The long-running debate of whether the dinosaur fossils first unearthed in&nbsp;Montana, US, in 1942, belonged to teenage&nbsp;Tyrannosaurus Rexes or not has finally been settled. A new study published has concluded that the skulls belonged to a different species of dinosaur, not the T-Rexes.&nbsp;

The researchers at the&nbsp;Milner Centre for Evolution at the University of Bath said the 66-million-year-old fossils are most likely from the Nanotyrannus. The findings were published in the&nbsp;journal Fossil Studies.

"I didn't expect it to be quite so conclusive.&nbsp;If they were young T. Rex they should be growing like crazy, putting on hundreds of kilogrammes a year, but we're not seeing that," said Dr Nick Longrich associated with the study.&nbsp;

Based on the modelling data, scientists observed that the dinosaurs would have grown to a&nbsp;maximum size of around 900 to 1,500 kilogrammes and five metres which is only about 15 per cent the size of a full-grown, adult T. Rex.&nbsp;

"We tried modelling the data in a lot of different ways and we kept getting low growth rates. This is looking like the end for the hypothesis that these animals are young T. Rex," added&nbsp;Longrich.&nbsp;

The research validates that&nbsp;Nanotyrannus is a separate species, one not closely related to Tyrannosaurus. The&nbsp;Nanotyrannus had longer arms, unlike the famously short-armed T. Rex.&nbsp;

While T. Rex relies on size and strength,&nbsp;Nanotyrannus used their small frame, pace, agility and arms as pretty formidable weapons to hunt down prey.&nbsp;&nbsp;

"I was very skeptical about Nanotyrannus myself until about six years ago when I took a close look at the fossils and was surprised to realize we'd gotten it wrong all these years," said&nbsp;Longrich.&nbsp;

<a href="https://www.wionews.com/videos/wion-climate-tracker-climate-change-played-keyrole-in-dominance-of-dinosaurs-545615">Watch |&nbsp;WION Climate Tracker: Climate change played keyrole in dominance of dinosaurs</a>

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<h2>T. Rex fossil remains highly sought after&nbsp;</h2>

Dinosaur skeletons and other specimens belonging to the majestic reptile that once roamed the face of the Earth remain highly sought after by collectors. No more than a couple of sales take place in a year worldwide which attract&nbsp;enormous attention, especially if it involves a T. Rex - the legendary 40-foot-long predator.&nbsp;

<a href="https://www.wionews.com/science/for-the-first-time-67-million-year-old-t-rex-skeleton-to-be-auctioned-in-europe-571024">Also read |&nbsp;For the first time, 67-million-year-old T-Rex skeleton to be auctioned in Europe</a>

Notably, in April last year, a 67-million-year-old T. Rex skeleton named 'Trinity' was auctioned in Switzerland. It was the first time that an entire T-Rex skeleton had gone under the hammer and fetched a record sum of $6.1 million at the Koller auction house.&nbsp;

(With inputs from agencies)

The long-running debate of whether the dinosaur fossils first unearthed in Montana, US, in 1942, belonged to teenage Tyrannosaurus Rexes or not has finally been settled.

The long-running debate of whether the dinosaur fossils first unearthed in Montana, US, in 1942, belonged to teenage Tyrannosaurus Rexes or not has finally been settled. A new study published has concluded that the skulls belonged to a different species of dinosaur, not the T-Rexes. The researchers at the Milner Centre for Evolution at the University of Bath said the 66-million-year-old fossils are most likely from the Nanotyrannus. The findings were published in the journal Fossil Studies. "I didn't expect it to be quite so conclusive. If they were young T. Rex they should be growing like crazy, putting on hundreds of kilogrammes a year, but we're not seeing that," said Dr Nick Longrich associated with the study. Based on the modelling data, scientists observed that the dinosaurs would have grown to a maximum size of around 900 to 1,500 kilogrammes and five metres which is only about 15 per cent the size of a full-grown, adult T. Rex. "We tried modelling the data in a lot of different ways and we kept getting low growth rates. This is looking like the end for the hypothesis that these animals are young T. Rex," added Longrich. The research validates that Nanotyrannus is a separate species, one not closely related to Tyrannosaurus. The Nanotyrannus had longer arms, unlike the famously short-armed T. Rex. While T. Rex relies on size and strength, Nanotyrannus used their small frame, pace, agility and arms as pretty formidable weapons to hunt down prey. "I was very skeptical about Nanotyrannus myself until about six years ago when I took a close look at the fossils and was surprised to realize we'd gotten it wrong all these years," said Longrich. Watch | WION Climate Tracker: Climate change played keyrole in dominance of dinosaurs × T. Rex fossil remains highly sought after Dinosaur skeletons and other specimens belonging to the majestic reptile that once roamed the face of the Earth remain highly sought after by collectors. No more than a couple of sales take place in a year worldwide which attract enormous attention, especially if it involves a T. Rex - the legendary 40-foot-long predator. Also read | For the first time, 67-million-year-old T-Rex skeleton to be auctioned in Europe Notably, in April last year, a 67-million-year-old T. Rex skeleton named 'Trinity' was auctioned in Switzerland. It was the first time that an entire T-Rex skeleton had gone under the hammer and fetched a record sum of $6.1 million at the Koller auction house. (With inputs from agencies)

