title: An endoparasitoid Cretaceous fly and the evolution of parasitoidism.
abstract: Parasitoidism is a key innovation in insect evolution, and parasitoid insects, nowadays, play a significant role in structuring ecological communities. Despite their diversity and ecological impact, little is known about the early evolution and ecology of parasitoid insects, especially parasitoid true flies (Diptera). Here, we describe a bizarre fly, Zhenia xiai gen. et sp. nov., from Late Cretaceous Burmese amber (about 99 million years old) that represents the latest occurrence of the family Eremochaetidae. Z. xiai is an endoparasitoid insect as evidenced by a highly developed, hypodermic-like ovipositor formed by abdominal tergites VIII + IX that was used for injecting eggs into hosts and enlarged tridactylous claws supposedly for clasping hosts. Our results suggest that eremochaetids are among the earliest definite records of parasitoid insects. Our findings reveal an unexpected morphological specialization of flies and broaden our understanding of the evolution and diversity of ancient parasitoid insects.
authors.affiliation: State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing, 210008, China.|University of the Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Qingqing
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing, 210008, China.|College of Palaeontology, Shenyang Normal University, Shenyang, 110034, China.
authors.forename: Junfeng
authors.initials: J
authors.lastname: Zhang
authors.affiliation: , Nanjiao Bieshu 394, Shanghai, 201108, China.
authors.forename: Yitao
authors.initials: Y
authors.lastname: Feng
authors.affiliation: State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing, 210008, China.
authors.forename: Haichun
authors.initials: H
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing, 210008, China. bowang@nigpas.ac.cn.|Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Science, Beijing, 100101, China. bowang@nigpas.ac.cn.
authors.forename: Bo
authors.initials: B
authors.lastname: Wang
mesh_terms: D018647:Amber; D000818:Animals; D005075:Biological Evolution; D004175:Diptera / Q000033:anatomy & histology / Q000145:classification*; D005580:Fossils; D010271:Parasites / Q000033:anatomy & histology / Q000145:classification*
chemical_list: D018647:Amber
keywords: Burmese amber; Cretaceous; Diptera; Insecta; Parasitoidism