Chiroptera is one of the few modern mammal orders for which no fossil record has been associated with the Paleocene-Eocene Thermal Maximum that happened 55.8 million years ago. With the exception of complete skeletons from the early Middle Eocene of the Messel Formation in Germany and the late Early Eocene Green River Formation in Wyoming, all early bats are only represented by isolated elements, mainly teeth and fragmentary jaws, making the diversity and taxonomic affinities more difficult to establish. Here we revise all of the Early Eocene bats from Europe based on dental features, including digitally reconstructed teeth using micro-CT scanning technology of some complete skeletons. The diversity of European early bats is composed of the families Onychonycteridae, Icaronycteridae, Archaeonycteridae, Palaeochiropterygidae, and some of undetermined affinities. Dental features and synapomorphies of each family are characterized for the first time. The earliest bats are dated from the early Early Eocene and are all of small size with lower molars less than 1.3 mm in length. They are represented by: Eppsinycteris anglica from Abbey Wood, east London, England, an onychonycterid with reduced lower p4 and long molars; Archaeonycteris? praecursor from Silveirinha, Portugal, an archaeonycterid with long postcristid on wide lower molars; a new archaeonycterid genus and species from Meudon, North France with long trigonid and shorter postcristid on wide lower molars. These results indicate that the diversity of European Early Eocene bats is higher than previously recognized and that diversification began early in the Early Eocene.

Abstract of an Oral Presentation or a Poster, RBINS Collection(s)

Paleontology