Ortmann, 1894
The carapace rounded quadrangular, the dorsal surface very flat but is vaulted down toward the fronto-orbital border and also on postero-lateral surfaces. The front marked with a shallow median groove, by which the free margin is imperfectly separated into two lobes. The lateral margins are well arched and convergent in anterior and posterior portions; there are two very shallow indentations on the anterior half of each border, thus two very indistinct lobes are distinguishable behind the external orbital angle. The infraorbital crest is composed of 20 to 29 fine tubercles.
Chelipeds are symmetrical, arm and wrist unarmed, the palm pronouncedly inflated and high, the general aspect in outer view being almost globular; the fingers are not gaping and their prehensile edges finely toothed. Ambulatory legs are feebly compressed and broad, naked, excepting the dactylus, which bears eight longitudinal rows of short pubescence around the whole surface. (T. Sakai, 1939: 689)
Type locality: Amami-Oshima, Japan.
Range: Indian Ocean (Ortmann, 1894a); Japan - Amami-Oshima (Ortmann, 1894a), Shimoda (Sakai, 1935), Sagami Bay, Izu Peninsula, Muroto-misaki and Nagasaki (Sakai, 1939), Hachijo-jima (Sakai, 1954), Sagami Bay (Sakai, 1965b), Sagami Bay, Shimoda, Kii Nagashima, Shiono-misaki, Kii Minabe, Muroto-misaki, and Nagasaki (Sakai, 1976a), Amakusa (Yamaguchi et al., 1976), Tobishima, Yamagata Prefecture (Suzuki S., 1979), Nanki Shirahama (Miyake, 1983), Okushiri (Komai et al., 1992), Hayama, Manazuru, Yugawara, and Mikuni (Muraoka, 1998), Kagoshima, Toyama Bay, Noto Peninsula; Korea - Jeju, Udo Island, Pyoseon, Guu Myeon, and Ulreung Island (Kamita, 1941), Cheonbu, Hyangnam Dong, Taeha Dong, Mijo Ri, Jeju, and Gapa Island (Kim, 1973); Taiwan (Dai & Yang, 1991); high tidal mark.