de Man, 1887
The carapace broadly hexagonal, dorsal surface moderately convex and covered with a dense coat of tomentum. There are two large elevations placed side by side on the gastric region. The metagastric and branchial regions are faintly defined but the cardiac and intestinal regions are scarcely delimited. The rostrum composed of two median subtruncate lobes and two lateral acuminate teeth, the former are granulated on the anterior margin and divided by a median notch, the latter are pronouncedly produced beyond the former and basally divided from the former by a deep notch. The antero-lateral borders are armed with two anterior lobes and two posterior teeth, the former are subequal, confluent, and granulated; the latter salient, well divergent and somewhat project upwards. The postero-lateral borders are convex and the posterior border is straight.
The infraorbital lobe is rather prominent and granulated, a small tooth, which is not markedly granulated, is placed between the infraorbital lobe and the first antero-lateral lobe. The anterior boundary of the buccal cavern is defined by four smooth lobes, which are almost confluent; the antero-external angle of the buccal cavern is rather thick and granulated.
Chelipeds of male are much longer than the ambulatory legs, the palm is much longer than the merus and is indistinctly sulcated along the upper border. The first pair of ambulatory legs are much slenderer and longer than the succeeding pairs, which are equally thick and subequal in length; merus of all pairs is spinulated along the anterior border. The dactylus of the first pair is by far the longest of all the dactyli of the legs. (Sakai, 1938: 349)
Carapace hexagonal, regions not well defined, usually with two tubercles on protogastric regions, but sometimes absent; surface usually thinly pubescent. Antero-lateral margins separated into four lobes; the first and second generally lobiform, very low, subtruncate, the margins usually straight, separated by wide cleft, not fused, lobe two might be elongate and appears dentiform; third and four lobes distinctly dentiform, directed obliquely outwards. Postero-lateral margin mildly tuberculated. Frontal margin with small median fissure, slightly deflexed, appearing straight from dorsal view, shallow median cleft. Infraorbital and subhepatic teeth not as strong. Merus of third maxilliped tuberculated. Surfaces of sternum highly tuberculated. Chelipeds cylindrical, surfaces highly tuberculated, carpus without large tubercle or spine on distal inner margin of carpus. Ambulatory legs short and stout, ratio of length to width of fourth ambulatory merus 2.7-3.6, anterior margin of the ambulatory merus lined with strong spinules; distal part of G1 bends approximately 45°, sometimes 90°. (Chia & Ng, 1998)
Type locality: Elphinstone Island, Mergui Archipelago.
Range: Somalia - Sar Unale (Castro, 1989, Chia & Ng, 1998); Pakistan - Mekran coast (Tirmizi & Kazmi, 1982), Jiwani and Gwadar Bay (Tirmizi & Kazmi, 1991); Gulf of Mannar (Laurie, 1906, Jones & Sankarankutty, 1961, Chia & Ng, 1998); Mergui Archipelago (de Man, 1887b); Thailand - Andaman Sea (Castro, 1989, Chia & Ng, 1998); Malay Peninsula - Sembilan Isles (Chia & Ng, 1998); Korea - Chuja Islands (Kim, 1970, 1973); South China Sea - Macclesfield Bank (Chia & Ng, 1998); Vietnam - Nha Trang Bay (Serène et al., 1958); Philippines - north of Lubang Island (Serène & Vadon, 1981, Chia & Ng, 1998); Indonesia - Ternate (de Man, 1902a), Ternate and Kepulauan Kai (Chia & Ng, 1998); Marshall Islands - Enewetak Atoll (Garth, 1964), Kwajalein Atoll (Castro, 1989); shoal waters.