Study Offers an Insight Into Dinosaur Colors
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What color were dinosaurs? Well, at least one of them had a feathered mohawk tail in a subdued palette of chestnut and white stripes.
That is what a team of Chinese and British scientists reported Wednesday in Nature, providing the first clear evidence of dinosaur colors from studies of 125-million-year-old fossils of a dinosaur called Sinosauropteryx.
"We might be able to start painting a picture in color of what these things looked like," said Lawrence M. Witmer, a paleontologist at Ohio University, who was not involved in the study.
Of course, such pictures have been painted many times, but the colors were products of a painter's imagination, not a scientist's laboratory.
Dinosaur fossils are mostly drab collections of mineralized bones. A few preserve traces of skin, and fewer still preserve structures that many scientists have argued are feathers.
In the new study, Michael Benton, a paleontologist at the University of Bristol, and colleagues have analyzed the structures of what appear to be feathers and say they match the feathers of living birds down to the microscopic level. They used microscopic features to determine the ancient feathers' color. The study builds on earlier work on fossil bird feathers by Jakob Vinther, a graduate student at Yale, and his colleagues. In 2006, Mr. Vinther discovered what looked like an ink sac preserved in a squid fossil. Putting the fossil under a microscope, he discovered the sac was filled with tiny spheres. The spheres were identical to pigment-loaded structures in squid ink, known as melanosomes.
Mr. Vinther knew that melanosomes created colors in other animals, including bird's feathers. He and his colleagues made a microscopic inspection of fossils of feathers from extinct birds. They discovered melanosomes with the same sausage-shaped structure as those found in living birds. By analyzing the shape and arrangement of the fossil melanosomes, they were able to get clues to their original color. They determined, for example, that a 47-million-year-old feather had the dark iridescent sheen found on starlings today.
First Published January 28, 2010 2:00 am
