A parent of Teeny T. rex discovered in the United States

A newly discovered parent of Tyrannosaurus rex a study shows that a little over a meter high was at the hip.

The tiny Tyrannosaurus reveals new crucial information about the T. rex established itself as a dominant carnivore in North America.

At the beginning of their evolution, the tyrannosaurs were small, but at one point, the big ones T. rex with others emerged as apex predators.

The new fossil helps fill a gap of 70 million years in the fossil record.

Discovered in Emery County, Utah, the animal lived about 96 million years ago, at the end of the Cretaceous period.

Tyrannosaurs, or "tyrant lizards" – the group to which this specimen and T. rex is part of the predator on the ground in the 15 million years that preceded the passage of the asteroid Chicxulub in the Yucatan Peninsula 66 million years ago. T. rex could reach more than 3.5 m tall as measured at the hip.

But as Lindsay Zanno, co-author of North Carolina State University, explained, it has not always been like this: the food chain, "she said.

Our understanding of the evolutionary events that led to the appearance of giant tyrannosaurs has been limited by the lack of complete fossils in North America.

Early primitive tyrannosaurs were found in North America, dating back to the Jurassic period (about 150 million years ago). About 81 million years ago, the tyrannosaurs of North America had become huge beasts. But the fossil record between these two periods is unequal.

The bones of the leg of the new species, Morphs Intrépidus, were discovered in the same area where Dr. Zanno and his team had already found Siats meekerorum, a giant meat-eating dinosaur belonging to a group known as carcharodontosaurs. This biggest predator lived during the same period as Moros.

The researchers believe that Morphs Intrépidus was about the size of a modern mule deer, weighing about 78 kg. He was seven years old when he died and was almost fully grown.

Although relatively light, he was probably very fast on his feet. "These adaptations, combined with advanced sensory capabilities, are the mark of a formidable predator, who could easily have shot prey while avoiding confrontation with the greatest predators of the day," said Dr. Zanno.

"Although the early Cretaceous tyrannosaurs were small, their predatory specialization allowed them to take advantage of the new opportunities offered by warmer temperatures, rising sea levels, and narrowing ranges at the beginning. Cretaceous.

"We now know that it took them less than 15 million years to gain power."

The scientific article, published in the journal Communications Biology, states that these environmental changes may have led to the decline of allosaurs – the apex predators that ruled until the emergence big tyrannosaurs.

An analysis of Moros'S place on the family tree of tyrannosaurs seems to suggest that the group may have migrated to North America from Asia.

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