An early feathered nonavian dinosaur was recently described by Hu et al. (2009) from the late Jurassic, China. This small but extremely well-preserved fossil exhibits feather impressions adjacent to the head, arms, legs, tail, trunk and even feet of the animal. Because Anchiornis is basal to Archaeopteryx and all other currently known feathered dinosaurs, it lends support to the hypothesis that dinosaurs are the ancestors of birds.
Hu, D., Hou, L., Zhang, L. and Xu, X. 2009. A pre-Archaeopteryx troodontid theropod from China with long feathers on the metatarsus. Nature. 461:640.