‘The missing link': Calgary researchers discover new early tyrannosaur species
Scientists from the University of Calgary have discovered a new dinosaur specimen that they say appears to be the 'missing link' in the evolution of tyrannosaurs.
The specimen was originally discovered in Mongolia's Gobi Desert over 50 years ago in the 1970s. But its significance wasn't recognized until Darla Zelenitsky, an associate professor in the university's faculty of science, sent graduate student Jared Voris to Mongolia on a research trip.
'He was there a couple of years ago on this research trip and looked at the fossil and texted me (that) he thought it was a new species. I was like, 'yay,'' Zelenitsky told The Canadian Press.
'I said, 'This is good, but we don't want to jump the gun on this.' It turned out it (was) a new species.'
The species, Khankhuuluu mongoliensis — meaning 'Dragon Prince' or 'Prince of Dragons of Mongolia' — is believed to have crossed via a land bridge from Siberia to Alaska roughly 85 million years ago.
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Zelenitsky said it appears to sit on the evolutionary scale between smaller tyrannosauroids and tyrannosaurs.
'It's the missing link between smaller tyrannosauroids and the large predatory tyrannosaurs,' she said.
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'This missing link was around 750 kilograms. Its ancestors were a couple of hundred kilograms and just tiny, but then when you get to tyrannosaurs proper, they were over a thousand kilograms, up to estimates of 5,000 kilograms.'
The findings were published Wednesday in the British weekly scientific journal Nature.
'It's really exciting to be involved in a discovery of something that's been sitting in a drawer for 50 years. But it's even more exciting when it's a PhD student that makes that discovery,' Zelenitsky added.
'This discovery forced us to look at the family tree of tyrannosaurs in a very different light. It ended up with us rewriting the family history of tyrannosaurs.'
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The arrival of Khankhuuluu or a similar species after moving from Asia to North America may have been the result of following their prey to a new location, said Zelenitsky.
'It's possible that there weren't many tyrannosaur type predators so it's possible they were able to take over that niche in North America and moved to the top of the food chain,' she said.
'Tyrannosaurs were in the right place at the right time. It allowed them to diversity and evolve a large body size, ultimately becoming the massive apex predator that terrorized North America and Asia during the late Cretaceous period.'
Zelenitsky said the evolution to the tyrannosaur happened rapidly, geologically speaking, and probably took a few million years.
She has co-authored over 50 different publications during her career and was part of a team that first found evidence of feathered dinosaurs in North America.
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CTV News
2 days ago
- CTV News
A ‘dragon prince' dinosaur is redrawing the tyrannosaur family tree
Lead study author Jared Voris, a postdoctoral scholar at the University of Calgary, can be seen studying a Tyrannosaurus rex fossil as an assembled specimen looms behind him. Darla Zelenitsky via CNN Newsource Scientists have identified a previously unknown 86 million-year-old dinosaur species that fills an early gap in the fossil record of tyrannosaurs, revealing how they evolved to become massive apex predators. Researchers analyzing the species' remains have named it Khankhuuluu mongoliensis, which translates to 'dragon prince of Mongolia,' because it was small compared with its much larger relatives such as Tyrannosaurus rex, whose name means 'the tyrant lizard king.' The newly identified dinosaur was the closest known ancestor of tyrannosaurs and likely served as a transitional species from earlier tyrannosauroid species, according to the findings published Wednesday in the journal Nature. Based on a reexamination of two partial skeletons uncovered in Mongolia's Gobi Desert in 1972 and 1973, the new study suggests that three big migrations between Asia and North America led tyrannosauroids to diversify and eventually reach a gargantuan size in the late Cretaceous Period before going extinct 66 million years ago. 'This discovery of Khankhuuluu forced us to look at the tyrannosaur family tree in a very different light,' said study coauthor Darla Zelenitsky, associate professor within the department of Earth, energy, and environment at the University of Calgary, in an email. 'Before this, there was a lot of confusion about who was related to who when it came to tyrannosaur species. What started as the discovery of a new species ended up with us rewriting the family history of tyrannosaurs.' Multiple migrations over millions of years Tyrannosaurs, known scientifically as Eutyrannosaurians, bring to mind hulking dinosaurs like Tyrannosaurus rex and Tarbosaurus, which weighed multiple metric tons and could take down equally large prey. dinosaur An artist's rendering shows how newly identified dinosaur Khankhuuluu, much smaller than T. rex, might have looked. Masato Hattori via CNN Newsource With short arms and massive heads, they walked on two legs and boasted sharp teeth, Zelenitsky said. But tyrannosaurs didn't start out that way. They evolved from smaller dinosaurs before dominating the landscapes of North America and Asia between 85 million and 66 million years ago, the researchers said. While Tarbosaurus, an ancestor of T. rex, clocked in at between 3,000 and 6,000 kilograms (6,613 pounds and 13,227 pounds), the fleet-footed Khankhuuluu mongoliensis likely weighed only around 750 kilograms (1,653 pounds), spanned just 2 metres (6.5 feet) at the hips and 4 metres (13 feet) in length, according to the study authors. Comparing the two dinosaurs would be like putting a horse next to an elephant —Khankhuuluu would have reached T. rex's thigh in height, Zelenitsky said. 