TESTING HYPOTHESES OF MIGRATION IN THE FOSSIL RECORD WITH ECOLOGICAL NICHE MODELING: A CASE STUDY USING THE WESTERN HEMISPHERE MEGAFAUNAL GENUS GLYPTOTHERIUM

The fossil record can serve as an ecological time machine to help us determine how and why species move across the landscape. In this study we use Ecological Niche Modeling (ENM) to determine the extent to which climatic factors can account for migration patterns in deep time. One such migrant is Glyptotherium, a giant extinct relative of armadillos that originated in South America and migrated to North America as a part of the Great American Biotic Interchange (GABI), a series of dispersal events between North and South America that peaked approximately 2.5 million years ago after the formation of the Isthmus of Panama. Specifically, we use ENM to construct niche models for Glyptotherium to test the plausibility of the hypothesis that the genus migrated from North America back to South America during the Rancholabrean (14,000-240,000 years ago). The resulting niche models show a corridor of suitable habitat through Central America during this time, supporting the hypothesis that Glyptotherium could have traveled back through Central America in the last 240,000 years. Our model results also indicate that the Antilles, which has been proposed as an avenue for migration during GABI, may have been a possible corridor for migration for Glyptotherium.