RT Journal Article
SR Electronic
T1 Fleas (Siphonaptera) are Cretaceous, and Evolved with Theria
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 014308
DO 10.1101/014308
A1 Qiyun Zhu
A1 Michael Hastriter
A1 Michael Whiting
A1 Katharina Dittmar
YR 2015
UL http://biorxiv.org/content/early/2015/01/24/014308.abstract
AB Fleas (order Siphonaptera) are highly-specialized, diverse blood-feeding ectoparasites of mammals and birds with an enigmatic evolutionary history and obscure origin. We here present a molecular phylogenetic study based on a comprehensive taxon sampling of 259 flea taxa, representing 16 of the 18 extant families of this order. A Bayesian phylogenetic tree with strong nodal support was recovered, consisting of seven sequentially derived lineages with Macropsyllidae at the base and Stephanocircidae as the second basal group. Divergence times of flea lineages were estimated based on fossil records and host specific associations to bats (Chiroptera), showing that the common ancestor of extant Siphonaptera split from its closest mecopteran sister group in the Early Cretaceous and basal lineages diversified during the Late Cretaceous. However, most of the intraordinal divergence into families took place after the K-Pg boundary. Ancestral states of host association and biogeographical distribution were reconstructed, suggesting with high likelihood that fleas originated in the southern continents (Gondwana) and migrated from South America to their extant distributions in a relatively short time frame. Theria (placental mammals and marsupials) represent the most likely ancestral host group of extant Siphonaptera, with marsupials occupying a more important role than previously assumed. Major extant flea families evolved in connection to post K-Pg diversification of Placentalia. The association of fleas with monotremes and birds is likely due to later secondary host association. These results suggest a relatively distant relationship between true siphonapterans and the fossil “fleas” recently discovered in Mesozoic formations of Northeast Asia.