'Khankhuuluu was almost a tyrannosaur, but not quite,' Zelenitsky said. 'The snout bone was hollow rather than solid, and the bones around the eye didn't have all the horns and bumps seen in T. rex or other tyrannosaurs.' Khankhuuluu mongoliensis, or a closely related ancestor species, likely migrated from Asia to North America across a land bridge between Alaska and Siberia that connected the continents 85 million years ago, Zelenitsky said. Because of this migrant species, we now know that tyrannosaurs actually evolved first on the North American continent and remained there exclusively over the next several million years, she said. 'As the many tyrannosaur species evolved on the continent, they became larger and larger.' Due to the poor fossil record, it's unclear what transpired in Asia between 80 million to 85 million years ago, she added. While some Khankhuuluu may have remained in Asia, they were likely replaced later on by larger tyrannosaurs 79 million years ago. dinosaur Alioramus was a small Mongolian tyrannosaur, sometime referred to as a "Pinocchio rex" for its long snout. Jared Voris via CNN Newsource Meanwhile, another tyrannosaur species crossed the land bridge back to Asia 78 million years ago, resulting in the evolution of two related but very different subgroups of tyrannosaurs, Zelenitsky said. One was a gigantic, deep-snouted species, while the other known as Alioramins was slender and small. These smaller dinosaurs have been dubbed 'Pinocchio rexes' for their long, shallow snouts. Both types of tyrannosaurs were able to live in Asia and not compete with each other because the larger dinosaurs were top predators, while Alioramins were mid-level predators going after smaller prey — think cheetahs or jackals in African ecosystems today, Zelenitsky said. 'Because of their small size, Alioramins were long thought to be primitive tyrannosaurs, but we novelly show Alioramins uniquely evolved smallness as they had 'miniaturized' their bodies within a part of the tyrannosaur family tree that were all otherwise giants,' Zelenitsky said. One more migration happened as tyrannosaurs continued to evolve, and a gigantic tyrannosaur species crossed back into North America 68 million years ago, resulting in Tyrannosaurus rex, Zelenitsky said. 'The success and diversity of tyrannosaurs is thanks to a few migrations between the two continents, starting with Khankhuuluu,' she said. 'Tyrannosaurs were in the right place at the right time. They were able to take advantage of moving between continents, likely encountering open niche spaces, and quickly evolving to become large, efficient killing machines.' Revisiting a decades-old find The new findings support previous research suggesting that Tyrannosaurus rex's direct ancestor originated in Asia and migrated to North America via a land bridge and underscore the importance of Asia in the evolutionary success of the tyrannosaur family, said Cassius Morrison, a doctoral student of paleontology at University College London. Morrison was not involved in the new research. dinosaur Voris (left) and Darla Zelenitsky have been studying the evolution of tyrannosaurs. Riley Brandt/University of Calgary via CNN Newsource 'The new species provides essential data and information in part of the family tree with few species, helping us to understand the evolutionary transition of tyrannosaurs from small/ medium predators to large apex predators,' Morrison wrote in an email. The study also shows that the Alioramini group, once considered distant relatives, were very close cousins of T. rex. What makes the fossils of the new species so crucial is their age — 20 million years older than T. rex, said Steve Brusatte, professor and personal chair of Palaeontology and Evolution at the University of Edinburgh. Brusatte was not involved in the new study. 'There are so few fossils from this time, and that is why these scientists describe it as 'murky,'' Brusatte said. 'It has been a frustrating gap in the record, like if you suspected something really important happened in your family history at a certain time, like a marriage that started a new branch of the family or immigration to a new country, but you had no records to document it. The tyrannosaur family tree was shaped by migration, just like so many of our human families.' With only fragments of fossils available, it's been difficult to understand the variation of tyrannosaurs as they evolved, said Thomas Carr, associate professor of biology at Carthage College in Wisconsin and director of the Carthage Institute of Paleontology. Carr was not involved in the new research. But the new study sheds light on the dinosaurs' diversity and clarifies which ones existed when — and how they overlapped with one another, he said. More samples from the fossil record will provide additional clarity, but the new work illustrates the importance of reexamining fossils collected earlier. 'We know so much more about tyrannosaurs now,' Carr said. 'A lot of these historical specimens are definitely worth their weight in gold for a second look.' When the fossils were collected half a century ago, they were only briefly described at the time, Brusatte said. 'So many of us in the paleontology community knew that these Mongolian fossils were lurking in museum drawers, waiting to be studied properly, and apt to tell their own important part of the tyrannosaur story,' he said. 'It's almost like there was a non-disclosure agreement surrounding these fossils, and it's now expired, and they can come out and tell their story.'
