An international team of paleontologists has discovered that the flying reptiles, pterosaurs, actually had four kinds of feathers, and these are shared with dinosaurs, pushing back the origin of feathers by some 70 million years.
Pterosaurs are the flying reptiles that lived side by side with dinosaurs, 230 to 66 million years ago. It has long been known that pterosaurs had some sort of furry covering often called 'pycnofibres', and it was presumed that it was fundamentally different to feathers of dinosaurs and birds.
In their work, published in the journal Nature Ecology & Evolution, a team from Nanjing, Bristol, Cork, Beijing, Dublin, and Hong Kong show that pterosaurs had at least four types of feathers:
simple filaments ('hairs')
bundles of filaments
filaments with a tuft halfway down
These four types are now also known from two major groups of dinosaurs, the ornithischians, which were plant-eaters, and the theropods, which include the ancestors of birds.
Birds have two types of advanced feathers used in flight and for body smoothing, the contour feathers with a hollow quill and barbs down both sides.
These are found only in birds and the theropod dinosaurs close to bird origins. But the other feather types of modern birds include monofilaments and down feathers, and these are seen much more widely across dinosaurs and pterosaurs.
The armoured dinosaurs and the giant sauropods probably did not have feathers, but they were likely suppressed, meaning they were prevented from growing, at least in the adults, just as hair is suppressed in whales, elephants, and hippos. Pigs are a classic example, where the piglets are covered with hair like little puppies, and then, as they grow, the hair growth is suppressed.