Multiple lineages of lice pass through the K–Pg boundary

Abstract

For modern lineages of birds and mammals, few fossils have been found that predate the Cretaceous–Palaeogene (K–Pg) boundary. However, molecular studies using fossil calibrations have shown that many of these lineages existed at that time. Both birds and mammals are parasitized by obligate ectoparasitic lice (Insecta: Phthiraptera), which have shared a long coevolutionary history with their hosts. Evaluating whether many lineages of lice passed through the K–Pg boundary would provide insight into the radiation of their hosts. Using molecular dating techniques, we demonstrate that the major louse suborders began to radiate before the K–Pg boundary. These data lend support to a Cretaceous diversification of many modern bird and mammal lineages.

Reconstructing evolutionary timescales using phylogenomics

“…The clade Polyneoptera was shifted by 80 million years into the past. The date estimates obtained by Tong et al (2015) shared biological interpretations with a number of other studies (Grimaldi & Engel, 2005;Garwood & Sutton, 2010;Smith et al, 2011;Wiegmann et al, 2011).…”

Host correlates of diversification in avian lice

“…All but 16 of 173 bird families are known to be parasitized and the number of species known from birds exceeds 3000 (Smith et al, 2011). Many species apparently still await description; however, it seems that the global fauna is relatively well explored at higher taxonomic levels: the last family was described in 1910, and new genera are rarely discovered in recent times (but see Valim & Weckstein, 2012).…”

“…Early mammals, birds or even feathered theropod dinosaurs might have served as the ancestral hosts of these parasitic lineages. About 15-18 clades of parasitic lice passed through the Cretaceous-Palaeogene boundary (65 mya), when a large-scale mass extinction decimated the majority of animals (Smith et al, 2011).…”

Evolutionary co-variation of host and parasite diversity—the first test of Eichler’s rule using parasitic lice (Insecta: Phthiraptera)

“…Lice are classified into four suborders: Amblycera, Ischnocera, Rhynchophthirina, and Anoplura (Price et al 2003). However, recent studies (Johnson et al 2004;Murrell and Barker 2005;Smith et al 2011) suggested that Phthiraptera do not form a monophyletic group. The parasitic way of life appeared two times independently in parasitic lice: once in the ancestors of Amblycera and once in the ancestors of the other three suborders.…”