Actinopterygians from the continental Permian–Triassic boundary section at Babiy Kamen (Kuznetsk Basin, Siberia, Russia)

Abstract

The Kuznetsk Basin in Siberia (Russia) is an important area for the study of the continental biota of late Permian to Early Triassic in continuous sections. This study presents a taxonomic description of ray-finned fishes (other fish remains are absent at the section) from the Permian–Triassic boundary section at Babiy Kamen. The new material was collected, bed by bed, during geological and paleontological excavations of coastal-floodplain, shallow-basin deposits of the Tailugan and Maltseva formations. The poorly preserved but diverse ichthyofaunal fossils of the Tailugan Formation consists predominantly of typical Late Paleozoic “palaeoniscoid” fishes (Eurynotoidiidae, Varialepididae, etc.). The earliest known Triassic (Induan) Kedrovo Member of the Maltseva Formation contained a less diverse but well preserved ichthyofaunal fossils including “palaeoniscoid” fishes (Korutichthys and Avamia). The same species were described earlier from the Induan of the Tunguska Basin. The ichthyofauna of the Early Triassic (Olenekian) Ryaboy Kamen Member of the Maltseva Formation consists of typical Triassic stem-neopterygian (Evenkia, Eoperleidus and Arctosomus) fishes. The same fishes have been described earlier from the Olenekian of Tunguska Basin. The composition of the ichthyofauna completely changed twice — at the Permian–Triassic and the Induan–Olenekian boundaries.