A New Ungulinid Species (Bivalvia: Ungulinidae) from the Paleogene Kishima Formation in Saga Prefecture, Kyūshū, Southwest Japan

Abstract

A new ungulinid bivalve species, Transkeia sagaensis n. sp., is described from the uppermost Eocene-lowest Oligocene Kishima Formation in Kyūshū, southwestern Japan. The present new species is the oldest member in the genus Transkeia Huber, 2015. In the previous molluscan studies of the formation, no ungulinid species have been recognized. This is probably due to misidentification as the venerid Cyclinella? compressa (Nagao, 1928b).