Abstract
A new species of septibranch bivalve is described from the Tsugaru Strait and Otsuchi Bay, northern Japan at depths ranging from 25 m to 200 m. The systematic status and species affiliation of Rhinoclama are briefly reviewed in this paper, to place the new species in the context of the genus. Rhinoclama is here found to contain 3 species groups, mainly based on rostrum morphology; the brevirostris species-group (= subgenus Austroneaera, with poorly developed rostrum), alta species-group (= species of Rhinoclama s.s., with straight developed rostrum) and adamsi species-group (= species of Rhinoclama s.s., with developed and upturned rostrum). R. tsugaruensis fits in the last species group, and differs from R. adamsi and R. rugata by the absence of concentric sculpture on the shell disc. This small- sized Cuspidariid is here described as Rhinoclama (Rhinoclama) tsugaruensis n. sp.
