Bulletin of the Mizunami Fossil Museum

Bulletin of the Mizunami Fossil Museum Vol. 53, No. 1

A new bivalve genus, Nipponocardium is proposed for Cardium shiobarense (Yokoyama, 1926) (type species) and C. angustum (Yokoyama, 1925), an exceptional genus of Laevicardiinae in the northwestern Pacific Ocean. Among them, Nipponocardium shiobarense flourished in Honshu during the Late Miocene while N. angustum has been mainly recorded from the Pliocene and Lower Pleistocene deposits in the Japan Sea borderland. This genus became extinct by the end of the Early Pleistocene in Japan.