侏罗纪中蜉属和珠蜉属蜉蝣昆虫化石研究的新进展

NEW DEVELOPMENT IN STUDYING THE JURASSIC GENERA: MESOBAETIS BRAUER ET AL., 1889 AND MESONETA BRAUER ET AL., 1889 (INSECTA: EPHEMEROPTERA)

长期以来,我国昆虫化石研究者所确认,并为众多地层古生物工作者所引用,作为地层对比和确定地质时代的两种侏罗系蜉蝣幼虫化石:西伯利亚中蜉(MesobaetissibiricaBrauer,RedtenbacheretGanglbauer,1889)和古珠蜉(MesonetaantiquaBrauer,RedtenbacheretGanglbauer,1889)在我国境内并不存在。迄今为止,这两个种仅局限于俄罗斯西伯利亚下侏罗统。此前,被我国昆虫化石研究者分别归入中蜉属(MesobaetisBrauer,RedtenbacheretGanglbauer,1889)和珠蜉属(MesonetaBrauer,RedtenbacheretGanglbauer,1889)的所有种类,其科级和属级分类位置有误。它们包括:西伯利亚中蜉,三间房中蜉(MesobaetissanjianfangensisHong,LiangetHu,1995),黑斑中蜉(MesobaetismaculataHong,LiangetHu,1995),古珠蜉和北票珠蜉(MesonetabeipiaoensisWang,1980)。道虎沟组、海房沟组、九龙山组和三间房组的水生蜉蝣组合完全不同,彼此不能对比。我国侏罗系—下白垩统蜉蝣幼虫全部是湖相,为原地埋藏,而非河流相,异地埋藏类型。

Two known species of mayfly larvae from Trans- baikal of Russia, Mesobaetis sibirica Brauer, Redtenbacher et Ganglbauer, 1889 and Mesoneta antiqua Brauer, Redtenbacher et Ganglbauer, 1889, are actually absent in China although some Chinese paleoentomologists advocated that these have been discovered from China; and some Chinese stratigraphic and paleontological researchers thought that these would be helpful in arriving at a conclusions of the stratigraphic correlation and deducing the geological age. To date, however, the two species are exclusively present in Transbaikal of Russia during the Early Jurassic age. The familial and generic placements of all the species assigned, respectively, into the genera Mesobaetis Brauer, Redtenbacher et Ganglbauer, 1889 and Mesoneta Brauer, Redtenbacher et Ganglbauer, 1889 from China are questionable： Mesobaetis sibirica, M. sanjianfangensis Hong, Liang et Hu, 1995, M. maculata Hong, Liang et Hu, 1995, Mesoneta antiqua and M. beipiaoensis Wang, 1980. The assemblages of mayfly larvae in the Daohugou, Haifanggou, Jiulongshan and Sanjianfang formations are entirely different, and can not be correlated to each other. All mayfly larvae from the Jurassic-Lower Cretaceous of China are lacustrine rather than lotic.