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World's largest tyrannosaurus rex discovered

Primeval Giant: A tyrannosaurus fossil discovered in Canada is the largest known representative of this species - and the most massive predatory dinosaur ever discovered. The animal was 13 meters long during its lifetime and weighed just under nine tons, as the paleontologists report. Especially: The tyrannosaur was quite old by dinosaur standards when he died and apparently suffered numerous injuries during his lifetime.

The Tyrannosaurus rex - the "king of the terrifying lizards" - was one of the largest predators in the history of the earth. So far, paleontologists have found skeletons up to twelve meters long from this two-legged walking dinosaur. Thanks to its unique skull, enormous bite force and teeth as sharp as steak knives, the T. rex could overpower even large prey and crack its bones. Despite its size, this carnivore was also amazingly agile.

A 13 meter long colossus

But how big could a T. rex get? So far, this is unclear because many of the known fossils of this predatory dinosaur come from under-grown specimens. But a skeleton discovered in 1991 in Saskatchewan, Canada, now provides new information. Because the bones were encased in extremely hard sandstone, it took more than ten years for researchers to uncover the fossil. Only then could they study the anatomy of this "Scotty" named T. rex in more detail.

The surprising result: the 66 million year old tyrannosaur must have been more than 13 meters long. It is thus larger than all known representatives of this species. "This really is the Rex of the T. rexen," says first author Scott Persons of the University of Alberta. "After we measured the legs, hips and shoulders precisely, Scotty is significantly bigger than any other T. rex specimen."

True dinosaur sizes underestimated?

In terms of body weight, the tyrannosaur "Scotty" not only outperformed its conspecifics, but also all other known predatory dinosaurs, as the paleontologists report. According to their estimates, the tyrannosaur must have weighed more than 8,800 kilograms during its lifetime - just under nine tons. “That is more than any other gigantic terrestrial theropod,” the researchers say.

According to Persons and his team, this could indicate that the true size of many tyrannosaurs, and possibly other dinosaurs, has been underestimated. "This specimen supports previous hypotheses that there might be a sampling-related distortion of our view of the dinosaurs," say the paleontologists. Because hardly any fully grown specimens have been found so far, the maximum size of many species is simply not yet known.

Old and full of battle marks

And “Scotty” has another special feature: He was quite old when he died. According to the growth rings of its boils, this tyrannosaur reached an age of around 30 years. "This makes Scotty the oldest known Tyrannosaurus rex," says Persons. “By tyrannosaur standards, it lived an unusually long life.” As the paleontologists explain, these predatory dinosaurs grew up relatively quickly, but usually died early.

The bones of "Scotty" prove how hard and violent the life of the tyrannosaurs was at that time. "We find pathological changes everywhere in the skeleton - places where injuries have left traces in the bones," reports Persons. Among other things, Scotty suffered broken ribs, a severe jaw infection and several bites on the tail from other conspecifics. (The Anatomical Record, 2019: doi: 10.1002 / ar.24118)

Scotty - the largest known T. rex T. rex. © Pro7

Source: University of Alberta

March 25, 2019

- Nadja Podbregar