Wednesday, July 09, 2008

Fossil Feather Colors

A group of scientists claim that they have found a way to determine the colors of fossilized feathers. The feathers used in the study are from a 100 million year-old specimen found in Brazil. The fossil itself (see right) shows dark and light contrasting bands.

Microscopic analysis of the dark bands showed they displayed a distinctive granular texture, made from thousands of tiny, densely-packed flattened spheres.

Researchers had previously interpreted these as fossilised bacteria, preserved as the feathers decomposed.

But analysis of modern birds' feathers showed a similar structure.

"There are particular cells that cluster into the dark areas of modern birds called melanosomes," explained Dr Benton.

"Somehow [the melanosomes] are retained and replaced during the preservation process and hence you preserve a very life like representation of the colour banding [in the fossils]."

Lighter areas in the fossils did not show the same textures, leading the team to conclude that the feathers once displayed distinct black and white stripes.
Apparently other colors in modern birds also have distinctive patterns when viewed under a microscope. If so, potentially palaeontologists could reconstruct more intricate feather patterns than just black and white (or dark and light). The methods should also work with materials other than feathers, such as fur.