Can the "dragon" and "phoenix" "combine"? The first dragon in Fujian with "bird wings" fills the gap of 30 million years!

On the 27th, it's time to kill the rooster! Chickens are common poultry and naturally belong to birds, but did you know that in paleontological research, chickens are also a branch of dinosaurs, called bird-winged dinosaurs. Dragons and phoenixes are both symbols of auspiciousness in Chinese traditional culture. The phoenix belongs to the ancient legendary bird; the dragon is a reptile with mixed characteristics of many animals. After the Western word Dinosaur was introduced to China, it was integrated with traditional culture and naturally translated the reptiles that dominated the land in the Mesozoic Era as "dinosaurs". Through the continuous discovery of biological evolution by scientists, it is proved that the dinosaur "dragon" and the phoenix "bird" are actually inextricably linked - combined! The best proof is the rich discovery of bird-winged dinosaurs.

Figure 1: Ecological restoration of the strange Fujian dragon. (Image source: Wikipedia)

01 How did dinosaurs have “bird wings”?

In China, dinosaur fossils have been unearthed in almost every province, such as Mamenchisaurus in Sichuan, Qingdaosaurus in Shandong, Lufengosaurus in Yunnan, and even the stegosaurus Mangkangsaurus in the Qinghai-Tibet Plateau, which makes Fujian, where no dinosaurs have been found, a special case. However, in recent years, a major breakthrough has finally been made in Fujian Province, piecing together a more complete and rich dinosaur puzzle, allowing people to have a more comprehensive understanding of the ecology, distribution, and evolution of dinosaurs.

The first dragon in Fujian Province, which broke the record of dinosaur fossils in the past, was published in the September last year and appeared in the journal Nature, attracting much attention from the academic community. This dinosaur was named Fujianvenator prodigiosus . It is not only the latest Jurassic in time, but also the southernmost Avialae dinosaur in space, filling in an important key link in the early evolution and distribution of birds .

As mentioned earlier, Fujianosaurus is the southernmost ornithological dinosaur, but what are ornithological dinosaurs?

When talking about dinosaurs, classic dinosaur images such as Tyrannosaurus, Triceratops, and Brachiosaurus come to mind. Since these tall and mighty images are so different from birds, although Archaeopteryx was discovered as early as 1861, the view that birds originated from dinosaurs was still "non-mainstream" until the 1970s. Later, with the discovery of a large number of feathered dinosaurs in the famous Jehol Biota in western Liaoning, a series of evolutionary processes from dragons to birds were fully established.

Figure 2: Sinosauroopteryx is the first feathered non-avian theropod dinosaur discovered in the Jehol Biota. (Drawing: Bob Nicholls, Image source: Wikipedia)

According to the most commonly used phylogenetics in current biological classification, a taxonomic unit must include the most recent common ancestor of all organisms in the phylum and all their descendants. Simply put, if you want to consider you and your brothers and sisters as a family, you must trace back to your parents and all your children, so that it can be considered a complete family . As descendants of theropod dinosaurs, birds naturally belong to the dinosaur family. Otherwise, deliberately excluding birds is as unnatural as deliberately excluding a nephew or niece when talking about our own family.

This approach is in line with the laws of nature, but it will cause a lot of inconvenience in communication, especially since the evolution of birds towards flight is too unique. If we have to think about the situation of birds every time we discuss dinosaurs, there will be too many special cases. In order to facilitate communication, when talking about dinosaurs, an "unnatural" classification that does not include birds is generally set up, called "non-avian dinosaurs"; and the branch that excludes non-avian dinosaurs and includes birds is called bird-shaped dinosaurs , or what we call "avian wing" here .

02 Avenomous dinosaurs ≈ birds?

It sounds like "avifauna" is equivalent to "birds". This answer is actually right or wrong, depending on how you define and understand birds.

Now it seems that it is not difficult for us to identify a bird, but evolution is a continuous and gradual process. In the process of tracing back to our ancestors, the classification boundaries gradually become blurred. We can see some dinosaurs that are very similar to birds, with tails, claws or teeth. In order to avoid different understandings between scientists in communication, clear classifications must be defined.

Figure 3: Archaeopteryx fossils show that it has many features that are different from modern birds, such as teeth, claws on the forelimbs, and tail. (Image source: Wikipedia)

In this classification, the birds we usually refer to in a narrow sense refer to "modern birds (Neornithes)", that is, traced back to the most recent common ancestor of all modern birds and all their descendants, excluding species that differentiated earlier such as Archaeopteryx, Confuciusornis, and Enantiornithes . In a broader sense, it is what we call "Aves", which are classified based on branches that are more similar to birds in morphology and appearance, and are different from their close relative Deinonychus (to be more strict, it is a group that is more closely related than other feathered non-avian dinosaurs and living birds).

After a series of analyses, scientists discovered that Fujiansaurus was more closely related to Arcniornis , Xiaotingia , etc., and therefore was classified together as an early branch of the Aves .

