More feathered dinosaurs from China

The exceptional preservation of fossil specimens in the Yixian formation in northeastern China has shown that there may have been many more feathered dinosaurs than we first thought. The newly discovered Sinornithosaurus millenii has fibrous structures which appear to be evolutionary precursors of feathers. Similar features were found in 1996 on another dinosaur called Sinosauropteryx, and two others have been found in the same area. Many of these discoveries have been made by a team headed by Xiao-Chun Wu, a geologist with Beijing's Institute of Paleontology and Paleoanthropology and the University of Calgary.

Sinornithosaurus is significant because it belongs to the family called dromaesaurids, which includes the Velociraptors of Jurassic Park fame. Many paleontologists believe that the dromaesaurids were the closests ancestors of the birds. Sinornithosaurus has a shoulder socket pointing outward from the body, which could have facilitated bird-like movement of the fore-limb.

Sinornithosaurus is now the fifth type of theropod dinosaur to posses feather-like features. A detailed study of anatomical features shows that the dromaesaurid group is the one which is most closely related to birds.

Reference

Xing Xu, Xiao-Lin Wang and Xiao-Chun Wu, A dromaesaurid dinosaur with a filamentous integument from the Yixian Formation of China, Nature, V. 401, p. 262-266 (September 16, 1999)