Chinommatia, 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 : 63

Genus Chinommatia n. gen.

Hephthopelta — Serène 1964a: 239; 1968: 92 [in list] (part).—Ng et al. 2008: 76 [in list] (part).

Type species. Chasmocarcinus cavimanus Rathbun, 1914 (gender feminine) Other species included:

Chinommatia bicuspida n. sp.

Chinommatia bruuni (Serène, 1964)

Chinommatia littoralis ( Tesch, 1918) Chinommatia turpis n. sp.

Diagnosis. Carapace subtrapezoidal to subovate, wider than long, gently convex dorsally; front bilobed, with shallow to well-defined median cleft; anterolateral margins arcuate, minutely granular, without distinct lobes or teeth (anterolateral row of low tubercles, some pointed, in C. cavimanus , C. bruuni ; conspicuous, pointed in C. turpis n. sp.). Epistome slightly depressed; broad to narrow, posterior margin with rectangular or semicircular median lobe with deep median fissure, semicircular lateral margins. Eye peduncle filling orbit, long or short, mobile, gently tapering to cornea; cornea not reduced, pigmented. Third maxillipeds not filling buccal cavern when closed; merus ovate, outer margin convex, slightly elevated anteriorly, anteroexternal angle rounded; ischium rectangular, about same length as 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, often sharp teeth. Ventral surface of cheliped merus with row of sharp tubercles or dentiform granules (teeth in large C. cavimanus ) along outer margin in both sexes, inner margin unarmed. Inner margin of carpi with short distal tooth, proximal part rounded. Inner margin of basis-ischium of adult major cheliped gently granuliform. Meri of P2, P3 with teeth or tubercles along ventral margin, meri of other ambulatory legs with microscopic granules, unarmed. P5 dactylus distinctly upcurved. Fused thoracic sternites 1, 2 distinctly broad, short; fused sternites 3, 4 broad. Male pleon lateral margins of somite 6 nearly straight, fused somites 3–5 concave; telson proportionally long; postero-lateral regions as in rest of somite, not particularly swollen. Sterno-pleonal cavity of male deep, press-button for pleonal holding as short tubercle at center of sternal somite 5 near edge of sterno-pleonal cavity. Male thoracic sternite 8 long, rectangular; “supplementary plate” long subovate; structures tightly appressed with most of penis concealed. G1 with slender basal part, gradually tapering along distal part to tip, with short spinules. G2 short, about half length of G1; distal segment short. Somites of female pleon with convex lateral margins; telson proportionally long. Sterno-pleonal cavity of female deep, vulvae relatively close together, located on outer margins of cavity close to suture 5/6.

Etymology. The name is derived from the arbitrary combination of kinesis, Greek for “movement,” and ommatos, Greek for “eye,” in reference to the mobile eyestalks diagnostic for the genus. Gender feminine

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

Distribution. Indo-West Pacific region: western Pacific Ocean.