New dinosaur skeleton redefines what we know about the T-Rex family tree

Scientists have recently determined that a fossil discovered in Mongolia belongs to a species that is the closest known ancestor of all tyrannosaurs, including the T-Rex. The species is known as Khankhuuluu mongoliensis, which means Dragon Prince of Mongolia.

The discovery was published in Nature (via the BBC) and shows how tyrannosaurs evolved to become the predators we know of today. Tyrannosauroids are the family of carnivorous dinosaurs that walked on two legs, but the first of their kind were incredibly small.

"They were these really small, fleet-footed predators that lived in the shadows of other apex predatory dinosaurs," said PhD student Jared Voris. Khankhuuluu represents a shift in their evolution to becoming larger.

Weighing in at 750kg, you might think that Khankhuuluu would be a bigger tyrannosauroid, but in fact, a large T-Rex could weigh as much as eight times that. It's why Khankhuuluu remains the Dragon Prince of Mongolia, and not the king.