Dueling Dinosaur Fossil Rewrites T-Rex Story

If everything we know about the growth of the T-Rex is wrong? A complete tyrannosaur skeleton has just settled one of paleontology’s longest-running debates—whether Nanotyrannus was a separate species, or just a juvenile version of Tyrannosaurus rex.

The fossil, which is part of the legendary “dueling dinosaur” specimen found in Montana, includes two dinosaurs locked in prehistoric combat: a triceratops and a small-bodied tyrannosaurus. The tyrannosaur has now been confirmed to be a fully grown Nanotyrannus lanensis – not a juvenile T-Rex, as many scientists once believed.

“This fossil doesn’t just settle the debate. It flips decades of T. rex research on its head,” says Lindsey Zano, associate research professor at Carolina State University, head of the North Carolina Museum of Natural Sciences. The nature.

Using growth rings, spinal fusion data and developmental anatomy, the researchers showed that the specimen was about 20 years old and physically mature when it died. Its skeletal features—including a larger number of teeth, fewer tail vertebrae, and a distinct pattern of cranial nerves—are set early in development and are biologically incompatible with T-rex.

“For a nanoterranus to become a juvenile T-rex, it would have needed to defy what we know about vertebrate growth,” says James Napoli, an anatomist at Stony Brook University and co-author of the study. “It’s just not likely — it’s impossible.”

The implications are profound. For years, paleontologists have used nanoterranean fossils to model T. Rex’s growth and behavior. This new evidence suggests that these studies were based on two completely different animals.

As part of their research, Zanno and Napoli examined more than 200 tyrannosaur fossils. They discovered that one skeleton, previously thought to represent a juvenile T. rex, was slightly different from the Daling dinosaur Nanoterranus lanensis.

They named the fossil a new species of nanoterranean, N. lattices. The name refers to the Leyte River from Greek mythology. An indication of how this species has been hidden in plain sight and “forgotten” for decades.

Confirmation of the authenticity of nanoterrans means that predator diversity was greater in the last million years of the Cretaceous than previously thought, and indicates that other small-bodied dinosaur species may have been misidentified.

“This discovery paints a much more competitive picture of the last days of the dinosaurs,” Zanno says. “With enormous size, a powerful bite force and stereoscopic vision, the T-rex was a formidable predator, but it was not outmatched. So was the Nanoterranus – a leaner, swifter and more agile predator.”