Feathered fossil proves that birds did not evolve from dinosaurs

A foot-long lizard that glided through the trees of prehistory 220 million years ago has overturned an established theory of how birds evolved from feathered dinosaurs.

A foot-long lizard that glided through the trees of prehistory 220 million years ago has overturned an established theory of how birds evolved from feathered dinosaurs.

The lizard, which lived 75 million years before the first known bird, may have sported a set of feathers yet was not a dinosaur, a study published today has found.

Finding feathers on a lizard which belongs to the ancestral stock of dinosaurs suggests that these most bird-like of biological structures are far more ancient that anyone has until now realised.

The scientists who made the discovery, reported in the journal Science, believe the existence of a 220 million-year-old fossil with feathers blows a hole in the idea that birds are "living dinosaurs".

The research has focused on the fossils of Longisquama insignis, an archosaur - the group that gave rise to the dinosaurs, crocodiles and birds - that lived in the forests of what is now central Asia by probably jumping from tree to tree.

"These are some amazing fossils, and at the very least they prove that feathers did not evolve from dinosaurs," said John Ruben, professor of zoology at Oregon State University in Corvallis and a member of the research team. "The supposed link between dinosaurs and birds is pretty entrenched in palaeontology, but it's not as solid as the public has been led to believe."

Soviet scientists originally found the fossils in Kyrgyzstan in 1969 but they laid in a museum drawer in Moscow for many years after an initial examination concluded that two parallel rows of appendages on the back of the animal were scales, not feathers.

However, closer scrutiny of the "scales" by a team of Russian and American scientists found that they have several key features in common with feathers. The scientists found that the appendages had a long, thin tube or shaft running down their centre, with projections or "pinnae" extending from the sides of the base, just like modern feathers, but quite unlike reptilian scales.

Another feature is that Longisquama appears to have a feather growing in the same manner as modern feathers, where the pinnae unfurl inside a tube called a feather sheath.

The scientists believe that they have identified an unfurled pinna inside a sheath where the outer wall has flaked away. Larry Martin, another member of the team at the University of Kansas, said this was the factor that clinched it for him. "I'd been holding back until that point, thinking that these were unusual andfeather-like scales, but scales none the less. The results were startling," he said.

Feathers are so distinctive that it is unlikely they they had evolved more than once, Professor Ruben said. "A point that too many people always ignored, however, is that the most bird-like of the dinosaurs, such as Bambiraptor and Velociraptor, lived 70 million years after the earliest bird, Archaeopteryx," he said.

"So you have birds flying before the evolution of the first bird-like dinosaurs. We now question very strongly whether there were any feathered dinosaurs at all ... they were probably flightless birds."