New tiny tyrannosaur helps show how T. rex got big

The gangly predator fills in a crucial gap in our understanding of how tyrannosaurs came to dominate during the Cretaceous.

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. (Get the best look yet at the face of a tyrannosaur.)

“What Moros does for us is help us understand the who, what, why, where, and when of how tyrannosaurs ascended to

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