'Sausage' feather fossils may reveal true colours of dinosaurs

London, July 9 : Palaeobiologists have found that 100-million-year-old fossilized bird feathers preserve microscopic colour-containing pouches, which when decoded, could reveal realistic colour patterns of the dinosaurs.

According to a report in New Scientist, Jakob Vinther, and colleagues Derek Briggs and Richard Prum, from Yale University in the UK, fired electron beams onto an unidentified bird feather fossil from Brazil to reveal precisely-arranged packets that colour plumage brown, black and grey.

"They look like small sausages, they're elongated and rounded at the edges," said Vinther. "We are quite confident that they aren't bacteria," he added.

The packets resemble similar structures on modern birds.

More rounded pouches make red and yellow plumage, while certain orientations create iridescent feathers. By analysing the shapes, orientations and density of these packets - called melanosomes - researchers may be able to colour fossilised feathers and even fur.

"We might able to get a palette of colours that we could assign to the fossils," said Vinther.

Working with Yale paleontologist Derek E. G. Briggs and Yale ornithologist Richard O. Prum, Vinther analyzed a striped feather found in 100 million-year-old rocks from the Lower Cretaceous Period in Brazil.

The team used a scanning electron microscope to show that dark bands of the feather preserved the arrangement of the pigment-bearing structures as a carbon residue - organized much as the structures are in a modern feather.

In another fossil of a bird from the Eocene Epoch - 55 million years ago - in Denmark there were similar traces in the feathers surrounding the skull.

That fossil also preserved an organic imprint of the eye and showed structures similar to the melanosomes found in eyes of modern birds.

"Of course, some dinosaurs boasted plumage, and their fossilised feathers have been discovered in China," said Kevin Padian, a palaeontologist at the University of California, Berkeley. "If these could be tested for the presence of melanosomes, it would be interesting," he said.

David Martill, a palaeontologist at the University of Portsmouth, UK, who discovered the fossilised bird feathers in Brazil and assumed bacteria made the stripes, agreed that the findings could lead to accurate colourings of ancient birds and even dinosaurs.

"Now that we have demonstrated that melanin can be preserved in fossils, scientists have a way to reliably predict, for example, the original colors of feathered dinosaurs," said Prum.

Knowing the colour of dinosaur plumage could reveal something about their daily lives and ecology, according to Vinther.

"We might also be able to tell whether they have sexual dimorphisms - whether males were more spectacularly coloured than females," he said.

ANI