Elasmobranchs from the Lower Eocene Kalinino Formation of the Alai River, Saratov Region of Russia.

A new elasmobranch assemblage including 14 shark taxa, mainly lamniformes (9 taxa), is described from the Lower Eocene (NP 10–11) Kalinino Formation of the Alai River Basin, Baltai District, Saratov Region of Russia. The Nikulinka elasmobranch assemblage may have characterised inner neritic environments of the eastern part of the sub-boreal European paleobiogeographic region, being closely related to assemblages from the south-most sector of the boreal Western Siberian Province (southern Trans-Urals and Turgay straight). The absence of myliobatids in Nikulinka and Trans-Uralian localities may have been caused by the influence of Arctic water masses through meridional straits in early Ypresian. This is the first chondrichthyan assemblage from the Palaeogene of the Middle Volga Region, European Russia. [ABSTRACT FROM AUTHOR]