A team of researchers at the University of Bristol suggest that feathers came 100 million years before birds. This discovery has stirred earlier beliefs about birds, dinosaurs, pterosaurs, and flying reptiles and also previous understanding about the evolution of feathers and their functions.
The study originated after a key discovery of feathers in pterosaurs was reported earlier in 2019. This discovery drew attention to the fact that if pterosaurs had feathers then the structures of feathers must have originated earlier than the point of time when birds originated.
“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 Professor Mike Benton, from the University of Bristol’s School of Earth Sciences, lead author of the paper.
“Those fossils all show a diversity of feathers – down feathers over the body and long, vaned feathers on the wings. But, since 1994, paleontologists have been contending with the perturbing discovery, based on hundreds of amazing specimens from China, that many dinosaurs also had feathers,” he added.
Baoyu Jiang, another co-author from the University of Nanjing reported that dinosaurs with feathers were similar to the origin of birds in the evolutionary tree. Since this proposition was not so hard to believe, the origin of feathers was pushed back to 200 million years ago, to the origin of bird-like dinosaurs. Baoyu Jiang continued: “The breakthrough came when we were studying two new pterosaurs from China. We saw that many of their whiskers were branched. We expected single strands – monofilaments – but what we saw were tufts and down feathers. Pterosaurs had feathers.”
A study on Kulindadromeus, dinosaurs from Russia led to the discovery of well-preserved skin with scales, tails and legs. Moreover, the dinosaurs had whiskery feathers all over its body which led to the belief that Kulindadromeus was perhaps far from birds from the evolutionary tree and that feathers were present in the very first species of dinosaurs, reports Dr Maria McNamara, co-author from University College Cork.
Danielle Dhouailly from the University of Grenoble who has also co-authored the study supports the new proposition saying that feathers were reversed to scales. Among modern birds like chickens, who have scales on their legs or necks showed signs of reversals.
According to reports, the major key to this new discovery was provided through the study of pterosaurs from China; the origin point of pterosaurs, dinosaurs and their relatives. According to a statement by Professor Benton, the early Triassic world was recovering from the most devastating mass extinction. “Palaeontologists had already noted that the new reptiles walked upright instead of sprawling, that their bone structure suggested fast growth and maybe even warm-bloodedness, and the mammal ancestors probably had hair by then.
“So, the dinosaurs, pterosaurs and their ancestors had feathers too. Feathers then probably arose to aid this speeding up of physiology and ecology, purely for insulation. The other functions of feathers, for display and of course for flight, came much later,” he adds.
A paper on this research has been published in the journal Trends in Ecology & Evolution which also includes information from paleontology and molecular developmental biology.