Fossil Ponerinae (Hymenoptera: Formicidae) in Early Eocene amber of France

The French Early Eocene (Ypresian, 52-55 million-year-old) amber of Oise contains a rich and well-diversified myrmecofauna, which has remained unstudied until now. A recent survey of these fossil ants revealed 40 different species, among which nine belong to the subfamily Ponerinae. We describe here the two best-preserved morphotypes: a possible ergatoid queen representing the earliest known occurrence of the extant genus Platythyrea Roger, and described as a new species P. dlusskyi sp. n.; and a male morphotype related to the equivocal, paraphyletic genus Pachycondyla Smith, thus described herein but not formally assigned to genus until the male-based taxonomy of Ponerinae is better established. This fauna provides an ecological context to make inferences about the paleoenvironment of northwestern Europe during the PETM and gives new arguments for a radiation of modern ants at that time.