TITLE:
Macrofossil Assemblages in the Ryazanian Stage (Lower Cretaceous) of the Stratotype Region
AUTHORS:
Olga S. Urman, Boris N. Shurygin, Oksana S. Dzyuba
KEYWORDS:
Fossil Mollusks, Brachiopods, Ryazanian, Central Russia
JOURNAL NAME:
Open Journal of Geology,
Vol.9 No.10,
September
20,
2019
ABSTRACT: 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.