150 million years ago, this oldest bird rewrote the history of bird evolution! What is the relationship between dinosaurs and birds?

Recently, a bird fossil named Baminornis zhenghensis was discovered in Fujian Province. Its weight is similar to that of a common magpie. Its pelvic structure is similar to that of modern birds, its tail is short, but its wings retain dinosaur-like claws. This discovery has attracted widespread attention in the scientific community.

Some people think

It rewrote the history of bird evolution

So, what’s so special about the Zhenghe Bamin Bird?

The world's first bird

How did it come about?

Reconstruction of the Zhenghe Bamin bird, with the strange Fujian dragon behind it (discovered at the same location)

Drawn by Zhao Chuang, source: University of Science and Technology of China English official website english.cas.cn

The origin of birds: from dinosaurs to modern birds

To understand the importance of Zhenghe Bamin Bird, we first need to understand the origin of birds. The ancestors of birds are dinosaurs under the order Saurischia and theropods, which have feathers, walk on two feet, and are small in size.

Note: Only a small number of theropod dinosaurs with smaller bodies and feathers have evolved into today's birds. Other theropod dinosaurs have disappeared in the long river of history, such as the familiar Tyrannosaurus Rex, Carcharodontosaurus and Yongchuansaurus.

During the evolution, these dinosaurs gradually lost their long tails, formed a pygostyle on their tail bones that could control the tail feathers during flight, and gradually lost their claws on their wings, and evolved a developed chest to facilitate flapping wings. In addition, they also had toes that could hold branches.

Theropod dinosaur evolution tree

Image source: IBTimes UK

Note: From top to bottom: Tyrannosauroids, Compsognathus, Ornithomimosaurs, Therizinosaurs, Alvarezsaurians, Oviraptorosaurs, Troodontidae, Dromaeosaurids and fossil birds (Archaeopteryx, Avicennia, Jeholornis, Jixiangornis, Confuciusornis, all of which are fossil birds discovered from the Late Jurassic to the Early Cretaceous) and modern birds.

The pygostyle of a modern bird (far left)

Image source: jurassic-park.fr

Note: Based on phylogenetic research and corresponding skeletal anatomical evidence, the current academic community believes that dinosaurs include birds, which are part of the Aves among theropod dinosaurs, and are often referred to as "birds" and "non-avian dinosaurs". To facilitate readers' understanding, this article still uses the relatively old term, that is, the word "dinosaur" is used to refer to "non-avian dinosaurs."

In the Late Jurassic period 150 million years ago, the famous Archaeopteryx lived in Germany. The academic community once believed that it was the most primitive bird.

Archaeopteryx fossil source fonds

However, 160 million years ago, a group of "bird-like dinosaurs" lived in Inner Mongolia and Liaoning , such as Anchiornis, Caihongsaurus and Eosinopteryx. Although these dinosaurs had long tails and large claws, their pelvis, skull and wrist bone structures were very similar to those of birds.

A restored model of Anchiornis, photographed at the China Paleozoological Museum

This is one of the few dinosaurs that has been accurately reproduced in color.

Melanosomes are preserved in its feathers

The discovery of these "bird-like dinosaurs" has led scientists to infer that birds may have gradually evolved from dinosaurs starting 160 million years ago. Archaeopteryx and these bird-like dinosaurs all belong to the Avialae, a family of dinosaurs that includes "true birds" and "bird-like" dinosaurs.

Caihongosaurus, one of the "bird-like dinosaurs" of the class Aviaria

Found in Qinglong County, Hebei Province, with feathers

Image source: Wikipedia

Note: Among theropod dinosaurs, there are also some other dinosaurs that have feathers like birds and similar wrist bones and other features, such as Troodontidae, Oviraptorosaurs, Dromaeosaurids, etc. However, they are more distantly related to Avifauna. There are also some views in the academic community that Archaeopteryx is not an Avifauna. In addition, Archaeopteryx and existing birds have fewer caudal vertebrae in their tails compared to Anchiornis, and some modifications have been made to the bone structure of the humerus and other bones.

The fossil of the gorgeous golden phoenix bird of the family Troodontidae lived in the Early Cretaceous

There are also feathers, photographed at the Rehe Geological Museum in Hebei Province

Microraptor of the Dromaeosauridae Source: Wikipedia

About 130 million years ago, in the Early Cretaceous, birds began to branch out. Some of them had long and primitive tails, such as Jeholornis. There were also birds with short tails and pygostyles. The appearance of the "pygostyle" bone marked the establishment of the body shape of modern birds .

Among this group of short-tailed birds, some with more developed sternums and tail synchondroses are called "true birds" (Euornithes). All birds on Earth today are members of the true birds.

