Locality of Permian Terrestrial Vertebrates in the Vicinity of the Town of Vyazniki

Resumo

The manuscript was written in the mid-1950s, providing the results of survey of an unusual tetrapod burial in the Upper Permian beds of the town of Vyazniki (Vladimir Region). The bone-bearing sand strata form here the top of the Permian beds, which are underlain by clays with conchostracans tentatively dated Early Tatarian. Abundant tetrapod remains obtained in the course of excavations are dominated by isolated bones; these are associated with scales and cranial bones of palaeoniscids, fin spines of hybodontid sharks and coprolites. The tetrapod assemblage includes the kotlassiomorph Bystrowiana permira Vjuschkov, the stegocephalian Dvinosaurus sp. (new species prevailing in number in the assemblage), the dicynodont Dicynodon sp., gorgonopians, therocephalians, and presumably cynodonts, along with procolophonoids (or other small reptiles, such as eosuchians or protorosaurians). The presence of one more stegocephalian is also probable. It is assumed that the Vyazniki assemblage represents an early developmental stage of the Severodvinian pareiasaurian fauna corresponding to the uppermost Lower Tatarian.