Early Paleogene thermophilic invertebrates from the eastern coast of Kamchatka and Sakhalin

Thermophilic marine invertebrates appeared on the eastern coast of Kamchatka in the Early Paleogene and on the island of Sakhalin in the Paleocene. Some mollusks and solitary corals probably migrated from the coast of North America to the far eastern coast of Russia by a warm marine current as the faunal assemblages of these areas contain some genera and even species in common. The warm marine current was protected from cold northern waters by the Bering Land, which was located between the Chukot Peninsula and Alaska. A new bivalve species, Gastrochaena beringiana sp. nov., is described.