Plio-Pleistocene herpetofauna in the vicinity of Korotoyak village (Voronezh Region)

Abstract

Introduction: Amphibian and reptile remains were found on the southeastern outskirts of Korotoyak (Voronezh Кegion) in three localities of different ages: Korotoyak-1, Korotoyak-3, and Korotoyak-4. The article describes the results of the analysis of these remains and their interpretation. Methodology: The found bones of amphibians and reptiles were described and identified. Results and discussion: Only two bones, identified as Pelophylax ridibundus and Natrix sp., were found at Korotoyak-1 of the Late Pliocene age. The bones found at the Early Eopleistocene localities Korotoyak-3 included Palaeobatrachus sp. (1 bone), Bufo sp. (2 bones), Anura indet. (2 bones), Lacertidae indet. (1 bone), and Serpentes indet. (2 bones). The Muchkap age Korotoyak-4 collection includes Bombina sp. (1 bone), Pelobates sp. (5 bones), Palaeobatrachus sp. (1 bone), Bufo verrucosissimus (1 bone), Bufo sp. (3 bones), Pelophylax ridibundus (1 bone), Rana temporaria (2 bones), Rana sp. (1 bone), Ranidae indet. (3 bones), Lacerta cf. agilis (1 bone), Elaphe dione (2 bones), Colubridae indet. (1 bone), and Vipera sp. (1 bone). The remains of amphibians and reptiles in all three localities indicate favourable environmental conditions during their formation. The remains of Bufo sp. and Palaeobatrachus sp. indicate that Korotoyak-3 was formed under relatively humid forest conditions. The herpetofauna of Korotoyak-4 suggests the existence of deciduous or mixed forests at the site and a warmer climate as compared to the current one. It appears that the herpetofauna included modern species, whose natural habitats are currently far from the site. Bufo verrucosissimus can now be found in the Caucasus. The northern border of the Elaphe dione habitat currently goes through the Rostov Region. The sphenethmoid bone of Paleobatrachus was found on the territory of the East European Plain for the first time. This specimen differs from all the sphenetmoid bones found in Western and Central Europe. However, we only managed to identify the genus of the specimen, since it is impossible to assess the variability of this skeleton element. Three fragments of this collection have pathological changes: ankylosis in the case of the spadefoot and thickening under the cotylar rim on the vertebrae of the steppe ratsnake and the viper.