Rediscovery of “Turbonilla (Cingulina)” morsei Yokoyama, 1926 from the Recent Fauna in the Sea of Japan, and its Relocation to the Genus Acirsa (Gastropoda: Epitoniidae)

Abstract

Recent specimens of "Turbonilla (Cingulina)" morsei Yokoyama, 1926, which was originally described from the early Pleistocene Sawane Formation, Sado Island, were found off the Noto Peninsula in the Sea of Japan. A search in literature revealed that the species is identical to one that has been recorded as "Tachyrhynchus sp." or "Turritellopsis acicula stimpsoni Dall, 1919" in the family Turritellidae. Based on the examination of the fossil type and the Recent material, this taxon is here transferred to the genus Acirsa in the family Epitoniidae (new combination). Recent specimens have been found only in the central part of the Sea of Japan, and are probably endemic to this area. In connection with this finding, the origin of endemic species in the upper bathyal depths in the Sea of Japan is discussed.