A new species of the family Ungulinidae from Wakkanai, Hokkaido, Japan

One new species of bivalve, Felaniella (Zemysia) ohtai Kase and Miyauchi, of the family Ungulinidae is described. This new species is common in shallow waters off the western coast of Wakkanai, Hokkaido and the first species of the subgenus Zemysia from the northwestern Pacific. The fossil forms of this species are known from the lower Pleistocene of Sado and the upper Pliocene of Akita, suggesting that this species provided into Japanese waters in late Pliocene age and extended its distribution more south than the living specimens.