New Species of Bivalves of the Genus Lopatinia (Arcoidea, Cucullaeidae) from the Upper Jurassic of Northern Siberia

New species Lopatinia (Lopatinia) prima sp. nov. has been described from the upper Oxfordian - lower Kimmeridgian deposits of Northern Siberia (Anabar River basin). The diagnosis of the genus Lopatinia as well as its stratigraphic and palaeobiogeographic distribution have been clarified. The boreal basins of Europe (most likely, the Russian Sea) were the center of the origin of the genus. Later, representatives of the genus spread to the Arctic basins as well as to the Southern hemisphere in the Notal Superrealm. Already in the early Kimmeridgian the genus Lopatinia had a bipolar distribution.