Eshanosaurus

coelurosaur

Lower Lufeng Formation in Yunnan, dating to Hettangian stage. The specimen is in the collection of the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, where it is catalogued under accession number IVPP V11579.^[1]

prosauropods or basal Sauropodomorpha.^[2] Xu, Zhao and Clark, however, had examined the possibility that Eshanosaurus was a prosauropod, given that it was found below numerous fossils of Lufengosaurus, a prosauropod of which the lower jaw closely resembles in general shape that of a therizinosaur. The authors arrived at their conclusion that the specimen represented an Early Jurassic therizinosauroid, by testing the possibility that it were a basal sauropodomorph as rigorously as they could using the comparative method: the six traits found were those shared between Eshanosaurus and therizinosaurs to the exclusion of prosauropods.^[1]

Paul M. Barrett again examined the question of Eshanosaurus classification. Barrett examined the type specimen in detail, noting six features shared with therizinosaurs but not shown by prosauropods. Barrett concluded by agreeing with the original interpretation, that Eshanosaurus is a therizinosaur, and that its presence in the early Jurassic has important implications for the evolutionary history of coelurosaurs, notably, that large portions of the coelurosaur fossil record remain missing.^[3]