Paleobiogeographical history of Prolagus, an European ochotonid (Lagomorpha)

Abstract

Prolagus is one of the world's longest mammalian lineage, dwelling for more than 20 million years, 24 Ma if its direct ancestor Piezodus is taken into account, in Europe, Anatolia and northern Africa. Prolagus fossils form locally very rich assemblages, indicating that it was a common prey supporting food webs like modern rabbits. This ochotonid was similar to modern pikas (Ochotona) in their body size and shape. Both share a cladogenetic evolutionary pattern, in contrast with most lagomorphs. Prolagus inhabited mainly in subtropical swamp and wetland forest habitats, analogous to modern leporid Sylvilagus palustris from the Everglades (Florida, USA). The Prolagus paleodistribution had a strong latitudinal component, related to its thermophile exigencies. Its area has been deformed by the Alpine arc kinematics during Late Miocene. Before its final isolation and extinction, Prolagus area experimented a southern displacement, fragmentation and reduction during the Pliocene, but it coincides with the highest species richness of its history, due to endemisms. Cooler climatic conditions probably influenced the displacement of the Prolagus area, but it seems not to be the main reason for the retreat and final extinction of Prolagus, since it persists in insular populations living in a climate similar to the surrounding continents. Predation pressure probably has been one determinant factor accounting for the selective extinction of Prolagus mainland species around Mid/Late Pleistocene boundary. Insularity at different scales leads to population extinction, in contrast to current theoretical expectations.