The Eocene–Oligocene ungulates from Western Europe and their environment

Abstract

A survey of Paleogene ungulates from Western Europe is drawn up from the results of previous work on the ungulate lineages of this period and from new data on two groups particularly representative of the Oligocene ungulate fauna: the ruminants and the Cainotheriidae based on new material collected in localities of the Quercy Phosphorites. The history of ungulates from Western Europe at the Eocene–Oligocene transition is marked by different phases of extinction and origination related to environmental changes. In this perspective, the relative diversity of groups and the modifications of their tooth morphology, which reflect a diet change, resulting from vegetation modifications are analysed from the Early Eocene to the Late Oligocene. In Western Europe, the Late Eocene and the Early Oligocene was a period of transition with an important change in faunal and floral composition. The diversity analysis of ungulates suggests that the Grande Coupure is the result of gradual climatic and geographic events that occurred from the Middle Eocene (Mammalian Paleogene (MP)13/14 reference levels) to the Early Oligocene (MP 21/22 reference levels). During this period, it has been demonstrated that important adaptive changes occurred in the ungulate dental pattern (selenodonty in artiodactyls, semihypsodonty in perissodactyls), and appendicular skeleton (fusion of the cuboid and navicular bones of the tarsus in artiodactyls). These morphological modifications coincided with environmental changes that were less extreme than in North America.