AN INVENTORY OF FOSSIL SHARK TEETH AND OTHER PALEONTOLOGICAL RESOURCES AT GULF ISLANDS NATIONAL SEASHORE

The purpose of this research is to gain a better understanding of the occurrence, diversity, and distribution of fossil shark teeth and other paleontological resources at Gulf Islands National Seashore (GUIS). This National Park Service (NPS) unit encompasses mainland areas as well as seven barrier island areas distributed over 160 miles along the Florida panhandle and Mississippi coastlines. Previous NPS reports did not include any mention of fossil shark teeth at GUIS, although anecdotal accounts of such finds demonstrated a need to learn more. While fossilized shark teeth are well-documented along the eastern edge of the Gulf of Mexico, few published reports note the presence of these fossils along other nearby coastlines, pointing to the significance of new fossil finds. By working in collaboration with the NPS as part of a pilot program with the Paleontological Society, we conducted a literature and field-based survey to examine the presence of fossil shark teeth at GUIS.

Fieldwork was conducted at the Florida units of GUIS in November and December of 2021 with many shark teeth recovered as well as other paleontological resources. The Mississippi units of GUIS were surveyed in March of 2022. Numerous fossiliferous formations are found in proximity to the park in both Florida and Mississippi; however, preliminary findings indicate that the source of shark teeth found on beaches is likely due to dredge material from beach renourishment projects. Teeth recovered during collection efforts confirm the presence of chondrichthyan genera Carcharhinus, Galeocerdo, Rhizoprionodon, and Sphyrna among others. Specimen identification is ongoing but our initial results suggest that these new fossils reported from GUIS add significant data to our understanding of fossil shark teeth from this part of the Gulf Coast. However, because these shark teeth are on publicly accessible beaches, careful consideration is needed for both interpretive programs and management strategies.