New Data on the Upper Bathonian (Middle Jurassic) Cephalopods of the Russian Platform

The Upper Bathonian locality of Alatyr III bis in Central Russia is described for the first time. The predominantly sandy deposits of this age, unconformably overlain by Lower Callovian clays, belong to the Calyx Zone (with the ammonites Cadoceras calyx Spath and Eckhardites atmensis Mitta) and the Apertum Zone (with Cadoceras apertum Callomon et Birkelund). The new locality is the only one in Russia where the sequence of the Calyx and Apertum zones is established in the same outcrop. An emended description of C. calyx, a species originally described from East Greenland, is presented. Some belemnite rostra are identified as Communicobelus subextensoides (Gustomesov), described for the first time from the Upper Bathonian of the Boreal regions.