Formally Unknown Relative Of The T. Rex Discovered In New Mexico

A formally unknown relative of the Tyrannosaurus rex has been discovered in New Mexico, according to a new study released in the Journal Scientific Reports.

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According to a new study released in the Journal Scientific Reports, there’s been a new, formally unknown, relative of the Tyrannosaurus rex identified in New Mexico. The new conclusions made about the T. rex’s relative, called Tyrannosaurus mcraeensis, can be utilized to help paleontologists learn even more about the evolutionary journey of the T. rex. 

The report stated that the Tyrannosaurus mcraeensis most likely walked the Earth 7 million years before the T. rex evolved. The authors of the study reported that the bones of the Tyrannosaurus mcraeensis were likely 72 to 73 million years old, which would mean the predator was around during the late Campanian-early Maastrichtian Period. 

Although the Tyrannosaurus mcraeensis was just officially classified with its scientific name, its bones were initially discovered decades earlier. One-quarter of its fossilized skull was found in the 1980s and early 1990s in New Mexico as well. Based on the paleontologists initial observations at the time, the fossils were categorized as T. Rex by the New Mexico Museum of Natural History. 

Anthony R. Fiorillo, coauthor of the study, spoke on one of the biggest differences between the T. Rex and T. Mcraeensis.

“The lower jaw in a Tyrannosaurus rex is actually quite robust. Our jaw is obviously big and toothy, but it’s more slender than what we normally see in a Tyrannosaurus rex. The robust jaw of T. rex meant it could do whatever it wanted. A more slender jaw, even with the big teeth, means that it would have less bite force.”

T. Mcraeensis also doesn’t have a prominent ridge over its eyes like the T. Rex, which scientists believe were used to help attract mates, the same way deers use their antlers, according to Fiorilo.

The authors also wrote that large members of the tyrannosaurs family likely emerged due to an increase in large herbivore populations. The herbivore’s evolution and population growth, however, is still thought of as an “unexplained mystery,” the study wrote. 

According to CNN, Fiorillo stated that it’s a “highly speculative idea for now, but unlike the pygmy tyrannosaur found in the Arctic — called Nanuqsaurus hoglundi — T. mcraeensis probably didn’t experience dramatic shifts in temperature and light in southern North America so it was able to continue to grow. 

The study’s research team is planning on continuing their research and analysis of the rock formation where the fossils were found, in hopes of finding more bones, according to Fiorillo

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“Then, because it’s so big, we need to actually shift some of our investigation to try to understand the paleoecology and environment in which this animal lived so we can begin to understand what was it about New Mexico that was so special that this animal’s adaptation to life was to get big.”

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“When the lower jaw was first found, there weren’t many T. rex specimens out there,” Fiorillo said.

Sebastian G. Dalman, the study’s first author who is an associate researcher at the natural museum, is the individual mainly responsible for identifying T. mcraeensis, with help from a paleontological consultant with the Springfield Science Museum in Massachusetts. 

Dalman began studying the T. mcraeensis bones in 2013, and was the first individual to suggest that the fossils “might be something different” than just a T. rex. 

Fiorillo also discussed that from a pop culture aspect, the resurgence of movies featuring dinosaurs, such as Jurassic World and King Kong, have sparked an overall public interest in this research, which motivated paleontologists even more. 

“That improved our sample size. That set the table for when Sebastian started to look at our specimen and say, ‘Hey, these don’t actually look the same as the famous Tyrannosaurus rex specimens from places like Montana,” he said.