Tyrannosaurus Rex, whose scientific name is Tyrannosaurus Rex, which means tyrant lizard, is one of the newest and largest carnivorous dinosaurs. Tyrannosaurus rex is also one of the largest land carnivores in the history of the earth. It went extinct 65 million years ago and ended in Cretaceous. Tyrannosaurus rex's head is very huge (about 1.55 meters long).
Jagged edge's teeth grow on a powerful jaw, which is huge and thick but like a bird's foot, and fingers have powerful claws. Compared with the stout feet, Tyrannosaurus rex's arms are inversely proportional to the skull and shorter than human hands. Paleontologists believe that this may be because Tyrannosaurus rex only eats with its mouth and rarely uses its forelimbs, so it gradually becomes shorter and smaller, and thus evolved into a hind leg, whose forelimbs degenerated and its hind legs became weapons, thus evolving into this strange body structure. Although Tyrannosaurus Rex was huge, his bones were hollow, and some of his heads were big and empty. Body length12m, body height about 4m and weight 9 tons. Tyrannosaurus rex's tail is long and thick, probably often centered on the hind legs and tail. It is estimated that the tail only plays a balancing role.
Time of appearance
Generally speaking, scholars believe that Tyrannosaurus Rex is the most ferocious dinosaur among carnivorous dinosaurs. It appeared in the late dinosaur era, about 65 million years ago. Tyrannosaurus rex's body is more than 5 meters high and weighs about 10 ton. Its hind feet are very thick. From the fossils of Tyrannosaurus rex, it is found that every tooth of Tyrannosaurus rex is different in size, some teeth are longer than human fingers, some teeth are as small as human tail fingers, and all teeth have oblique serrations from the tip to the root. Its ferocity can be seen, and its jaw is also amazing, which is the sum of the jaw strength of several bay crocodiles. This dinosaur will mercilessly kill its prey with its huge jaws and saber-like teeth, and then make it strong. An open maw is even more terrible. There are two rows of sharp teeth bent inward, each row is ten centimeters long. Once bitten, even herbivorous dinosaurs with tough bones could not bear it.
Tyrannosaurus evolution
The earliest ancestors of Tyrannosaurus rex came from eoraptor in the late Triassic. It is only 0.9 meters long, less than 1 meter, and weighs only 5 to 7 kilograms. The middle part of Gu Long's mandible didn't have some extra connecting devices like vegetarian dinosaurs. But in the middle of the jaw, there is a movable joint that can bend the jaw. When the jaw bites something, it will tightly clamp the prey. Tyrannosaurus Rex has this jaw!
There are some interesting things about it. For example, protosaurus had five "fingers", and then the number of "fingers" of carnivorous dinosaurs tended to decrease. In the end, only two "fingers" of large carnivorous dinosaurs such as Tyrannosaurus Rex were left. For another example, there were only three vertebrae supporting its small belt at the waist of the original dragon. Later, the dinosaurs became bigger and bigger, and the number of lumbar vertebrae supporting the belt increased.
So how did Tyrannosaurus Rex evolve from the size of a dog to a monster with a length of 15 meters? For decades, paleontologists have always believed that Tyrannosaurus Rex was the offspring of other giant carnivores, and it was the last dinosaur with the largest teeth. This is the hypothesis of super carnivorous dinosaurs, which seems to be taken for granted, but it is not correct.
Differences and differences
There are many differences between Tyrannosaurus Rex and carnivorous dinosaurs discovered in recent years. Take its feet for example. Its prominent third toe is the characteristic of many dinosaurs at the end of Cretaceous, but all of them are small dinosaurs. They are not the large carnivorous dinosaurs we are familiar with, such as ostriches. Tyrannosaurus rex was actually a small carnivore, but it later evolved into a very huge body. They have nothing to do with other large carnivorous dinosaurs. Anatomically, it is easy to conclude that those dinosaurs had nothing to do with Tyrannosaurus Rex.
Evolution course
However, it is very difficult to trace the evolution of Tyrannosaurus Rex-there was a big gap in the fossil record, and then the first giant ancestor of Tyrannosaurus Rex suddenly appeared, and new clues were found in the mountainous area at an altitude of 1300 meters in Alberta, Canada. There is a well-preserved prehistoric seashore, where clues have been branded for millions of years. The largest dinosaur footprint in Canada is a coal mine named' Okura' in Alberta. The footprints of dinosaurs such as Ankylosaurus were found there. They crossed the huge cliff, which used to be a piece of coastal mud. This place is important because it has a history of 1 100 million years, but no bones and fossils of the same period have been found nearby. Therefore, experts speculate that there is no Tyrannosaurus rex in these footprints left by dinosaurs during migration, but judging from these slender footprints, it must have been left by some giant dinosaurs, probably the ancestors of Tyrannosaurus rex.
turning point
This dragon is a turning point in the evolution of Tyrannosaurus Rex. Unlike other small carnivorous dinosaurs at that time, it killed its prey with its jaws instead of its forelimbs. This adaptive change resulted in the rise of Tyrannosaurus Rex and its unique shape. Tyrannosaurus rex originated from the stone dragon, which was slender and had long forelimbs. When it evolved into an Alberta dragon, its head became bigger and its forelimbs became shorter. Alberta is similar to Tyrannosaurus Rex, but when we carefully observe its characteristics, it is more primitive than Tyrannosaurus Rex.
Who is the next of kin of Tyrannosaurus Rex? Paleontologists believe that there are two possibilities:
Tyrannosaurus North America has a large bony process above its eyes, but the bony process of Tyrannosaurus Rex fossils found in Montana is not so prominent, and it is even smaller in early Tyrannosaurus Rex.
Tyrannosaurus Asia, Tyrannosaurus Rex was originally called Tyrannosaurus Rex, but in fact they have many differences, such as the back brain stem connecting the head.