Chinese fossil of a Jurassic bird rewrites history of avian evolution

NBC News

13-02-2025

The fossil of a Jurassic bird unearthed in southeastern China has major implications for the history of avian evolution, researchers say.
The newly discovered Baminornis zhenghensis, a quail-sized bird, roamed the skies some 150 million years ago during the Jurassic period, according to a study published Wednesday in the journal Nature, meaning it is among the oldest birds known to mankind, along with the iconic Archaeopteryx that was discovered in Germany in 1862 and is of similar age.
"For more than 150 years now, Archaeopteryx has stood alone," said Steve Brusatte, a University of Edinburgh paleontologist who wrote a commentary accompanying the study.
"During all of that time, it has remained as the only unquestionable bird fossil from the Jurassic Period," he told NBC News in an email.
While there were other bird-like Jurassic fossils found here and there, Brusatte said there was a "huge mystery and a frustrating gap" in the fossil record: If Archaeopteryx was flying by then, other birds must have been too. So where were their fossils?
The 2023 discovery of Baminornis in Zhenghe county in China's Fujian province, now among the most important discoveries since Archaeopteryx, helps fill that gap, he said, making it the "second unquestioned bird from the Jurassic Period."
Unlike the half-bird, half-reptile Archaeopteryx, which had a long and skinny tail similar to that of a velociraptor, Baminornis had a short tail with some of its vertebrae fused into a short, stubby nubbin called a pygostyle — a crucial aerodynamic feature that pushes the body's center of mass toward the wings, similar to those in modern-day birds that helps them fly better.
Until the discovery of Baminoris, short tails had been found only in birds known to have lived around 20 million years later, such as Eoconfuciusornis and Protopteryx.
"What excites me most is that it is a more advanced bird than Archaeopteryx, and it could fly much better," Brusatte said.
Baminoris was much more anatomically complex than Archaeopteryx, which Brusatte said was a "primitive" bird with claws and sharp teeth like its dinosaur ancestors.
Archaeopteryx, which played a crucial role in determining that today's birds evolved from dinousaurs, was a "textbook example of a creature caught in the act of evolution like a freeze frame," he added.
The vast difference between the two similarly aged birds, discovered about 5,500 miles apart, has led the team behind the Nature study to believe that avian evolution occurred millions of years earlier than previously thought, with the estimate now at about 172-164 million years ago.
In addition to dozens of fossils of aquatic or semi-aquatic animals, the Zhenghe Fauna collection includes at least three avialan fossils so far. The researchers said that suggests the collection holds great potential to "enrich our understanding of early bird diversification" and "fill a critical gap in the evolutionary history of terrestrial ecosystem" toward the end of the Jurassic period.
Though the Baminornis fossil preserved much of the skeleton, the feathers were not preserved, leaving unanswered questions about the size and structure of its wings. It was also missing the skull, limiting clues about the bird's diet.
Nevertheless, "Baminornis tells us that a variety of birds lived during the Jurassic, and they flew in different ways," Brusatte said.