The tail of Sinosauropteryx was provided with a reddish-brown striped pattern. Credit: Original artwork copyright © Jim Robbins.
An international team of researchers has for the first time revealed the secret of the color of the dinosaurs: In fossil feathers of the lynx dinosaur Sinosauropteryx and several other species, the scientists discovered remains of pigment cells that are responsible for the coloration and on the plumage clearly outlined patterns. According to the new findings, for example, the Sinosauropteryx should have been noticed by a reddish brown and white striped tail. The conspicuous coloration and the fact that the feathers did not cover the whole body support a much-discussed theory that springs did not originally develop as either cold protection or flying aid. Rather, they would have served the courtship, suspect the researchers around Michael Benton from the University of Bristol. The feathers of Sinosauropteryx, also known as the Chinese Lizard Wing, and other feathered dinosaurs are a kind of prototype: the tubular constructs have not yet been divided into shafts, branches and rays, as was the case with birds. With the aid of a scanning electron microscope, Benton and his colleagues now examined the fossil feathers of a sinosauropteryx and some other feathered dinosaurs and primitive birds that were discovered in the well-known Jahol group in northeastern China. In their investigations, the researchers found so-called melanosomes, components of the pigment cells, which are responsible for the coloring of skin, hair or feathers.

Although the discovered structures could in principle have been very similar-looking bacteria. However, the researchers excluded this because the tiny cell organs in their arrangement form clearly demarcated patterns? both on the individual feathers and in relation to the entire plumage. In the case of a bacterial lawn, there would have been no reason for such a sharp demarcation, say the scientists. In addition, the mini-organs had formed no superficial coating, but were firmly connected to the spring structure, similar to feathers of already extinct and still living bird species. This property is probably the reason why the melanosomes are still so well after 120 to 131 million years.

The researchers were unable to determine the color of the feathers down to the last detail. However, they discovered in them the two pigment types Eumelanin and Phäomelanin: Eumelanin produces brownish-black shades, while Phäomelanin is responsible for the yellow to red color palette. Benton and his team conclude that the stripes of Sinosauropteryx were reddish brown, while, for example, the plumage of the prehistoric bird Confuciusornis may have had white, black and orange brown spots.

Michael Benton (University of Bristol) Nature, online pre-publication, doi: 10.1038 / nature08740 ddp / Mascha Schacht advertisement


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