Author(s)

Olga S. Urman^1*, Boris N. Shurygin^1,2, Oksana S. Dzyuba¹

¹Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia.
²Novosibirsk National Research State University, Novosibirsk, Russia.

The stratotype region of the Ryazanian stage is located in the Oka River Basin near Ryazan, Central Russia. Since ammonites are very well studied here, we investigated other groups of macrofossils. We report a large number of bivalve genera: Arctica, Astarte, Buchia, Camptonectes, Chlamys, Ctenostreon, Entolium, Gomomya, Gresslya, Hartwellia, Lima, Meleagrinella, Modiolus, Oxytoma, and Pleuromya. The belemnites are represented by two cylindroteuthidid genera, Acroteuthis and Liobelus. In addition, brachiopods (Rhynchonellidae and Terebratulidae) and unidentifiable gastropod fragments have been revealed. The highest taxonomic diversity of macrofauna is observed in the Surites spasskensis ammonite Zone.

Fossil Mollusks, Brachiopods, Ryazanian, Central Russia

Urman, O. , Shurygin, B. and Dzyuba, O. (2019) Macrofossil Assemblages in the Ryazanian Stage (Lower Cretaceous) of the Stratotype Region. Open Journal of Geology, 9, 558-561. doi: 10.4236/ojg.2019.910041.