Taxonomy And Faunal Analysis Of The Chinese Bittacidae(Mecoptera)

Bittacidae is the only cosmopolitan family in Mecoptera,currently comprises 20 extant genera and over 200 described species,and is distinctive by having three pairs of raptorial legs and grasping flying prey by the mid-and hindlegs.They are commonly known as hangingflies because the adults are unable to stand on a surface,instead hang themselves from the edges of leaves or twigs of plants using the prehensile tarsi of the forelegs.Forty-nine species in three genera(Bittacus Latreille,1805;Bicaubittacus Tan&Hua,2009;and Terrobittacus Tan&Hua,2009)have been documented in China to date.In this paper,we rediscribed the morphology of the Chinese Bittacidae,studied the distribution and fauna of the Chinese Bittacidae based on adult specimens and related literature.In taxonomy,53 species belonging to three genera known in China are recorded and illustrated,a key to the species of Bittacus is provided,including four new species,i.e.B.liupanshuicus sp.n.,B.acutus Zhang et al.,2020,B.shaoguanensis Zhang et a/.,2020 and B.longilobus Zhang et al,2020.Photographs of habitus,head,throax,legs,wings and genitalia of male and female of 34 species were shown.In the world zoogeographical regions,the Chinese Bittacidae are distributed both in the Palaearctic Realm and the Oriental Realm,with 3 species only in the Palaearctic Realm(5.66%),39 species only in the Oriental Realm(73.59%)and 11 species both in the Palaearctic Realm and the Oriental Realm(20.75%).In the Chinese zoogeographical regions,Bittacidae are in 6 regions of insect biogeographical regions in China,but mainly in South China region and the Middle China region:3 genera and 17 species in the South China region(32.08%),3 genera and 13 species in the Middle China region(34.52%).By using the multivariate similarity coefficient formula and the multicariate similarity clustering analysis(MSCA),53 species of the Chinese Bittacidae were analyzed.The general similarity coefficient of 6 regions was 0.028.At the similarity level 0.1,China was divided into three geographic regions.At last,taxonomy of Bittacidae,similarities and diagnosis between species of Bittacidae and faunal analysis have been discussed.