中文摘要：

Euestheria jingyuanensis（靖远真叶肢介）命名于甘肃靖远中侏罗统王家山组油页岩段,是广泛分布于我国中侏罗世E.ziliujingensis（自流井真叶肢介）群的重要分子之一,其壳瓣具有典型的小网状装饰。通过对E.jingyuanensis模式标本进行扫描电镜观察发现：其生长带上具有不规则的网状和线状装饰,与同属E.luanpingensis（滦平真叶肢介）,E.ziliujingensis等具有细小网状壳饰的种易于区分。E.jingyuanensis常与E.ziliujingensis等种共生,以前认为内蒙古宁城道虎沟层含有E.jingyuanensis,但目前看道虎沟层可能只含有E.luanpingensis。E.jingyuanensis壳瓣装饰超微结构的确定对Euestheria属的分类以及中侏罗统地层对比研究工作具有一定意义。

英文摘要：

Euestheria is a genus of conchostracans with elliptical, round or squarish carapaces. Its occurrence is widespread in Triassic-Jurassic strata, across various regions all over the world. Euestheria jingyuanensis yields in the oil shale member of the Middle Jurassic Wangjiashan Formation in Jingyuan, Gansu Province, China. It＇s an important member of the Euestheria ziliujingensis as- semblage which is widespread in Middle Jurassic continental beds in China. The ornamentations on the growth bands of E. jingyuanensis was originally described as typical small reticulations. How- ever, according to the SEM observation on the type specimens, it is characterized by irregular small reticulations and gradually change into linear alignment from the middle to ventral areas of the carapace. This kind of special ornamentations were considered as ornamental variation of the genus Euestheria and are quite different with the round reculate ornamentations of generitype E. minuta and E. ziliujingensis, E belong to the same genus. luanpingensis which It was considered that Euestheria jingyuanensis yields in Daohugou beds in Ningcheng, Inner Mongonia previously. But now, the conclusion tends to be that Daohugou beds may only contains E. luanpingensis according to the SEM observation researches of conchostraans from Daohugou. The defining of the micro arnamentations makes it easy to distinguish E. jingyuanensis and those from Daohugou and is sigaificant to the contrast work of the Middle Jurassic ：ontinental strata in China.DESCRIPTION Diplostraca Gerstaecker, 1866 Spinicaudata Linder, 1945 Eosestherioidea Zhang and Chen, 1976 Euestheriidae Defretin, 1965 Euestheria Deperet and Mazeran, 1912 Euestheria jingyuanensis Chen, 1976 Material The specimens are preseved in dark grey paper shales from upper part of the Oil shale member of Wangjiashan Formation, Dongsheng township, Jingyuan County, Gansu Province, housed in Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences （NIGP）.Holotype A complete specim