云南禄丰川街盆地早侏罗世早期分化蜥脚型类恐龙新材料研究*

目前中国早期分化的蜥脚型类恐龙化石主要发现于云南省禄丰市早侏罗世地层。本文描述的是一件产自禄丰川街盆地禄丰组的早期分化蜥脚型类恐龙新材料, 包括较完整的颈椎、背椎以及破碎的肩胛骨、耻骨和脚趾骨骼。本文对其进行了详细的骨骼形态学描述, 并与其他早期分化蜥脚型类进行了对比。结果表明, 在禄丰组发现的所有早期分化蜥脚型类中, 该标本与禄丰龙(Lufengosaurus)在形态上相似程度较高。系统发育分析结果显示, 该标本与Coloradisaurus和Glacialisaurus构成一个多分支, 该分支又和禄丰龙一起被归入大椎龙科。由于颈椎和背椎的椎体与椎弓未完全愈合, 推测该标本的个体发育阶段为幼年—亚成年。该标本的发现提高了大椎龙科在亚洲的属种分异度, 进一步扩充了对禄丰早侏罗世恐龙动物群的认识。

A new specimen of the early-branching sauropodomorph dinosaur from the Chuanjie Basin, Lufeng, Yunnan Province

At present, early-branching sauropodomorph dinosaurs from China are mainly discovered in the Lower Jurassic in Lufeng, Yunnan Province. A new specimen of the early-branching sauropodomorph from the Lufeng Formation of the Chuanjie Basin, Lufeng, including relatively complete cervical and dorsal vertebrae as well as a broken scapula, pubes and pedal elements, is described here. The osteological morphology of the new specimen is described in detail and compared with other early-branching sauropodomorphs. The specimen is more similar to that of Lufengosaurus than to other early-branching sauropodomorphs from the Lufeng Formation. Phylogenetic analysis recovers this specimen as a part of a polytomy with Coloradisaurus and Glacialisaurus, and they are referred to Massospondylidae along with Lufengosaurus. The unfused centrum and neural arch of the cervical and dorsal vertebrae of the new specimen indicate that the ontogenetic stage of this individual is juvenile–subadult. This discovery increases the diversity of Massospondylidae from Asia, and expands our knowledge of the Lufeng dinosaur fauna.