February 5, 2010
For the first time ever, paleontologists can look at dinosaurs in color.
In last week’s issue of the journal Nature, scientists described the discovery of melanosomes, biological structures that give feathers their color, in the wispy “dinofuzz” of the small theropod Sinosauropteryx. Not only did this provide unequivocal evidence that the dinosaur had a downy coat of feathers, but the presence of the microscopic structures provided scientists the potential to find out what color those feathers were.
When I read the Nature study I wondered how long it would be before scientists would be able to find a way to conclusively determine the colors of feathered dinosaurs from their preserved melanosomes. As it turned out, I would only have to wait a week. In this week’s issue of Science, a second team of scientists has restored a recently-discovered feathered dinosaur, Anchiornis huxleyi, in living color.
As described in last week’s study there are two major varieties of melanosomes: eumelanosomes (associated with black-grey shades) and phaemelanosomes (indicative of reddish to yellow tints). Both of these kinds of structures can be seen in the fossilized feathers of exquisitely-preserved dinosaurs, but the question is how they corresponded to the actual colors of the animal. The melanosomes cannot speak for themselves; they require a key to unlock what colors might have been present.
Acquiring that key was a two-step process. To figure out how melanosomes were distributed across the plumage of Anchiornis, the team behind the Science paper took 29 chips from different parts of a well-preserved specimen. Each chip had a different combination of melanosomes, and to translate these associations into colors the team turned to the closest living relatives of dinosaurs like Anchiornis, birds. By looking at how melanosomes create colors in these modern dinosaurs the scientists could determine how different mixes creates different tints and shades.
While the restoration of Anchiornis the team produced is still provisional, it is the first time that scientists have been able to hypothesize the full coloration of a dinosaur on direct fossil evidence. According to the new research, Anchiornis would have been mostly black with white accents on its wings (which it carried on both its arms and legs). Its head, however, would have been a little more brightly colored. It appears that Anchiornis had a burnt-orange headdress and freckles, possibly meaning that these bright colors played a role in communicating to other birds. (Which makes me wonder if, like modern birds, colors differed between the sexes.)
And this is just the start. In the past decade paleontologists have described dozens of species of feathered dinosaurs from hundreds of known specimens. There is a vast store of paleobiological information just waiting to be tapped, and it will literally change the way we see dinosaurs.
Li, Q., Gao, K., Vinther, J., Shawkey, M., Clarke, J., D’Alba, L., Meng, Q., Briggs, D., Miao, L., & Prum, R. (2010). Plumage Color Patterns of an Extinct Dinosaur Science DOI: 10.1126/science.1186290
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