Overview of Psocodea in Eocene Oise amber and implications for the transition to modern‐day barklice communities

Abstract Psocodea is an insect order including barklice, booklice and parasitic lice. The oldest evidence of diversification in the crown group dates back to the Cretaceous, represented by a high diversity and abundance in several amber deposits. However, the Cenozoic record of psocodeans is less known. Here, we present a review of the Psocodea from the lower Eocene amber of Oise in France, including a study of 83 new specimens. The record of psocids in Oise amber is currently represented by 144 specimens corresponding to 14 species in 14 genera in 10 families of the three suborders: Trogiomorpha, Troctomorpha and Psocomorpha. The only known ‘archaeatropid’ Empheriidae from the Eocene, Danyazarius magnificus gen. et sp. nov., is described. In addition, the genera Annulipsyllipsocus and Sinopsyllipsocus are formally synonymized under Psyllipsocus . Wing venations of all psocid species from Oise amber are illustrated, enabling easier comparison with other taxa. A key for determination of all known psocodean species from Oise amber is given. We notice a rarity of nymphs in relation to the total number of specimens, and provide an account of known sexes, the female being more numerous than the male. We also compare the diversity with that of Baltic amber. Interestingly, Psocomorpha is the least diverse suborder in Oise amber, as in Cretaceous amber, although this suborder is the most numerous, as in current ecosystems. This study opens a window onto the evolutionary history of Psocodea during the Cenozoic and the transition to the modern‐day barklice communities.