Taxonomy Of Fossil Palaeontinidae From The Late Mesozoic In Northeast China (Insecta: Homoptera: Cicadomorpha)

Eastern Inner Mongolia and Western Liaoning are located in the northeast part of China. Its non-marine sedimentary strata, especially in Jiulongshan Formation of Middle Jurassic and Yixian Formation of Early Cretaceous, yield a mass of notable fossils including abounded insects which providing important evidence for study of the origin and early evolution of insects. Among these abundant insect fossils, the record of fossil palaeontinid is well preserved. These valuable materials are the important supplement to the record of world fossil palaeontinid and may aid study of their origin as well as their interactions between insects and plants.In present dissertation, the location, geological age of the strata fossil Palaeontinidae of Northeast China and same representative geological sections are introduced. A brief researching history and actuality on fossil Homoptera, and geological history of Homoptera are given. The morphology and phylogenetic study of the Palaeontinidae of the suborder Cicadomorpha are reviewed. A comprehensive taxonomic work on fossils from eastern Inner Mongolia and western Liaoning and north Hebei is presented.In total, 36 species within 14 genera assigned to Palaeontinidae are treated, including 1 new genus, 3 new species and 5 new combinations: Synapocossus succinctus gen. et sp. nov., S. sciacchitanoae gen. et sp. nov., S. praelongus gen. et sp. nov, Plachutella punctulosus (Wang and Ren, 2006) comb. nov., P. bellus (Wang and Ren, 2006) comb. nov., P. ancylivenius (Wang and Ren, 2006) comb. nov., P. decorus (Wang and Zhang, 2008) comb. nov., P. cheni (Wang and Zhang, 2008) comb. nov.; and 7 genera and 14 species were published, Daohugoucossus shii Wang and Zhang, 2006, D. parallelivenius Wang, Ren and Shih, 2007, D. lii Wang, Ren and Shih, 2007, Eoiocossus validus (= E. conchatus Wang, Ren and Shih, 2007) Wang and Zhang, 2006, E. giganteus (Wang, Ren and Shih, 2007) Wang and Zhang, 2009, E. pteroideus (Wang, Ren and Shih, 2007) Wang and Zhang, 2007, Quadraticossus fangi Wang and Ren, 2007, Q. longicaulis Wang and Ren, 2007, Q. eumorphus Wang, Wang and Ren, 2008, Hamicossus laevis Wang and Ren, 2007, Suljuktocossus yinae Wang and Ren, 2007, S. coloratus (Wang, Zhang and Fang, 2006) Wang, Zhang and Szwedo, 2009, Cladocossus undulates Wang and Ren, 2009 and Cricocossus paradoxus Wang and Ren, 2009. Totally 48 line drawing and 68 photos are presented. This finding documents the first records of nearly complete fossil Palaeontinidae in world and offer more morphologic characters for the study of evolutional relationship between this extinct family and other cicadas. The fossil species of Palaeontinidae occurring in northeastern China are listed for each genus and their type localities are given.According to the references of extant family of the suborder Cicadomorpha, and Clypeus characters of Palaeontinidae, the coevolution between palaeontinid and plants and extinction of palaeontinid are discussed. A chart is provided that shows the number of the described Palaeontinidae fossils in different geological ages. By comparison, the Middle Jurassic palaeontinid diversity is greater than those in any other epoch, suggesting that the family probably went into its most prosperous stage in the Middle Jurassic. Based on wing color pattern occurred in most species of Palaeontinidae, mimicry of palaeontinid is analyzed.All the type specimens of the species are preserved at the Key Laboratory of Insect Evolution & Environment Change, Capital Normal University in Beijing, China.