Chinommatia Ng & Castro, 2016

Ng, Peter K. L. & Rahayu, Dwi Listyo, 2017, Rediscovery of Chinommatia littoralis (Tesch, 1918) (Crustacea: Decapoda: Brachyura: Chasmocarcinidae) from Tanimbar Island, Indonesia, Zootaxa 4294 (4), pp. 494-500 : 494-495

Genus Chinommatia Ng & Castro, 2016

Type species. Chasmocarcinus cavimanus Rathbun, 1914 , by original designation. Gender of genus feminine.

Included species: Chinommatia bicuspida Ng & Castro, 2016 ; C. bruuni (Serène, 1964) ; C. littoralis ( Tesch, 1918) ; C. turpis Ng & Castro, 2016 .

Remarks. Ng & Castro (2016: 49) separated Hephthopelta Alcock, 1899 , into six genera on the basis of the carapace shape, form of the anterolateral margins, shape and mobility of the eye peduncles, structures of the posterior margin of the epistome, third maxilliped, ventral surface of the adult cheliped merus, inner margin of the cheliped carpus of adults, inner margin of the major cheliped basis-ischium of adults, fingers of the minor chela, male and female thoracic sternites 1–4, male thoracic sternite 8 and supplementary plate, P5 dactylus, G1, G2, and vulvae. Chinommatia Ng & Castro, 2016 , belongs to a group of genera with mobile eye peduncles which are not fused to the cephlalothorax, the ischium and merus of the third maxilliped are proportionately more slender and elongated, and the G2 is about three-quarters the length of the G1.

Ng & Castro (2016: 64) included Zarenkov’s (1972) record of “ Hephthopelta cavimanus ” from Vietnam under the synonymy of Chinommatia cavimanus (Rathbun, 1914) , but this is not correct. It is clear now that what Zarenkov (1972: 238, fig. 3) calls “ Hephthopelta cavimanus ” is actually Chasmocarcinops gelasimoides Alcock, 1900 . His figures of a granular carapace with a conspicuously short front and composed of two convex lobes with a deep median cleft ( Zarenkov, 1972: fig. 3Cp; cf. Ng & Castro, 2016: fig. 9A, C, E–H); the largest male chela possessing strongly curved fingers with a large gape ( Zarenkov, 1972: fig. 3ch; cf. Ng & Castro, 2016: figs. 9B, 40A, C); a distinctive, slender, and elongated third maxilliped with the merus much smaller than the ischium ( Zarenkov, 1972: fig. 3IIImxp; cf. Ng & Castro, 2 016: fig. 30E, F); and male pleon ( Zarenkov, 1972: fig. 3Abd; cf. Ng & Castro, 2016: fig. 51F) agree very well with what has been described and figured for Chasmocarcinops gelasimoides by Ng & Castro (2016). Zarenkov’s (1972: fig. Ipl) figure of a G1 is almost certainly for this species as well, the number “3” probably accidentally left out; it was positioned just under his figure 3Cp. This G1 looks exactly like that figured for Chasmocarcinops gelasimoides by Ng & Castro (2016: fig. 70A–D). Zarenkov’s (1972: 238) specimens of “ Hephthopelta cavimanus ” were collected from waters 7–42 m, a typical depth range for Chasmocarcinops gelasimoides but shallower than what has been reported for adult Chinommatia cavimanus s. str. (123–549 m) (Ng & Castro, 2016: 65).