de Haan, 1841
Carapace almost circular but very slightly longer than broad. The upper surface is thickly covered with miliary granules of different sizes; the hepatic, cardiac and intestinal regions are faintly delimited. The front is divided into two sharp, triangular teeth, which are microscopically covered with vesiculous granules. There are eleven spines situated on the margins of the carapace, of which the most anterior one on either side belongs to the pterygostomial region and is smallest of all, and the median posterior one belongs to the intestinal region and is deviated above, while the other eight are on the true margins of the carapace. The anterior boundary of the efferent branchial channels is armed with two sharp spines, each divided by a wide U-shaped sinus, above which the prominent infraorbital lobe is detected. The merus of the external maxillipeds is half as long as the ischium measured along the inner border; its exopodite is long and almost reaches the level of the tip of the merus.
The chelipeds are slender; the arm is cylindrical and curved, covered with miliary granules; the wrist and palm are very minutely granulated, the former is very short, the latter is proximally swollen. The fingers are filiform and are longer than the palm, especially so in the male. The merus of the ambulatory legs is finely granulated but the following segments are almost smooth; the propodus and dactylus are somewhat compressed, the latter being fringed with hair.
The abdomen in both sexes consists of five spieces, the formula in the male being as: 1 + 2 + R + 6 + T, while that of the female as: 1 + 2 + 3 + R + T. (Sakai, 1937)
Type locality: Japan.
Range: Seychelles (Miers, 1884b); Pakistan - Karachi (Tirmizi & Kazmi, 1991); India - Palk Strait (Alcock, 1896); Andaman Islands (Alcock, 1896); Gulf of Martaban (Henderson, 1893); Japan - (de Haan, 1841), Tokyo Bay and Kagoshima (Ortmann, 1892), Suruga Bay, Omae-zaki, Owase, Goto-retto and Kyoga-misaki (Yokoya, 1933), Shimoda (Sakai, 1935), Tokyo Bay, Sagami Bay, Shimoda, Ise Bay, Kii Peninsula, Tosa Bay and Nagasaki (Sakai, 1937a), Amakusa, Sea of Ariake, Tsuyazaki, Tottori, and Toyama (Miyake et al., 1962), Sagami Bay (Sakai, 1965b), Oga Peninsula, Tokyo Bay, Sagami Bay, Izu Peninsula, Mikawa Bay, Shima Peninsula, Kii Peninsula, Tosa Bay, and Nagasaki (Sakai, 1976a), Amakusa (Yamaguchi et al., 1976), Yamagata Prefecture (Suzuki S., 1979), Shiono-misaki (Takeda, 1979a), Tanabe Bay (Miyake, 1983); Korea - Bangpo, Bangjugpo, Jinhae, and Hae-undae (Kim, 1973); East China Sea - (Takeda & Miyake, 1970a), east of Cheju-do (Yokoya, 1933); China - Hong Kong (Shen, 1931), Jiaozhou Bay (Shen, 1937), Xiamen, Tsimei, and Liuwutien, Fujian Province (Shen, 1940b), Guangdong including Hainan Island and Fujian (Dai & Yang, 1991); Taiwan (Lin, 1949); Vietnam; Thailand (Rathbun, 1910a); Singapore (Waiker, 1878); Philippines - west and north of Lubang Island (Serène & Vadon, 1981), north of Lubang, Verde Island Passage and Mompog Pass (Chen H., 1989); Sulu Sea (Ihle, 1918); Australia - Moreton Bay (Miers, 1877b), off Cape Moreton and off Caloundra (Campbell, 1971), Capricorn Group (Davie & Short, 1989); Marquesas Islands, Loyalty Islands (Galil, 2001a); 14-420 m.