Birds are the most diverse land vertebrates. Some studies suggest their earliest diversification dates back to the Jurassic period, around 145 million years ago. However, the early history of birds is unclear due to a fragmentary fossil record, with Archaeopteryx being the only widely accepted Jurassic bird.
Although Archaeopteryx had feathered wings, it looked like non-avialan dinosaurs because of its long, reptilian tail, unlike modern birds with short tails.
Recent studies have questioned whether Archaeopteryx is an actual bird, suggesting it might be a deinonychosaurian dinosaur, a sister group to birds. This raises the question of whether there are any clear records of Jurassic birds.
A research team led by Professor WANG Min from the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) of the Chinese Academy of Sciences discovered two bird fossils in Jurassic-era rocks in Fujian Province, China, which are around 149 million years old. These fossils help fill a gap in the early history of birds and show that birds were diverse by the end of the Jurassic period.
One fossil, named Baminornis zhenghensis, has unique features: bird-like shoulder and pelvic girdles and a hand structure similar to non-avialan dinosaurs. This shows the role of mosaic evolution (where different traits evolve separately) in early bird development. Baminornis zhenghensis also has a short tail ending in a bone called the pygostyle found in modern birds.
Prof. WANG, the lead and corresponding author of the study, said, “Baminornis zhenghensis is the sole Jurassic and the oldest short-tailed bird yet discovered, pushing back the appearance of this derived bird feature by nearly 20 million years.”
The researchers used various methods to determine where Baminornis zhenghensis fits the bird evolutionary tree. They found that it is slightly more evolved than Archaeopteryx and is one of the oldest birds.
Dr. ZHOU Zhonghe from IVPP, co-author of the study, stated that considering Archaeopteryx’s uncertain evolutionary position, they believe Baminornis zhenghensis is a true Jurassic bird.
The second fossil found was incomplete and only had a furcula (wishbone). Researchers used different analyses to study its relationship with other dinosaurs and birds. They found that this furcula likely belongs to Ornithuromorpha, a group of Cretaceous birds.
However, due to its poor condition, they didn’t name a new species based on this single bone, and more fossil evidence is needed to confirm its place in the bird family tree.
Journal Reference:
- Chen, R., Wang, M., Dong, L. et al. Earliest short-tailed bird from the Late Jurassic of China. Nature 638, 441–448 (2025). DOI: 10.1038/s41586-024-08410-z
Source: Tech Explorist
