中国陕西铜川中三叠世二叠蝎蛉科两新属两新种(昆虫纲,长翅目)

TWO NEW MIDDLE TRIASSIC GENERA AND SPECIES OF PERMOCHORISTIDAE (INSECTA, MECOPTERA) FROM TONGCHUAN REGION, SHAANXI PROVINCE, CHINA

记述中国陕西中三叠统铜川组二叠蝎蛉科PermochoristidaeTillyard,19182新属及2新种:陕西蝎蛉属Shaanxichoristagen.nov.,何家坊陕西蝎蛉S.hejiafangensissp.nov.和化石蝎蛉属Choristitesgen.nov.,马廷生化石蝎蛉C.matinsonisp.nov.,前一新属以其翅呈近三角形;Sc很长,伸达R端部,带3支脉;Rs与MA各自带2支;Rs+MA主干明显短于MA;MP带5支,很早与Sc+R+MA汇合,之后与之分离,又与CuA汇合,形成一支合并脉M+CuA;Pt不明显等特征与中蝎蛉属Mesochorista、秦蝎蛉属Qinochorista区别。后一新属以其翅呈近卵形;Sc、Rs很长,伸达R端部;Sc带6支脉;Rs与MA各自带2支;MA柄稍短于Rs+MA主干;MA基部弯曲;MP带5支,基部弯曲,直接与CuA汇合,形成R+MP+CuA;Pt不明显等特征的脉序结构可与中蝎蛉属Mesochorista、里阿斯蝎蛉属Liassochorista明显区别。新属、种系陕西昆虫群(属中三叠世陕西生物群、也是陕西动物群的一个化石门类)铜川昆虫组合的新成员。时代相当于欧洲拉丁尼期(或阶)(LadinianStage)。

Two new genera and species Shaanxichorista gen. nov. and S. hejiafangensis sp. nov. and Choristites gen. nov. and C. martinsoni sp. nov. of Permochoristidae are described. The former genus differs from Mesochoraista and Qinochorista in forewing nearly triangular, Sc long, extending to R terminal part, with 3 branches, Rs and MA respectively with 2 branches, main stem Rs ＋ MA shorter obviously than stem MA, MP with 5 branches and coalesced early with merged vein Sc ＋ R ＋ MA, than separating from it and connecting again to CuA, and forming a nerged vein M ＋ CuA, Pt indisct. The latter genus differsfrom Mesochoraista and Liassochorista in forewing nearly oval in shap, Sc long, extending to R terminal part, with 6 branches, Rs ＋ MA with 4 branches, stem MA shorter than Rs ＋ MA, MA curved, MP with 5 branches and coalesced directly with CuA and forming a merged vein R ＋ MP ＋ CuA, Pt indistinct. The two new genera are discovered from the Midtriassic Tongchuan Formation （Trzt） of Tongcuan region, Shaanxi Province. The are new members of the Tongchuan assemblage of Shaanxi Entomofauna and can be corresponded to the European Ladinian Stage in age.