First discovery of fossil Parachoristidae(Insecta: Mecoptera) in China

Triasoparachorista huaxiaensis gen. et sp. nov.(T2), Junggaarochorista tuzigouensis Hong nom nov. (J1) and a transfered old genus with two species, Jibeiorthophlebia xiaofanzhangziensis Hong, 1983 and J. internata Hong, 1983(J2) are firstly discovered in China. According to wing venational features, these genera and species should be referred to family Parachoristidae Tillyard, 1937. The main features of Parachoristidae mixed both features of the Orthophlebiidae in the Rs1 with at least 2 (Protorthophlebia)-3 (Orthophlebia) or more pectinate branches, and of the Permochoristidae in the MP with 6 branches. It formed a unique intermediate group between Orthophlebiidae and Permochoristidae , and it is different from them, meanwhile its venational features can be distinguished in “Dinopanorpidae” Carpenter, 1972. The discovery of fossil Parachoristidae in China has certain significances, firstly it fills the gap of the field of Parachoristidae in the Midtriassic, Early Jurassic and Midjurassic of China. Secondly, In the meantime it can be used to trace the evolutionary relationship of this family in various geological age, especially to the study on the evolutionary relationship between Permochoristidae and Orthophlebiidae from the Late Paleozoic to Early Mesozoic. Thirdly, the author reported that the Yanliao Biota (J2) and Jehol Biota (K1) dervided from North China Palaeocontinent. Yanliao region is the origin center of Yaoliao Biota and Jehol Biota, and then they migrated outwards to eastern Mongolia and arrived Zabaikalia of Russia, and formed widely a faunal province of Yanliao Biota and Jehol Biota in the Eastoasian Paleocontinent. Fourthly, the problem on the exact horizon of Ningcheng strata is discussed in this paper.