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

Sharks have existed on Earth for over 400 million years occupying oceans worldwide. Fossilized teeth are well-documented along the Eastern Gulf of Mexico, yet few published reports note the presence of these fossils along the panhandle of Florida and Northern Gulf Coast (although anecdotal accounts of fossil finds indicate a need to learn more). The purpose of this project 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 on resources at GUIS do not include any mention of fossil shark teeth, only shell material and microfossils. Working in collaboration with the NPS, we conducted a literature and field-based survey to examine the presence of fossil shark teeth at GUIS. To date fieldwork has been completed at the Florida portion of GUIS; future investigation will focus on the Mississippi coastline. Fossiliferous sediments underlying or nearby the Florida portions of GUIS include the Oligocene Chickasawhay Limestone, Pliocene Perdido Key and Citronelle Formations, and Pleistocene Biloxi and Gulfport Formations. Teeth recovered during collection efforts confirm the presence of Chondrichthyan genera Carcharhinus, Galeocerdo, and Rhizoprionodon, among others. Fossil stingray dental plates, fish otoliths, chimaeran dorsal spines, and other marine paleontological resources were also found. Specimen identification is ongoing but preliminary results suggest that the fossils recovered from GUIS add significant data to our understanding of fossil shark teeth reported from this part of Florida. Furthermore, new knowledge of fossil shark teeth at GUIS provides an opportunity to expand park interpretation efforts to include paleontological resources as well as demonstrates a need for increased management actions to help protect these important fossils.