A New Kotlassiid (Amphibia, Seymouriamorpha) from the Terminal Permian of Eastern Europe

Abstract

© 2020, Pleiades Publishing, Ltd. Abstract—: The first kotlassiid species of the Vyazniki Faunal Assemblade, Microphon terminalis sp. nov., is described from the terminal Permian of the Bykovka locality (Vladimir Region, Russia). The diagnostic characters of M. terminalis are the preservation of nasolacrimal duct throughout ontogeny and some features of the marginal teeth, such as the moderately thickened proximal parts of the crowns, sharply lingually recurved apices, presence of narrow shoulder-like projections of the cutting edges and strongly ornamented enamel. The tooth shape and the location of crista paraquadrata of the squamosal indicate that M. gracilis can be regarded as an ancestral species for M. terminalis that is confirmed by stratigraphic data. The dentition morphology suggests carnivorous mode of life of M. terminalis and show the prevalence of strongly chitinized invertebrates in its diet. This corresponds to the general evolutional trend in the Kotlassiidae (the abandonment of obligate algophagy as a general trophic specialization and the expansion of feeding preferences).