Drivers of the artiodactyl turnover in insular western Europe at the Eocene-Oligocene Transition

The fossil and geological records provide unique insight into the history of species and how they responded to environmental changes over time. We analyzed an original, high-resolution dataset of fossil European ungulate mammals during the Eocene-Oligocene major faunal turnover ("Grande Coupure") to establish diversity dynamics over 15 My and infer potential biotic and abiotic drivers. This transition involved the partial replacement of endemic by immigrant lineages (77% of species became extinct), and our results do not support a long-standing hypothesis of competitive exclusion. Instead, we show that environmental disruptions during a period of tectonic and global climatic changes were more likely the drivers of Grande Coupure faunal extinction and diversification.