A new eusauropod (Dinosauria, Sauropodomorpha) from the Middle Jurassic of Gansu, China.

Sauropod dinosaurs were gigantic quadrupedal herbivores. They range from Early Jurassic to Late Cretaceous and have been found on all continents. The rich sauropod faunas in the Middle and Late Jurassic of China are mainly from southern or western China. Here, we describe a non-neosauropod eusauropod from the Middle Jurassic Xinhe Formation of Gansu Province, northwestern China, based on an associated partial skeleton that includes a nearly complete skull with mandible, the five anteriormost cervical vertebrae appressed with the skull and the posterior 29 articulated caudal vertebrae. It can be diagnosed as a new taxon Jinchuanloong niedu gen. et sp. nov. based on several cranial and postcranial autapomorphies. In Jinchuanloong, the posterior margin of the external naris lies in front of the posterior margin of the antorbital fenestra, similar to that in basal eusauropods, and the base of the maxillary ascending process presents a foramen, similar to that in neosauropods. The finding of Jinchuanloong adds diversity and helps elucidate the evolution of the sauropods in East Asia.