Chewing cycle analysis of Lesmesodon edingeri (Mammalia; Hyaenodonta) and implications for carnivoran feeding adaptions

The dentition of the proviverrine hyaenodont Lesmesodon edingeri from Messel is known only from preservation in full occlusion.Moreover, only subadult individuals have been recovered so far.The CT-based study provides new details from lingual, buccal, and occlusal aspects of its dentition, indicating new insights on the ecology of Lesmesodon and its niche occupation in the Messel ecosystem and what dietary range it had.We analyzed the dental function of the Eocene species Lesmesodon edingeri and its close relative Proviverra typica by reconstructing the wear facets and their respective chewing cycle with the Occlusal Fingerprint Analyser (OFA) software and compared them with those of three modern carnivorous taxa.The teeth were compared by quantification of their contact areas (wear facets) and the calculation of the duration of the contact.Subsequently the masticatory path was reconstructed in detail.Differences in morphologically similar dentitions are revealed by the OFA analysis.The insectivorous species show similarities in their respective chewing cycle in terms of duration and maximum intercuspation, while species more specialized in either carnivory or omnivory show contrary trends, that can be clearly separated from the insectivores.Our study showed that the small hyaenodont Lesmesodon edingeri apparently occupied a primarily insectivorous-carnivorous dietary niche in the Messel ecosystem and how the dentitions of the insectivorous species in this study differ despite having adaptions that look similar at first glance.