de Haan, 1841
The outline of the carapace resembles that of Leucosia obtusifrons, but the neck is somewhat narrower and the free edge of the front is thin and provided with a very obscure denticle in the middle. The upper surface is dark bluish grey, with four ocelli on the gastric region, the ocelli have purplish circumference and white centre.
The chelipeds are as in L. obtusifrons, but the palm is defined by two parallel rows of granules along the inner border. The anterior and posterior borders of the merus of the ambulatory legs are also very indistinctly granulated.
The thoracic sinuses and the anterior pleopods of male are also utilized to distinguish this species from its allied congeners as shown in text-figs. 26 and 28. (Sakai, 1937)
Type locality: Japan.
Range: India - off Malabar coast (Alcock, 1896); Japan - (de Haan, 1841), Tokyo Bay (Ortmann, 1892), Manazuru (Sakai, 1935), Manazuru, Shimoda, Nanki Shirahama and Nagasaki (Sakai, 1937a), Amakusa (Miyake et al., 1962), Sagami Bay (Sakai, 1965b), Tokyo Bay, Sagami Bay, Kii Nagashima, Kii Minabe, and Nagasaki (Sakai, 1976a), off Kochi (Miyake, 1983); East China Sea (Takeda & Miyake, 1970a); Taiwan; China - Guangdong including Hainan Island (Dai & Yang, 1991); Hong Kong (Alcock, 1896); Gulf of Tongking (Zarenkov, 1990); Indonesia - Halmahera; Torres Strait, Australia - (Haswell, 1879b), off Cape Moreton (Campbell, 1971); 30-100 m.