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根据一件产自云南罗平中三叠世关岭组II段的新标本并结合产自相同地点和地层中的模式标本对纤细滇美龙(Dianmeisaurus gracilis Shang&Li,2015)进行了详细研究。原模式标本暴露其腹面,而新标本暴露其背面,两者互相补充提供了更完整、精确的纤细滇美龙解剖学信息。新材料揭示该种具有非常短小的吻部,眶前区的长度不仅短于眶后区长度,甚至短于眼眶的长度;外鼻孔小且位置靠前,即鼻孔前区的长度短于鼻孔后缘与眼眶前缘之间的距离;由两额骨构成的眼眶间隔非常狭窄,宽度小于顶骨平台宽度的1/3;额骨前后两端均具渐尖的突起;顶骨后部不收缩,顶骨平台后缘呈深V型。补充了新信息和包含更多属种(如Dawazisaurus)后的系统发育学分析支持了之前滇美龙和滇东龙互为姊妹群的结论,同时它们和马家山龙、滇肿龙、贵州龙和大洼子龙一起构成了一个仅由中国的属种组成的单系类群。与欧洲肿肋龙类群(Dactylosaurus,Anarosaurus,Serpianosaurus和Neusticosaurus)相比,这一单系类群与幻龙类有更近的亲缘关系。
A detailed study of Dianmeisaurus gracilis Shang & Li (2015) was conducted based on a new specimen from Stage II of the Guanling Formation in Middle Triassic of Luoping, Yunnan Province, combined with model specimens from the same place and formation. The original model exposed its ventral surface, while the new specimen exposed its back, complement each other to provide a more complete and accurate slender Dior Aralon anatomical information. The new material reveals that this species has a very short snout. The length of the orbital anterior region is not only shorter than the length of the retro-orbital region, but is even shorter than the length of the orbit; the external nostril is small and forward, ie, the anterior nostril is shorter than the nostril Margin and orbital front of the distance between the two frontal orbital composition of the orbital space is very narrow, width less than the width of the parietal platform 1/3; forehead both front and back with acuminate protrusions; The trailing edge of the platform is deep V-shaped. Phylogenetic analyzes, supplemented by new information and inclusion of more genera (eg, Dawazisaurus), support the conclusion that Dianamonu and Dianlon were sister to each other, and that they were associated with Majiashan, Diancaolong, Guizhou Together with Dazu Long, it forms a monophyletic group consisting of only genera of China. This monophyletic group has a closer genetic relationship with the dinosaurs than the European swarm (Dactylosaurus, Anarosaurus, Serpianosaurus and Neusticosaurus).