Spider wasps (Hymenoptera: Pompilidae) from Xiede (Eocene, central Tibetan Plateau): systematics and paleoecological implications

Spider wasps (Pompilidae), best known for capturing and paralysing a spider to serve as food resource for the larva, commonly placed together in an underground nest, is represented by about 5000 extant species. The fossil record of this diverse family spans from the Eocene to the Miocene, with 26 occurrences to date, but only four of them are well-ascertained members of the Pompilinae, one of the most diverse Pompilidae subfamilies. Herein, we report two new records of fossil Pompilinae, namely Gubuzhu orientalis n. gen., n. sp. and Paleoferreolina xiedensis n. gen., n. sp., from the Xiede locality (Niubao Formation, Nima Basin, central Tibetan Plateau, China). The former species can be confidently assigned to the tribe Pompilini, while the latter shares morphological similarities with members of Aporini, as well as members of other tribes within Pompilidae. The two new species represent the earliest occurrences of Pompilinae, and the first ones at Asian deposits, suggesting that the subfamily was already widespread in the Northern Hemisphere during the late Eocene. More­over, Gubuzhu orientalis n. gen., n. sp. lacked a tarsal comb, indicating that it may have had a limited excavation activity in its nesting behaviour.