中国东北早白垩世一种新的昼蜓化石(蜻蜓目:昼蜓科)(英文)

A new hemeroscopid dragonfly from the Lower Cretaceous of Northeast China (Odonata: Hemeroscopidae)

本文记述昼蜓科化石一新属新种———孟氏丽昼蜓Abrohemeroscopusmengigen .etsp .nov.。化石采自辽宁省义县早白垩世九佛堂组地层中。新属与巴依萨昼蜓HemeroscopusPritykina,1977在形态上比较相似 ,但在演化程度上更为原始 ,主要体现在下面几个方面 :(1)后翅臀套较小 ,仅有 6～ 7个翅室 ;(2 )径增脉 (Rspl)缺 ;(3)后翅CuAa脉弯曲 ,带有 5个明显的后分支 ;(4 )前翅MP脉不显短 ,终止于翅后缘近翅结处 ;(5 )翅痣下有一个明显的支脉 ;(6 )后翅CuAa和MP域基部较窄 ,在三角室下方仅有 1排翅室。

A new genus and species of hemeroscopid dragonfly, Abrohemeroscopus mengi gen. et sp.nov., of the family Hemeroscopidae Pritykina, 1977, from the Lower Cretaceous Jiufotang Formation, Liaoning Province, Northeastern China, is described and illustrated. This new genus is rather similar to Hemeroscopus Pritykina,1977, but differs from the latter in the following characters: (1) hindwing anal loop is smaller, only with 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 is not shortened, reaching 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). This is the oldest fossil record of the Hemeroscopidae in China.