March 30, 2010

What’s Black and White and Red All Over?

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Although extinct for 65 million years, dinosaurs find themselves deeply imbedded in popular culture. Dinosaurs project strong imagery, along the lines of a Jurassic Park chase scene. Audiences rarely think of dinosaurs with bright feathers.

However, recent Yale research shifted this dinosaur imagery, determining the true colors of the feathered dinosaur, Anchiornis huxleyi.

“Visitors to the museum always want to know what color dinosaurs really were, but the answer is we don’t know. We know about the texture of their skin, about their internal organs, and even senses from small fossils of brain, but not color,” said Prof. Warren Allmon, earth and atmospheric science. Allmon is director of The Museum of the Earth.

Texts in the ’70s and ’80s painted dinosaurs with dull greens and grays, reflecting patterns in modern reptiles. In the past 20 years, new evidence of the relationship between birds and reptiles drew new attention, transforming dinosaurs into “Mardi Gras, based on nothing,” explained Allmon.  

The Yale research, based on a lake fossil deposit in China, aimed to produce the first accurate depiction of the extinct dinosaur, Anchiornis huxleyi. As Yale graduate student and key researcher in the discovery, Jakob Vinther explained, the team studied fossilized cellular structures, pigment-containing “melanosomes,” to determine the true color of Anchiorinis.   

“Melanin has a chemical property that makes it possible to fossilize under certain circumstances. This is a bit like when plant matter transforms into coal,” said Vinther. The fossilization process preserved the melanosomes in certain shapes, allowing the team to infer the original color.

Yale researchers compared the fossilized melanosomes of Anchiornis to the melanosomes of modern birds. Melanosomes have different combinations of shapes for given colors. 

For red, hair pigments are shaped like meatballs; for black, they are shaped like sausages. Therefore, Anchiornis likely possessed bright red, black and white plumage.

The eventual objective of this research aims to expand this analytical approach to other dinosaurs. “The goal is to eventually be able to create textbooks with dinosaurs’ original color,” said Vinther.

In addition to describing dinosaurs’ appearances, this research generates information about the behavioral and evolutionary significance of dinosaur plumage.

“Sex drove evolution towards flying,” said Vinther. Feathered dinosaurs likely used their simple, bright plumage to attract mates. However, eventually, the influence of natural selection altered the early feathers, which evolved to perform functions in flight. Eventual increase in feather surface area likely allowed dinosaurs to fly.

According to Allmon, the most remarkable part of this research lies in the source. He said, “It is a neat discovery, not because of color, but because of the extraordinary quality of the tiny structures preserved.”

Original Author: Tajwar Mazhar