Summary
A 57-centimetre fossil from China has been named Norellraptor barsboldi, a new feathered microraptorine dinosaur. Comparing its anatomy with birds, the researchers conclude that many similar aerial adaptations evolved in different sequences in the two lineages.
A new feathered dinosaur from China is adding evidence to a long-running debate about the origins of bird flight. Described in Nature Communications on 29 September 2026, Norellraptor barsboldi is a microraptorine dinosaur represented by a nearly complete, 57-centimetre skeleton. Comparing its anatomy and bone growth with those of birds, the researchers argue that the two lineages assembled many similar aerial adaptations in different evolutionary sequences.
The study concerns the evolution of traits associated with aerial locomotion; those traits are inferred from fossil anatomy and evolutionary comparisons. They do not record the animal’s behaviour directly.
Contents
A nearly complete microraptorine
The fossil was found near Lamadong Town in western Liaoning, in rocks of the Lower Cretaceous Jiufotang Formation. It preserves a complete skeleton and traces of plumage. The researchers describe some probable asymmetrical flight feathers near the hand, but say the feathers are too poorly preserved to determine their full length and detailed form.
The animal had a mix of features shared with other microraptorines and distinctive traits of its own, including an unusually large opening in the front part of the skull’s antorbital region and a small, reduced foot at the end of the pubis. Its forelimbs were shorter and less robust than its hindlimbs. The study places Norellraptor among later-diverging microraptorines, close to Zhongjianosaurus.
Microraptorines were close relatives of birds, but their relationship to the evolution of bird flight has been disputed. Similarities could reflect adaptations inherited from a common ancestor, or could have developed separately as the groups evolved. The new fossil gives researchers another anatomical comparison for testing those possibilities.
Similar features, different sequences
The researchers mapped anatomical changes onto a phylogenetic analysis—a reconstruction of evolutionary relationships based on shared traits. They identified 194 changes along microraptorine branches, of which 57, or about 30%, were also acquired along the bird lineage. The shared features include changes to the sternum, forelimb and hand.
The order of those changes differed between the groups. In microraptorines, shortening of some hand bones appeared early. Other changes, including fusion of wrist and hand bones and a relatively elongated sternum, came later in the group’s history. In birds, the researchers reconstructed those latter changes as occurring before the shortening of some hand bones.
That mismatch matters because a shared developmental pattern might be expected to produce a more similar sequence of changes. The researchers also found no significant correlation between the order of the shared traits in the two lineages (Spearman’s rank correlation coefficient −0.08; p = 0.50). They interpret the differing sequences as evidence that microraptorines and birds evolved their aerial adaptations under separate evolutionary regimes, rather than inheriting one common process for building a flight apparatus.
What the bone sample adds
The team examined a thin cross-section of the radius, a forearm bone, to study growth. The sample contains lines interpreted as interruptions in bone growth. From these and other features, the researchers estimate that the animal was at least three years old when it died, while still in a late juvenile stage.
The radius’s growth pattern differs from that reported in a femur from a Microraptor specimen. The authors suggest this may point to an unusual pattern of forelimb growth among microraptorines, distinct from the patterns considered in living birds. They describe this histological evidence as preliminary: the interpretation comes from one sampled radius, and the authors note that the unusual pattern could also relate to an unknown physiological condition in this individual.
Together, the fossil’s anatomy, the comparison of evolutionary sequences and the bone-growth evidence support the researchers’ case for independently evolving aerial adaptations in microraptorines and birds. The conclusion is an evolutionary reconstruction from fossils, not a direct record of how Norellraptor moved through the air.