Amphibians of the Permian Sundyr Tetrapod Assemblage of Eastern Europe

Abstract

Amphibian remains from Sundyr-1 (Russia, Mari El Republic), the reference locality of the Sundyr Tetrapod Assemblage, are identified and described. The assemblage is assigned to the lower Upper Severodvinian Substage (Lower Putyatinian Subhorizon). It is shown that the taxonomic list of the Sundyr-1 locality includes five species, which belong to five genera and four families (Kotlassiidae, Dvinosauridae, Chroniosuchidae, and Enosuchidae). The aquatic tetrapod association of the Sundyr Assemblage occupies an intermediate position between Isheevo and Sokolki tetrapod communities and is mostly composed of genera and species from both of them. Archegosauroid temnospondyls are completely absent; the trophic niche of predominate piscivorous hunter of the community is occupied by the chroniosuchian Suchonica vladimiri. Except for the last taxon, amphibians of the Sundyr-1 locality are represented by pedomorphic, constantly aquatic taxa varying in trophic specialization.