The feathers came first, then the birds

A new research, led by the University of Bristol, suggests that feathers appeared 100 million years before the birds, which changes the way we view dinosaurs, birds and pterosaurs, reptiles in flight.

It also changes our understanding of the feathers themselves, their functions and their role in some of the most important events of evolution.

The new work, published today in the journal Trends in ecology and evolution combines new information from paleontology and molecular biology of development.

The key discovery occurred earlier in 2019, when feathers were reported in pterosaurs. If the pterosaurs were actually feathered, it meant that these structures were deep in the evolutionary tree, much deeper than at the time of the birds' birth.

Professor Mike Benton, from the School of Earth Sciences at the University of Bristol, said: "The oldest bird is still Archeopteryx, first discovered in the Upper Jurassic of southern Germany in 1861 although some Chinese species are slightly older.

"These fossils all carry a variety of feathers – down feathers on the body and long wing-shaped feathers on the wings – but since 1994, paleontologists have been fighting the disturbing discovery, based on hundreds of specimens. amazing from China – many dinosaurs also had feathers. "

Co-author, Baoyu Jiang of Nanjing University, added, "In the beginning, feathered dinosaurs were close to the origin of birds in the evolutionary tree.

"This was not so hard to believe.So, the origin of the feathers was pushed back at least to the origin of these bird-like dinosaurs, there may be 200 million d & rsquo; # 39; years. "

Maria McNamara, co-author of University College Cork, said: "We then had the chance to work on a new Russian dinosaur, Kulindadromeus.

"This dinosaur exhibited an incredibly well preserved skin, covered with scales on the paws and tail, as well as weird feathered whiskers all over the body.

"What surprised people was that it was a dinosaur as far from the birds as possible in the evolutionary tree." that feathers were present in the very first dinosaurs. "

Danielle Dhouailly of the University of Grenoble, also co-author, is working on the development of feathers in baby birds, in particular on their genomic control. She said: "Modern birds, like chickens, often have scales on their legs and neck, and we have shown that they are spills: what was once feathers had reversed to become scales.

"In fact, we have shown that the same network of genome regulation regulates the development of reptile scales, bird feathers and mammal hairs.The feathers could have evolved very early."

Baoyu Jiang continued, "The breakthrough occurred when we studied two new pterosaurs from China.

"We saw that a lot of their whiskers were branched in. We were expecting single wicks – monofilaments – but what we saw were tufts and feathers." Pterosaurs had feathers. "

Professor Benton added, "It brings the origin of the feathers back to at least 250 million years.

"The point of origin of pterosaurs, dinosaurs, and their relatives." The early Triassic world was recovering from the most devastating mass extinction of all time, and life on earth had come back to life. An almost total erasure.

Paleontologists had already noted that the new reptiles were walking upright instead of spreading, that their bone structure suggested rapid growth and perhaps even warm blood, and that mammal ancestors probably already had hair.

"Thus, the dinosaurs, the pterosaurs and their ancestors also had feathers, so feathers probably appeared to help this acceleration of physiology and ecology, only for isolation. for the display and of course for the flight, arrived much later. "