Jurassic fossil from China rewrites history of bird evolution

13/2/2025 6:14

Scientists have unearthed in

southeastern China the fossil of a quail-sized bird that lived

about 150 million years ago during the Jurassic Period and

possessed surprisingly modern traits, a discovery that rewrites

the history of avian evolution.



The newly identified bird, called Baminornis zhenghensis,

joins the similarly aged Archaeopteryx, discovered in Germany in

1861, as the oldest-known birds. But Baminornis, about six

inches (15 cm) long, was far more advanced anatomically and a

better flier than crow-sized Archaeopteryx, a creature seemingly

half bird and half reptile.



While Archaeopteryx boasts a long and skinny tail resembling

a raptor dinosaur like Velociraptor, Baminornis has the

shortened tail of a modern bird - an important aerodynamic

innovation that helps shift the body's center-of-mass forward

toward the wings.



The fact that the two earliest-known birds display quite

different anatomies and inhabited different parts of the world -

separated by about 5,500 miles (8,800 km) - suggests that

millions of years of avian evolution had already occurred before

their appearance.



Birds evolved from small feathered dinosaurs. Based on the

new discovery, the first birds arose 172-164 million years ago,

millions of years earlier than previously believed, according to

paleontologist Min Wang of the Institute of Vertebrate

Paleontology and Paleoanthropology of the Chinese Academy of

Sciences, lead author of the study published on Wednesday in the

journal Nature.



"Baminornis zhenghensis looks more like modern birds than

Archaeopteryx," Wang said, calling its discovery "a landmark to

me and other evolutionary biologists."



Until now, Archaeopteryx was the only unquestionable bird

known from the Jurassic, which ended roughly 145 million years

ago.



"This fossil (Baminornis) indicates that Jurassic birds

probably already had a global distribution and were much more

diversified than previously thought," said paleontologist and

study co-author Zhonghe Zhou of the Institute of Vertebrate

Paleontology and Paleoanthropology in China.



The Baminornis fossil was discovered in 2023 during

scientific fieldwork in Fujian Province's Zhenghe County. The

fossil preserves much of the bird's skeleton but lacks the

skull, leaving a gap in the understanding of its diet and

lifestyle that could be interpreted from its jaws and teeth.

Wang said Baminornis probably had teeth, as did Archaeopteryx.



Until now, the oldest-known birds with short tails lived

about 20 million years later than Baminornis, including

Eoconfuciusornis, Protopteryx, Cruralispennia and

Archaeornithura.



Unlike Archaeopteryx, Baminornis has a pygostyle - a bone

plate formed by fused vertebrae at the end of the vertebral

column.



"A short tail ending with a pygostyle is a universal feature

of extant birds. It provides attachment for fan-shaped tail

feathers facilitating more sophisticated and powerful flight,"

Zhou said.



The pectoral and pelvic bones of Baminornis also were more

like modern birds than Archaeopteryx. Baminornis did share some

primitive characteristics with Archaeopteryx, such as clawed

dinosaurian hands.



The researchers found during the same fieldwork a solitary

wishbone that was more advanced than that of Archaeopteryx and

dating to the same time as Baminornis, but apparently belonging

to yet another early bird species. With such incomplete remains,

the researchers did not give this apparent new species a name.



Baminornis lived in a swampy area alongside the meat-eating

dinosaur Fujianvenator as well as various semi-aquatic reptiles,

turtles and fish, based on other fossils found in the area.



The 19th century discovery of Archaeopteryx, now known from

about a dozen specimens, lent support to British naturalist

Charles Darwin's ideas about evolution and provided evidence

that today's birds descended from dinosaurs. Archaeopteryx was,

as University of Edinburgh paleontologist Steve Brusatte put it,

"the textbook example of a creature caught in the act of

evolution, like a freeze frame."



"Yet, for more than 150 years now, Archaeopteryx had stood

alone. During all of that time it had remained as the only

unquestionable bird fossil from the Jurassic Period," said

Brusatte, who wrote a commentary accompanying the Baminornis

study.



"Baminornis tells us that a variety of birds lived during

the Jurassic, and they flew in different ways. There was a bevy

of birds flying overhead of Allosaurus and Stegosaurus and

Brontosaurus and the other iconic Jurassic dinosaurs," Brusatte

added.