Implications of a Dating Analysis of Hippoboscoidea (Diptera) for the Origins of Phoresis in Feather Lice (Psocodea: Phthiraptera: Philopteridae)

Hippoboscidae (Samouelle 1819) is a family of blood feeding Diptera, which can be phoretic vectors for para- sitic feather lice (Philopteridae Burmeister 1838). Hippoboscid flies are understood to provide opportunities for increased instances of dispersal and host-switching for feather lice. This intimate relationship between hippoboscid fly and feather louse may have hypothetically existed since the origin of avian-specialized Hippoboscidae. Thus, phoretic dispersal may have affected patterns of diversification in feather lice over millions of years. To test this, a dating analysis of a previously published Hippoboscoidea data set was per- formed using known fossil calibrations.The results of the dating analysis suggest Hippoboscoidea diversified shortly after the K-Pg boundary, similar to their modern vertebrate hosts. A maximum age of the avian feeding Ornithomyini is estimated to have occurred around the origin of parasitic feather lice. This maximum diver- gence date suggest this phoretic relationship could have existed for much of the diversification of avian feather lice and had the potential to influence patterns of diversification due to dispersal and host-switching among avian hosts.