Debate settled: Teenage T. Rex skulls unearthed in 1942 belonged to a different dinosaur species

Ferocious tyrannosaur dinosaurs may not have been solitary predators as long envisioned, but more like social carnivores such as wolves, as per a recent study unveiled.

Paleontologists developed the theory while studying a mass tyrannosaur death site found seven years ago in the Grand Staircase-Escalante National Monument in southern Utah, one of two monuments that the Biden administration is considering restoring to their full size after former President Donald Trump shrunk them.

Also read|&nbsp;<a href="https://www.wionews.com/science/thats-a-lot-of-teeth-researchers-discover-25-billion-tyrannosaurus-rex-377881" hreflang="en">‘That’s a lot of teeth’: Researchers discover 2.5 billion Tyrannosaurus rex</a>

Using geochemical analysis of the bones and rock, a team of researchers with the University of Arkansas determined that the dinosaurs died and were buried in the same place and were not the result of fossils washing in from multiple areas.

According to&nbsp;Kristi Curry Rogers, a biology professor at Macalester College, the new Utah site is the third mass tyrannosaur gravesite that’s been discovered in North America,&nbsp;bolstering a theory first developed 20 years ago that they lived in packs. However, more research needs to be done to make that argument.

“It is a little tougher to be so sure that these data mean that these tyrannosaurs lived together in the good times,” Rogers said. “It’s possible that these animals may have lived in the same vicinity as one another without traveling together in a social group, and just came together around dwindling resources as times got tougher.”

In 2014, Bureau of Land Management paleontologist Alan Titus discovered the site, which was later named the Rainbows and Unicorns quarry because of the vast array of fossils contained inside. Excavation has been ongoing since the site’s discovery because of the size of the area and volume of bones.

“I consider this a once-in-a-lifetime discovery for myself,” Titus told reporters during a virtual news conference. “I probably won’t find another site this exciting and scientifically significant during my career.”

The social tyrannosaurs theory began over 20 years ago when more than a dozen tyrannosaurs were found at a site in Alberta, Canada. Another mass death site in Montana again raised the possibility of social tyrannosaurs. Many scientists questioned the theory, arguing that the dinosaurs didn’t have the brainpower to engage in sophisticated social interaction, Titus said.

“Going that next step to understand behavior and how animals behave requires really amazing evidence,” Joseph Sertich, curator of dinosaurs at the Denver Museum of Nature &amp; Science, said at the news conference. “I think that this site, the spectacular collection of tyrannosaurs but also the other assembled pieces of evidence ... pushes us to the point where we can show some evidence for behavior.”

In addition to the tyrannosaurs, researchers have also found seven species of turtles, multiple fish and ray species, two other kinds of dinosaurs and a nearly complete skeleton of a juvenile Deinosuchus alligator. These other animals do not appear to have all died together.

Paleontology groups have been among those pushing the federal government to restore the Bears Ears National Monument and Grand Staircase-Escalante to their original sizes to protect the region’s rich paleontological and archaeological record.

Interior Secretary Deb Haaland visited southern Utah earlier this month as she prepared to submit recommendations on whether to reverse Trump’s decision to downsize the monuments. Titus said he showed Haaland some of the fossils at his lab during her visit and said she “appreciated getting to see the material.”

“The (Bureau of Land Management) is protecting these fossils as national treasures.” Titus said. “They’re part of the story of how North America came to be and how ultimately we came to be.”

(With input from agencies)

Ferocious tyrannosaur dinosaurs may not have been solitary predators as long envisioned, but more like social carnivores such as wolves, as per a recent study unveiled.

