(de Haan, 1835)
Carapace subquadrate, surface almost flat, covered with fine piles and the ridges of the postero-lateral surface also furnished with piles. Front broad, deeply concave medially, the postfrontal ridge 4-lobed; the median lobes with tufts of setae, the lateral lobes not strongly convex. Groove between the gastric and cardiac regions deeper than that between the cardiac and intestinal regions. Branchial region with oblique striae. One tooth behind the outerorbital tooth, acuminate and deeply separated.
Merus of the chelipeds short, prismatic, with a strong subdistal spine on its inner border. Carpus convex, rugose, the inner-distal angle bluntly rounded. Palm with granules and rugae on its outer surface, and 2 oblique pectinated ridges on the dorsal surface. The ridge of the dorsal border of the movable finger composed of about 12 ovate tubercles, which are in line with a row of fine granules close to the inner side. Merus of the ambulatory legs very broad, more than half as broad as long, with several transversely fine striae and a sharp subdistal tooth on the anterior border; the last 3 segments of the legs densely furnished with stiff short setae.
First pleopod of the male straight, the distal chitinous process bent ventrally outwards. Abdomen triangular; telson semicircular distally. Carapace length 25 mm, breadth 28.5 mm. (Dai & Yang, 1991)
Type locality: Japan.
Range: Zanzibar (Lenz, 1905); Sri Lanka (Alcock, 1900b); Bay of Bangal (Alcock, 1900b); Andaman Islands (Alcock, 1900b); Nicobar Islands (Alcock, 1900b); Mergui Archipelago (Chopra & Das, 1937); Japan - (de Haan, 1835), Kochi (Ortmann, 1894a), Shimoda (Stimpson, 1907, Sakai, 1935), Shimoda and Nagasaki (Sakai, 1939), Sagami Bay (Sakai, 1965b), Yokohama, Sagami Bay, Shimoda, Kii Minabe, and Nagasaki (Sakai, 1976a), Amakusa (Yamaguchi et al., 1976), Nanki Shirahama (Miyake, 1983), Okukubi River, Okinawa (Shokita et al., 1998), Ginowan, Okinawa (Shokita et al., 2000); Korea - Cheju-do (Kamita, 1941); Taiwan - Tan-shui (Sakai, 1939), Tung-kang and Tan-shui (Lin, 1949); China - Hong Kong (Stimpson, 1907), Hainan Island (Shen, 1936), Liuwutien, Tsimei, Xiamen, and Hainan Island (Shen, 1940b), Guangxi, Guangdong and Fujian (Dai & Yang, 1991); Indonesia - Ambon (de Man, 1887a), Gane, Halmahera Island (Rathbun, 1910b), Karakelong, Kepulauan Talaud (Tesch, 1918a); Fiji (Dana, 1852); near estuary or inland sea.