Two hundred and thirty million years ago, the first dinosaur was as big as a dog and supported itself on its two hind legs.

Tens of millions of years later, its descendants have multiplied into a huge family of different shapes: some run on two legs, some walk on four legs; some are huge, some are small; some are ferocious, and some are docile.

Some of these predatory dinosaurs gradually became smaller and more like birds, with hollow bones, enlarged brains, light bodies, agile movements, longer and longer forelimbs that could flap like bird wings, and feathers growing on their bodies.

, without scales or armor.

Some went to trees to survive in order to avoid enemies or find food. They jumped and landed on trees, gained the ability to glide, and later were able to fly.

Feathered dinosaurs ran on the ground and learned to fly.

So a dinosaur evolved into a bird and flew into the blue sky. Pterosaurs are close relatives of dinosaurs. They lived in the same era and were reptiles that flew into the blue sky. They are sometimes mistaken for "flying dinosaurs".

Pterosaurs originated in the Late Triassic about 215 million years ago and became extinct at the end of the Cretaceous 65 million years ago.

While dinosaurs ruled the land, pterosaurs controlled the skies.

?Pterosaurs are a very special type of reptiles with unique skeletal structure characteristics.

As early as 1784, when the Italian paleontologist Colini discovered the first pterosaur fossil in Germany, he was not even sure what type of animal it belonged to. Some people thought it lived in the ocean, while others thought it was a bird or bat.

transition types and so on.

It was not until 1801 that Cuvier identified it as a pterodactyl, a reptile.

?Pterosaurs cannot soar freely and long distances in the sky like birds. They can only glide near their living environment, such as rocks on the seaside, lakeside or in the woods, and sometimes hover on the water.

?Pterosaurs took to the sky about 70,000 years earlier than birds. They began to adapt to life in the air around the late Triassic period and successfully survived on the earth for 150 million years.

In order to adapt to the needs of flying, pterosaurs have many bird-like skeletal characteristics, such as porous skulls, hollow and light bones, developed sternum and its keel, etc.

?So far, more than 120 named pterosaur fossils have been discovered in the world.

The individual sizes and shapes of pterosaurs vary greatly. The larger ones are like the pterodactyl fossils discovered in Texas in the 1970s. Its wings spread about 16 meters, and its width is equivalent to an F-1.6 fighter jet. The smaller ones are similar in shape.

Like a sparrow.

There are two major categories of pterosaurs. The early rhinocerosaurs were relatively primitive, mainly lived in the Jurassic period, and had a very long tail; the late pterodactyls mainly lived in the Cretaceous period, and had very short or even disappeared tails.

?Pterosaurs are reptiles, however they were probably warm-blooded.

At the beginning of the 20th century, British paleontologists speculated that pterosaurs had the ability to move quickly, were like bats, had hair on their bodies, and had living habits similar to birds. They were warm-blooded animals with a constant body temperature.

Later, traces of hair were found on the rhinoceros fossils discovered in Germany.

In 1970, a relatively complete pterosaur fossil with "hair" was discovered in Kazakhstan. British paleontologists studied the hairy and wing membrane structures of this specimen and concluded that it was undoubtedly a warm-blooded animal.

These "hairs" on the pterosaur's body insulate and maintain heat, prevent the loss of body heat, and regulate body temperature.

Another piece of evidence comes from the bones of pterosaurs, which like birds had small air sacs used to regulate body temperature.

Recently, the discovery of "hairy" Jehol pterosaurs in western Liaoning, my country, further proves that at least some small pterosaurs are warm-blooded animals.

More and more fossil evidence shows that in order to adapt to the needs of flight, some pterosaurs already have physiological mechanisms for internal heat and constant body temperature, higher metabolic levels, developed nervous systems, and efficient circulatory and respiratory systems, becoming a type of

The least reptile-like reptile.