Ortmann, 1894
Carapace more than 1.9 times as broad as long, the dorsal surface moderately convex fore and aft and is punctulated near the marginal surface. The frontal margin is only slightly convex and is a little narrower than the major diametre of the orbit; the eyestalks are of good length. Antero-lateral borders are slightly arcuate and divergent backwards, the greatest width of carapace lies at their hindmost end; therefore, the outer margin of the well defined postero-lateral facet is very oblique outwards. The external maxillipeds generally resembles those of the next species, Tritodynamia rathbuni. The chelipeds of female are slender, arm and wrist somewhat hairy but the palm is naked and its superior border cristate, the outer surface traversed by three longitudinal ridges, one of which occurs in the middle. The cutting edges of the fingers are regularly denticulated. The second pair of ambulatory legs are largest, the merus is elongate oval in outline but the carpus and propodus are very slender. The third pair of legs much like the second pair in shape but are remarkably smaller and more hairy. The first pair of legs are sensibly smaller and the merus prismatic; the last pair are extremely slender and smallest. (T. Sakai, 1939: 602)
Type locality: Tokyo Bay, Japan.
Range: Japan - Tokyo Bay (Ortmann, 1894a, Shen, 1935), Ise Bay (Sakai, 1939), Oga Peninsula, Tokyo Bay, Sagami Bay, Mikawa Bay and Ise Bay (Sakai, 1976a), Sea of Ariake (Miyake, 1961), Tanabe Bay (Miyake, 1983).