Sinosauropteryx
Three specimens have been assigned to "Sinosauropteryx prima": the holotype GMV 2123 (and its counter slab [opposite face], NIGP 127586), NIGP 127587, and D 2141. Another specimen, IVPP V14202, was assigned to the genus but not to the only species by Zhang and colleagues. The assignment of an additional larger specimen to "S. prima", GMV 2124, was later found to be in error. All of the fossils were found in the Jianshangou or Dawangzhangzi Beds of the Yixian Formation in the Beipiao and Lingyuan regions of Liaoning, China. These fossil beds have been dated to 124.6–122 million years ago, during the early Aptian stage of the Early Cretaceous.
Sinosauropteryx
Longrich's conclusions were supported in a paper first published online in the journal "Nature" in January 2010. Fucheng Zhang and colleagues examined the fossilized feathers of several dinosaurs and early birds, and found evidence that they preserved melanosomes, the cells that give the feathers of modern birds their colour. Among the specimens studied was a previously undescribed specimen of "Sinosauropteryx", IVPP V14202. By examining melanosome structure and distribution, Zhang and colleagues were able to confirm the presence of light and dark bands of colour in the tail feathers of "Sinosauropteryx". Furthermore, the team was able to compare melanosome types to those of modern birds to determine a general range of colour. From the presence of phaeomelanosomes, spherical melanosomes that make and store red pigment, they concluded that the darker feathers of "Sinosauropteryx" were chestnut or reddish brown in colour. More research on the coloration of "Sinosauropteryx" reveals that it had a raccoon-like bandit mask and countershading patterns most likely associated with an open habitat, indicating that the Jehol likely had a range of habitat types.