【摘要】 发现于辽宁省义县早白垩世九佛堂组上段地层中的昼蜓化石(孟氏丽昼蜓AbrohemeroscopusmengiRen,Liu et Chen,2003)与北京西山卢尚坟组的巴依萨昼蜓(HemeroscopusbaissicusPritykina,1977)在形态上比较相似,但在演化程度上更为原始,主要体现在后翅臀套较小(仅有6～7个翅室),径增脉(Rspl)缺,后翅CuAa脉弯曲、带有5个明显的后分支,前翅MP脉短、终止于翅后缘近翅结处,翅痣下有一个明显的支脉,后翅CuAa 和MP域基部较窄、在三角室下方仅有1排翅室。据此,九佛堂组上段的地质时代定为早白垩世早期(Berriasian-Hauterivian)较为合理。更多还原

【Abstract】 A new hemeroscopid dragonfly fossil,Abrohemeroscopus mengi Ren,Liu et Chen,2003,found from the upper part of the Jiufotang Formation,Liaoning Province,northeastern China,is similar to the Hemeroscopus baissicus Pritykina,1977,and more primitive phylogenetically than H. baissicus in the following characters:① hindwing anal loop is smaller,with only 6～7 cells(plesiomorphy);② Rspl is absent(plesiomorphy);③ the hindwing vein CuAa is curved and has five distinct posterior branches(plesiomorphy);④ the forewing MP shortened,reaches the posterior wing margin slightly beyond the level of the nodus(plesiomorphy);⑤ pterostigmata more distinctly braced(plesiomorphy);⑥ the hindwing area between MP and CuAa is narrow,with only one row of cells near the discoidal triangle(plesiomorphy). These facts demonstrate that the upper part of the Jiufotang Formation should be early Early Cretaceous in age.更多还原