(Sakai, 1969)
Rostrum of two spines distinct from close to base; preorbital angle of eave not produced; carapace with plates which are usually large and dominate the surface; branchial region with three small plates; hepatic plate smooth, without a spine; epibranchial plate projecting obliquely; cardiac plate pyriform, narrow posteriorly. (Davie 1996)
Type locality: off Kumano-nada, Japan.
Range: Japan - Kumano-nada (Sakai, 1969).