Sanxiasaurus modaoxiensis
Sanxiasaurus was a genus of neornithischian dinosaur from the Middle Jurassic. The only specimen was found in the Xintiangou Formation of Yunyang, Chongqing Municipality, China. It is the oldest known neornithischian from Asia.
Its autapomorphies include at least four sacrals, a laterally bowed humerus, an obturator process located midway on the ischial shaft, a broadened and wing-shaped lesser trochanter of the femur, which is also subequal in anteroposterior width to the greater trochanter; and a distal tibia with elongate posterolateral process.
It is more basal than Lesothosaurus, but more derived than Hexinlusaurus. The holotype fossil consists of 55 postcranial bones, including vertebrae, both humeri, radii, and ulnas, and several leg bones.
Original paper: Ning Li, Hui Dai, Chao Tan, Xufeng Hu, Zhaoying Wei, Yu Lin, Guangbiao Wei, Deliang Li, Li Meng, Baoqiao Hao, Hailu You & Guangzhao Peng (2021) A neornithischian dinosaur from the Middle Jurassic Xintiangou Formation of Yunyang, Chongqing, China: the earliest record in Asia, Historical Biology, 33:7, 1089-1102, DOI: 10.1080/08912963.2019.1679129
Wikipedia article: https://en.m.wikipedia.org/wiki/Sanxiasaurus