Mid-Mesozoic Flea-like Ectoparasites of Feathered or Haired Vertebrates

SummaryParasite-host associations among insects and mammals or birds are well attended by neontological studies [1]. An Eocene bird louse compression fossil [2 and 3] and several flea specimens from Eocene and Oligocene ambers [4, 5, 6, 7 and 8], reported to date, are exceptionally similar to living louse and flea taxa. But the origin, morphology, and early evolution of parasites and their associations with hosts are poorly known [9 and 10] due to sparse records of putative ectoparasites with uncertain classification in the Mesozoic, most lacking mouthpart information and other critical details of the head morphology [11, 12, 13, 14 and 15]. Here we present two primitive flea-like species assigned to the Pseudopulicidae Gao, Shih et Ren familia nova (fam. nov.), Pseudopulex jurassicus Gao, Shih et Ren genus novum et species nova (gen. et sp. nov) from the Middle Jurassic [ 16] and P. magnus Gao, Shih et Ren sp. nov. from the Early Cretaceous in China [ 17]. They exhibit many features of ectoparasitic insects. Large body size and long serrated stylets for piercing tough and thick skin or hides of hosts suggest that these primitive ectoparasites might have lived on and sucked the blood of relatively large hosts, such as contemporaneous feathered dinosaurs and/or pterosaurs or medium-sized mammals (found in the Early Cretaceous, but not the Middle Jurassic).

► Flea-like ectoparasites from the mid-Mesozoic (165 and 125 Mya) of China ► Flea-like fossil insects exhibit long serrated stylets for piercing skin of hosts ► These insects might have sucked the blood of feathered dinosaurs and/or pterosaurs ► Pseudopulicidae proffers insight into the evolution of the early fleas