Sakai, 1961
The carapace of the new species is subcircular in outline, being as long as broad, the dorsal surface is slightly convex. The front is thick and rather wide, its anterior border being one third as broad as the carapace, and it is divided into two lobes by a rather distinct median sinus, each lobe being finely granulated.
The antero-lateral border has only two lobes, the first or postorbital one is arched on its outer border and its anterior border is transverse; the second lobe is a little smaller than the first. These lobes are not at all acuminate and are finely granulate; their edges are finely denticulate. The antero-lateral border behind these teeth is also denticulate and is continuous with the postero-lateral one.
The dorsal surface is only slightly convex, and moderately areolated by smooth narrow grooves. Among the areas thus divided, the gastric, intestinal and branchial ones are markedly convex and are covered with studded granules; the branchial region is subdivided into two areas by an oblique shallow groove. The cardiac and hepatic areas are low and only sparingly granulated. The eyestalk is very thick and short and the cornea is well developed.
The chelipeds are thin and short, each segment is unarmed but uniformly granulate. The fingers are slightly gaping near the proximal half, the movable finger is armed with a sharp spine-like tooth near the distal end, and the immovable finger has two such teeth also near the distal end; these teeth are directed obliquely backward.
The ambulatory legs are stouter and much longer than the chelipeds; the second and third pairs are subequal, the first and fourth pairs also subequal and somewhat smaller. Each segment is uniformly covered with studded granules which are visible when examined with a lens; the dactylus is very slender and long, its outer and inner borders bear minute spinules and its tip is sharp and curved inward.
The male abdomen consists of seven free segments, the first and second segments are sparingly granulate near the lateral surface. The female abdomen is not much broader than that of the male. (Sakai, 1961)
Type locality: Amadaiba, off the coast of Hayama, Sagami Bay, Japan, 85 m.
Range: Japan - Sagami Bay (Sakai, 1961, 1965, 1976), Shiono-misaki (Miyake, 1983); 85-100 m.