Capitamon clarki, Pati & Peter & L., 2024

Pati, Sameer K., Mitra, Santanu & Ng, Peter K. L., 2024, Identity of the freshwater crab Indochinamon beieri (Pretzmann, 1966), with the description of a new genus and four new species from northeastern India (Decapoda, Brachyura, Potamidae), Zoosystema 46 (23), pp. 589-615 : 602

publication ID	https://doi.org/ 10.5252/zoosystema2024v46a23
publication LSID	lsid:zoobank.org:pub:9195A8AB-6FA8-4828-B8D1-DDEC94E99A6D
DOI	https://doi.org/10.5281/zenodo.13843705
persistent identifier	https://treatment.plazi.org/id/66331159-75CC-4D8E-B15A-B65CCD51A361
taxon LSID	lsid:zoobank.org:act:66331159-75CC-4D8E-B15A-B65CCD51A361
treatment provided by	Plazi
scientific name	Capitamon clarki
status	sp. nov.

Treatment

Capitamon clarki n. sp.

( Figs 8 View FIG ; 9 View FIG ; 10 View FIG )

urn:lsid:zoobank.org:act:B9049FED-7231-43FC-B80D-7ACFDF268F42

Potamon beieri View in CoL – Pretzmann 1966b: 301, pl. 4, fig. 12; pl. 5, figs 16- 18 [not Potamon beieri Pretzmann, 1966 View in CoL ].

Potamiscus beieri – Brandis 2000: 75 (in part) [not Potamon beieri Pretzmann, 1966 View in CoL ].

TYPE MATERIAL. — Holotype. ♂ (42.1 × 32.9 mm); “ Burma ” [ probably from Nagaland , India]; [c. 26°0’0”N, 95°0’0”E]; [alt. c. 1200 m]; no date; Captain Butler leg.; NHM 1909.5.1.1 (“Presd: Indian Museum” “4115/4”). GoogleMaps

DIAGNOSIS. — Carapace ovate, broader than long (CW/CL = 1.3), relatively high ( CH /CW = 0.5); epigastric cristae well-developed, rugose; postorbital cristae well-developed, relatively sharp, oblique in dorsal view; external orbital angle triangular, with short outer margin, c. 2 × inner margin; epibranchial tooth low, blunt, positioned above level of postorbital cristae; cervical grooves continuous, reaching to level of postorbital cristae; epistome posterior margin with well-developed, triangular median tooth, outer parts sloping downwards laterally ( Figs 8A View FIG ; 9A, C View FIG ). Third maxilliped exopod with short flagellum, equal to half width of merus ( Fig. 9B View FIG ). Chelipeds rugose, subequal, inner distal tooth on carpus relatively broad ( Figs 8A View FIG ; 9E View FIG ). Male s3/s4 shallow, running from sternopleonal cavity to lateral edges of sternum ( Fig. 8B, E View FIG ). Male pleonal somite 6 relatively narrower (proximal width c. 1.9 × medial length), longer than pleonal somite 5, with almost straight lateral margins ( Figs 8B View FIG ; 9D View FIG ). Male telson relatively broader (proximal width c. 1.3 × medial length), with gently concave lateral margins ( Figs 8B View FIG ; 9D View FIG ). G1 ultimate article relatively less strongly bent at angle of about 75° from longitudinal axis, with straight outer margin, dorsal flap relatively low, broadly triangular ( Figs 8C View FIG ; 10A, B, D View FIG ). G2 c. 1.2 × length of G1; ultimate article long, c. 0.5 × length of penultimate article ( Figs 8C, D View FIG ; 10A, C View FIG ).

ETYMOLOGY. — The species is named after English carcinologist Dr Paul Clark, the curator of Crustacea in the NHM, whose help with the collections was important in helping the authors solve the confusion with I. beieri . The species name is conceived as a noun in the genitive singular.

GEOGRAPHICAL DISTRIBUTION. — The precise geographical distribution of C. clarki n. gen., n. sp. is not known (see Remarks for I. beieri ). The species is possibly originated from Nagaland state of northeastern India ( Fig. 1 View FIG ).

REMARKS

Capitamon clarki n. gen., n. sp. has a relatively high carapace ( CH / CW = 0.5) ( Fig. 9C View FIG ) among the nominal species of the genus with the relatively low carapace ( CH /CW = 0.4) ( Figs 5B View FIG ; 12B View FIG ; 15B View FIG ; see Pati et al. 2020: fig. 2b). While C. clarki n. gen., n. sp. most resembles C. capitatum n. gen., n. sp. in the structure of the G1 ultimate article (see Remarks for C. capitatum n. gen., n. sp.), C. clarki n. gen., n. sp. also resembles C. manipurense View in CoL n. comb. as both have a G1 ultimate article with the straight outer margin and the relatively low, broadly triangular dorsal flap ( Figs 8C View FIG ; 10A, B, D View FIG ; 11A View FIG , C-E; see Pati et al. 2020: figs 4a-d; 5a-c). The G1 ultimate article, however, is little more strongly bent at an angle of about 75° from longitudinal axis of the G 1 in C. clarki n. gen., n. sp. ( Figs 8C View FIG ; 10A View FIG ), while it is little less strongly bent at an angle of about 60° from longitudinal axis of the G 1 in C. manipurense View in CoL n. comb. ( Fig. 11D, E View FIG ; see Pati et al. 2020: figs 4a, d; 5a, c). Capitamon clarki n. gen., n. sp. can be also distinguished from C. manipurense View in CoL n. comb. by the shallow male s3/s4, running from the sternopleonal cavity to the lateral edges of the sternum ( Fig. 8B, E View FIG ) (vs male s3/s4 indiscernible except for two short lateral clefts; see Pati et al. 2020: figs 1b; 2e), and the relatively broader male telson, proximal width c. 1.3 times the medial length, with the lateral margins gently concave ( Figs 8B View FIG ; 9D View FIG ) (vs male telson relatively narrower, proximal width c. 1.2 times the medial length, with the lateral margins strongly concave; see Pati et al. 2020: figs 1b; 2d).