Meeting Abstract
Two and three-dimensional quantitative dental surface data can be used to understand dietary ecology of extinct mammals using information from only one or a few teeth. We used these methods to investigate dietary ecology of therian mammals following the Cretaceous-Paleogene (K-Pg) mass extinction, to elucidate the tempo and mode of dietary change during the earliest Pg, a pivotal period in the evolution of modern mammalian diversity. Previous work has investigated change in mammalian dietary ecology at the K-Pg boundary, but has not extended later than the very earliest Pg (within 80,000 years of the extinction), and consequently has not captured changes in dental ecomorphology during the period of main faunal recovery. This recovery period lasted approximately one million years in western North America, during which the fossil record documents a change from species-poor “disaster” faunas to richer, more ecologically even “recovery” faunas. To fill this gap in our knowledge of the origins of mammalian dietary diversity, we studied 3D scans of tooth rows of earliest Pg mammals from the western interior of North America. We measured relief index (RFI), a homology-free ratio comparing 2D and 3D area of mammalian teeth, on μCT scans of 11 species of earliest Pg therian mammals and compared them to RFI values of extant species with known dietary ecologies. We also compared mean RFI values and ranges through time. Our results suggest a variety of dietary ecologies present in the earliest Pg, with higher RFI values, indicative of insectivory, in the Puercan 1 (Pu1) North American Land Mammal Age (NALMA), and an expansion into lower RFI values, indicative of the emergence of omnivory and frugivory, by the Torrejonian 1 (To1) NALMA.
