Scientifically named Khankhuuluu mongoliensis, the newly-identified tyrannosauroid species is the closest-known ancestor to Tyrannosaurus rex. Khankhuuluu mongoliensis. Image credit: Julius Csotonyi. Khankhuuluu mongoliensis roamed our planet during the Cretaceous period, some 86 million years ago. This dinosaur was a medium-sized, fleet-footed predator that evolved after the extinction of other large predatory dinosaurs. As the closest-known ancestor,...