Meet Scotty. The heaviest Tyrannosaurus rex ever unearthed was unveiled last week in The Anatomical Record, weighing in at an estimated 19,500 pounds during its existence. Paleontologists first dug “Scotty” up in 1991 at a site in Saskatchewan, Canada where they found about 65% of its skeleton. The dinosaur’s eight-inch femur across impressed the team, hinting that its two legs could’ve carried more than 19,500 pounds. However, even with Scotty’s top role in the hierarchy of predatory dinosaurs, injuries such as a broken and healed rib, an infection of bone growth between two teeth and broken tailbones likely caused by another specimen’s bite proves that it didn’t lead an easy life. Calculated to be at least 28 years old (a senior in the world of tyrannosaurs), Scotty’s bearings suggest that large predatory dinosaurs were much older and bigger than paleontologists originally deemed to be based on the data they have on currently available fossils. “As more specimens of those other theropods are found, we’re going to find their Scottys: their particularly large, particularly old individuals,” study leader Scott Persons said. “It would not surprise me that those animals turn out to increase the range of body size—potentially to overlap or even surpass what we know from T-rex.” In other news, a stolen Picasso painting has been recovered after 20 years.<doc-sep>The Scotty T. rex on display. Image : Amanda Kelley Updated measurements of a large fossil found in Saskatchewan nearly 30 years ago confirm it as the world’s largest known Tyrannosaurus rex skeleton. Remarkably, the new work suggests T. rex and other dinosaurs grew to a greater size than is typically appreciated. Advertisement New research published last week in The Anatomical Record describes “Scotty,” a T. rex skeleton otherwise known as specimen RSM P2523.8. Scotty is now officially the largest and most aged T. rex ever discovered, and the most gigantic of any of the known two-legged carnivorous dinosaurs known as theropods. At an estimated 19,555 pounds (8,870 kg), it’s also the biggest dinosaur ever discovered in Canada. The new study was led by paleontologist Scott Persons from the University of Alberta. Scotty’s skeleton was discovered near Eastend, Saskatchewan in 1991, but work to remove it from the ground didn’t fully start until 1994. It took paleontologists nearly a decade to excavate the fossil because it was encased in compact, cement-like sandstone. The extra effort to excavate the bones, plus the sheer size of the specimen, resulted in further delays. That said, the paleontologists were able to recover around 65 percent of the T. rex specimen, which terrorized Cretaceous Canada some 66 million years ago. Early attempts to characterize the skeleton between 2008 and 2014 were marred by inaccuracies owing to the fact that the fossil hadn’t been fully prepared for analysis. Consequently, and as Persons pointed out in the new study, Scotty “has never been formally described and its skeletal proportions scientifically quantified.” The new study is now the first to offer detailed and accurate measurements of the skeleton, including a comparative analysis with other known T. rex fossils. Measurements of Scotty’s legs, hips, and shoulder point to a T. rex of enormous size. Persons and his colleagues relied on an equation developed by other researchers to infer its body mass, using the circumference of the femur, or thigh bone, to glean the amount of weight the legs could reasonably support. In this case, Scotty’s femur suggested a weight of 19,555 pounds, which is nearly 1 0 tons. At 13 meters in length, Scotty may not have been the tallest or longest T. rex that ever lived—but it was certainly big in terms of mass. Analysis of the growth patterns in Scotty’s bones suggests the dinosaur died in its early 30s, making it the most elderly T. rex skeleton ever discovered. Extensive injuries were detected throughout the body, pointing to a particularly brutal life. Scotty had broken ribs, an infected jaw, and bite marks on its tail, the latter of which appeared to be inflicted by a rival T. rex, the new study suggests. Persons and his colleagues compared Scotty’s skeleton to 11 other well-preserved T. rex skeletons, including Sue—a specimen otherwise known as FMNH PR 2081. Sue’s bones were found in 1990, and it was once considered the biggest T. rex skeleton, a title that now belongs to Scotty. Sue weighed in at 18,651 pounds (8,460 kg), which is around 5 percent lighter than Scotty. Advertisement “I’ve been waiting a long time for the description of this awesome T. rex fossil, as have many paleontologists,” Steven Brusatte, a University of Edinburgh paleontologist not involved with the study, told Gizmodo. “It is one of the largest and oldest T. rexes out there, and it gives us a glimpse at just how big T. rex got during those last years of its life.” Brusatte said the new study provides good evidence that a 13-meter-long, 7-to-8 ton body plan was “as big as the King got—but that’s pretty big,” adding that T. rex is still the “biggest pure meat-eating animal that has ever lived on land as far as we currently know.” Advertisement Indeed, other large theropod species, such as Spinosaurus aegyptiacus, Giganotosaurus carolinii, and Tyrannotitan chubutensis, may have been larger than T. rex, but more fossil evidence is needed for paleontologists to be sure. For now, T. rex