GeoMedia: Fossilized Bird Pigments

A recent groundbreaking palaeontological discovery was made by researchers from the University of Manchester that will allow us to find out what extinct organisms actually looked like. Most of our reconstructions of extinct organisms are accurate from an anatomical perspective, but are more or less just guesses when it comes to what colours the animals were. However, this new discovery, which used a 120 million year old fossil bird feather from the extinct bird Confuciusornis sanctus actually detected a fossilized chemical signature of pigments in the feather. This is the first time we have found fossilized pigments and will allow palaeontologists to accurately depict the colouring of extinct animals, which was never before possible.

Confuciusornis sanctus

The research paper, titled, Trace Metals as Biomarkers for Eumelanin Pigment in the Fossil Record was published in the prestigious journal Science last week. The authors used a very interesting technique to find the presence of the eumelanin pigment in the fossilized feather. This technique was synchrotron analysis of the feather. A synchrotron, despite the Star Trekkie sounding name, is a useful piece of analytical equipment that can determine chemistry without destroying the sample. It basically takes an "x-ray" of the sample using electrons that have been accelerated close to the speed of light. This allows researchers to examine the detailed chemistry of sensitive materials that would otherwise be impossible. 

A schematic of a synchrotron (University of Saskatchewan)

The results suggest that Confuciusornis sanctus, a bird that lived 120 million years ago in the Cretaceous had dark areas on its body and tail feathers. This conclusion was determined by using the synchrotron to analyse for organic copper that is commonly found in the pigment eumelanin. Eumelanin is a dark coloured pigment found in feathers, fur and skin. Using the synchrotron the researchers found copper on the bird's body and tail feathers suggesting that these were once coloured by eumelanin. Using other techniques the researchers were able to say that the copper had indeed come from organic molecules proving that it was part of fossilized pigment. 

A blue jay feather, squid, and fossil fish with feather are shown in optical images (top) and X-ray images (bottom)showing the distribution of copper (red). Copper in the dark parts of the feathers, the fish eye, and the squid ink sack indicates the presence of eumelanin pigmentation.Phil Manning, Nick Edwards, Holly Bardeon/University of Manchester; SSRL; SLAC (cbc.ca)

This discovery is of great importance not only in reconstruction what extinct animals actually looked like, but also in understanding their behaviour. In the modern world animals use colour for camouflage, hunting, mating displays, etc. We assume that these behavioural characteristics were evolved in the pre-historic world but there was no way to confirm this. Further advances in these techniques and this research may allow us to do just that. 


Here is the CBC story that drew my attention to the article and here is the abstract from Science.