New data on the jaw apparatus of fossil cephalopods

Abstract
A newly discovered fossil cephalopod jaw apparatus that may belong to Permian representatives of Endocochlia is described. PERMORHYNCHUS dentatus gen. et. sp. nov. is established on the basis of apparatus. The asymmetry of jaws in the Ectocochlia may be connected with the double function of ventral jaw apparatus, and the well-developed, relatively large frontal plate of the ventral jaw should be regarded as a feature common to all representatives of ectocochlian cephalopods evolved from early Paleozoic stock. Distinct features seen in the jaw apparatus of Upper Permian endocochlians include the pronounced beak form of both jaws and the presence of oblong wings on the ventral mandible.