Takeda & Ng, 1997
Male holotype: Carapace appears rounded, broader than long, convex fore and aft; dorsal surface of carapace relatively smooth, almost glabrous, densely and uniformly covered with short stiff setae and with numerous but scattered long, non plumose setae (denser on anterior and lateral parts of carapace); protogastric, mesogastric and cardiac regions indistinctly demarcated by longitudinal and transverse shallow furrows. Antero-lateral margin arcuate, with 3 low, widely separated tubercle-like teeth, with rounded tips, last one smallest; external orbital angle small, very acute, sharp, followed posteriorly by 2 small, rounded granules almost on upper part of subhepatic region; epimeral surface weakly convex and can be seen when carapace is viewed dorsally, not hidden by antero-lateral teeth. Postero-lateral margin gently convex, slightly longer than antero-lateral margin; branchial regions lined with low, oblique striae. Frontal margin sinuous, with deep V-shaped median cleft; outer lobe separated from inner lobe by shallow, V-shaped cleft. Supraorbital margin gently sinuous, lined with small, bead-like granules; infraorbital margin also lined with similar granules and fringed with stiff setae for entire lengths with subacute inner angle. Posterior margin of epistome separated into 4 lobes by shallow clefts; 2 median lobes broadly triangular in shape, lateral ones unevenly convex. Third maxilliped with exopod reaching distal edge of merus; antero-lateral angle of merus rounded, not expanded; inner margin of ischium uneven, but not lined with sharp setae; ischium with shallow but distinctly oblique median sulcus.
Chelipeds slightly unequal in size and shape (right larger), densely covered with long, silky setae; outer surfaces strongly granular, merus armed with strong tubercles on upper margins with median tubercle largest, spiniform and directed anteriorly, ventral margin with numerous small granules; outer surface of carpus granuliform, with several strong spines, on inner and outer margins but no distinct teeth; fingers of chela shorter than palm, cutting edges with broad, blunt teeth; teeth and tips of smaller chela relatively sharper. Ambulatory legs setose, elongated, slender; surfaces smooth; dorsal and ventral margins of merus unarmed but with blunt distal terminal tooth of dorsal margin.
Anterior thoracic sternites smooth; suture between sternites 1 and 2 not discernible; suture between sternites 2 and 3 deep, but become shallower at edges; suture between sternites 3 and 4 incomplete. Abdomen triangular as a whole; telson with lateral margin gently convex; 5th segment about twice length of 6th segment. Male first pleopod slender, very sinuous; distal part not lined with spines or setae, strongly tapering. Male second pleopod very short, with distal part cup-like, with very short distal segment.
Female paratype. The female specimen, an adult, agrees with the male holotype in almost all key, non-sexual characters. On the right antero-lateral margin, the last tooth is very low and almost undiscernible, although on the left side, this tooth is well developed. The absence of the last tooth on the right side is probably due to damage. The antero-lateral teeth of this female specimen, when present, however, are generally sharper, relatively stronger and curve gently anteriorly as well. The subdistal dorsal tooth of the ambulatory meri is also distinct and sharper, in contrast to the blunter and broader tooth on the meri of the holotype male. (Takeda & Ng, 1997)
Type locality: north-east of Ototo-jima, Ogasawara-shoto, 180 m.
Range: Japan - Kurose, off Izu-shoto, and Ototo-jima, Ogasawara-shoto (Takeda & Ng, 1997); 130-190 m.