Therefore, scientists have come up with the idea of ​​the evolution of birds: 160 million years ago, primitive bird-like dinosaurs appeared → 150 million years ago, they changed from primitive bird-like dinosaurs to long-tailed birds like Archaeopteryx → 130 million years ago, they changed into short-tailed birds with a pygostyle.

Among these birds with a pygostyle, there is a branch called true birds that gradually evolved into the birds we have today.

Member of the Euavis fossil family, Ge's Yixianornis

The discovery of Zhenghe Bamin bird: rewriting the history of bird evolution

The discovery of Zhenghe Baminornis has changed our understanding of bird evolution. It lived in the Late Jurassic 150 million years ago, the same era as Archaeopteryx, but its pygostyle and short tail indicate that it is closer to modern birds than Archaeopteryx.

The pelvic structure, furcula and scapula of Zhenghe Bamin Bird are similar to those of modern birds, showing its "advancedness" in evolution, and it is not wrong to say that it is the first bird.

Of course, they are not the only ones vying for the title of "first bird". Contemporaneous with Baminornis and Archaeopteryx is Germany's Alcmonavis, but its fossils are relatively few and incomplete, and it does not have a pygostyle like Baminornis.

The fossil of Zhenghe Bamin Bird, the upper left corner shows its pygostyle and tail, which is relatively short

Zoom in

The long tail of Archaeopteryx on the left and the short tail of the modern bird's pygostyle on the right

Image source: Wikipedia

However, compared to the cute little wings of existing birds, Zhenghe Baminbird still had two terrifying large claws, which are more similar to the claws of Archaeopteryx and other long-tailed bird species (such as Anchiornis).

These terrifying claws show that the "advanced" evolved Zhenghe Bamin bird also retained its original characteristics - only its butt was changed, and the claws on its wings were not changed.

From left to right, the claws of Zhenghe Baminornis, Archaeopteryx, Anchiornis, Fujianosaurus, Jeholornis, and Confuciusornis. Among them, Confuciusornis is a bird with a short tail and a pygostyle, and its claws are still there but not so prominent. Jeholornis is a primitive bird with a long tail and relatively unprominent claws.

Small sun parrot without claws on its wings

Photographed at Beijing Wildlife Park

"Evolution changes bit by bit, just like eating rice bite by bite." The discovery of the Zhenghe Bayunbird demonstrates the characteristics of "mosaic evolution", that is, evolution proceeds step by step.

Just as apes first modified their waist structure to allow for long-distance upright walking and then developed a larger brain, the evolutionary process of snakes is to first degenerate their forelimbs and then their hind legs.

The discovery of the Zhenghe Bamin bird shows that the "short-tailed bird" appeared 150 million years ago, which is about 20 million years earlier than previously believed.

Aren't birds dinosaurs?

Compared with Archaeopteryx and Fujianosaurus, Zhenghe Minnori has a more bird-like bone morphology. So, does Zhenghe Minnori have dinosaur ancestors?

According to relevant researchers, the bird-winged dinosaur ancestor of Zhenghe Baminnice may have lived 164-172 million years ago, and the time when this ancestor modified the tail and pelvic structure was earlier than scholars thought. Finding bird-winged dinosaur fossils 150-180 million years ago to complete the chain of bird evolution may become a new research direction for scientists.

The current pattern of dinosaur evolution towards birds may be:

164-172 million years ago, the earliest and most primitive bird-like dinosaurs appeared on Earth.

In the following tens of millions of years, the transformation from "primitive winged dinosaurs" to "long-tailed birds" and then to "short-tailed birds" was completed.

150 million years ago, the Zhenghe Minbird appeared with a shorter tail and a pygostyle.

After that, from the Late Jurassic period 150 million years ago to the present day, these birds with tail spurs continued to evolve and survive to this day with the blood of dinosaurs.

The following table shows the key time points of the evolution of avian dinosaurs to birds before and after the discovery of Zhenghe Baminornis. Since primitive avian species older than 160 million years ago and long-tailed birds older than 150 million years ago have not been found in the fossil record, the relevant numbers marked in red in the table below are only speculations based on literature and research:

Note: Some scholars have questioned the tailbone of the Minnice bird. Based on the morphology and taphonomy of the bones, they believe that its tailbone is not a real tailbone, but a fusion of the sacral vertebrae of the waist bones. According to this view, the Minnice bird may still be a guy with a long tail. This article will not use this view for the time being.

Aurora, a primitive bird, not a bird

It lived about 160 million years ago

What is even more surprising is that in the strata from the same period as the primitive bird-winged creature Tongzheng and Baminbird, a bird furcula dating back 150 million years was also discovered . The furcula fossil is very similar to the morphology of true birds.

