Diagnosis: Carapace rather quadrate; postorbital region with short striae; epibranchial tooth distinct; subbranchial region not distended laterally. Chelipeds subequal in both sexed; second ambulatory leg 1.8 times the breadth of carapace; seventh abdominal segment longer than the 6th. Penultimate segment o first pleopod slightly curved inwards, broad proximally and depressed ventrally; ultimate segment slender, triangular and slightly curved outwards; synovial membrane slender, 5.0 times as long as broad.
Description of holotype: The length of the carapace is fully 7/8 times its greatest breadth and the depth is slightly more than half the length. The dorsal surface behind the postfrontal region is moderately convex in a fore and aft direction and nearly flat from side to side. The postfrontal region is distinct, bears five smooth, short, transverse rugae. The median groove is distinct and the postfrontal region is readily distinguished from the postorbital region by the short lateral groove. The postorbital region bears ten smooth, short transverse rugae, and is distinguished from the epibranchial region by the short groove. The inflated portions of the branchial regions bear large, smooth, tubercles. The epibranchial tooth is small but distinct. The antero-lateral margin is faintly arched, finely crenulate, shorter than the postero-lateral margin and about as long as the posterior margin. The postero-lateral and subbranchial regions bear many fine crenulate striae. The subbranchial region is not inflated.
The frontal region is moderately declivous, and one-third as broad as the carapace; its margin is faintly bilobed, slightly crenulate, and bears above large smooth tubercles. The orbital margin is composed of rounded crenulate striae. The upper parts of the pterygostomial and subhepatic regions bear indistinctly granulate and short striae; the lower parts are smooth. The exopod of the third maxilliped reaches the proximal fourth of the merus; the merus is as long as broad.
The 6th abdominal segment is 0.47 times as long as broad and slightly shorter than the 7th. The 7th segment is 0.63 times as long as broad. The first pleopod is stout; its length is 2.9 times the greatest breadth; the penultimate segment is 4.1 times as long as the ultimate; slightly curved inwards; it is broad proximally and depressed ventrally. The ultimate segment is slender, triangular and slightly curved outwards; the synovial membrane is slender, being 5.0 times as long as broad.
The chelipeds are similar and subequal, but the left is slightly longer than the right. The merus bears short rugae. The dorsal surface of the carpus bears rugae and one large spine and two spinules on the inner margin. The palm is smooth on the inner surface and has indistinct rugae and granules on the outer surface. The upper margin of the palm is slightly longer than broad, and are 0.65 times as long as the dactylus. The fingers are slender, bear 22 to 26 small teeth; they are do not gaped when closed. The dactylus is 0.56 times as long as the chela. The ambulatory legs are slender, with short hairs. The 2nd ambulatory leg is 1.84 times the breadth of the carapace; the propodus is 3.0 times as long as broad, and bears a longitudinal row of spinules medially. The propodus and the dactylus bear each two rows of spinules dorsally and ventrally. Seventeen spinules are present on the ventral margin of the dactylus. (Minei, 1973)
Type locality: Akirigami-gawa, Amagi-cho, Tokuno-shima, Japan.
Range: Japan - Amami-Oshima and Tokuno-shima (Minei, 1973).