Introduce "loong Bird"

I lived in the early Cretaceous, 654.38+0.4 billion years ago. 1996 Its fossil was found in the Jehol biota in western Liaoning, China. At first, it was considered as a primitive bird, named "Hualong sauropod", and was later confirmed by scientists as a small carnivorous dinosaur. Its initial bone size is about 1 m, its forelimbs are thick and short, its claws are sharp, its hind legs are long, it is suitable for running, and its whole body is covered with one to the original fluff. For a long time, whether birds are descendants of dinosaurs has been debated, and the discovery of Chinese bird dragons provides some evidence.

Fossil Chinese arowana was found in Shangyuan Township, Beipiao, western Liaoning. There are fringed fiber structures on the spine and body surface of the Chinese arowana, which may be the precursor of feathers. No flight function, mainly to protect skin and body temperature.

China arowana has short forelimbs and sharp claws, which is favorable for predation. In fact, it is a small carnivorous dinosaur. Its teeth have obvious serrated structure, its head has not healed, it has four cervical vertebrae and 13 vertebrae, and its tail is almost two and a half times the length of its trunk, belonging to the theropod family. The discovery of dinosaur fossils in China is one of the most important discoveries in the research history of dinosaur fossils since 100, which is of inestimable significance not only to the study of the origin of birds, but also to the study of the physiology, ecology and evolution of dinosaurs.

When a large number of dinosaurs withdrew from the historical stage in the late Mesozoic, people thought that this reptile that had ruled for a period of time had completely ended. In fact, dinosaurs were not extinct. One or several of them are trying to leave the land and develop into the air.

Pterosaurs were the first to have flying "wings", but they didn't have real feathers. Pterosaurs have broad sternum and keel like birds, but they can't fly long distances. They were not conquerors in the air and disappeared from the earth before they became real pilots. Who is the conqueror in the air? Birds appeared.

1In August 1996, a farmer in Liaoning Province donated a fossil specimen. It's small, but it looks like a dinosaur. It has thick and sharp teeth on its mouth, and its tailbone is particularly long. It has more than 50 coccyx, and its hind limbs are long and thick. In addition, the most attractive thing is that it is covered with feather-like skin derivatives from beginning to end. This strange feathery substance is about 0.8 cm long. After careful study, scientists confirmed that this is the earliest primitive bird fossil. Because it was found in China, it was named "Chinese Dragon Bird".

According to textual research, "Chinese dragon bird" and "feathered dinosaur" are indeed Sihetun people in Beipiao, Liaoning Province. Fossils are all produced in a layer of shale with a thickness of 2 ~ 7 meters deposited by lakes containing volcanic ash, which is located in the lower part of a set of extremely thick strata called Yixian Formation in jehol group by geologists. Moreover, the "feathered dinosaur" is actually the positive model of the fossil specimen of "Chinese dragon bird", both of which are individuals of the same animal. Originally excavated by a farmer in Sihetun, it was divided into two pieces (positive mode and negative mode) along the bedding of rock strata from the middle of fossils. Subsequently, the positive model was obtained by researcher Chen Piji and the negative model was obtained by researcher Ji Qiang.

Studies have proved that the morphological characteristics and body size of China arowana are similar to those of a small theropod dinosaur-monitor lizard, which is produced in Germany, and can be classified into one category. The Chinese dragon bird is a biped, which can grow to 2 meters long in adulthood. On its back, there is a string of epidermal derivatives similar to "hair". Some paleontologists believe that this is a primitive "feather", so the Chinese dragon bird should be a primitive bird; Other paleontologists believe that this skin derivative does not have the characteristics of feathers, but is similar to the epidermis-derived structure of the back of some existing reptiles (such as lizards)-horny bristles, and may also be fibrous tissue.

Judging from the fossil bones, the Chinese dragon bird has many typical dinosaur characteristics: the skull is low and long, and the skull (anatomically called skull) is very small; There is obvious retroorbital bone behind the orbit, and the square bone behind the chin (anatomically called mandible) is straight; Its tooth side is flat, like a knife, and its edge has a serrated structure; Its waist and hip bones (anatomically called waistband) have a thick pubic bone extending forward; Its tail is quite long, with more than 60 coccygeal vertebrae with developed nerve spines and pulse arcs; Its forelimbs are very short, only one-third of the length of its hind limbs. The characteristics of its forelimbs show that it lived later than the German Megatron. Chen Piji and other researchers published a research paper in the British journal Nature published on 19981October 8, and thought that the Chinese dragon pterosaur was a small theropod dinosaur. Of course, according to the biological naming rules, Ji Qiang's original name "Chinese dragon bird" was still used.