Figure 4. Classification relationship between Fujianosaurus and Aviaria. The branches from top to bottom are Neornithes, Enantiornithes, Confuciusornis, Jeholornis, Archaeopteryx, Eosinopteryx, Aurorax, Xiaotingsaurus, Anchiornis, Fujianosaurus. (Image source: Reference [1])

03 The mystery of time and space between dinosaurs and birds

In the past, the earliest bird records mainly came from Archaeopteryx. This creature from the late Jurassic period about 150 million years ago was already very "bird-like" in appearance, especially in its wings and feathers, resulting in a large number of gaps in the study of the evolution from dinosaurs to birds.

After the discovery of a large number of feathered dinosaurs in the Jehol Biota, these gaps in morphological evolution were gradually made up, but these creatures all came from the early Cretaceous period, so the age still could not make up for the lack of fossils from earlier periods. As scientists continued to explore, they finally discovered the Yanliao Biota in Northeast China, which was about 160 million years old and came from the middle and late Jurassic period .

Many amazing animals were found in the Yanliao Biota, including the Yi qi, which flew with wing membranes like a bat. This proves that dinosaurs briefly tried to take off with wing membranes before or at about the same time as they flew into the blue sky with feathers and wings. The amazing discoveries of the Yanliao Biota don't stop there. Many specimens of early bird-winged dinosaurs were also found here, filling the gap in the past where no related transitional species could be found in strata older than Archaeopteryx .

Figure 5. Restoration of Pterosaur. It can be seen that this dinosaur had wings and feathers different from those of birds, and flew using wing membranes (drawing: Emily Willoughby, image source: Wikipedia).

Anchiornis is a good example. When this bird-winged dinosaur was first discovered, it was thought to be a type of troodontid, which means it has many characteristics similar to dinosaurs. In addition, Anchiornis also has feathers on its hind limbs, which is a four-winged structure similar to Microraptor. These appearance features are well connected to the process of dinosaurs flying into the blue sky and turning into birds . In addition, melanosomes were found in the feather fossils of Anchiornis , which is the first dinosaur fossil to be confirmed to have different distributions of fur colors throughout the body . In addition to the black body and black and white wing feathers, there is also a brown-red head crown.

Figure 6. Reconstruction of Anchiornis (drawn from reference [2])

04 The Southernmost Jurassic Bird-like Dinosaur

The recently discovered Fujianosaurus dates from the late Jurassic period, about 148 to 150 million years ago. In addition to the Archaeopteryx in Germany, it fills the 30 million-year gap between the Yanliao Biota about 160 million years ago and the discovery of a large number of bird fossils in the early Cretaceous . In addition, the early bird species in the past were concentrated in the northern regions such as the Yanliao Biota and Solokhofen in Germany (where Archaeopteryx was discovered). This discovery of the southernmost Jurassic also makes up for this shortcoming, proving that these early bird dinosaurs had a wider geographical distribution.

Figure 7. Fossil of Fujianosaurus (Source: Reference [1])

In addition to these important significances in time and space, the most distinctive feature of Fujiansaurus is its hind limbs , which have relatively short thighs, long calves and feet . Such proportions are generally found in animals that run fast ; in modern birds, they are similar to wading birds that live near water, such as egrets . Therefore, researchers have determined that this dinosaur was either a fast runner or lived near water . Either way, it tells us that early bird-like dinosaurs had a richer and more diverse lifestyle.

In addition to the Fujianosaurus, the fossil site also contains a large number of reptile fossils, including aquatic or semi-aquatic turtles and tortoises, as well as crocodile-like scaphosaurs. Based on these abundant fossils, researchers named this site the "Zhenghe Fauna" and can expect more and richer discoveries in the future.

Figure 8. The strata of the Zhenghe fauna and the fossil cluster found (Image source: Reference [1])

05 Today's Dinosaur World

Through the study of Avifauna dinosaurs, we can better understand the origin of today's birds. It also makes us realize that we are still living in an age surrounded by dinosaurs and even eat them. For example, the duck meat, eggs, and goose liver on the table are all classified as part of the Avifauna dinosaurs.

This year is the Year of the Dragon, so I have specially selected an article about the ancient bird-winged dinosaurs that are a combination of dragon and phoenix to share with you. I wish you all good luck, prosperity, and everything goes well after reading this article!

References:

1. Xu, Liming; Wang, Min; Chen, Runsheng; Dong, Liping; Lin, Min; Xu, Xing; Tang, Jianrong; You, Hailu; Zhou, Guowu; Wang, Linchang; He, Wenxing; Li, Yujuan; Zhang, Chi; Zhou, Zhonghe (2023-09-06). "A new avialan theropod from an emerging Jurassic terrestrial fauna". Nature. 621 (7978): 336–343.

2. Li, Q.; Gao, K.-Q.; Vinther, J.; Shawkey, MD; Clarke, JA; d'Alba, L.; Meng, Q.; Briggs, DEG; Prum, RO (2010). "Plumage color patterns of an extinct dinosaur" (PDF). Science. 327 (5971): 1369–1372.

Author: Liao Junqi, PhD, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, visiting scholar at Yale University

Reviewer: Pei Rui, Associate Researcher, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences

Produced by: Science Popularization China

Produced by: China Science and Technology Press Co., Ltd., China Science and Technology Publishing House (Beijing) Digital Media Co., Ltd.