Taxonomic Relations of Russian and Persian Sturgeons (genus Acipenser, Acipenseridae): an Updated Synthesis.

A comparative analysis of data on the morphological, genetic and ecological features of Russian, Persian and Colchic sturgeons was carried out in order to assess their taxonomic relations, diagnostic characteristics and distribution patterns in the Ponto-Caspian basin. The results confirmed the presence of two close related and morphologically similar species in the Caspian basin—Acipenser gueldenstaedtii and A. persicus, the reproductive isolation of which was proved by genetic data. The complex of diagnostic characters of these species includes, in addition to the traditionally accepted body color and the shape of the snout, several craniological indices: Pds/Ri and W/Ri. The Colchic sturgeon remains virtually unstudied from a genetic point of view. The results obtained allow us to consider it an independent subspecies – A. persicus colchicus. It differs from the Caspian Persian sturgeon, as well as from the Russian sturgeon with a longer snout and larger values of the craniological index B/Ri. The distribution of the Colchic sturgeon in the Black Sea basin requires further research. [ABSTRACT FROM AUTHOR]