Two feathered dinosaurs from northeastern China

Current controversy over the origin and early evolution of birds centres on whether or not they are derived from coelurosaurian theropod dinosaurs. Here we describe two theropods from the Upper Jurassic/Lower Cretaceous Chaomidlanzi Formation of Liaoning province, China. Although both theropods have feathers, it is likely that neither was able to fly. Phylogenetic analysis indicates that they are both more primitive than the earliest known avialan third), Archaeopteryx. These new fossils represent stages in the evolution of birds from feathered, ground-living, bipedal dinosaurs.