鄂尔多斯盆地下白垩统志丹群产出丰富的四足类动物化石:龟类、离龙类、鳄形类、鹦鹉嘴龙类、剑龙类、甲龙类、兽脚类、鸟类和早期哺乳类.采自内蒙古杭锦旗老龙豁子志丹群罗汉洞组剑龙类关联的荐椎与肠骨化石新标本,其形态特征显示该标本可被归为鄂尔多斯乌尔禾龙(Wuerhosaurus ordosensis).该标本解剖学研究表明,鄂尔多斯乌尔禾龙腰带还具有以下特征:上髋臼面前缘向后凹而后缘内侧更加内凹.鄂尔多斯乌尔禾龙(Wuerhosaurus ordosensis)和新疆准噶尔盆地的平坦乌尔禾龙(Wuerhosaurus homheni)在腰带上存在明显区别:①鄂尔多斯乌尔禾龙肠骨前突延伸较短,肠骨前突背缘向后逐渐向背侧拱曲、高度逐渐加大,而平坦乌尔禾龙肠骨前突后端背腹缘大致平行;②鄂尔多斯乌尔禾龙上髋臼面较小;③鄂尔多斯乌尔禾龙左右肠骨前突延伸方向与中轴线之间的夹角略小于平坦乌尔禾龙.这些区别进一步表明,鄂尔多斯乌尔禾龙和平坦乌尔禾龙是不同的种.%The Early Cretaceous Zhidan Group in the northern Ordos Basin of Inner Mongolia yielded a large number of tetrapods, which included turtles, choristoderes, crocodyliforms, psittacosaurs, stegosaurs, ankylosaurs, theropods, birds and primitive mammals. A well-preserved stegosaurian sacrum with paired ilia found from the Luohandong Formation, a middle-upper unit of Zhidan Group, is referred to as Wuerhosaurus ordosensis. The new findings give some additional characteristics to the pelvic girdle in W. ordo?sensis, such as both concave anterior margin and concave medio-posterior margin of the supra-acetabular flange. Based on compari?son of Wuerhosaurus ordosensis with W. homheni known from Xinjiang, the authors point out the differences in ilia between the two species:①a relatively short anterior iliac process in W. ordosensis;②the anterior iliac process with arched posterior portion of the dor?sal margin in W. ordosensis, and anterior iliac process with nearly parallel dorsal and ventral margins in W. homheni; ③the relatively small angle between anterior iliac processes and midline in W. ordosensis. These characteristics further provide the evidence that W. or?dosensis and W. homheni are different species.
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