A NEW DVINOSAUR (AMPHIBIA, TEMNOSPONDYLI) FROM THE UPPER TATARIAN OF THE MIDDLE VOLGA REGION

Abstract

A new species of the neotenic amphibian, Dvinosaurus campbelli sp. nov., is described from the Upper Tatarian deposits of the Middle Volga Region (Vyatka Horizon, Scutosaurus karpinskii Zone; Vladimir Region, town of Gorokhovets). The species is characterized by a long interchoanal tooth row, long adductor depression with a sharpened lingual edge, the shape of the crista arquata, flat ventral flank of the splenial, relatively weakly twisted humerus, and short femur with a rounded diaphysis. Morphologically, the dvinosaur from Gorokhovets is most similar to D. primus. The ontogenetic and intraspecific variations of the new species are discussed.