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本文研究了采自甘肃宝积山盆地中侏罗统新河组的叶肢介化石,经室内鉴定为椭圆真叶肢介(Euestheria fabiformis)和靖远真叶肢介(Euestheria jingyuanensis),两者均为我国中侏罗世自流井真叶肢介(Euestheria ziliujingensis)动物群的重要分子。椭圆真叶肢介主要特征为壳瓣小,长椭圆形,腹缘呈宽弧状拱曲,生长带窄而密集,后端在壳顶之后依次与背缘明显相交,交角相对较大,生长带上具有较小的不规则的网孔状装饰。而靖远真叶肢介主要特征为壳瓣中等大小,呈不规则的卵形,生长带后端与背缘相汇于一点,靠近腹缘的生长带较窄,有线状装饰,其他部位的生长带有不规则的网孔状装饰。甘肃宝积山盆地叶肢介化石的研究,进一步补充了研究区中侏罗世叶肢介的化石记录,表明中侏罗世时期沉积环境有利于叶肢介的生长。
In this paper, the leaf-shaped fossils collected from Xinhe Formation of the Middle Jurassic in the Bajingshan Basin of Gansu Province were identified as Euestheria fabiformis and Euestheria jingyuanensis in the laboratory, All of them are important molecules of the Euestheria ziliujingensis fauna in the Middle Jurassic Artesian well. The main characteristics of the elliptic true exoteric limbs are small, long oval shell, wide arc arch arches, with narrow and dense growth, the back end of the shell top followed by the back edge of the obvious intersection angle is relatively large, growth zone On the smaller irregular mesh-like decoration. The main characteristics of Jingyuan really leaf limb mediated shell size, was irregular oval, with the back of the growth zone and the back edge of the phase at a point near the growth of the abdominal margin with a narrower, linear decoration, the other parts of the Growing with irregular mesh-like decoration. The study of leaf-shaped fossils in the Bajishan basin of Gansu Province further complements the fossil record of the Middle Jurassic limbs in the study area, indicating that the sedimentary environment during the Middle Jurassic was favorable for the growth of leaf-limbs.