On Some Volgian Ammonites and Their Nomenclatural Types

Resumo

Nomenclature types of ammonites of the genera Dorsoplanites, Pavlovia, Zaraiskites and Craspedites from the Volgian Stage of the Russian platform are discussed; for some species type specimens are designated and illustrated. The date of the establishment of the genus Pavlovia Ilovaisky, 1915 is emended, and it type species is detailed. The name Ammonites panderi Eichwald, 1840 is recognized as nomen dubium; for the species Dorsoplanites panderi auctt. non Eichwald, 1840 the new name D. typicus nom. nov. is proposed; the index species of the Panderi Zone of the Volgian Stage is replaced by Zaraiskites scythicus (Vischniakoff). The species Craspedites ivanovi Gerasimov, the index species of the upper subzone of the Virgatites virgatus Zone is re-described. The interval with Craspedites milkovensis can be only considered as the terminal faunal horizon of the Craspedites nodiger Zone interpreted to include the Mosquensis and Nodiger subzones.