7-5 A Marine Vertebrate Assemblage from the Upper Cretaceous (Latest Cretaceous: Maastrichtian) Peedee Formation of Greenville, North Carolina

Session: Undergraduate Research, Part I (Posters)

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Abstract:

The Late Cretaceous (Maastrichtian) Peedee Formation is a well known, well described Upper Cretaceous unit in North and South Carolina, with outcrops exposed along every major waterway across the Coastal Plain, but most prominently within the Cape Fear and Pee Dee river basins. This formation represents a prolonged period of marine shelf sedimentation and contains a rich marine vertebrate assemblage. After the first publications describing Cretaceous vertebrate assemblages in North Carolina by Ebenezer Emmons and Joseph Liedy, relatively few papers have been published subsequently, especially compared to contemporaneous strata of the American West. Most reviews of the fossil record of the Peedee Formation focus on sites in South Carolina, with a few from Greenville, North Carolina, a city famous among private collectors for its fossiliferous “outcrops” (river banks). We have received and reviewed a collection of Cretaceous vertebrate fossils from the Greenville Wastewater Treatment Plant in Greenville, North Carolina, collected by Ramona Krailler and Joe Magura of the North Carolina Fossil Club.

The collection represents more than 40 vertebrate taxa, of which at least 25 are chondrichthyan, making elasmobranchs the most dominant component of the collection. None of the taxa were specifically described from Greenville previously, although some have been mentioned in general accounts of Peedee Formation assemblages. The chondrichthyans include the sawskates Ischyrhiza, Texatrygon, and Ptychotrygon; the myliobatiform Rhombodus; lamniformes Cretolamna, Odontaspis, Squalicorax, Serratolamna, and Scapanorynchus; charcharhinodontiformes Palaeogaleus and Galeorhinus; orectolobiformes Nebrius and Plicatoscyllium; and the hybodonts Lissodus and Meristodonoides. Several species, while perhaps known anecdotally, were not previously described from North Carolina, including Ischyrhiza texana, Tomewingia problematica, Hexanchus microdon, and Archaeomanta melenhorsti. 

In addition to chondrichthyans, the collection contains fragmentary teeth of actinopterygians: ichthyodectiformes, pycnodontiformes, and other teleost groups. Mosasaur tooth fragments are also present within the collection. Crocodylomorph material includes vertebrae that may belong to the large-bodied Deinosuchus or smaller Borealosuchus. Combined, the chondrichthyan, squamate, fish, and crocodilian remains indicated a predominantly marine fauna residing within a shallow coastal environment. All taxa presently identified within the collection align with the expectations of Maastrichthian fauna. Review of the systematics of this collection demonstrate that the Peedee Formation represents a fossil-rich yet understudied unit of the Atlantic Coastal Plain, emphasizing the need for further study across similar localities.

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