Meeting Abstract
The end of the Pleistocene saw the extinction of many megafaunal taxa in North America as climate changed and habitats shifted. North American Martes, comprised of three species, was one of the few small-bodied clades to decline in taxonomic diversity entering the Holocene, with the extinction of the Noble marten, ?M. nobilis. Using morphological and isotopic evidence, we sought to determine the ecology of the Noble marten in order to better understand the cause of its extinction. We quantified limb bone shape in ?M. nobilis using 3D geometric morphometrics and compared this shape to that of the extant M. americana and M. caurina. To determine diet, we measured δ13C values from the enamel and dentin of ?M. nobilis collected from the same locality as the limb elements. We found that the Noble marten significantly differs in limb shape from both of the extant species and possesses a more robust morphology. This suggests that the taxon was less arboreal than the extant species. δ13C values, adjusted with a 13‰ fractionation for diet, ranged between -24.19‰ and -20.37‰, indicating that the Noble marten was eating a mix of C3 and C4 plants and/or prey with this diet. The results of this study suggest that ?M. nobilis lived within an ecotone between Pleistocene forests and grasslands. This is supported by the mix of woodland and plains taxa found at fossils sites with ?M. nobilis. Ecotones are highly dynamic environments and often act as buffers for the adjacent communities. Within an ecotone, the Noble marten likely encountered more drastic habitat changes at the end of the Pleistocene than extant Martes, which are found entirely in forested habitats. Such habitat instability could then have resulted in the extinction of ?M. nobilis.
