X-rays reveal ‘dinobird’ shook patterned tail feather

Using X-rays to complete the first chemical analysis of feathers from a fossil linking dinosaurs and birds reveals that the feathers were patterned rather than all black as was previously assumed.

The team from University of Manchester worked with colleagues at the US Department of Energy’s (DOE) SLAC National Accelerator Laboratory to find chemical traces of the original ‘dinobird’ Archaeopteryx and dilute traces of plumage pigments in the 150 million year old fossil.

“This is a big leap forward in our understand of the evolution of the plumage and also the preservation of feathers,” said Dr Phil Manning, a palaeontologist at The University of Manchester and lead author of the paper published in the Journal of Analytical Atomic Spectrometry.

Only 11 specimens of Archaeopteryx have ever been discovered and until a few years ago, scientists assumed minerals would have replaced all the bones and tissues of the original creature during fossilisation, leaving behind no chemical traces. But recently discovered methods have revealed more information about the prehistoric creature and its plumage.

The first is the discovery of melanosomes – the structures in which pigment was once made, but is still visible in some rare fossil feathers. When a team at Brown University analysed melanosomes in a fossil of a single Archaeopteryxfeather, they concluded it was black.

However, that study examined melanosomes in just a few locations in the fossilised feather.

“It’s actually quite a beautiful paper, but they took just tiny samples of the feather, not the whole thing,” said SLAC’s Dr Uwe Bergmann.

So Bergmann and colleagues developed a method for rapidly scanning entire fossils and analysing their chemistry with an X-ray beam.

Over the past three years, the researchers have used this technique to discover chemical traces in the dinobird’s bones and feathers as well as pigments from the fossilised feathers of another species of early bird. For the first time, the team were able to recreate the plumage pattern of an extinct bird.

In the latest research, the team scanned the entire Archaeopteryx feather fossil with the X-ray beam to find trace-metals associated with pigment and organic sulphur compounds that could only have come from the animal’s original feathers.

Together, these chemical traces show that the feather was light in colour with areas of darker pigment along one edge and on the tip,” said Dr Manning. “The fact that these compounds have been preserved in-place for 150 million years is extraordinary.”