Résumé
Peradectidae and Herpetotheriidae are mostly Laurasian, superficially ‘opossum-like’ metatherians (marsupials and related fossils) known by their generalist dentition and frequently regarded as arboreal stem-metatherians and terrestrial stem-marsupials, respectively. A systematic revision of Early Eocene European Peradectes integrates new dental rows together with an analysis of dental polymorphisms. It allows us to define the oldest European Peradectes species and to further show that a unique dispersal event towards Europe occurred during the history of peradectids. We also report the first metatherian from the Paleocene of Europe and oldest undisputed herpetotheriid. It reveals the simultaneous independent acquisition of the same stylar cusp features on upper molars in the European Eocene species of the coeval families. Finally, we carried out a cladistic analysis at the metatherian level based on a majority of newly defined dental characters. For the first time, a Laurasian monophyletic group Peradectidae including all Paleocene-Eocene species is recovered. Peradectidae are a part of a robust and resolved unnamed clade, emerging consecutive to the K-Pg boundary and encompassing ‘Notometatheria’ (all South American and Australian metatherians plus herpetotheriids).