First Finds of Eckhardites (Ammonoidea: Cardioceratidae) in the Upper Bathonian of the Russian Platform

The genus Eckhardites was known until now only from the Lower Callovian of Central Russia and Northern Germany, from three species of one phyletic line. This paper describes another representative of this genus, E. atmensis Mitta, sp. nov., based on the type series from the Calyx Zone of the Upper Bathonian of the Middle Volga area. New records significantly push back the time of origin of the genus and strongly support its boreal origin. The shells of Cadoceras calyx Spath found in the interval of distribution of E. atmensis, and C. apertum Callomon et Birkelund, which characterizes the overlying beds, are illustrated.