Washington: Scientists at the Department of Energy``s SLAC National Accelerator Laboratory have discovered chemical traces of a pigment that gave colour to the feathers of first birds, around 100 million years ago, when their relatives, the dinosaurs, still ruled the Earth.
The pigment, eumelanin, is one of the colouring agents responsible for brown eyes and dark hair in many modern species, including humans. It would have been one of the factors that determined the birds`` colour patterns, along with structural properties of the birds`` feathers and other pigments they ingested as part of their diets.
"This is a pigment that evolved a very, very long time ago but is still actively synthesized by organisms on the planet, and we found a way to map it and show its presence over 120 million years of geological time passing," said geochemist Roy Wogelius of the University of Manchester, one of the leaders of an international team that reported the discovery.
"It is a direct relationship between you, me, and some extremely old organisms,” added Wogelius.
Working at SLAC``s Stanford Synchrotron Radiation Lightsource, the researchers examined two fossilized birds. Confuciusornis sanctus, which lived 120 million years ago, was one of many evolutionary links between dinosaurs and birds, sporting the first known bird-like beak. Gansus yumenensis, considered the oldest modern bird, lived more than 100 million years ago and looked a bit like a modern grebe.
The team looked for chemical traces of the pigments themselves with two sophisticated X-ray techniques developed at SSRL.
The research team was faced with a mind-boggling conclusion: They had seen actual colour patterns in the fossil bird feathers.
"There is a stunningly remarkable preservation of pigments," said Wogelius.
"These new techniques for teasing out evidence of pigmentation will take a lot of the guesswork out of reconstructing the appearance of extinct dinosaurs and birds," said renowned dinosaur illustrator James Gurney, author of the best-selling Dinotopia series.
The study id detailed in Science Express.