Evolution of the elephants of the mammoth lineage in the Northern Caucasus (Russia) in the Pliocene and Pleistocene

Abstract

The Northern Caucasus (Russia) was an area of distribution of the elephants of the mammoth lineage (genus Archidiskodon Pohlig, 1885) from the Pliocene (early/?middle Villafranchian) to the early Pleistocene (Bicharian). The reexamination of the type specimen of Archidiscodon gromovi Alexeeva et Garutt, 1965 has demonstrated that it does not differ from A. meridionalis (Nesti, 1825) in structure of M3 and, therefore, should be considered a junior synonym of the latter species. M3/m3 structure of the oldest Archidiskodon from Sablino pit (lower layer) differs from those of Archidiscodon from the Apsheronian (late Villafrancian), that allows to establish Archidiskodon from Sablino pit as a new species – A. garutti sp. nov. M3/m3 structure of «A. gromovi» has variations which appeared due to use of a mixed sample, consisting of specimens of A. meridionalis and A. garutti sp. nov. This study improves diagnosis of A. meridionalis and clarifies systematic position of Mammuthus rumanus (Stefanescu, 1924), which is considered as Elephas antiquus rumanus. Part of material, previously assigned to Mammuthus rumanus, is considered as Archidiskodon sp. Thus, the elephants of the mammoth lineage in the Northern Caucasus were represented by two successive species: Archidiscodon garutti sp. nov. and A. meridionalis (A. m. meridionalis, A. m. tamanensis). The chronological distribution of the genus Archidiskodon in the Northern Caucasus covers interval of about 2 millions years (about 3.0–1.25 millions years BP; middle/late? Akchagylian – early Apsheronian, roughly corresponds to the middle – late Villafranchian and, possibly, Biharian).