Will T. rex Have to Share the Crown?

Tyrannosaurus rex was believed to be the only dinosaur species of its kind. Its name means “tyrant lizard king”! But recently, a group of scientists suggested that this dinosaur was actually three separate species.

The scientists studied differences in the size and shape of fossilized T. rex bones and teeth. The researchers think the animal we know as T. rex should include the original species plus two more. Those two other species would be T. imperator and T. regina. The word imperator means “emperor.” The word regina means “queen.”

These massive meat eaters lived between 90 million and 66 million years ago, toward the end of a period called the Cretaceous. “In principle, there is no reason to think that Tyrannosaurus didn’t go through a couple of species during the last few million years of the Cretaceous,” says Thomas Holtz. He’s a scientist at the University of Maryland who was not involved with the study.

Rethinking our understanding of T. rex might seem strange for some dino fans. But it’s normal for science to change. Triceratops and Brontosaurus, for example, have gone through  name changes. In fact, for much of human history, people didn’t realize that fossilized bones could be the remains of long-dead creatures!

These big meat eaters lived between 90 million and 66 million years ago. That was near the end of a period called the Cretaceous. “In principle, there is no reason to think that Tyrannosaurus didn’t go through a couple of species during the last few million years of the Cretaceous,” says Thomas Holtz. He’s a scientist at the University of Maryland. Holtz was not part of the study.

Thinking about T. rex as three different species might seem strange for some dinosaur fans. But it’s normal for science to change. Triceratops and Brontosaurus now have different names. For much of human history, people didn’t realize that fossils could be animal bones!

Still, the study “is super controversial,” says Gregory Paul. He’s the study’s lead author.

Until scientists find more evidence, Holtz and other experts believe that T. rex should keep its throne to itself.

Use what you know about rounding to answer the questions below.

Use what you know about rounding to answer the questions below.