A new basal eusauropod from the Middle Jurassic of Yunnan, China, and faunal compositions and transitions of Asian sauropodomorph dinosaurs
Many sauropod ghost lineages cross the Middle Jurassic, indicating a time interval that requires increased sampling. A wide taxonomic spectrum of sauropodomorphs is known from the Middle Jurassic of China, but the braincase of a new sauropod, named here Nebulasaurus taito gen. et sp. nov., is distinct. Nebulasaurus is sister taxon to Spinophorosaurus from the Middle Jurassic of Africa and represents a clade of basal eusauropods previously unknown from Asia. The revised faunal list indicates dramatic transitions in sauropodomorph faunas from the Jurassic to Cretaceous of Asia; these are consistent with geographic isolation of Asia through the Late Jurassic. Non-sauropod sauropodomorphs, non-mamenchisaurid eusauropods (including basal macronarians), and mamenchisaurids successively replaced previous grades through the Jurassic, and titanosauriforms excluded all other sauropod lineages across the Jurassic–Cretaceous boundary.
Key words: Dinosauria, Sauropoda, Eusauropoda, Jurassic, China.
Lida Xing [firstname.lastname@example.org] and Jianping Zhang [email@example.com], School of the Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China; Tetsuto Miyashita [firstname.lastname@example.org] and Philip J. Currie [email@example.com], Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E9 Canada; Hailu You [firstname.lastname@example.org] Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China; Zhiming Dong [email@example.com], Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China.
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