Controversial New Study Says T. rex Was Actually Three Species
- Since its discovery in 1902, there has only been one known type of Tyrannosaurus: the rex.
- However, a new study indicates that there are three types of Tyrannosaurus, based on differences in the femurs and teeth of the fossils.
- Scientists are skeptical of the new study, saying there is not enough evidence to make this claim.
The Tyrannosaurus rex has been one of the most iconic dinosaurs to ever exist, thanks in large part to its terrorizing role in the 1993 classic “Jurassic Park” and its subsequent films.
What if the popular dinosaur that terrorized visitors to Isla Nublar wasn’t exactly a Tyrannosaurus rex? New search published Tuesday in the peer-reviewed journal Evolutionary Biology suggested that there were not just one or two, but actually three different types of Tyrannosaurus.
To understand the possibility that there is more than one Tyrannosaurus, start with genus versus species. A genus is a category or class used to classify living things while a species is a certain type of organism under a genus. Since the first Tyrannosaurus fossil was discovered in Montana in 1902, there has only been one confirmed species: rex.
Although there is only one confirmed species, different fossils of the dinosaur have been discovered, ranging from smaller and larger bones to different teeth.
This is something that intrigued Gregory Paul, a paleontologist and paleoartist who is the lead author of the new study. Paul and his team analyzed the bones and dental remains of 37 different Tyrannosaurus remains.
What the data showed was a wide range of forces in the femur regardless of how old the dinosaur was when it died, which they believe eliminated the reason for the differences being gender. The team also noticed that those with thin femurs also had an incisor tooth.
After analyzing the fossils, the team then looked at which layers of sediment each fossil was found in. The results showed that Tyrannosaurs with sturdier femurs and two incisors were only found in deeper layers, while different variations were found in younger sediments.
The team concluded that the Tyrannosaurus timeline began with Tyrannosaurus imperator – which translates to “emperor lizard tyrant”. Millions of years later, Tyrannosaurus then evolved into two species, Tyrannosaurus rex with sturdy femurs and an incisor tooth, and the new Tyrannosaurus regina – or “tyrant lizard queen” – which had thin femurs and an incisor tooth. incisor.
So the first fossil found in Montana may not have been a Tyrannosaurus rex.
“We propose that changes in the femur may have evolved over time from a common ancestor that exhibited more robust femora to become more gracile in later species. Differences in femur robustness across sediment layers can be considered distinct enough that the specimens could potentially be considered separate species,” Paul said in a press release.
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Scientists skeptical of new species
Despite the team’s new discovery, paleontologists around the world aren’t too thrilled and are skeptical of the results.
Paul Barrett, dinosaur expert at the Natural History Museum in London, said he was skeptical of the study because the team didn’t seem to have enough evidence to come to their conclusion, and “would be very surprised if the experts who work on these dinosaurs supported them.”
David Hone, an expert in carnivorous dinosaurs at Queen Mary, University of London, added to Barrett’s comments, saying the team shouldn’t base new species on just two traits known to vary.
Part of the research identified two popular Tyrannosaurus rex fossils in museums in the United States – Sue at the Field Museum in Chicago and “The Nation’s T. Rex” at the Smithsonian National Museum of Natural History in Washington D.C. Under the new species, Sue would be a Tyrannosaurus imperator, while the one in the nation’s capital would be a Tyrannosaurus regina.
But Jingmai O’Connor, associate curator of fossil reptiles at the Field Museum, told the New York Times they will not change Sue’s official species as it is not “widely accepted by the scientific community”.
“The new hypothesis about Tyrannosaurus diversity is very poorly substantiated and unlikely to go through this rigorous process,” O’Connor told the outlet. “The diagnoses provided for each species are incredibly vague.”
Paul and others admit they can’t entirely rule out that the differences could be the result of extreme individual differences and not knowing the exact location of where the dinosaurs were found, but for now, they stand by their claim: Tyrannosaurus rex wasn’t alone.
Follow Jordan Mendoza on Twitter: @jordan_mendoza5.