Calgary: A newly identified mid-sized dinosaur from Mongolia dubbed the “Dragon Prince” has been identified as a pivotal forerunner of Tyrannosaurus rex in an illuminating discovery that has helped clarify the famous predator’s complicated family history.

Named Khankhuuluu mongoliensis, it lived roughly 86 million years ago during the Cretaceous Period and was an immediate precursor to the dinosaur lineage called tyrannosaurs, which included some of the largest meat-eating land animals in Earth’s history, among them T. rex. Khankhuuluu predated Tyranno­saurus by about 20 million years.

It was about 13 feet long, weighed about 1,600 pounds, walked on two legs and had a lengthy snout with a mouthful of sharp teeth. More lightly built than T. rex, its body proportions indicate Khan­khuuluu was fleet-footed, likely chasing down smaller prey such as bird-like dinosaurs called oviraptorosaurs and ornithomimosaurs. The largest-known T. rex specimen is 40-1/2 feet long.

Khankhuuluu means “Dragon Prince” in the Mongolian language. Tyranno­saurus rex means “tyrant king of the lizards.”

“In the name, we wanted to capture that Khankhuuluu was a small, early form that had not evolved into a king. It was still a prince,” said paleontologist Darla Zelenitsky of the University of Calgary in Canada, co-author of the study published on Wednesday in the journal Nature.

Tyrannosaurs and all other meat-eating dinosaurs are part of a group called theropods. Tyrannosaurs appeared late in the age of dinosaurs, roaming Asia and North America.

Published in Dawn, June 12th, 2025