In 2019, paleontologists announced they had found the largest and oldest Tyrannosaurus rex known to science. The dinosaur had weighed roughly 19,555 pounds, which means it weighed almost as much as four pick-up trucks, and it had been about 42 feet long. It had also lived into its early 30s, which makes it the longest-lived T. rex known.
What have scientists learned so far?
The paleontologists described their find in the science journal “The Anatomical Record.” They dubbed the dinosaur “Scotty” after the scotch they had used to toast their discovery. Scotty had lived 66 million years ago in what is now Saskatchewan, a province in Canada. Scientists had actually found the specimen back in 1991, but it had taken them nearly three decades to excavate the enormous theropod from sandstone with the hardness of cement.
The lead author, W. Scott Persons, commented about the beast’s size, “This is the rex of rexes. There is considerable size variability among Tyrannosaurus. Persons added that some T. rexes had had lanky builds, while others had been stocky. Scotty was an example of a stocky tyrannosaur.
While Scotty’s fossil is only 65 percent complete, the paleontologists were still able to gauge his overall size. They measured the bones in his shoulders, hips, and legs, and they were able to calculate Scotty’s weight by measuring the circumference of the femurs. That particular measurement told them how much weight Scotty’s legs had been able to support.
Source: ShutterstockHow does Scotty compare to other T. rexes?
Scotty is believed to be the heaviest T. rex known. The paleontologists have compared his fossil to that of 11 other well-preserved tyrannosaur fossils. Scotty had the greatest mass of the group, but he may not have been the longest or the tallest. Scotty’s new status as heaviest known tyrannosaur dethroned the old record-holder, Sue, who had weighed 18,651 pounds, which is about five percent less than Scotty.
A writer for “Scientific American,” Brian Switek, pointed out that the phrase “biggest dinosaur” is an imprecise term. It could refer to length, weight, or both. He added that two tyrannosaurs that were the same length could have had different weights. Similarly, two tyrannosaurs that weighed the same could have been different lengths.
Switek also noted that Scotty’s skeleton is far less complete than that of Sue, which is an impressive 90 percent complete. He stated that Scotty and Sue were probably fairly close in size. Similarly, John Hutchinson, an expert in evolutionary biomechanics from the Royal Veterinary College at the University of London, didn’t believe that Scotty was that much larger than other T. rexes.
What were some other findings?
The scientists found that Scotty had taken quite a beating during his 30-plus years of existence. They found injuries like broken ribs, an impacted tooth, and an infected jaw. They also found damage to his tail vertebrae that had apparently been caused by the bite of a fellow T. rex.
Roni Dengler, a writer for “Discover” magazine commented that it was not a coincidence that Scotty had been both large and long-lived. She noted that the lack of similarly-sized fossils indicates that most T. rexes had died before they could reach Scotty’s size.
Source: ShutterstockHow do scientists know how long Scotty lived?
Scientists used to believe that behemoths like T. rex grew slowly and lived for about 50 to 100 years. Recently, however, scientists have studied the cellular structure of dinosaur bones through microscopic analyses.
Researchers have found that dinosaur bones contain growth rings similar to those seen in trees. They can thus tell how quickly a dinosaur grew and how old it was at the time of death. Scientists have learned that tyrannosaurs grew at a pace similar to those of birds, which are their closest living relatives. They also now know that T. rexes reached sexual maturity when they were about 20 years old.
A tyrannosaur that weighed over nine tons and lived longer than any of its fellows is certainly an impressive specimen. Scientists hope to learn more about the lives of large carnivorous dinosaurs. Fans of dinosaurs can visit Scotty at the Royal Saskatchewan Museum, where he has been on display since May 2019.
