Tyrannosaurus rex is currently the most famous dinosaur that has been widely studied. However, no less interesting is its origin in the process of evolution, to understand which relatives of the thyrex you need to know. A new species from the same tyrannosaurid family has been identified in Mexican rocks. Unlike related species, Labocania anomala had long hind legs, was slender, and lived in southern Laramidia, an island continent corresponding to the western part of modern North America.

The Mesozoic period of Earth history is known as the reign of dinosaurs on land, pterosaurs in the air, and sea lizards in the water. It was a completely different world with its unusual climate, location of continents and seas, ecosystems and populations.

Among dinosaurs, tyrannosaurus has been the most popular for many years. Tyrannosaurus rex literally “royal cruel lizard”. It lived at the end of the Cretaceous, the last period of the Mesozoic, and gained a reputation as the largest and most dangerous predator of its time. Scientists continue to actively study the tyrannosaur and its environment, identifying new interesting details.

Authors of a new article in the journal Fossil Studies A new species has been added to the Tyrannosaurids family, including T-rex Labocania aguillonae. They also learned a lot about the biogeography, or geographic distribution patterns, of these dinosaurs. The explanation was made thanks to fossils from Mexico, which have been waiting to be included in museum collections for a long time. Their age is estimated to be approximately 73 million years.

In those days, North America looked very different to the observer both on the ground and on the world map. Instead of a single large continent, there were two large island continents: to the west was Laramidia, which stretched in a strip from modern Alaska to Mexico, and to the east was compact Appalachia. Between them, instead of the plain, the Western Inland Sea splashed.

Separated by water, Laramidia and Appalachia had their own unique faunas, with many endemics and sharp geographical contrasts. The evolution of known tyrannosaurids is associated with the eastern continent, where it culminated in the emergence of the same “king” at the end of the Cretaceous period. T. rex. But even within Laramidia, tyrannosaurs were very different from each other. Some of them lived in the north, in the south they were completely different, and we know much less about them.

In Mexico, it was previously possible to find only one closely related species: Labocania anomalyand he too had a questionable systematic attitude. Even more valuable is the description of a new dinosaur made with the help of fossilized skull, spine, pelvic bones and limbs. L. aguillonae confidently attributed to tyrannosaurids, at the same time the right to refer to them is confirmed and L. abnormality.

By the standards of its family, the dinosaur was modest in size: a maximum length of 6.3 meters and a skull about 78 centimeters long. And here are the hips L. aguillonae It was relatively large, about 0.7 meters, making it quite leggy. In general, the close relative of tyrannosaurids, which, unlike them, lived much further north, turned out to be easily complex. But it had large eyes that could help it hunt at dusk and many anatomical features characteristic of the family.

The authors of the article highlighted an interesting pattern. As wide as the range of modern large animals is, the correlation is especially clear when it comes to predators. But the largest superpredators of Mesozoic America – tyrannosaurs – on the contrary, had limited ranges and seemed to divide the territory of the New World among themselves.