The snakefly family Mesoraphidiidae (Insecta: Raphidioptera) from the Lower Cretaceous Yixian Formation, China: systematic revision and phylogenetic implications

Mesoraphidiidae is one of the major groups among the Mesozoic Raphidioptera, with 70 described species in 30 genera. However, many mesoraphidiid taxa need to be revised and the monophyly of this family is still questionable, lacking conclusive support from convincing autapomorphies. Here, we present a systematic revision of Mesoraphidiidae from the Lower Cretaceous Yixian Formation of north-eastern China. Nine genera and 12 species are described or re-described based on 27 fossil specimens, including four new genera and five new species, namely <i>Allocotoraphidia</i> gen. nov., <i>Yixianoraphidia</i> gen. nov., <i>Beipiaoraphidia martynovi</i> gen. et sp. nov., <i>Grammoraphidia ponomarenkoi</i> gen. et sp. nov., <i>Proraphidia jepsoni</i> sp. nov., <i>Proraphidia yixianensis</i> sp. nov. and <i>Styporaphidia willmanni</i> sp. nov. Two new combinations are proposed, <i>Yixianoraphidia anomala</i> (Ren, 1997) comb. nov. and <i>Allocotoraphidia myrioneura</i> (Ren, 1997) comb. nov. <i>Proraphidia</i> Martynova, 1947 and <i>Styporaphidia</i> Engel &amp; Ren, 2008 are first recorded from the Lower Cretaceous of China. <i>Phiradia</i> Willmann, 1994 stat. rest. is restored as a valid genus. A preliminary phylogenetic analysis is performed to investigate the relationships among the genera of Mesoraphidiidae based on morphological data. The monophyly of the subfamily Alloraphidiinae and the tribe Nanoraphidiini, respectively, were supported in the present analysis; several genera with three forewing radial crossveins or with subradial crossveins (i.e. <i>Cretinocellia</i> Ponomarenko, 1988, <i>Allocotoraphidia</i> gen. nov., <i>Kezuoraphidia</i> Willmann, 1994 and <i>Xuraphidia</i> Hong, 1992) were assigned to earlier diverging groups in Mesoraphidiidae; however, the monophyly of Mesoraphidiinae was not recovered. The present study sheds light on the evolutionary history of Raphidioptera. http://zoobank.org:pub:610CD366-6328-4F5D-9AD0-71A69866C18B