Scientists discovered a new dinosaur species that was comparable in size to T. rex.
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Scientists identified a new species of Tyrannosaurs that’s likely a predecessor to T. Rex.The new species shows the dinosaurs got bigger a lot earlier than scientists originally thought.It also supports the theory that T. Rex originated in North America, not Asia.
Scientists recently identified a new dinosaur species that could be the closest relative to T. rex ever found.
Named T. mcraeensis, the new dinosaur suggests that Tyrannosaurs grew to enormous sizes millions of years earlier than experts previously thought.
A new discovery from old bones
Tyrannosaurus quickly grew from about the size of a horse to supersized monsters.
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Interestingly, the discovery comes from a fossilized skull and jawbone that were dug up more than 40 years ago in New Mexico.
For decades, the bones were thought to belong to a T. rex. But a team of researchers decided to take a closer look when another fossil tipped them off.
They found that a Sierraceratops sample from the same area was older than originally thought. This made the researchers wonder about the Tyrannosaurus sample’s age, Nick Longrich, a paleontologist and evolutionary biologist from the University of Bath who led the study, told Business Insider in an email.
“We realized that the traditional assumptions about the ages of these fossils were probably wrong,” Longrich wrote.
Upon reexamination, the scientists found that the bones belonged to a dinosaur that lived 6 million to 7 million years before T. rex existed.
Moreover, the fossils had a few key differences from a typical T. rex that ultimately led Longrich and his team to conclude that they belonged to a new species.
For example, the skull lacked ridges behind its eyes — a distinct feature of T. rex. And the jawbone revealed a shallower lower jaw than the T. Rex, Spencer Lucas, a paleontologist on the project, told NPR.
The researchers published their findings in the peer-reviewed journal Scientific Reports.
How Tyrannosaurs got so big
T. rex was about the length of a school bus and towered about 12 feet tall.
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It’s tough to estimate how big T. mcraeensis was simply from a skull and jawbone, but it was probably comparable in size to a T. rex, measuring about 40 feet long, Longrich said, or about the length of a US school bus.
That means that Tyrannosaurus, “also got bigger a lot earlier than we thought,” Longrich said. He added that placing the T. mcraeensis fossils at this particular time in ancient history could help explain the dinosaur’s massive size.
Around the Campanian period of the late Cretaceous Epoch, between 83 million to 72 million years ago, plant-eating dinosaurs, like hadrosaurs, were getting larger. To prey on those animals, the Tyrannosaurus family had to grow bigger, too.
These evolutionary pressures would have contributed to the Tyrannosaurus’s massive size, Longrich said.
Despite what many scientists thought, the T. Rex wasn’t the first Tyrannosaurus, but the last, Longrich said.
North America v. Asia
As famous as T. rex is, little is understood about its origins. Scientists disagree about whether T. Rex originated in North America or Asia.
But the researchers’ new analysis may offer more clues on the matter.
Because T. mcraeensis’s fossils were discovered in New Mexico and are the first known ancestor to the T. rex, this supports the idea that T. Rex originated in North America, not Asia, Longrich said.
“It’s interesting that there are still new things to learn about an animal as seemingly well-known as T. rex,” he said. “There’s a lot left to discover.”