Feathered dinosaurs may have been the rule, not the exception

Dinosaurs may have all bundled up in flashy feather coats.

The skulls and bones of a new dinosaur species unearthed in Siberia support what some scientists have suspected: Dinosaurs with feathers were probably the norm.

“For the first time we have a feathered dinosaur that is far from the lineage leading to birds,” says study author Pascal Godefroit, a paleontologist at the Royal Belgian Institute of Natural Sciences in Brussels. “It means that all dinosaurs were potentially covered by feathers.”

Paleontologists had previously dug up fossil evidence of feathers that adorned dinolike birds of the Archaeopteryx genus and other more ancient avian ancestors. These include one dinosaur recently discovered to have a fluffy, feathery tail. Its finders held the creature as proof that every dinosaur could have worn feathers (SN Online: 7/2/12). But the dinos were all theropods — a group of bird forebears that also includes the massive meat eaters T. Rex and Megalosaurus.

Whether all dinosaurs or just avian relatives flaunted feathers has been up for debate. In recent years, scientists have found evidence of bristle- and quill-like strands — perhaps early versions of feathers — that speckled the hides of ornithischian dinosaurs. This herbivorous group is more distantly related to birds than theropods. But these fibers aren’t clearly feathers, says Godefroit.

He believes the structures sprouting from his team’s newly discovered dinosaur species are. Excavations revealed hundreds of skeletons and six partial skulls of the Jurassic-era dinosaur Kulindadromeus zabaikalicus lying sandwiched between layers of volcanic rock at the bottom of what was probably once a shallow lake.

Though the dinosaurs were ornithischians, and thus far removed from the lineage that led to birds, the fossils bore scales and three types of feathers, Godefroit and colleagues report in the July 25 Science.

Stringy strands of feathers once blanketed the dinosaur’s head and its torso in a hairy sweater vest; tufts of ribbons trimmed its shins; and feathers like a chicken’s budded from scales to sheathe the creature’s upper arms and swaddle its thighs in downy bloomers. From the tip of its rounded snout to the end of its scaly tail, the plant eater stretched about as long as a gray wolf, with strong legs, stubby arms and a squat little skull.

Godefroit thinks the feathers could have kept the dinosaur warm; gussying up in fuzzy duds may also have attracted mates.

The authors are the first to spot a scale-feather combo in dinosaurs, says ornithologist Gerald Mayr of the Senckenberg Research Institute Frankfurt. “That is something completely new,” he says. “It’s a great discovery.”

The new find makes the possibility that all dinosaurs sported feathers “more likely now than it was before,” Mayr says. “But I think we have to wait for the discovery of more fossils to be sure.”