Feathers were a more common feature among dinosaurs than previously thought. The revision follows the discovery of feather-like structures on fossils from a plant-eating dinosaur that lived during the Jurassic period.
The new species, unearthed in Siberia, provided compelling evidence that a fuzzy plumage was not just a trait of the dinosaurs that gave rise to the first birds, but was also a feature of the other main group of dinosaurs.
The new Siberian species, named Kulindadromeus zabaikalicus, possessed ‘‘diverse epidermal appendages’’ that included grouped filaments, which an international team concluded were avian-like feathers.
‘‘This suggests that all Dinosauria could have had feathers,’’ said Pascal Godefroit, the lead palaeontologist from the Royal Belgian Institute of Natural Sciences.
But this suggestion is likely to get a few scientists in a flap. Last year several prominent palaeontologists dismissed the idea that all dinosaur groups had feathers.
Over the past two decades thousands of feathered dinosaur specimens, from about 40 species, have been unearthed, mainly in China.
But these fossils almost exclusively belong to a group of carnivorous dinosaurs called theropods, members of one of the two major branches of the dinosaur family tree.
Only two species from the other main group, plant-eaters known as the ornithischians, have previously been found with bristle or filament-like structures that may have been related to feathers.
John Pickrell, author of the recently released non-fiction book Flying Dinosaurs, said that based on this evidence, some scientists claimed feathers were not widespread across all dinosaurs.
But this new member of the ornithischians, which possessed both scales and filaments that were clearly feather-like structures, turned this idea on its head, Mr Pickrell said.
''This exciting discovery is possibly our best evidence to date that all dinosaur groups had feathers,’’ he said.
That K. zabaikalicus was a very early member of the Ornithiscian group to grow feathers meant it was likely its descendants would have sported them too, Mr Pickrell said.
Other members of this group include the duck-billed hadrosaur and the armoured stegosaurs.
Dr Godefroit and his colleagues, who published their findings in the journal Science, say the filament structures on the new species support the idea that dinosaurs developed primitive feathers first for insulation, then later used their plumage to attract mates. Most researchers believe feathers used for flying developed much later.
Mr Pickrell said it was also significant that this new species had been uncovered outside of China, where the vast majority of feathered dinosaurs had been discovered to date.
‘‘The fact that this was found in Siberia is really increasing the spread of feathered dinosaurs around the world,’’ he said.
