A new study sheds light on a long-standing debate about a dinosaur fossil discovered decades ago. For years, scientists have wondered if the bones belonged to a young Tyrannosaurus rex or a separate, smaller species.
The discussion started with a skull found in the 1940s. Later, another skeleton called “Jane” added to the mystery, but the answer remained unclear.
Now, a team of researchers believes they have solved the puzzle. A complete skeleton, unearthed in Montana in 2006, suggests the dinosaur is not a juvenile T. rex, but a distinct species.
The finding could change how we understand Earth’s most famous predator, according to one of the study’s authors.
By studying growth rings in the bones, scientists determined the dinosaur was an adult, but only about half the size of a full-grown T. rex. Comparisons with other reptiles, like crocodiles, revealed significant differences in skull structure, nerve patterns, and sinuses, making it unlikely these differences were simply due to the dinosaur going through a growth spurt.
The researchers believe the skeleton belongs to a distant cousin of the T. rex, called Nanotyrannus lancensis. Their report was published in the journal Nature.
While some experts are excited by the new evidence, others remain cautious. One fossil bone expert said there’s now more support for the idea of a T. rex relative, but isn’t convinced that other mysterious skeletons like Jane belong to the same new species.
Another scientist pointed out similarities between the skull shapes of T. rex and the mystery specimens, suggesting the new skeleton could be a sister species to T. rex, rather than a distant relative.
Regardless of the final answer, understanding the identity of this dinosaur is important for understanding how T. rex developed, and whether a smaller predator shared the landscape with the mighty T. rex 67 million years ago.
The skeleton, called “Dueling Dinosaurs” because it was found with the bones of a Triceratops, is now on display at the North Carolina Museum of Natural Sciences.