Calgary Herald
2 days ago
- Calgary Herald
Ancient T. rex ancestor discovered: Khankhuuluu, ‘prince of dragons'
A new species of early tyrannosaur, dubbed the 'prince of dragons,' has been discovered lurking in a collection of fossils first excavated in Mongolia in the early 1970s, scientists said Wednesday in the journal Nature. Article content Khankhuuluu mongoliensis — its scientific name — is an evolutionary ancestor of the most famous tyrannosaur, the 'tyrant lizard king,' T. rex. Article content Article content Article content With their bone-crushing bites and spindly little arms, large tyrannosaurs (scientifically known as 'eutyrannosaurians') are the celebrities of the dinosaur world. But they started off as small-bodied tyrannosauroids some 150 million years ago in the Jurassic period. It wasn't until the late Cretaceous that they began evolving into the giants that ignite people's imaginations. Article content Article content Their precise evolutionary origins, however, have long been murky. A critical swath of the family tree is blank. Article content Khankhuuluu, known from two partial skeletons in fossil collections at the Institute of Paleontology in Mongolia, helps fill in this gap — a transitional 86 million-year-old species that represents the closest known ancestor to the famed late tyrannosaurs. Article content Previously, it had been described as an alectrosaurus, another early tyrannosaur. Asked for a modern-day comparison, University of Calgary graduate student Jared Voris, who led the work, said to imagine a large, predatory horse. Article content Article content 'What makes them so important is their age,' said Stephen Brusatte, a paleontologist at the University of Edinburgh who was not involved in the study. 'They are about 86 million years old, a good 20 million years older than T. rex. It has been a frustrating gap in the record.' Article content Voris was on a research trip in Mongolia in 2023 when he sent a text halfway across the world to his adviser, Darla Zelenitsky, an associate professor of paleontology. He told her that he thought some of the fossils he had examined in a museum collection were actually a new species. Article content Those specimens had been classified for decades as alectrosaurus, 'an enigmatic and poorly represented tyrannosauroid species,' Zelenitsky and Voris wrote in their study. Article content What leaped out to Voris initially was that the snout bone was hollow, a clear sign that this was an early ancestor of the tyrannosaur family. It was the first of what would come to be dozens of features that suggested this creature was something new.
Global News
2 days ago
- Global News
‘The missing link': Calgary researchers discover new early tyrannosaur species
Scientists from the University of Calgary have discovered a new dinosaur specimen that they say appears to be the 'missing link' in the evolution of tyrannosaurs. The specimen was originally discovered in Mongolia's Gobi Desert over 50 years ago in the 1970s. But its significance wasn't recognized until Darla Zelenitsky, an associate professor in the university's faculty of science, sent graduate student Jared Voris to Mongolia on a research trip. 'He was there a couple of years ago on this research trip and looked at the fossil and texted me (that) he thought it was a new species. I was like, 'yay,'' Zelenitsky told The Canadian Press. 'I said, 'This is good, but we don't want to jump the gun on this.' It turned out it (was) a new species.' The species, Khankhuuluu mongoliensis — meaning 'Dragon Prince' or 'Prince of Dragons of Mongolia' — is believed to have crossed via a land bridge from Siberia to Alaska roughly 85 million years ago. Story continues below advertisement Zelenitsky said it appears to sit on the evolutionary scale between smaller tyrannosauroids and tyrannosaurs. 'It's the missing link between smaller tyrannosauroids and the large predatory tyrannosaurs,' she said. Get breaking National news For news impacting Canada and around the world, sign up for breaking news alerts delivered directly to you when they happen. Sign up for breaking National newsletter Sign Up By providing your email address, you have read and agree to Global News' Terms and Conditions and Privacy Policy 'This missing link was around 750 kilograms. Its ancestors were a couple of hundred kilograms and just tiny, but then when you get to tyrannosaurs proper, they were over a thousand kilograms, up to estimates of 5,000 kilograms.' The findings were published Wednesday in the British weekly scientific journal Nature. 'It's really exciting to be involved in a discovery of something that's been sitting in a drawer for 50 years. But it's even more exciting when it's a PhD student that makes that discovery,' Zelenitsky added. 'This discovery forced us to look at the family tree of tyrannosaurs in a very different light. It ended up with us rewriting the family history of tyrannosaurs.' Story continues below advertisement The arrival of Khankhuuluu or a similar species after moving from Asia to North America may have been the result of following their prey to a new location, said Zelenitsky. 'It's possible that there weren't many tyrannosaur type predators so it's possible they were able to take over that niche in North America and moved to the top of the food chain,' she said. 'Tyrannosaurs were in the right place at the right time. It allowed them to diversity and evolve a large body size, ultimately becoming the massive apex predator that terrorized North America and Asia during the late Cretaceous period.' Zelenitsky said the evolution to the tyrannosaur happened rapidly, geologically speaking, and probably took a few million years. She has co-authored over 50 different publications during her career and was part of a team that first found evidence of feathered dinosaurs in North America.
