150 Million-Year-Old Bird Fossil in China Rewrites Evolution

A remarkable fossil discovery in China has upended scientists’ understanding of bird evolution, pushing back the timeline for modern bird features by 20 million years. The newly discovered species, named Baminornis zhenghensis, is approximately 150 million years old and features a short tail similar to today’s birds rather than the long, reptilian tail seen in other Jurassic-era bird fossils.

The find, made in Fujian Province and detailed in the journal Nature, represents the first definitive short-tailed bird from the Jurassic period. Until now, paleontologists believed birds with modern characteristics didn’t appear until the early Cretaceous period, about 20 million years later.

Photograph and interpretive line drawing of the 150-million-yaer-old bird Baminornis zhenghensis (Image by WANG Min)

“If there are still any doubts about how birdy Archaeopteryx is,” said Wang Min, a researcher at the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, “Baminornis is undoubtedly a real bird.”

For over 160 years, Archaeopteryx—a winged dinosaur discovered in Germany with a mix of bird and reptile features—was considered the earliest known bird. Around a dozen Archaeopteryx fossils have been found, all in Bavaria, southern Germany.

Key Features Reveal Evolutionary Advances

Weighing about 100-130 grams (equivalent to about 3.5 ounces) and roughly the size of a quail, Baminornis zhenghensis shows a critical adaptation found in modern birds: a fused pygostyle, or compound tailbone, that supports fan-shaped tail feathers. This feature shifts the bird’s center of mass forward, making flight more agile.

The evolutionary tree showing the position of *Baminornis zhenghensis*, and the morphometric space illustrating the modular evolution of different body parts (Image by WANG Min)

The fossil displays what scientists call “mosaic evolution,” where different body parts evolve at different rates. While its shoulder and pelvic girdles resemble those of modern birds, it retains primitive, dinosaur-like hand proportions—a combination that provides valuable insight into the transition from dinosaurs to birds.

Stephen Brusatte, a paleontologist at the University of Edinburgh who wasn’t involved in the research, commented on the significance: “Paleontologists once expected more Jurassic bird fossils to emerge, but none did—until now. This is very exciting.”

A possible Jurassic ornithuromorph furcula from the 150-million-yaer-old Zhenghe Fauna (Image by WANG Min)

Fossil Findings Expand the Picture

The Baminornis fossil was among more than 100 creatures—mostly fish and turtles—found at the site in Zhenghe County. Isotope dating of the surrounding mudstone confirmed the fossils were between 148 million and 150 million years old.

In the same excavation, researchers uncovered a solitary wishbone (furcula) believed to belong to another early bird species. This discovery hints at a richer and more complex bird ecosystem during the Jurassic period than previously thought.

Bird fossils are particularly rare because of their fragile bones. When Wang held the Baminornis fossil for the first time, he said his heart raced—a testament to the exceptional nature of the find.

The discovery of Baminornis and other ancient bird remains suggests that the roots of modern birds extend deeper into the Jurassic than scientists had imagined, compelling researchers to reconsider the evolutionary timeline and processes that led to the diverse bird species we see today.

FAQs About the Jurassic Bird Discovery

What is Baminornis zhenghensis and why is it important?

Baminornis zhenghensis is a newly discovered bird fossil from the Late Jurassic period (approximately 150 million years ago) found in China. It’s important because it has modern bird features like a short tail that scientists previously thought didn’t evolve until 20 million years later, forcing a rewrite of bird evolutionary history.

How does Baminornis differ from Archaeopteryx?

Unlike Archaeopteryx, which has a long reptilian tail, Baminornis has a short tail with fused vertebrae (pygostyle) similar to modern birds. This feature improves flight by shifting the body’s center of mass forward. Archaeopteryx shows more dinosaur-like features, while Baminornis displays more characteristics of modern birds.

Where was this fossil discovered?

The fossil was discovered in Zhenghe County in China’s Fujian province during excavations that began in 2021. It was found among more than 100 other fossils, mostly fish and turtles, in mudstone dated to 148-150 million years old.

How old is the Baminornis fossil?

The Baminornis fossil is approximately 150 million years old, dating from the Late Jurassic period. This makes it roughly the same age as Archaeopteryx, which was previously thought to be the oldest bird-like creature.

What does this discovery tell us about bird evolution?

This discovery indicates that birds began diversifying and developing modern features much earlier than previously thought. It suggests that multiple bird lineages with different flight adaptations may have coexisted during the Jurassic period, making bird evolution more complex and branching rather than linear.

What physical characteristics made Baminornis better at flying?

Baminornis had a fused pygostyle (a shortened, fused tailbone) that supported fan-shaped tail feathers. This adaptation shifted the bird’s center of mass forward toward its wings, improving balance and making it more agile in flight—a key aerodynamic feature still found in modern birds today.

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