New T. Rex Research Awakens Paleontology World; Scientists Suggest Tyrannosaurus Was Actually Three Separate Species | The Weather Channel – Articles from The Weather Channel


Representative image.

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Either like the huge, fearsome T. Rex featured in the Jurassic Park movies, or the gigantic, playful “Rexy” from the Night at the Museum franchise, the tyrannosaurus rex is an extremely popular species of dinosaur – and not just for movie buffs, but also among paleontologists.

The T. rex was the only species of the genus Tyrannosaurus recognized since its description in 1905. And all dinosaur enthusiasts were pretty sure to know that when it comes to the iconic T. rex, there is hardly any new information that could be revealed.

However, much to the surprise of the paleontological community, researchers suggest that the apex predator that roamed the Earth around 66 million years ago may actually be three separate species: T. rex, T. regina and T. imperator. !

Scientists have long identified discrepancies in the skeletal morphology of Tyrannosaurus specimens, especially the femur (thigh bone) in individuals of similar size and specimens with one or two narrow incisors on the anterior edges of the jaw.

But until now, these differences have been attributed to sexual dimorphism, different stages of genetic development, or simply individual variance.

In search of differences

In this particular study, the researchers looked at a dataset of 37 specimens; the group examined the sturdiness of the femur of 24 specimens and measured the diameter of the base of the teeth or the space in the gums to determine whether the specimens had one or two thin incisor-like teeth.

Scientists observed variants in the femur, with twice as many robust femurs as thin femurs on the specimens. “Robust” femora were also found in some juvenile specimens, while “slender” femora occurred in some that were of adult size, suggesting that the variation may not have been related to growth.

Their tooth structures also differed, with individuals with an incisor-like tooth having a higher femoral gracilis.


29 Tyrannosaurus specimens have been discovered in different geological strata of sediments in the Upper Maastrichtian Lancien formations in North America, which are around 67.5–66 million years old.

Now there are three levels in these sediments: lower, middle and upper. Surprisingly, the six femurs discovered in the lower layer were robust. A single gracile femur was identified in the middle layer, and the upper layer had a more homogeneous mixture of the two types. This variance in the upper layer was also much higher than in other theropod species reported in these strata.

These results strongly suggest that over time, Tyrannosaurus diverged into physiologically distinct specimens.

“We found that changes in Tyrannosaurus the femurs are probably not related to the sex or age of the specimen. We propose that changes in the femur may have evolved over time from a common ancestor that exhibited more robust femora to become more slender in later species,” said paleontologist Gregory Paul, lead author of the study.

The King, Queen and Emperor

Upon examination, it was found that of the two proposed new species, the Imperator Tyrannosaurus or “tyrant lizard emperor” refers to individuals discovered in the lower and middle strata of the sediment, and is distinguished by sturdier femurs and usually two incisors.

The second, tyrannosaurus regina or “tyrant lizard queen”, had thinner femurs and a single incisor tooth, and is found in upper and possibly intermediate sediment levels.

And the good old tyrannosaurus rex or “tyrant lizard king” has been discovered in the upper and probably middle layers of the sediment, with specimens classified as having sturdier femurs but a single incisor tooth.

While the results of this study are staggering, it should be noted that some skeptics remain skeptical. For example, Thomas Carr, a paleontologist at Carthage College in Wisconsin, US, suggests the new research only shows subtle differences that could be attributed to variation between individuals.

The findings of the study have been published in Springer link on March 1 and accessible here.


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