Ferocious tyrannosaur dinosaurs may not have been solitary predators as long envisioned, but more like social carnivores such as wolves, as per a recent study unveiled. Paleontologists developed the theory while studying a mass tyrannosaur death site found seven years ago in the Grand Staircase-Escalante National Monument in southern Utah, one of two monuments that the Biden administration is considering restoring to their full size after former President Donald Trump shrunk them. Also read| ‘That’s a lot of teeth’: Researchers discover 2.5 billion Tyrannosaurus rex Using geochemical analysis of the bones and rock, a team of researchers with the University of Arkansas determined that the dinosaurs died and were buried in the same place and were not the result of fossils washing in from multiple areas. According to Kristi Curry Rogers, a biology professor at Macalester College, the new Utah site is the third mass tyrannosaur gravesite that’s been discovered in North America, bolstering a theory first developed 20 years ago that they lived in packs. However, more research needs to be done to make that argument. “It is a little tougher to be so sure that these data mean that these tyrannosaurs lived together in the good times,” Rogers said. “It’s possible that these animals may have lived in the same vicinity as one another without traveling together in a social group, and just came together around dwindling resources as times got tougher.” In 2014, Bureau of Land Management paleontologist Alan Titus discovered the site, which was later named the Rainbows and Unicorns quarry because of the vast array of fossils contained inside. Excavation has been ongoing since the site’s discovery because of the size of the area and volume of bones. “I consider this a once-in-a-lifetime discovery for myself,” Titus told reporters during a virtual news conference. “I probably won’t find another site this exciting and scientifically significant during my career.” The social tyrannosaurs theory began over 20 years ago when more than a dozen tyrannosaurs were found at a site in Alberta, Canada. Another mass death site in Montana again raised the possibility of social tyrannosaurs. Many scientists questioned the theory, arguing that the dinosaurs didn’t have the brainpower to engage in sophisticated social interaction, Titus said. “Going that next step to understand behavior and how animals behave requires really amazing evidence,” Joseph Sertich, curator of dinosaurs at the Denver Museum of Nature & Science, said at the news conference. “I think that this site, the spectacular collection of tyrannosaurs but also the other assembled pieces of evidence ... pushes us to the point where we can show some evidence for behavior.” In addition to the tyrannosaurs, researchers have also found seven species of turtles, multiple fish and ray species, two other kinds of dinosaurs and a nearly complete skeleton of a juvenile Deinosuchus alligator. These other animals do not appear to have all died together. Paleontology groups have been among those pushing the federal government to restore the Bears Ears National Monument and Grand Staircase-Escalante to their original sizes to protect the region’s rich paleontological and archaeological record. Interior Secretary Deb Haaland visited southern Utah earlier this month as she prepared to submit recommendations on whether to reverse Trump’s decision to downsize the monuments. Titus said he showed Haaland some of the fossils at his lab during her visit and said she “appreciated getting to see the material.” “The (Bureau of Land Management) is protecting these fossils as national treasures.” Titus said. “They’re part of the story of how North America came to be and how ultimately we came to be.” (With input from agencies)

Scientists say ferocious Tyrannosaurs may have hunted in packs like wolves

Researchers on Thursday unveiled the first calculation of the total T. rex population during the estimated 2.4 million years that this fearsome species inhabited western North America during the twilight of the age of dinosaurs.

They considered factors including the size of its geographic range, its body mass, growth pattern, age at sexual maturity, life expectancy, duration of a single generation and the total time that T. rex existed before extinction 66 million years ago. They also heeded a doctrine called Damuth's law linking population to body mass: the bigger the animal, the fewer the individuals.

Their analysis put the total number of T. rex individuals that ever existed at about 2.5 billion, including approximately 20,000 adults alive at any one time.

Fossils of more than 40 T. rex individuals have been found since it was first described in 1905, providing a wealth of information about a beast that thrives in the popular imagination.

"I think it probably is the iconic dinosaur, " said paleontologist Charles Marshall, who led the study published in the journal&nbsp;Science. "It is huge. It's got a huge head and huge teeth. It's really scary. I think we like feeling small. And boy, do you feel small when you're standing underneath a skeleton."

It was among the largest carnivorous dinosaurs, possessing a skull about 5 feet (1.5 meters) long, massive and muscular jaws with a bite force capable of crushing bone, a mouthful of banana-sized serrated teeth, a keen sense of smell, strong legs and puny arms with hands boasting just two fingers.

Perhaps the largest-known T. rex is a specimen named Sue at the Field Museum in Chicago, measuring 40-1/2-foot-long (12.3-metres), weighing an estimated 9 tons and living about 33 years.

The new study put the weight of the average adult T. rex at 5.2 tons, average lifespan at 28 years, generation time at 19 years, total number of generations of the species at about 125,000, and its geographic range at roughly 890,000 square miles (2.3 million square kilometres).

