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'Reaper of death' tyrannosaur was a massive meat-munching monster

The dashing dinosaur is now the oldest tyrannosaur species discovered in Canada.

Amanda Kooser
Freelance writer Amanda C. Kooser covers gadgets and tech news with a twist for CNET. When not wallowing in weird gear and iPad apps for cats, she can be found tinkering with her 1956 DeSoto.
Amanda Kooser
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This artist's illustration show what Thanatotheristes degrootorum might have looked like.

Julius Scotonyi, courtesy Royal Tyrrell Museum

It's been 50 years since paleontologists last discovered a new species of tyrannosaur in Canada. Now say howdy to Thanatotheristes degrootorum. It may be the new dino on the block, but it dates back further than any other known Canadian tyrannosaur species.

"This is the oldest occurrence of a large tyrannosaur in Canada, found in an older window of time than where previous tyrannosaurs have been found," said Darla Zelenitsky, a paleontologist at the University of Calgary and co-author of a study published in the journal Cretaceous Research in January. 

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The  tudy co-authors Darla Zelenitsky, Jared Voris, Caleb Brown and François Therrien pose with the tyrannosaur fossil fragments.

Royal Tyrrell Museum

The dinosaur's name is a combination of the Greek god of death Thanatos and the Greek word "theristes," which translates to reaper. Put the two together and we get the stunning nickname "Reaper of Death."

The "degrootorum" part of the name is a tribute to John and Sandra De Groot of Alberta, Canada. John De Groot discovered the fossil fragments while on a hike. "The jawbone was an absolutely stunning find. We knew it was special because you could clearly see the fossilized teeth," he said in a release from the Royal Tyrrell Museum on Monday.

The researchers studied the skull and jaw bone. "The fossil has several physical features, including ridges along the upper jaw, which clearly distinguishes it as being from a new species," said the study's lead author Jared Voris, a PhD student at the university. 

The team estimated the reaper's age at about 79.5 million years old, which beats out the next-oldest known Canadian tyrannosaur species by 2.5 million years. "This discovery is significant because it fills in a gap in our understanding of tyrannosaur evolution," said Royal Tyrrell Museum dinosaur curator Francois Therrien

The analysis suggests the specimen may have been about 26 feet (8 meters) long. Compare that with Sue, a famous example of Tyrannosaurus rex, that measures in at over 40 feet (12 meters) in length. The Canadian dinosaur would still have been an intimidating sight.

The researchers hope to take a deeper dive into how tyrannosaurs from various regions may differ from each other when it comes to body type, size and physical features. There is still plenty of mystery surrounding the tyrannosaurid family tree.

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