Some people have inferred from this that the true bird branch to which existing birds belong may have appeared earlier. Perhaps we can find true birds and other primitive bird fossils in earlier Jurassic strata!

However, since this fossil is relatively fragmented, it has not been completely confirmed to be the bone of a true bird. It is also possible that some kind of winged dinosaur may have "transformed" its furcula into the appearance of its descendants through convergent evolution.

Wishbone diagram of living birds from dinodata.de

Based on morphological analysis, this furcula fossil (the number is the red dot in the picture) is more similar to the furcula fossil of true birds marked in green, compared to the blue furcula of other dinosaurs (not birds but with feathers) and the brown part of the furcula of primitive birds such as Archaeopteryx.

Seeing this, some people may wonder, aren’t birds descendants of dinosaurs? The discovery of the mysterious forkbone fossils of Zhenghe Bamin Bird and similar true birds only shows that dinosaurs have a skeletal morphology that is "bird-like" and gradually evolved into birds earlier than we thought, but it does not deny the homology and evolutionary relationship between dinosaur and bird bones.

Zhenghe Bamin Bird, like other members of the Avifauna and other dinosaur evolutionary trees, belongs to the Avifauna, which is part of the Anchiornis (Anchiornis also includes dinosaurs such as the Troodontidae), while Anchiornis and the three dinosaurs above it, as well as the strange Fujianosaurus, are not birds. The four Cretaceous birds marked with blue stripes are birds with short tails, while Jeholornis has a relatively slender tail. Image source: https://doi.org/10.1038/s41586-024-08410-z, translated by the author

Who is the predecessor of Zhenghe Bamin Bird? Let's wait for follow-up research. The feathered dinosaur fossils of Sinosauropteryx, first discovered in western Liaoning about 30 years ago, opened a new era of bird origin and dinosaur evolution, and the discovery of Zhenghe Bamin Bird today must be the same.

END

References

Chen, R., Wang, M., Dong, L. et al. Earliest short-tailed bird from the Late Jurassic of China. Nature 638, 441–448 (2025). https://doi.org/10.1038/s41586-024-08410-z

"A new avialan theropod from an emerging Jurassic terrestrial fauna". Nature. 621 (7978): 336–343. doi:10.1038/s41586-023-06513-7.

theropoddatabase.blogspot.com/2025/02/no-pygostyle-for-baminornis.html?m=1 Oliver WM Rauhut

Helmut Tischlinger,Christian Foth (2019) A non-archaeopterygid avialan theropod from the Late Jurassic of southern Germany. eLife 8:e43789.

Foth, C.; Rauhut, OWM (2017). "Re-evaluation of the Haarlem Archaeopteryx and the radiation of maniraptoran theropod dinosaurs". BMC Evolutionary Biology. 17 (1): 236. doi:10.1186/s12862-017-1076-y. PMC 5712154. PMID 29197327.

Alan Hamilton Turner, Peter J. Makovicky and Mark Norell (2012). "A review of dromaeosaurid systematics and paravian phylogeny". Bulletin of the American Museum of Natural History. 371: 1–206.

Godefroit, Pascal; Cau, Andrea; Hu, Dong-Yu; Escuillié, François; Wu, Wenhao; Dyke, Gareth (2013). "A Jurassic avialan dinosaur from China resolves the early phylogenetic history of birds". Nature. 498 (7454): 359–362. Bibcode:2013Natur.498..359G. doi:10.1038/nature12168.

Brusatte SL, O'Connor JK, Jarvis ED. The Origin and Diversification of Birds. Curr Biol. 2015 Oct 5;25(19):R888-98.

Currie, Philip J.; Padian, Kevin (October 1997). Encyclopedia of Dinosaurs. Academic Press. pp. 530–535. ISBN 0-12-226810-5.

Rhodes, MM, Henderson, DM & Currie, PJ Maniraptoran pelvic musculature highlights evolutionary patterns in theropod locomotion on the line to birds. PeerJ 9, e10855 (2021).

Xu, X., Han, F. & Zhao, Q. Homologies and homeotic transformation of the theropod 'semilunate' carpal. Sci. Rep. 4, 6042 (2014).

Pittman, M. et al. The fossil record of Mesozoic and Paleocene pennaraptorans. Bull. Am. Mus. Nat. Hist. 440, 37–96 (2020).

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Author: Great Qing Dragon

Student member of Shanghai Science Writers Association

Editor: Dong Xiaoxian

Reviewer: Zhang Chao, Li Peiyuan