the genus (Crustacea, Decapoda, Brachyura, Goneplacidae) Author Ng, Peter K. L. Lee Kong Chian Natural History Museum, National University of Singapore, 2 Conservatory Drive, Singapore 117377 (Republic of Singapore) Author Castro, Peter Biological Sciences Department, California State Polytechnic University, Pomona, CA 91768 (United States) pcastro @ cpp. edu (corresponding author) pcastro@cpp.edu text Zoosystema 2020 2020-06-09 42 17 239 284 journal article 21685 10.5252/zoosystema2020v42a17 d5f2bb15-439a-45d2-9121-beb168fcb637 1638-9387 3894945 urn:lsid:zoobank.org:pub:52C73176-6867-4415-A6FA-BAD328E9781D Carcinoplax fasciata Ng & Kumar, 2016 ( Figs 18 ; 25 J-P) ? Carcinoplax specularis [part] – Castro 2007: 641 [ Maldives ]. Carcinoplax fasciata Ng & Kumar, 2016: 193 , figs 1-4 [ type locality: Kerala , India ]. TYPE MATERIAL. — Holotype . Arabian Sea • ♂ , 25.8 × 19.3 mm , DABFUK , India . TYPE LOCALITY. — Arabian Sea, off Kerala , India . MATERIAL EXAMINED. — India . Holotype ♂ , 25.8 × 19.3 mm ; Arabian Sea , Neendakara fishing port, Kerala , southwestern India ; 8°38›N 76°14’E ; 450-500 m depth ; coll. B. Kumar , from trawler, 27.XI.2015 ; DABFUK . DIAGNOSIS ( HOLOTYPE MALE , FEMALES UNKNOWN). — Carapace ( Fig. 18A, B ) quadrate, slightly wider than long (1.3 × wider than long in holotype ); slightly convex, smooth. Front ( Fig. 18C, D ) straight, notch between front, inner edge of supraorbital border absent. Slightly pointed, short tooth on outer orbital angle preceded by low protuberance near orbit; two slender, acute-tipped anterolateral teeth on each side of carapace, first slightly curved. Conspicuous granules on subhepatic, pterygostomial regions ( Fig. 18C, D ), becoming more pronounced in pterygostomial crest, ridge; short granules on anterior. Posterior margin of epistome ( Fig. 18C, D ) sinuous, with median salient tip, lateral margins wide, strongly concave. Distal third of fingers pale brown ( Figs 21A, I, J ; 28G ). “Window” not observed on cheliped propodi. Inner (ventral), distal margin of cheliped carpus ( Fig. 18G, H ) with long, acute tooth. P2-P5 ( Fig. 18A , 28G ) moderately short in appearance, P5 just reaching base of second anterolateral tooth. Male pleon ( Fig. 18E ) proportionally narrow. G1 ( Fig. 25 J-L) slender, straight; slightly pointed tip with scattered spinules, distal end slightly distended; G2 ( Fig. 25 M-P) slender, slightly longer than G1, slightly curved flagellum, tip weakly birufcated, sharp. COLOUR IN LIFE. — “Dorsal surfaces of carapace and chelipeds bright orange; tips of anterolateral teeth and cheliped carpal spine white; fingers of chelipeds mostly white except for orange base, distal third light brown; ambulatory legs with dorsal surfaces mostly orange except for white patches on propodus, ventral surfaces paler; prominent red band present that stretches from ventrum of posterolateral carapace margin to below frontal margin; rest of ventral surfaces pinkish-white.” ( Ng & Kumar 2016: 197 ) ( Fig. 28G ). GEOGRAPHICAL DISTRIBUTION. — Western India . DEPTH. — 450- 500 m . REMARKS Carcinoplax fasciata is unusual among the species treated here in that its life coloration is distinctive. The front has a prominent red band below it and the fingers of the cheliped are not pigmented black, with only the distal part light brown ( Fig. 28G ). The condition of the fingers is most like C. polita and C. jugum n. sp. , although in these species, the distal parts of the fingers are black or dark brown ( Figs 16H ; 17I ; 21I, J ; 22I, J ), not pale brown. The life coloration of C. jugum n. sp. , unfortunately, is not known. The posterior margin of the epistome of C. fasciata ( Fig. 18C, D ) most closely resembles that of C. jugum n. sp. with the median part salient and the lateral margins wide and prominently concave ( Figs 21C, D ). The dorsal carapace features of C. fasciata are, however, very different, being evenly convex ( Fig. 18A, B ); in C. jugum n. sp. (and C. polita ) the gastric and cardiac regions are distinctively swollen laterally and the surface appears gently corrugated with a distinct transverse furrow between the regions ( Figs 16A, B ; 17A, B, E ; 27G, H ). The G1 of C. fasciata is distinct among the species treated here in that it is relatively straight with the structure gradually tapering from the broad base ( Fig. 25J ), although the distal part ( Fig. 25K, L ) resembles those of C. abyssicola , C. longipes , and C. verdensis ( Fig. 23B, C, F, G, J, K ; 24B, C ).