Capitamon aff. mizoramense

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 : 613

Capitamon aff. mizoramense

Potamiscus (Ranguna) rangoonensis – Bott 1966: 481, fig. 15 (part) [not Potamon (Potamon) rangoonensis Rathbun, 1904 ].

Ranguna (Ranguna) rangoonensis – Bott 1970: 163, pl. 38, fig. 35; pl. 47, fig. 31 (part) [not Potamon (Potamon) rangoonensis Rathbun, 1904 ].

Ranguna beieri – Türkay & Naiyanetr 1987: 391 (list) [not Potamon beieri Pretzmann, 1966 ].

Potamiscus beieri – Brandis 2000: 75, pl. 10, fig. 2a-c (in part) [not Potamon beieri Pretzmann, 1966 ].

MATERIAL EXAMINED. — None.

DIAGNOSIS. — Carapace ovate, broader than long (CW/CL = 1.4); 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 (see Brandis 2000: pl. 10, fig. 2a). Chelipeds rugose, unequal, inner distal tooth on carpus relatively broad (see Brandis 2000: pl. 10, fig. 2a). G1 ultimate article relatively more strongly bent at angle of about 110° from longitudinal axis, with sinuous outer margin, dorsal flap relatively low, broadly triangular (see Brandis 2000: pl. 10, fig. 2b, c).

REMARKS

The male specimen (SMF 2807) of an unknown species of Capitamon n. gen. reported by Bott (1966, 1970) and Brandis (2000) also possesses a G1 ultimate article as strongly bent as that of C. mizoramense n. gen., n. sp. The dorsal flap on the G1 ultimate article of the SMF 2807 male, however, is relatively low and broadly triangular (see Brandis 2000: pl. 10, fig. 2b, c) against the relatively high and narrowly triangular dorsal flap of C. mizoramense n. gen., n. sp. ( Figs 16F ; 17A , C-E). In addition, the cervical grooves of the SMF 2807 male are continuous, which reach to the level of the postorbital cristae (see Brandis 2000: pl. 10, fig. 2a); whereas those of C. mizoramense n. gen., n. sp. are not continuous and do not reach to the level of the postorbital cristae ( Fig. 15A ). The SMF 2807 male specimen has some affinities with C. mizoramense n. gen., n. sp., but it is certainly not that species. The said SMF material is a distinct species of Capitamon n. gen. but is not described here as we could not access the actual material during this study. Fresh specimens of this species will also need to be collected.

Figures

FIG. 16. — Capitamon mizoramense n. gen., n. sp., holotype ♂ (46.3 × 35.7 mm) (ZSIK C.6122/2A) (A-G), paratype ♀ (51.3 × 37.6 mm) (ZSIK C.6122/2B) (H, I): A, mouthparts; B, right third maxilliped; C, chela (outer view); D, s1-s8 showing right G1 in situ; E, pleon and telson; F, left G1 (dorsal view); G, left G2; H, pleonal somites 3-6 and telson; I, s1-s8 showing vulvae. Scale bars: A, B, D, E, H, I, 5 mm; C, 10 mm; F, G, 2 mm.

FIG. 17. — Capitamon mizoramense n. gen., n. sp., holotype ♂ (46.3 × 35.7 mm) (ZSIK C.6122/2A): A, left G1 ultimate article (dorsal view); B, left G2; C, left G1 ultimate article (ventral view); D, left G1 (dorsal view); E, left G1 (ventral view). Scale bar: A, C, 1 mm; B, D, E, 2 mm.

FIG. 15. — Capitamon mizoramense n. gen., n. sp., holotype ♂ (46.3 × 35.7 mm) (ZSIK C.6122/2A): A, overall dorsal view; B, frontal view of cephalothorax; C, overall ventral view. Scale bars: A, C, 20 mm; B, 10 mm.