By Jacqueline Ali
BBC News Online
The fossilised brain of a 150 million- year-old bird has given up the secret of whether or not the creature could fly: apparently it could, say experts.
Did Archaeopteryx ever take off? (Image: John Sibbick)
Hi-tech scanning equipment was used to X-ray the brain case of the Jurassic era bird, called Archaeopteryx.
It revealed structures similar to those that modern birds use for flight and balance, the study in Nature reports.
This adds significant weight to the popular theory that the birds' wings were used for more than just flapping.
Since the discovery of the first Archaeopteryx fossil in 1861, the species has been a source of some contention among the palaeontology community.
The carnivorous bird, which measured a maximum of around 50cm with wings outstretched, had features that were both dinosaur-like and bird-like in nature.
It had the distinctly avian characteristic of being feathered, yet also had teeth and clawed hands.
Until now, little was known about the inner workings of the ancient creature.
But Dr Angela Milner, of the Natural History Museum in London, used a state-of-the-art scanning method called computed tomography scanning to take X-rays of the preserved brain case.
The equipment, which was provided by the University of Texas, Austin, US, enabled the scientist to view extremely fine slices of the precious specimen.
The images were then converted into a 3D reconstruction of the brain case and inner ear using a computer.
The results surprised even the experts.
"We were fully expecting to find a dinosaur like brain," Dr Milner told BBC News Online. "Instead, it was completely bird-like."
The computer-generated image revealed that the anatomy of the brain corresponded very closely with that of modern flying birds.
It revealed well-developed semicircular canals in the inner ear, which are used for balance, and enlarged optic lobes for vision. Both essential features for efficient flight.
"The brain scan basically showed that the Archaeopteryx had all of the structures that allow birds to fly," added Dr Milner.
The findings present fairly conclusive evidence that Archaeopteryx was once airborne, according to the lead researcher.
Dr Milner commented: "This all suggests that the development of the bird brain goes hand in hand with that of the physical structures, e.g. the wings, that allow it to fly.
"In fact, the brain is so bird-like, that the flying process must have evolved much sooner than anyone thought."
Dr Graham Taylor, an expert in animal flight dynamics at Oxford University, said the paper was "very exciting".
"The findings are consistent with what we know about Archaeopteryx flight," he commented.
"But this sheds a lot of light on the evolution of the brain.
"Its regional development is similar to that of modern birds. But, as you might expect for a transitional form, the brain as a whole remains relatively small."
Researchers will now examine fossils of other birds to look for further evidence of early flight. However there are no fossils that predate the study specimen, which has now been returned to its home in the Natural History Museum.
There are just six Archaeopteryx fossils in existence, and one feather sample.