STABLE ISOTOPE ECOLOGY OF A NEWLY DISCOVERED AMERICAN MASTODON (MAMMUT AMERICANUM) FROM NORTH CHARLESTON, SOUTH CAROLINA

American mastodons (Mammut americanum) have been recovered from late Pleistocene (Rancholabrean) sediments across North America. Stable isotope analysis of tooth dentin and enamel from this keystone species has produced a substantial amount of paleoecological data for Midwestern mastodons, but fewer studies have focused on mastodons of the southeastern United States. Within the southeast, Florida has produced the most mastodons. Fewer of these fossils – and Pleistocene localities in general – have been found in South Carolina and Georgia. Although differential distribution of mastodons in this region may be based largely on taphonomy, environmental conditions could have played a role as well. Recently, an in situ mastodon was discovered in a dry creek bed in North Charleston, South Carolina. To date, the site has produced a tusk, both mandibles, three molars, a humerus, four vertebrae, and several ribs from a single individual. Based on tusk circumference, the individual is most likely male. Stable isotope analysis of the carbon, oxygen, and nitrogen composition in tooth enamel and dentin as well as palynological analysis of the surrounding matrix will be conducted to obtain evidence of the animal’s diet, nutritional status, habitat and climate. During the Last Glacial Maximum (LGM), the area between the Southern Appalachian Mountains and the Atlantic Ocean was likely a thermal enclave, an area of warmer temperatures and increased biodiversity. It has been proposed that megafaunal extinctions were more severe in the thermal enclave than in northern regions. Stable isotope data from mastodons living before, during, and after the LGM can be used to evaluate this hypothesis, as a drastic shift in climate should have a noticeable effect on the stable isotope composition of these animal’s teeth. The geologic age of this new mastodon has not yet been refined beyond Rancholabrean, but palynological analysis could be used to date the specimen relative to the LGM. Ultimately, results from analysis of this specimen will be compared to existing data on southeastern mastodons in order to explore environmental factors that may be responsible for the unequal distribution of mastodons in this region.