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Source: Novosibirsk State University – Novosibirsk State University –

As part of the popular science marathon “Darwin Week”, a lecture was held at NSU by the head of scientific and educational center “Evolution of the Earth” NSU Igor Kosenko, dedicated to the most popular prehistoric animals – dinosaurs. Listeners learned how scientists’ ideas about these amazing creatures changed, how diverse the “terrible lizards” were and what they could look like. It turns out, contrary to a fairly common misconception, some dinosaurs did not become extinct, but survived to this day.

Dinosaurs (superorder Dinosauria) are terrestrial reptiles belonging to the group of archosaurs (Archosauria), which also includes crocodiles and birds. The first archosaurs appeared at the turn of the Permian and Triassic periods, dinosaurs arose later – at the end of the Triassic period, about 230 million years ago. Dinosaurs went extinct at the end of the Cretaceous period 66 million years ago. In total, dinosaurs dominated the planet for more than 160 million years. Currently, more than 500 genera and more than a thousand species of dinosaurs are known, and every year scientists find new ones. So, last year, at the Shestakovo dinosaur site in the Kemerovo region, scientists discovered a new species of predatory dinosaur from the Early Cretaceous period of Western Siberia.

— Dinosaurs are divided into two groups: lizard-hatched and ornithischian. The division is based on the structure of the pelvic bones. The saurischians include all carnivorous dinosaurs and sauropods, and the ornithischians include all the others, mainly herbivores, such as stegosaurs, ankylosaurs and horned dinosaurs. It is noteworthy that the first dinosaurs that appeared were small (knee-high to modern man) generalist animals and looked approximately the same, but the division into ornithischians and lizards apparently existed almost from the moment of their appearance. This is evidenced by paleontological finds,” said Igor Kosenko.

The greatest diversity of dinosaurs occurs during the Cretaceous period. At this time, representatives of the previous Jurassic period (for example, sauropods), and characteristic only of the Cretaceous (advanced horned dinosaurs) continued to exist. The dominance of dinosaurs is often attributed to the Jurassic period, but during this period the dinosaur fauna was not as diverse as in the Cretaceous period.

During the Cretaceous period, dinosaurs reached their maximum size. According to evolutionary laws, at the initial stages of evolution, each group of organisms has its own universal ancestor. As a rule, it is small in size. Further, as the group evolves, the size of its representatives becomes larger. The largest dinosaurs lived on Earth 75 million years ago. Then some species reached gigantic sizes and were record holders in size among terrestrial animals. The largest were the long-necked sauropods, namely the Argentinosaurs. The length of its body from the tip of its tail to its nose was 39 meters. And in terms of height, giraffatitan is recognized as the largest representative of this group. His height was 12 meters.

Among the predators, the leader in size was not the tyrannosaurus, although it was one of the five largest and ranked fourth in it. And the first was a spinosaurus, found in Africa, whose length from the tip of its nose to the tip of its tail was 13 meters. However, not all predatory dinosaurs were giants. Most of the “terrible lizards” were quite compact in size. There were insectivorous small predatory dinosaurs the size of a modern domestic cat or even a chicken.

— Ideas about dinosaurs are constantly changing. At different times, scientists had their own idea of what they looked like. In part, the image of a dinosaur is a figment of scientists’ imagination plus real facts. The more facts, the closer we are to the real image of this or that prehistoric animal. Finding a complete skeleton is an incredible success. Scientists usually discover individual bones, and even more often, teeth. When Spinosaurus was discovered, paleontologists found large spinous vertebrae forming a high crest on its back. And they tried to reproduce his appearance. Scientists at the time believed that dinosaurs walked on two legs, and the Spinosaurus reconstruction was created accordingly. Over time, the reconstruction of this dinosaur was changed, and now scientists agree that it walked on four legs, its body parallel to the ground. Spinosaurus was semi-aquatic and most likely hunted large fish, since its jaws were elongated, almost like a crocodile. Recently, the image of this animal has been supplemented with a wide tail, like a newt’s, thanks to the wide caudal vertebrae of this giant that were found,” said Igor Kosenko.

In recent years, it has become clear that many dinosaurs, especially small ones, were feathered. This is confirmed by numerous paleontological finds made in China. Another striking piece of evidence is amber found in Myanmar that preserves the tip of the tail of a small carnivorous insectivorous dinosaur with plumage. The age of the find was established as 100 million years. Scientists have recreated the appearance of this animal. Outwardly, it looks more like a large chick of some strange bird than a “terrible lizard.” Now a hypothesis has emerged that the tyrannosaurus was also feathered, since it has been established that the remains of its ancestors had feather-like structures. But the Triceratops was covered with scales – scientists were able to detect imprints of the skin of this creature.

The Age of Dinosaurs ended approximately 66 million years ago when our planet was hit by a giant asteroid. But as a result of this catastrophic event, they were not the only ones who disappeared from the face of the Earth. The extinction also affected other prehistoric terrestrial and aquatic animals – ammonites, belemnites, pterosaurs, plesiosaurs, mosasaurs and many others. There are theories according to which destructive volcanic processes occurring at the same time also contributed to this extinction. Many animals could not withstand such a double blow, but not dinosaurs.

– In fact, dinosaurs did not become extinct. The hypothesis that they evolved into birds arose in the 19th century, when Archeopteryx was discovered in Germany. Over time, evidence in its favor grew more and more. In northeast China, many transitional forms between birds and dinosaurs, as well as early birds, have been found. An interesting example demonstrating the relationship between dinosaurs and birds is the hoatzin, which lives in South America. Her chicks have claws on their wings that help them move along tree branches. By adulthood they disappear. And now none of the serious scientists question the hypothesis that birds are the same dinosaurs that have survived to this day,” explained Igor Kosenko.

Note; This information is raw content directly from the source of the information. This is exactly what the source states and does not reflect the position of MIL-OSI or its clients.

Please note; This information is raw content directly from the information source. It is accurate to what the source is stating and does not reflect the position of MIL-OSI or its clients.

EDITOR’S NOTE: This article is a translation. Apologies should the grammar and or sentence structure not be perfect.

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