(Ihle, 1918)
Carapace transversely ovate, strongly convex as a whole, with regions paved with flattened or rounded granules and engraved with deep grooves; gastric and branchial regions completely fused without sutures, except for meso- and metagastric parts which are also fused together, united with frontal region through a short and narrow bridge; entire margin of this gastro-branchial region jagged with pavement; meso- and metagastric part isolated laterally from branchial part and posteriorly from cardiac region by deep grooves; cardiac region wider than meso- and metagastric part, with jagged or minutely serrated margin; intestinal region transverse, almost perpendicular in dorsal view. Lateral margin of carapace cut into four teeth; first tooth conical, with obtuse tip, its anterior margin being transverse; second tooth prominent, subacute at tip, with anterior margin divided into two by a median shallow depression; third tooth obliquely directed posteriorly outward, with its transverse posterior margin shorter than anterior one; fourth tooth formed at posterior end of lateral margin, deeply isolated anteriorly from branchial region and laterally from cardiac region by transverse and longitudinal grooves, respectively; circumferential groove submarginal along anterior three teeth and marginal along postero-lateral part of lateral margin of carapace. (Takeda & Tachikawa, 1995)
Type locality: Banda, 9-36 m.
Range: Japan - Ogasawara-shoto (Takeda & Tachikawa, 1995); Indonesia - Banda (Ihle, 1918); 9-36 m.