Researchers closely examined 29 feather samples from the dinosaur and measured melanosomes (cellular organelles that contain melanin) within the feathers. A statistical analysis of how those melanosomes compared to the types known to create particular colors in living birds allowed scientists to discern with 90 percent certainty the colors of individual feathers and, therefore, the colorful patterns of an extinct animal.
"This means a color-patterning function — for example, camouflage or display — must have had a key role in the early evolution of feathers in dinosaurs, and was just as important as evolving flight or improved aerodynamic function," said University of Texas at Austin Professor Julia Clarke.
Unlike recently published work from China that inferred the existence of two types of melanin pigments in various species of feathered dinosaurs, the new study analyzed melanosomes from an entire fossil of a single animal, a feat which enabled researchers to reveal rich color patterns of the entire animal.
In fact, the analysis of melanosomes allowed the researchers to assign colors to individual feathers of Anchiornis huxleyi, a four-winged troodontid dinosaur that lived during the late Jurassic period in China. This dinosaur sported a generally gray body, a reddish-brown, Mohawk-like crest and facial speckles, and white feathers on its wings and legs, with bold black-spangled tips.
"This was no crow or sparrow, but a creature with a very notable plumage," said Richard O. Prum, chair and the William Robertson Coe Professor of Ornithology, Ecology and Evolutionary Biology at Yale. "This would be a very striking animal if it was alive today."
The color patterns of the limbs, which strongly resemble those sported by modern day Spangled Hamburg chickens, probably functioned in communication and may have helped the dinosaur to attract mates, suggested Prum.
Citation: Li et al., 'Plumage Color Patterns of an Extinct Dinosaur', Science, February 2010; doi: 10.1126/science.1186290