Scientists Discover ‘Groundbreaking’ Jurassic Fossil That Could Overhaul the Evolutionary History of Birds

Researchers have discovered a 149-million-year-old bird fossil in southeastern China, featuring a short tail structure that could rewrite the evolutionary history of birds. As detailed in a study published Wednesday in the journal Nature, the fossil could represent the oldest bird known to scientists and sheds light on the surprising diversification of birds during the Jurassic Period (145 million to 201.3 million years ago).

Paleontologists hypothesize that birds evolved from dinosaurs about 160 million years ago. There is, however, scarce fossil evidence of this early transformation. In fact, the feathered Archaeopteryx—seen as an intermediate link between dinosaurs and modern avians—was the single widely accepted bird to have lived around that time. That is, until now.

“This is a groundbreaking discovery. It overturns the previous situation that Archaeopteryx was the only bird found in the Jurassic Period,” Zhonghe Zhou, a paleontologist at the Chinese Academy of Sciences and co-author of the study, tells the Chinese news agency Xinhua.

The fossil was uncovered in China’s Fujian province in November 2023. While much of the skeleton was intact—including the pelvis, trunk, forelimbs and part of the hindlimbs—the skull was not included. The team also discovered another fossilized bird wishbone from the same site, but it likely dates to the Cretaceous Period (66 million to 145 million years ago).

Researchers named the newly discovered Jurassic bird Baminornis zhenghensis. It was a contemporary of Archaeopteryx, roughly quail-sized and featured several characteristics of modern birds, including shoulder and pelvic girdles as well as—most excitingly for paleontologists—a short tail. The evolution of short tails was crucial to the improvement of bird flight, Min Wang, a paleontologist from the Chinese Academy of Sciences who co-led the study, tells Xinhua. It helps shift the bird’s center of mass forward, making the animal more aerodynamic.

“Previously, the oldest record of short-tailed birds is from the Early Cretaceous,” Wang further explains in a statement. Baminornis is now the “oldest short-tailed bird yet discovered, pushing back the appearance of this derived bird feature by nearly 20 million years.”

The short tail of Baminornis is in sharp contrast to Archaeopteryx’s long, reptile-like tail. In fact, that tail has caused some researchers to call into question Archaeopteryx’s classification as a bird, especially in comparison to the recently discovered fossil. And it doesn’t help that Archaeopteryx could only engage in short bursts of active flight, like pheasants today.

“Baminornis zhenghensis looks more like modern birds than Archaeopteryx,” Wang says to Reuters’ Will Dunham. “In light of all this, I would say Baminornis is probably the oldest unambiguous record of birds,” he adds to New Scientist’s James Woodford.

That’s not to say that Baminornis was all modern bird. Its hands, for example, were distinctively dinosaur-like, which demonstrates that different body parts evolved independently to make birds what they look like today.

Either way, the existence of two very different early birds (or bird-like creatures) that were located so far apart at roughly the same time in history suggests that millions of additional years of bird evolution likely occurred before either of these creatures lived. Wang thus speculates that birds first emerged between 164 million and 172 million years ago, per Reuters.

“Baminornis is a landmark discovery and ranks among the most important bird fossils unearthed since the discovery of Archaeopteryx in the early 1860s,” Stephen Brusatte, a paleontologist from the University of Edinburgh who was not involved in the study but wrote a commentary accompanying it, tells Xinhua.

Margherita Bassi | READ MORE

Margherita Bassi is a freelance journalist and trilingual storyteller. Her work has appeared in publications including BBC Travel, Discover magazine, Live Science, Atlas Obscura and Hidden Compass.