Paleontologists have discussed the role of hairy epidermal derivatives on Chinese arowana, and some people think that it may be a "decoration" to express gender; Some people think it is a kind of heat preservation device. The latter explanation seems more reasonable, because little dinosaurs and little archaeopteryx should have a high metabolic rate in order to be efficient, so they need to keep their body temperature. Therefore, it can be inferred that the hairy epidermal derivatives of the Chinese dragon bird indicate that the small dinosaur may be a warm-blooded animal (that is, a warm-blooded animal). Some paleontologists speculate that this kind of "hair" is the predecessor of feather evolution, so it is called "pre-feather". At present, paleontologists are still using new methods to further study it.

Interestingly, a small lizard fossil was found in the abdominal cavity of China arowana. Obviously, this lizard was captured and swallowed by China arowana.

As for the age of the Chinese dragon bird, according to the recent in-depth study of its occurrence stratum, scientists basically determined it as the early Cretaceous, about 65.438+0.3 billion years ago.

According to the online report of Nature magazine, scientists' latest research on loong bird fossils shows that this dinosaur that later evolved into a bird probably didn't have feathers, and the early evolution of feathers probably wasn't for flying. This discovery challenges the theory of feather evolution. This achievement was published in the recent Journal of the Royal Society.

The sauropod dinosaur fossils in this study were unearthed in Rehe, Liaoning Province, China. This "bird-like" dinosaur lived in the early Cretaceous period10.40 billion years ago, which is of great scientific value for studying the origin of feathers.

Theagarten Lingham-Soliar from KwaZulu-Natal University and his colleagues found that the skin fibers in the neck and tail of China arowana are very disordered, and they don't have herringbone features to prove the existence of feathers. They think that the filamentary "feather" structure of China arowana should be the degradation residue of soft tissues such as collagen fibers.

The origin of birds is one of the main unsolved problems in the scientific community. As early as 100 years ago, German paleontologists discovered Archaeopteryx. In order to further reveal the secret of the origin of birds, scientists have made unremitting efforts, but it was not until the 1980s that total * * * discovered seven archaeopteryx fossils with different degrees of preservation, which became all the basis for human beings to describe the story of the origin of birds. Did birds evolve from dinosaurs? How did birds evolve and develop? It is difficult to conduct a comprehensive and in-depth study based on limited archaeopteryx data.

The discovery of loong birds spread all over the world immediately, because it provided us with new evidence of the evolution from reptiles to birds. After the research of paleontologists in China, it is pointed out that the Chinese dragon bird not only retains some characteristics of small theropod dinosaurs, but also has some basic characteristics of birds, which has become an intermediate link in the evolution from dinosaurs to birds. The "feathers" of loong birds are flaky and have a feather axis. These feathers are different from those of modern birds and represent the initial stage of early bird evolution. Judging from the characteristics displayed by the Chinese dragon bird, it is older and more primitive than the German archaeopteryx. The Chinese dragon bird has the skeletal characteristics of a dinosaur, with a big head, many teeth, many coccygeal vertebrae and agility, but it does not have the ability to fly. But according to this important feature that the whole body is covered with primitive feathers, it may be classified as a bird rather than a dinosaur, because reptiles are covered with shields or scales. Birds put on feathers to keep warm and help them fly.

In Beipiao area, Liaoning province, fossils such as Chinese dragon bird are preserved, which records rare events in geological history. Because of the low probability of occurrence and discovery, this geological phenomenon is extremely rare and precious. The discovery and value of Sinosauropod fossils will naturally attract more and more attention from the scientific community. With the in-depth study of the Chinese dragon bird, the world ornithologists have gradually realized that the archaeopteryx is closer to modern birds, and the Chinese dragon bird is the real intermediate link in the evolution from dinosaurs to birds, and the secret of the evolution and development of birds is being revealed step by step.

Some people say that the Chinese dragon bird is an early empty-boned dinosaur, which has nothing to do with birds. Feathers exist in a large number of dinosaurs. Dinosaurs are the ancestors of birds, but China's dragon birds are not. Among dinosaurs, the ancestor of birds is Chironomidae.