New Dinosaur Species Discovered in Mongolia Sheds Light on T. rex Origins

A recent discovery is reshaping what scientists thought they knew about the evolution of tyrannosaurs. Two fossilized skeletons, stored for decades in a museum in Mongolia, have now been identified as belonging to a previously unknown species, considered the closest known relative of the iconic Tyrannosaurus rex.

Named Khankhuuluu mongoliensis, meaning “Dragon Prince of Mongolia,” this dinosaur lived approximately 86 million years ago. It plays a key role in understanding how tyrannosaurs evolved, bridging the gap between the smaller, faster hunters of the Jurassic period and the massive predators that dominated Earth during the final age of dinosaurs.

According to paleontologist Darla Zelenitsky from the University of Calgary, this new species is a primitive tyrannosauroid — part of the broader family that eventually led to the T. rex. The Khankhuuluu weighed around 750 kg (1,650 lbs), a fraction of the size of an adult T. rex, which could exceed 6 tons.

The research, led by PhD student Jared Voris, began when he reexamined fossils originally found in the 1970s, previously classified as belonging to a different species, Alectrosaurus. Upon closer study, Voris noticed features in the skull and nasal bone that aligned more closely with later tyrannosaurs, indicating the early development of a powerful jaw — a defining trait of T. rex.

“This discovery reveals an intermediate stage in the evolution of these animals,” explains Voris. “It shows how they gradually developed traits like their strong bite, which allowed them to prey on larger animals and even crush bone.”

Published in the journal Nature, the study positions Khankhuuluu as a crucial missing link in the tyrannosaur family tree. This new evidence helps rewrite the story of how these apex predators evolved — from nimble, mid-sized hunters into the fearsome giants that ruled the Cretaceous.

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