remains king. As an interesting aside, paleontologists have noticed substantial size variations among the T. rex fossils. Some scientists have proposed a classification scheme based on two forms: “gracile” T. rexes with long and slender skeletons and “robust” T. rexes featuring stockier builds and greater bulk. Other paleontologists say these size discrepancies can be explained by individual variation or age. Another possibility is sexual dimorphism, in which females are larger than males. The reason for the hypothesized larger female T. rexes could have something to do with the increased physical demands of having to lay and protect eggs. Advertisement A fascinating conclusion reached in the new study is that the sizes of T. rex and other dinosaurs are being understated by paleontologists. The reason, according to the authors, is that very few dinosaurs managed to survive into full maturity. Consequently, there are more fossils of younger, smaller dinosaurs than there are of bigger, older dinosaurs, resulting in a kind of selection bias. Looking at Scotty’s skeleton, with its wide-ranging display of injuries, life as a dinosaur was clearly tough—even when you’re a T. rex. John Hutchinson, professor of evolutionary biomechanics at the University of London’s Royal Veterinary College and an expert on T. rex physiology, was a bit blasé about the new study. Advertisement “If you read between the lines in past studies and this new one, the Scotty specimen is not appreciably larger than other known specimens—at best, maybe 5 percent larger, and that is with a wide margin of error,” Hutchinson told Gizmodo. Which is fair; the margin of error for the weight estimates presented in the study are at a whopping plus-minus 25 percent. What’s more, “some bones are smaller than known skeletons, while others are larger,” said Hutchinson, so “we do not learn something truly major, unambiguous, and new about the size of T. rex from this specimen.” Advertisement Paleontologist Thomas Carr from Carthage college, also not affiliated with the new study, said the absolute difference in size between Scotty, Sue, and others may not be great, but the Scotty specimen raises the ceiling for the maximum size of T. rex, which is now higher than previously thought. “That changes our picture of what is within the range of possibility for these large animals and expands our understanding of the biology of large theropods at that extreme end of the size range,” Carr told Gizmodo. “Without Scotty, our estimate of the ceiling of the maximum size would be inaccurate—Scotty sharpens that picture.” Advertisement [The Anatomical Record] Correction: A previous version of this article incorrectly converted pounds to tons. We regret the error.<doc-sep>
We all knew the mighty Tyrannosaurus rex was big. But palaeontologists in Canada have just identified the biggest lizard tyrant king yet - its name is Scotty, and boy was it a corker. From nose to tail-tip, Scotty measures 13 metres (43 feet), and would have cracked the scales at 8,800 kilograms (19,400 pounds), based on a calculation using its mighty thigh-bones. "This is the rex of rexes," said palaeontologist Scott Persons of the University of Alberta in Canada. "There is considerable size variability among Tyrannosaurus. Some individuals were lankier than others and some were more robust. Scotty exemplifies the robust. [It] comes out a bit heftier than other T. rex specimens." The bones are not actually new. They were discovered in Saskatchewan in 1991, but since they were embedded in some pretty solid sandstone, the excavation was a slow and painstaking process, taking over a decade. Then palaeontologists had to put the bones back together - another slow and painstaking process. But it was worth it, because now those bones are finally giving up their secrets. For instance, we know that Scotty (named for the bottle of Scotch whisky opened to celebrate the skeleton's initial discovery) was exceptionally old - it has lived longer than any other T. rex discovered to date. Palaeontologists can figure this out by looking at a dinosaur's bones. Annual variations in climate and food availability would slow dinosaurs' bone growth, which results in a ring. These rings - much like the rings of a tree trunk - can be counted to estimate a dinosaur's age of death. It was thought that T. rex had a lifespan of around 30 years; the previous oldest ever found, Trix, had an estimated age of about 30. Scotty had a year or two on Trix - it died in its early 30s. "By Tyrannosaurus standards," Persons said, "it had an unusually long life." Scotty's bones also had extensive injuries that showed signs of healing. Which means the old animal who lived 66 million years ago in the Cretaceous, got into a lot of scrapes - and somehow survived them. The injuries include broken ribs, an infection in the dino's jaw, and marks on its tail that could be from a bite inflicted by another T. rex in an epic battle. It may come from somewhat teeny tiny origins, but there's a reason T. rex became one of the most beloved extinct animals to have ever trod Earth. As Scotty demonstrates, it was a formidable beast indeed. "I think there will always be bigger discoveries to be made," said Persons. "But as of right now, this particular Tyrannosaurus is the largest terrestrial predator known to science." The research has been published in The Anatomical Record.