Tenagopelta, Ng, Peter K. L. & Castro, Peter, 2016

Ng, Peter K. L. & Castro, Peter, 2016, Revision of the family Chasmocarcinidae Serène, 1964 (Crustacea, Brachyura, Goneplacoidea), Zootaxa 4209 (1), pp. 1-182 : 78-79

Genus Tenagopelta n. gen.

Hephthopelta — Komai et al. 2012: 149.—Davie & Richer de Forges 2013: 795.

Type species. Tenagopelta pacifica n. sp. (gender feminine) Other species included:

Tenagopelta brachyphallus n. sp.

Tenagopelta potens (Davie & Richer de Forges, 2013)

Diagnosis. Carapace subtrapezoidal, globose, slightly wider than long; front bilobed, with shallow to well-defined median cleft; anterolateral margins arcuate, with low tubercle or without distinct lobes or teeth. Epistome slightly depressed; posterior margin with broadly semicircular median lobe with deep median fissure, semicircular lateral margins. Eye peduncle filling orbit, distinctly short, mobile; cornea reduced, pigmented. Third maxillipeds nearly fill buccal cavern when closed; merus quadrate, outer margin raised, anteroexternal angle rounded; ischium rectangular, about same length as merus or slightly longer than merus. Chelipeds subequal in length, slightly dissimilar in female, heteromorphic in males; fingers of minor chela subcircular in cross-section, not distinctly laterally flattened, gently tapering to tip, scissor-like, cutting margins with distinct sharp teeth; cutting margins of major chela with broad, blunt teeth in both sexes. Ventral surface of cheliped merus with 3, 4 large teeth (sometimes additional small teeth or large tubercles) on outer margin in both sexes, inner margin unarmed. Inner margin of cheliped carpus with long distal tooth, proximal part prominently dentiform. Inner margin of basisischium of adult major cheliped gently granuliform. Meri of ambulatory legs with microscopic granules, unarmed (P2, P3 with small teeth in T. brachyphallus n. sp.). P5 dactylus straight or slightly upcurved. Fused thoracic sternites 1, 2 broad, short; fused sternites 3, 4 broad. Male pleon with lateral margins of somite 6, fused somites 3‒5 nearly straight; postero-lateral regions only slightly swollen; telson proportionally short. Sterno-pleonal cavity of male deep, press-button for pleonal holding as small, short tubercle posterior to thoracic sternal suture 4/5 near edge of sterno-pleonal cavity. Male thoracic sternite 8 short, rectangular; “supplementary plate” long, subovate; structures separated by relatively wide gap with most of the penis exposed. G1 with stout basal part; distal part tapering, with short spinules. G2 longer than G1; distal segment long, median part abruptly narrowing, with proximal part wider than distal part. Somites of female pleon with convex lateral margins; telson proportionally short. Sterno-pleonal cavity of female deep, vulvae widely separated on outer margins of cavity between sutures 5/ 6, 6/7.

Etymology. The name is derived from the arbitrary combination of tenagos, Greek for “shallows” in reference to the presence of the new species found in shallower water, and pelta, Greek for “shield”, which is derived from the generic name Hephthopelta . Gender feminine.

Remarks. The eyestalks, although very tightly fitting the orbit, are actually mobile and need to be nudged vertically to move the peduncle. The short eye peduncle and small orbit make moving the eye out of the orbit particularly difficult.

The characteristics and differences between Tenagopelta n. gen. and the other genera once treated as part of Hephthopelta s. lato are summarised in Table 2 .

Distribution. Indo-West Pacific region: eastern Indian and western Pacific oceans.