de Haan, 1837
A small species, the outline of carapace of which is triangular and the regions less deeply defined; the dorsal surface is sparingly tuberculated. There are three gastric tubercles, one cardiac and four or five of predominant size on the branchial regions; they are all covered with rasp-like granules as well. The rostrum very broad and indistinctly trilobate, the supraocular eave covered with rasp-like tubercles and the postocular lobe very large and divided into two lobules. The upper orbital sinus deep and V-shaped; the hepatic region granulated, produced into an obtuse lobe; the branchial margin armed with 8 or 9 teeth, of which the last one is of huge size, produced obliquely backwards from the postero-lateral angle of this region. The postero-lateral border armed with a somewhat large tooth, and the posterior border with 6 or 7 smaller granules. The pterygostomial region of this subgenus is peculiar in having a longitudinal deep channel extending from the orbit to the afferent branchial orifice, closed and converted into a tube by thick fringes of hairs.
Merus of chelipeds with a row of 4 or 5 tubercles on the dorsal surface, with 11 or 12 granulated teeth along the anterior border and with 5 or 6 larger and 2 or 3 smaller teeth on the outer border; the palm with about 5 huge obtuse teeth on the outer border, with 12 to 13 small teeth of nearly equal size along the inner border; these teeth are invariably fringed with hairs. Fingers sharply taper and are incurved at tip. Ambulatory legs are compressed and unarmed, both anterior and posterior borders of each segment fringed with long hairs. (Sakai, 1938: 335)
Type locality: Japan.
Range: Red Sea; Zanzibar (Lenz, 1905); various localities in Indian Ocean; Andaman Islands (Alcock, 1895a); Nicobar Islands (Alcock, 1895a); Japan - (de Haan, 1837), Shimoda (Sakai, 1935), Shimoda, Nagasaki and Amakusa (Sakai, 1938a), Sagami Bay (Sakai, 1965b), Tokyo Bay, Sagami Bay, Izu Peninsula, Kii Peninsula, Kagoshima, Amakusa and Nagasaki (Sakai, 1976a), Ogasawara-shoto (Takeda, 1977a); Philippines; New Caledonia (A. Milne Edwards, 1872).