Now, a fossil found in Utah is helping paleontologists better understand how this region's tyrannosaurs went from ecological paupers to princes. Weighing about 170 pounds and standing less than five feet tall, the newly named species Moros intrepidus is one of the smallest dinosaurs of its kind dating back to the Cretaceous period, the time between 66 million and 145 million years ago.

At 96 million years old, Moros is also the oldest Cretaceous tyrannosaur skeleton found in this region, pushing back that particular record by 15 million years