Dinosaur species older than T. rex : A fossil discovery in New Mexico in 1998 eventually revealed a dinosaur scientists had never seen before, a tyrannosaur that lived about 75 million years ago, roughly 10 million years before Tyrannosaurus rex appeared.
Named Bistahieversor sealeyi, the dinosaur belonged to the same lineage as T. rex, although it was much smaller, as per a report.
