Takeda, 1974
Description of holotype: The carapace is quadrilateral, or rather hexagonal with the rounded, or more or less angulated median part of each lateral border, being slightly wider than long. The ratio between the length and width is 1.14. The dorsum is moderately and evenly convex in both directions; it is naked and glabrous, but minutely and irregularly punctate under the binocular microscope. The frontal width is 1.2 mm and just one fourth the carapace width; the front is almost truncated only with the dorsal obsolete depression in the middle, being fringed with a narrow rim; in the dorsal view each lateral end is very rounded, but very weakly angulated in the facial view, being not separated from the supraorbital border which is also narrowly rimmed throughout the length without any interruption. The fronto-orbital width is 3.4 mm, being two thirds or slightly more the carapace width. The lateral and posterior borders are also narrowly rimmed. The very small space of the epimeron is detected in the dorsal view; the posterior border is straight and only slightly narrower than the fronto-orbital width. The suborbital ridge is composed of nine smooth and transverse tubercles. The third maxillipeds are broad and completely close the buccal cavern; the ischium and merus are widely sculptured with a large depression, being covered with the worn-out granules of good size; the palp is stout with the extremely long apical hairs that in the natural position exceed the posterior end of the ischium and are folded in the cavity of the first sternal segment in front of the abdominal trench. The chelipeds are minutely granulated, equal and large with the inflated palms. The outer surface of the palm is ornamented with a transverse ridge. There is a small tuft of soft hairs at the base of the immovable finger. The ambulatory legs are comparatively slender and fringed with sparse hairs, both borders of the meri being covered with minute granules. (Takeda, 1974b)
Type locality: Onagawa Bay, Japan.
Range: Japan - Onagawa Bay (Takeda, 1974b), Hakodate Bay (Komai et al., 1992), off Matsuyama, Seto Inland Sea (Takeda et al., 2000), Yoshino-gawa river, Tokushima Prefecture, and Hijikawa river, Ehime Prefecture (Sakai K., 2000); Hong Kong (Davie, 1992).