Dinosaur Feathers More Bird-Like Than Previously Known

Certain feathered dinosaurs were incapable of flying, at least not in the same way as modern birds. However, scientists may have underestimated how much the reptiles' feathers resembled those of birds. A distinct, more flexible type of the keratin protein, which is responsible for contemporary bird beaks, scales, and feathers, was found to be predominant in the feathers of a flightless dinosaur discovered through fossil analysis in 2019. Then, scientists proposed that as birds — the last extant dinosaurs — took to the skies, their feathers underwent a chemical evolution throughout time, becoming increasingly rigid.

Researchers reveal in the October Nature Ecology & Evolution that fossilisation can alter feather proteins, causing one keratin protein to resemble another. On October 19, the group also gave a presentation on their research at the annual meeting of the Cincinnati-based Society for Vertebrate Palaeontology.

According to the findings, the beta-keratin proteins present in bird feathers may have been the primary component in dinosaur feathers. This study raises fresh issues concerning feather evolution even though it does not prove that all dinosaurs with feathers were able to fly.

Palaeontologist Tiffany Slater of University College Cork in Ireland and colleagues conducted a new investigation in which they exposed contemporary bird feathers to heat conditions similar to those that preserved dinosaur feathers could have experienced during fossilisation. The feathers' beta-keratins unfurled and rearranged into the form of alpha-keratins, which is a more pliable form that was previously discovered to predominate in dinosaur feathers. This suggests that a comparable process took place in those feathers.

Next, the scientists looked at two feathers from the nonavian dinosaur Sinornithosaurus, one from 125 million years ago and the other from a bird that was around 50 million years old. They were surprised to see that alpha-keratins made up the majority of the feathers in the bird. The researchers believe that the proteins changed during fossilisation since they should have been abundant in the beta variety. The majority of the beta-keratins found in the dinosaur feather, on the other hand, indicate that it was not subjected to enough heat to cause its proteins to change.

However, Mary Schweitzer, a molecular palaeontologist from North Carolina State University in Raleigh who was involved in the 2019 research, notes that the settings the researchers investigated in the current study might not precisely recreate what happened during centuries of burial.

In her own research, rather than being taken out of the soil as in the current study, feathers subjected to even greater temperatures effectively maintained their proteins. She thinks that the impact that fossilisation has on feather proteins may be more intricate and little understood.

There is a growing consensus among scientists that feathers did not develop for flight. Rather, they most likely helped dinosaurs find mates and kept them warm. However, some dinosaurs that weren't birds did jump into the air and glide around. Even those who were unable to fly continued to flap their wings while sprinting.