They calculated an average population density of about one T. rex for every roughly 40 square miles (100 square kilometres).

Marshall said he suspects there may have been "perhaps two in area of Washington, D.C., about one in the area of Manhattan, about one in the area of the city of San Francisco." He added, "But I suspect they were clumpy. They were following herds of prey around. So rather than just being like sentinels, one every 40 square miles, they probably moved in groups following prey."

T. rex fossils have been found in Canada's Alberta and Saskatchewan provinces and the US&nbsp;states of Montana, Wyoming, South Dakota, North Dakota, Utah, Colorado, New Mexico and Texas. T. rex apparently met a fiery end when an asteroid slammed into Mexico, exterminating three quarters of Earth's species.

While the uncertainties in the estimates were large and some of the assumptions may be challenged by other paleontologists, the study was a worthwhile effort to expand the understanding of this famous dinosaur, said Marshall, director of the University of California Museum of Paleontology and a University of California, Berkeley professor of integrative biology.

The formula could be applied to other extinct animals, Marshall added.

Paleontologist and study co-author Ashley Poust of the San Diego Natural History Museum said while 2.5 billion is a lot, it represents only about a third of Earth's current human population - and 20,000 is merely the size of a small town.

(With inputs from agencies)

Researchers on Thursday unveiled the first calculation of the total T. rex population during the estimated 2.4 million years that this fearsome species inhabited western North America during the twilight of the age of dinosaurs.

Researchers on Thursday unveiled the first calculation of the total T. rex population during the estimated 2.4 million years that this fearsome species inhabited western North America during the twilight of the age of dinosaurs. They considered factors including the size of its geographic range, its body mass, growth pattern, age at sexual maturity, life expectancy, duration of a single generation and the total time that T. rex existed before extinction 66 million years ago. They also heeded a doctrine called Damuth's law linking population to body mass: the bigger the animal, the fewer the individuals. Their analysis put the total number of T. rex individuals that ever existed at about 2.5 billion, including approximately 20,000 adults alive at any one time. Fossils of more than 40 T. rex individuals have been found since it was first described in 1905, providing a wealth of information about a beast that thrives in the popular imagination. "I think it probably is the iconic dinosaur, " said paleontologist Charles Marshall, who led the study published in the journal Science. "It is huge. It's got a huge head and huge teeth. It's really scary. I think we like feeling small. And boy, do you feel small when you're standing underneath a skeleton." It was among the largest carnivorous dinosaurs, possessing a skull about 5 feet (1.5 meters) long, massive and muscular jaws with a bite force capable of crushing bone, a mouthful of banana-sized serrated teeth, a keen sense of smell, strong legs and puny arms with hands boasting just two fingers. Perhaps the largest-known T. rex is a specimen named Sue at the Field Museum in Chicago, measuring 40-1/2-foot-long (12.3-metres), weighing an estimated 9 tons and living about 33 years. The new study put the weight of the average adult T. rex at 5.2 tons, average lifespan at 28 years, generation time at 19 years, total number of generations of the species at about 125,000, and its geographic range at roughly 890,000 square miles (2.3 million square kilometres). They calculated an average population density of about one T. rex for every roughly 40 square miles (100 square kilometres). Marshall said he suspects there may have been "perhaps two in area of Washington, D.C., about one in the area of Manhattan, about one in the area of the city of San Francisco." He added, "But I suspect they were clumpy. They were following herds of prey around. So rather than just being like sentinels, one every 40 square miles, they probably moved in groups following prey." T. rex fossils have been found in Canada's Alberta and Saskatchewan provinces and the US states of Montana, Wyoming, South Dakota, North Dakota, Utah, Colorado, New Mexico and Texas. T. rex apparently met a fiery end when an asteroid slammed into Mexico, exterminating three quarters of Earth's species. While the uncertainties in the estimates were large and some of the assumptions may be challenged by other paleontologists, the study was a worthwhile effort to expand the understanding of this famous dinosaur, said Marshall, director of the University of California Museum of Paleontology and a University of California, Berkeley professor of integrative biology. The formula could be applied to other extinct animals, Marshall added. Paleontologist and study co-author Ashley Poust of the San Diego Natural History Museum said while 2.5 billion is a lot, it represents only about a third of Earth's current human population - and 20,000 is merely the size of a small town. (With inputs from agencies)

‘That’s a lot of teeth’: Researchers discover 2.5 billion Tyrannosaurus rex

Some of the most recognized props and memorabilia from cinema history are going under the hammer in an up-coming two-day auction.

Iconic movie props go under the hammer