Beipiaosaurus /ˌbeɪpjaʊˈsɔːrəs/ is a genus of therizinosauroid theropod dinosaur from the Early Cretaceous of China. Before the discovery of Yutyrannus, it was among the largest dinosaurs known from direct evidence to be feathered. Beipiaosaurus, being considered to be a primitive therizinosauroid, has features which suggest that all therizinosauroids, including the more derived Therizinosauridae, to be coelurosaurian theropods, not sauropodomorph or ornithischian relatives as once believed.
Description
Beipiaosaurus measured 2.2 meters (7.3 ft) in length, and before the discovery of Yutyrannus is among the largest dinosaurs known from direct evidence to be feathered. The feet of Beipiaosaurus' still have reduced inner toes, showing that the derived therizinosaurid condition may have evolved from a three-toed therizinosauroid ancestor. Beipiaosaurus had a toothless beak with cheek teeth. The head was large relative to other therizinosaurs, with the lower jaw measuring about same length as the femur.