Tooth wear and diets of extant and fossil xenarthrans (Mammalia, Xenarthra) - Applying a new mesowear approach

Xenarthrans comprised an ecologically significant and diverse group of small to gigantic sized terrestrial insectivorous, omnivorous and herbivorous mammals during the Cenozoic in South America and during the Pleistocene in North America. Their peculiar tooth morphology has proven to be challenging for palaeodietary analyses of this group. Here we introduce a new approach to this problem by utilising the recently developed mesowear angle analysis for xenarthran palaeodietary analyses. The method is based on recording the relief of worn teeth as angles measured from the occlusal surfaces. We compare our results with other lines of evidence of extant and fossil xenarthran diets, based on direct observation, orthodentine microwear analyses and analyses of fossilised faecal material. Our results support previous findings and hypotheses on fossil xenarthran diets, but also provide new information on the diversity of dietary preferences in the diverse assemblages of large Pleistocene xenarthrans such as ground sloths and glyptodonts.