Simultaneous radiation of bird and mammal lice following the K-Pg boundary.

The diversification of parasite groups often occurs at the same time as the diversification of their hosts. However, most studies demonstrating this concordance only examine single host-parasite groups. Multiple diverse lineages of ectoparasitic lice occur across both birds and mammals. Here, we describe the evolutionary history of lice based on analyses of 1107 single-copy orthologous genes from sequenced genomes of 46 species of lice. We identify three major diverse groups of lice: one exclusively on mammals, one almost exclusively on birds and one on both birds and mammals. Each of these groups radiated just after the Cretaceous-Paleogene (K-Pg) boundary, the time of the mass extinction event of the dinosaurs and rapid diversification of most of the modern lineages of birds and mammals.