Microraptor’s Group Shares 57 Features With Birds. They Evolved Separately

Birds are dinosaurs. That’s settled science.

But how dinosaurs first took to the air is still one of palaeontology’s great puzzles. A newly described fossil from China adds an unexpected twist.

It’s a close relative of Microraptor, the famous four-winged dinosaur. And its researchers argue that this group built its flying gear on its own, separately from birds.

What was Microraptor?

Microraptor was a tiny, feathered dinosaur that lived about 120 million years ago in what is now China.

The Natural History Museum in London describes it as “about the size of a crow”, around 77 cm long and weighing about 1 kg.

Its most famous feature is that it had wings on its legs as well as its arms. That’s why it’s often called the four-winged dinosaur.

It was a dromaeosaur, related to Velociraptor. The museum lists its movement as “on 2 legs, gliding or flying”.

Microraptor belongs to a small group called the microraptorines. These are among the closest known relatives of birds.

Meet Norellraptor

The fossil

The new species was described in Nature Communications in September 2026, by a team from China, Italy and Slovakia.

A local farmer found the fossil near Lamadong Town in Liaoning province, north-east China. It was donated to the museum of Hebei GEO University in 2023.

The researchers checked the specimen’s integrity and the original site. They report that its completeness and articulation support that it’s a genuine, single animal.

The name

The name honours two palaeontologists who died in 2025. Mark Norell was American, and Rinchen Barsbold was Mongolian.

Both made major contributions to the study of bird-like dinosaurs.

What makes it special

The skeleton is complete, with only slight disturbance. Some feathers are preserved, including what are probably asymmetrical flight-type feathers near the hand.

It has a distinctive skull, with unusually large openings in the snout. Its pubic bone, part of the hip, is also shaped differently from its relatives.

The team’s family-tree analysis places it as a close relative of Zhongjianosaurus, among the later members of the microraptorine group.

How old it was

The researchers sliced a thin section of its forearm bone to read growth rings, like tree rings. Two growth lines showed it lived at least two years.

Because some early bone had been reabsorbed, they estimate it was at least three years old when it died.

What the study found

Similar features, different order

The team compared the features that evolved along the microraptorine branch with those along the bird branch.

They found 194 features that evolved within the microraptorine group. About 30%, or 57 of them, also evolved separately in the bird lineage.

These include things like a longer breastbone, extra rib supports and fused bones in the hand.

But the order in which these features appeared was different. Statistically, the sequences along the two branches weren’t correlated.

Why that matters

There are two main ideas about these flying dinosaurs. One says a simple form of flight evolved once, in a shared ancestor, and was later lost by some groups.

The other says flight-related features evolved several times, in different branches, for different reasons.

If birds and microraptorines inherited a shared developmental pattern, they’d likely assemble their wings in a similar order. They didn’t, so the team rejects a shared developmental pattern.

The authors conclude that flying dinosaurs arose under “multiple and independent selective regimes”.

Growing differently from birds

The bones offered another clue. In strong-flying birds like ducks, the wing bones grow much faster than the leg bones, the authors note.

Microraptorine bones don’t clearly show that bird-like pattern. Norellraptor’s forearm bone shows interrupted growth, while a Microraptor leg bone studied earlier grew without interruption.

The authors say this hints at a “peculiar limb growth model” in the group. It’s another sign they may have taken their own route towards flight.

Where these fossils come from

Microraptorines are mainly known from the Jehol Biota, a famous set of Early Cretaceous fossil beds in north-eastern China.

These rocks preserve remarkable detail. Some microraptorine fossils keep true flight-type feathers and even remains of their last meals.

A twist in the family tree

The analysis also placed two other dinosaur groups, the halszkaraptorines and unenlagiines, closer to birds than Microraptor’s group.

That challenges several earlier studies. It suggests Microraptor may be a less direct guide to how birds learned to fly.

Why the result needs caution

This rests on one new specimen, and family trees for these dinosaurs often shift as new fossils are found.

The growth analysis came from one bone, and the authors call their histology evidence “preliminary”.

Even when the team forced Microraptor’s group into the bird branch, the result was 23 steps less efficient. That’s a sign the placement is fairly robust, but debate continues.

The study was funded by the National Natural Science Foundation of China and Slovak research agencies. The authors declared no competing interests.

What earlier research found

The four-winged discovery

In 2003, a study in Nature described four-winged dromaeosaurs from China. The authors argued they “probably could glide”, an intermediate stage before flapping flight.

Shimmering feathers

A 2012 study in Science studied the pigment structures in a Microraptor fossil. It predicted the dinosaur’s plumage was mostly iridescent, with a shimmering sheen.

Flight evolved more than once

A 2020 study in Current Biology estimated flight ability across early birds and their relatives, using wing loading and lift.

It found powered flight potential was rare outside early birds, but several relatives came close. It supported “multiple origins of powered flight potential in theropods (≥3 times)”.

How it fits together

The new fossil fits a growing picture. Dinosaurs seem to have experimented with flight several times, not along a single path to birds.

How much should you trust this?

Promising. The fossil is exceptional, and the analysis is large. But dinosaur family trees are notoriously changeable.

What makes it convincing

• The skeleton is nearly complete, which is rare for small dinosaurs.
• The team analysed hundreds of features across many species.
• The result fits earlier work suggesting flight evolved more than once.
• Three outside experts reviewed the paper, and the peer review file is public.

What makes me cautious

• It’s based on a single specimen.
• Fossils bought or donated from farmers can raise questions, though the team checked this one.
• The growth evidence comes from one bone and is preliminary.
• Family trees for bird-like dinosaurs often change with new finds.

What this means for you

• Rethink the textbook picture. Flight probably wasn’t a single straight line from dinosaurs to birds.
• Expect more surprises. China’s Jehol fossils keep changing what we know about feathered dinosaurs.
• Follow the debate. New fossils regularly move dinosaurs around the family tree.

The Natural History Museum’s Microraptor page has a clear guide to the four-winged dinosaur.

In this clip, BBC Earth shows how Microraptor may have glided through ancient forests:

What we still don’t know

1. Could Norellraptor fly? The fossil shows flight-related features, but not proof of powered flight.
2. How many times did flight evolve? Estimates range from two to three or more.
3. Why did these features evolve? Gliding, display and escape are all possible.
4. How did microraptorines grow? Their limb growth may differ from birds’, but the evidence is thin.
5. Where do they sit in the family tree? New fossils keep moving them.

My take: flight was a team experiment

What I like about this study is that it tests an idea directly.

If birds and Microraptor shared a blueprint, they’d build their wings in the same order. They didn’t.

I’m less convinced that one fossil can settle the family tree. These trees change often.

Still, the bigger picture is fascinating. Feathered dinosaurs seem to have tried flying in more than one way.