Chimaeroidei

The record of a mandibular tooth plate of the chimaeroid fish Ischyodus sp. from the Lower Cretaceous deposits of the north of the Saratov Volga River Right Bank is described. The presumed age of the find is the Lower Aptian. This is the first recorded occurrence of chimaeroid remains in the Lower Cretaceous (pre-Albian) deposits of the Middle and Lower Volga regions, and the fourth record in deposits of this age in Eastern Europe.

Based on new finds of mandibular tooth plates of the chimaeroid Stoilodon aenigma Nessov &Averianov, 1996 (Holocephali, Chimaeroidei) from the Lower Cretaceous of central Russia, the diagnosis of the genus is modified and validity of the taxon is confirmed. New record of mandibular plate of the species from the Ryazanian regional stage (boreal Berriasian stage) of the Moscow Region has allowed us to expand stratigraphical distribution of the species within the whole early Cretaceous.

An assemblage of chondrichthyans is described from the new locality near Serafimovich town (the western part of Volgograd region). More than 2500 fossils were collected from the basal gravel-pebble bed and phosphorite-bearing layer from the lower part of the Buzinovka formation (upper Paleocene). There are reworked Cretaceous and Paleocene chondrichthyans (6 species) and synchronous 21 species of sharks and 2 species of chimaeroids.