All dinosaurs may have had feathers, researchers say, after a new fossil discovery suggests not just the avian dinosaurs, considered the direct ancestors of modern birds, displayed feathers alongside scales.
Fossilized feathers found on a newly identified species of dinosaur that was far off the evolutionary line heading towards birds may change our understanding of why and how feather first evolved, the scientists behind the discovery say.
The newly discovered dinosaur, dubbed Kulindadromeus zabaikalicus, was a plant eater living in the Jurassic period in what is now Siberia between around 175 million years and 145 million years ago.
It only grew to about 5 feet in length, and although it definitely had feathers there was nothing bird-like about it, says study leader Pascal Godefroit of the Royal Belgian Institute of Natural Sciences where he is head of life and earth sciences.
"It's impossible that they flew," he says. "They were bipedal and had long legs with very, very short arms."
Instead the two-legged dinosaur, most likely a fast runner, was a type of "ornithischian" or beaked dinosaur ancestrally distinct from the theropod group of "raptor" dinosaurs also considered the ancestors of all modern birds, the researchers said.
"Probably that means the common ancestor of all dinosaurs had feathers," Godefroit says. "Feathers are not a characteristic [just] of birds but of all dinosaurs."
Several partial skeletons of the new dinosaur, including six skulls along with numerous other bones, add considerably to the species of dinosaurs known to have sported feathers, the researchers say.
Still, in true dino fashion Kulindadromeus also possessed scales in rows along its fairly long tail.
A number of different feather forms, from primitive structures like hair or bristles to downy feathers similar to those found on modern birds, were found on the fossils, the researchers say.
They all provide new clues to a better understanding of feather evolution, as each type was different from those found on the fossils of flying reptiles or modern birds.
The exact purpose of the feathers is still unknown, admits paleontologist Jakob Vinther at the University of Bristol in Britain, who was not a part of the research team.
They may have been a form of insulation or used to signal other members of its species considered potential mates. But at this point, that's only speculation, the researchers say.
"I don't know; nobody knows for sure," Godefroit says. "These animals couldn't fly, that's all we can tell you."
