Takeda, 1984
Male: Carapace narrowly quadrate and very weakly convergent posteriorly; breadth of front almost equal to, or only slightly broader than breadth of orbit, fronto-orbital breadth almost taking greatest breadth of carapace. Dorsal surface of carapace markedly flattened, and regions not defined, only with an usual gastro-cardiac transverse furrow which is weakly curved forward; cardiac part delimited from branchial part at each side by a longitudinal outward-curved furrow originated from lateral end of gastro-cardiac furrow. In dorsal view, median third of front margin shallow, but distinctly concave; in frontal view, median concave part traversed by a linear ridge continuous with margin of each lageral part of front. Orbit long and transverse; supraorbital border undulate, being marked with two shallow depressions; external orbital angle, or anterior end of first lateral lobe directed forward and sharply angulated; outer border of first lobe nearly longitudinal; second lobe as large as the first and separated from it by a small notch, its anterior end being sharp, but not protruded from general contour of lateral border of carapace; second lobe followed by third lobe through a smaller notch which is sometimes obscure; third lobe not distinctly delimited from posterior part of lateral border of carapace; dorsal surface along posterior part of lateral border sunk and delimited for its posterior half from main dorsal surface of carapace by a linear ridge originated from posterior border of carapace; posterior border of carapace as wide as, or only slightly narrower than front.
Eyestalk long, occupying whole length of orbit; infraorbital border beaded with more than 15 pearly granules. Third maxilliped typical for the genus; exopod about one and a half times as wide as ischium; merus strongly auriculated at antero-external angle as figured.
Both chelipeds equal and stout; inner margin of merus heavily fringed with soft shaggy hairs; carpus and palm smooth, inner angle of carpus being rounded; outer surface of immovable finger furnished with a prominent tuft of soft hairs, which is not extended onto palm; fingers leave only a narrow gape throughout their lengths; each finger with some sharp teeth, those of immovable finger being much larger; tips of fingers shallowly cupped and reinforced by horny nail; tip of immovable finger provided with a prominent tuft of stiff setae, and that of movable finger with a small one.
Ambulatory legs rather slender and sparsely covered with short tomenta and longish setae.
Female: The general formation of the carapace is not much different from that of the male. The chelipeds are small, having short tomenta on the outer surface of the immovable finger instead of long shaggy hairs in the male; the immovable finger bears as brush of stiff hair at the tip on its outer surface like in the male chelae. (Takeda, 1984)
Type locality: Tonda-gawa River, Shirahama-cho, Wakayama Prefecture, Japan.
Range: Japan - Shirahama-cho, Wakayama Prefecture (Takeda, 1984), Kinokawa, Wakayama (Nomoto et al., 1999).