DIVERSITY AND PALEOECOLOGY OF EARLY MIOCENE CHONDRICHTHYANS FROM THE BELGRADE QUARRY (MAYSVILLE, NORTH CAROLINA)

The Belgrade Quarry operated by the Martin Marietta Corporation in Maysville, North Carolina exposes a fossil-rich, temporally diverse assemblage, spanning from the Eocene through the Pleistocene. Typically, fossil collecting at the Belgrade Quarry occurs during quarterly field trips, in which visitors can collect in spoil piles that homogenize these strata. Throughout these field trips, a modest collection of terrestrial vertebrates has been amassed, some of which have definitive early Miocene affinities. Given the sparse record of early Miocene terrestrial mammals in the southeast United States, the Belgrade Quarry graciously excavated and deposited roughly two tons of sediment from the early Miocene Belgrade Formation for a special field trip associated with the 2018 Aurora Fossil Festival. This field trip served as a pilot test for the myFossil mobile app and was comprised of 30 participants from the Florida Museum of Natural History, the National Museum of Natural History (Smithsonian), the Special Friends of the Aurora Fossil Museum, the North Carolina Fossil Club, and a myriad of other avocational collectors from across the United States. This citizen science, collaborative effort not only provided the opportunity to uncover rare terrestrial mammals, but also to document the marine vertebrates which dominate the assemblage. Surface collecting and screenwashing revealed a marine fauna composed of chondrichthyans, osteichthyans, cetaceans, chelonians, and crocodilians. Among these, chondrichthyans are the most abundant, diverse, and informative for biostratigraphy and paleoecology. Chondrichthyans are represented by 6 orders, 10 families, 17 genera, and at least 18 species. Taxa such as Carcharocles chubutensis and Galeocerdo mayumbensis support the early Miocene designation. The presence of Carcharhinus, Rhizoprionodon, Negaprion, Hemipristis, Ginglymostoma, and Anoxypristis all suggest a neritic paleoenvironment, less than 200 m depth.