Coevolutionary reconstruction of primate lice and their hosts based on reconciliation analysis and divergence date estimation. Thick grey lines represent the host phylogeny for humans, chimpanzees, gorillas, and Old World monkeys. Thin black lines (solid and dashed) represent the louse lineages. This evolutionary scenario depicts a parasite duplication ca. 13 MYA leading to the extant genera Pediculus (solid lines) and Pthirus (dashed lines). One species from each lineage is depicted as having gone extinct (dagger), and a single host switch ca. 3–4 MYA is shown by an arrow within the Pthirus lineage. The divergence of the chimpanzee and human lice (Pediculus spp.) are shown as having diverged in tandem with their hosts.