Findings show: Earth has 2 new species of tyrannosaurs

Tyrannosaurus imperator and tyrannical queen Tyrannosaurus regina have been added to the list of the most terrifying monsters to ever walk the Earth, alongside the famous Tyrannosaurus rex (T-rex).

According to New Scientist, a new analysis by American paleontologists, based on 40 tyrannosaur skeletons ever unearthed, has shown that Earth must have 3 species of tyrannosaurs, not 1. with clearly defined species.

Experts from many museums, institutes and schools across the US, led by paleontologist Gregory S. Paul have found the biggest difference in the femurs of some tyrannosaurs. Some specimens show 1-2 more slender incisors on each side of the jaw.

The famous Sue is a T.imperator, not a regular T-rex

Specifically, some femurs are structurally stronger than others, and some have more slender femurs. But there were females with thin femurs that were more than twice as strong as the "gentle" animals in the samples, suggesting that the bone difference is not due to gender, according to the Daily Mail.

The dental examination results and the way the specimens are searched gradually help to further solve the puzzle.

Of the Tyrannosaurus samples considered, 29 were in separate deposits in Masstrichtian, Lancian, North America, a well-known "dinosaur mecca".

Nine tyrannosaurs skeletons were found in the lower layer, three in the lower-middle boundary, four in the middle layer, and 15 in the upper layer.

The six strongest females were found in the lower layer with femurs similar to specimens found at other sites indicating only one species of Tyrannosaurus at this time. But the further up, the more distinctly different specimens of the femur suggest the possibility that species divergence was occurring.

Since then, the authors have classified Tyrannosaurus into 3 species:

1. The first is the Tyrannosaurus imperator - "tyrant emperor" - related to the lower and middle sedimentary specimens, extremely strong femur and having 2 incisors.
2. The second is the "tyrant queen" Tyrannosaurus regina, related to the upper and middle sedimentary specimens, featuring a more slender femur and the presence of an incisor.
3. Meanwhile, the famous T-rex located in the named sedimentary layer, is a "late calving" species, also has 1 incisor but stronger females,

Many famous tyrannosaurs skeletons have "participated" in the study. In it, the dinosaur Sue from the Field Museum in Chicago, was identified as T. imperator; while Stan - sold to a private buyer for $32 million in 2020 - T. regina.

The study has just been published in the scientific journal Evolution Biology.