Feathers arose 100 million years before birds, changing how we look at dinosaurs, birds, and pterosaurs, the flying reptiles.
The research, led by the University of Bristol and published in the journal Trends in Ecology & Evolution, combines new information from paleontology and molecular developmental biology.
“The oldest bird is still Archaeopteryx first found in the Late Jurassic of southern Germany in 1861, although some species from China are a little older,” says Bristol professor Mike Benton, the lead author. “Those fossils all show a diversity of feathers – down feathers over the body and long, vaned feathers on the wings. But, since 1994, palaeontologists have been contending with the perturbing discovery, based on hundreds of amazing specimens from China, that many dinosaurs also had feathers.”
According to a news release from the university, the key discovery came earlier this year when feathers were discovered in pterosaurs, meaning they appear much deeper in evolutionary history than birds.
“We saw that many of their whiskers were branched,” says Baoyu Jiang, a co-author from the University of Nanjing. “We expected single strands – monofilaments – but what we saw were tufts and down feathers. Pterosaurs had feathers.”
“This drives the origin of feathers back to 250 million years ago at least,” explains Benton.
The research team also had the opportunity to work on Kulindadromeus, a new dinosaur from Russia, which had well-preserved skin covered with scales on the legs and tail, and strange whiskery feathers all over its body.
“What surprised people was that this was a dinosaur that was as far from birds in the evolutionary tree as could be imagined. Perhaps feathers were present in the very first dinosaurs,” explains Maria McNamara, a co-author from University College Cork.
The researchers surmised that feathers arose in the Early Triassic period while the world was recovering from the most devastating mass extinction ever. “Feathers then probably arose to aid the speeding up of physiology and ecology, purely for insulation” of dinosaurs, pterosaurs and their ancestors, Benton explains. “The other functions of feathers, for display and of course for flight, came much later.”