Roughly twenty years ago scientists started uncovering the first firm evidence of feathered dinosaurs. From digs in China, and then elsewhere, fossilized feathers started to crop up in the palaeontological record. Soon, it seemed, feathers were everywhere; adorning the bodies of not just the ancient relatives of modern birds, but long-lost and genetically disconnected groups of dinosaurs as well. The final blow for feather-free dinosaurs seemed to have come in July of last year, when a new study reported that the ancestor of all dinosaurs may have sported fuzzy plumage.
It took a long time for the idea of vibrant, colorful, feathered dinosaurs to supplant the idea of the scaled killer in the public's imagination.
But, it seems, some of this new-found enthusiasm may have been misplaced.
Two palaeontologists, Paul Barrett and David Evans, think that maybe we've been getting a little too gung ho on the feather front. According to Nature, reporting on a presentation given by Barrett and Evans, the two palaeontologists “created a database of all known impressions of dinosaur skin tissues. They then identified those that had feathers or feather-like structures, and considered relationships in the dinosaurian family tree.”
The results... indicate that although some ornithischians...had quills or filaments in their skin, the overwhelming majority had scales or armour. Among sauropods, scales were also the norm.
“I’d go so far as to say that all dinosaurs had some sort of genetic trait that made it easy for their skin to sprout filaments, quills and even feathers,” says Barrett. ”But with scales so common throughout the family tree, they still look like they are the ancestral condition.”
This isn't to say that dinosaurs didn't have feathers. Many of them undoubtedly did. Rather, the prevalence of scales cuts against the increasingly popular idea that all dinosaurs had feathers.
More from Smithsonian.com:
Did All Dinosaurs Have Feathers?