New Dinosaur Norellraptor Suggests Flight Evolved Independently Twice

Paleontologists have described a new species of miniature dinosaur, Norellraptor barsboldi, which challenges the conventional narrative of how flight evolved in theropod dinosaurs. The discovery suggests that the ability to fly did not emerge through a single linear pathway but developed independently at least twice in dinosaur history.

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Pterosaur fossil

The fossilized remains were discovered in China in 2023, but the detailed analysis was only recently published in Nature Communications. The species is named in honor of paleontologists Mark A. Norell and Rincheniin Barsbold, both of whom passed away in 2025.

Four-winged anatomy in the Cretaceous

The specimen dates back approximately 120 million years and belonged to a three-year-old individual that had nearly reached adult size, measuring just 57 centimeters in length. Despite its age, the skeletal preservation is exceptional. Norellraptor belongs to the Microraptoria group, a clade known for possessing long, flight-feather-like structures on both its forelimbs and hindlimbs. This configuration effectively gave the animal four wings. Researchers suggest this anatomy allowed for gliding between trees, similar to modern flying squirrels, though the capacity for active flapping flight remains a possibility.

Parallel evolutionary trajectories

Previous models often depicted the transition from dinosaur to bird as a straightforward lineage. The Norellraptor skeleton complicates this view. Analysis identified more than 50 anatomical features associated with flight that are present in both the direct ancestors of birds and in microraptors. The critical distinction lies in the sequence of their development.

In the lineage leading to modern birds, flight adaptations emerged in one specific order. In microraptors, the same functional mechanisms developed in a different sequence. This indicates that nature "invented" a biological flying machine twice. Microraptors, while closely related to birds, followed a distinct evolutionary path, creating an alternative system of flight rather than simply preceding the avian one.

"The main value of the find is that it proves flight in dinosaurs emerged at least twice and independently," the authors note. "This turns the history of life on Earth into an even more complex and intriguing process."

Externally, these creatures resembled the famous Archaeopteryx, yet genetically and anatomically they represented a separate, sister branch. The question remains why birds ultimately dominate the skies today, while four-winged gliders survive only as fossils.