Redescription of “Calyptogena” shiretokensis Uozumi (Bivalvia: Vesicomyidae) from the Miocene Rusha Formation on the Shiretoko Peninsula, Eastern Hokkaido, Japan

Abstract

Some additional specimens of Archivesica shiretokensis (Uozumi) (Bivalvia: Vesicomyidae), whose original description was insufficient were collected from the upper Miocene Rusha Formation on the Shiretoko Peninsula, eastern Hokkaido, and the species is described here in detail. This is the only fossil record of Archivesica in Hokkaido and the entire Okhotsk Sea borderland. The late Miocene coincides with the appearance of Archivesica in Japan, and marks the onset of the development of the modern Japanese vesicomyid fauna.