Fossilized feather in dung may reveal one of science’s greatest mysteries

A bird feather eaten by a dinosaur 66 million years ago may provide the answer to one of science’s greatest mysteries.

Unfortunately, the bird’s death resulted in the finest example of a feather ever found since the dinosaurs, preserved as fossilized dung.

By studying this feather, researchers have found clues that help explain why birds are the only group of dinosaurs to survive the mass extinction caused by the impact of a huge asteroid.

“This is such a beautiful, well-preserved feather from such an unexpected source, and it’s great that it can help us answer this huge question in paleontology,” said Jingmai O’Connor, lead author of the new paper and assistant curator of fossil reptiles at the Field Museum in Chicago.

The earliest known bird was Archeopteryx, which appeared 150 million years ago, and birds continued to evolve and live alongside their dinosaur cousins ​​for nearly 100 million years. After the Earth’s collision with an asteroid 66 million years ago, almost all dinosaurs became extinct, including most birds.

But one group of birds, the Neornithes, survived, and every bird alive today is one of their descendants.

Why this small group survived is one of the biggest questions in paleontology.

“To my knowledge, no one had ever thought of looking for feathers or studying feathers in coprolites, so this project was really exciting,” Dr O’Connor said.

The fossil was found in 2016 when David DeMar Jr., co-author of the journal article Current biologyconducted fieldwork in northeastern Montana.

“I was crawling up a rocky outcrop collecting fish fossils when I came across a dark reddish-brown knot about half the size of a golf ball,” he said.

“I picked it up and scanned the surface through a hand lens, and then I couldn’t believe what I saw – a tiny fossil feather.

“I was cautiously optimistic about its discovery because feathers had not yet been found in the Hell Creek Formation, even after more than 150 years of searching.”

Researchers studied its mineral composition and did a computed tomography scan.

It contained many feathers, tiny fish scales from a pike, and the leg bones of a hesperonite bird. Hesperornithiforms are close relatives of the Neornithes birds, which survived the mass extinction and are still alive today, but they were not themselves part of Neornithes.

Some scientists believe that a branch of the Neornithes family of birds survived because they lived near water, which helped protect them from the effects of the mass extinction.

However, hesperornithiforms also lived in water and became extinct, suggesting that there is another reason why neornithines are the only surviving birds.

“We think that the types of feathers these birds had and/or the way those feathers molt may have been one of the main reasons for the selectivity of the mass extinction at the end of the Cretaceous – essentially why some birds went extinct and others survived,” Dr O’Connor said.

“Some of the feathers of these diving birds looked modern and waterproof, but they also had the smaller, fuzzy, primitive body feathers that we associate with dinosaurs and enantiornithines,” she added.

Greg Wilson Mantilla, a professor at the University of Washington and co-author of the study, said the study’s findings are important because “we rarely find fossils of birds, and even more rarely their feathers, that give us such important insight into the evolution of this key aspect of their biology.

“In addition, these bird feathers found in the fossilized dung of a large dinosaur give us incredible insight into predator-prey interactions 66 million years ago.”