Abstract
Among the Afro-Arabian Palaeogene chiropterans, philisids were the most common and diversified members. ThePhilisidae are considered as an extinct primitive group of Vespertilionoidea, a well-diversified superfamily that todayincludes Natalidae, Molossidae and Vespertilionidae. However, the position of Philisidae within this superfamily has neverbeen clearly established. These bats are characterized by a very distinctive dental morphology, and include somerepresentatives that were among the largest bats to be known. Here we describe new dental remains attributable to philisidsfrom the EarlyMiddle Eocene of Chambi, Tunisia and Gour Lazib area, Algeria. These fossils allow us to reconsider thedental morphology of the oldest philisids: Dizzya exsultans Sige, 1991 and Witwatia sigei Ravel, 2012. We haveundertaken a cladistic assessment of the dental evidence (47 dental and mandible characters) to clarify the phylogeneticrelationships within Philisidae, and its position within Vespertilionoidea, in order to highlight the origin, historicalbiogeography and patterns of dispersion of the most diversified extant bat group. The specialized dental morphology ofphilisids implies particular occlusion seen in the three-dimensional reconstructions of teeth of Witwatia sigei and Dizzyaexsultans. The peculiar morpho-functional anatomy of the teeth and the large size of these bats were well adapted to anopportunistic diet, and probably contributed to the early success of the family in North Africa.