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Tyrannosaurus jaw

Tyrannosaurus jaw fossil

TMM 41436-1
Lived about 65 million years ago
Found in Big Bend National Park, Brewster County, Texas

This fossil is the upper jaw of the dinosaur Tyrannosaurus. The University of Texas at Austin graduate student, Doug Lawson, found this specimen in Big Bend National Park in 1970. Most Tyrannosaurus fossils are found in the foothills of the central and northern Rocky Mountains, so this find is special to scientists. It shows us that Tyrannosaurus once ranged as far south as present-day West Texas.

This Tyrannosaurus was relatively small, and had grown to only about thirty feet long when it died. You can see many of the tooth roots on this fossil because part of the outer jaw is broken away. Can you see how deeply the roots fitted into the jaw? Tyrannosaurid teeth were very thick, and had deep roots that anchored the teeth during powerful biting. Scientists believe that the strength of tyrannosaurid teeth evolved to deal with more dangerous prey like Torosaurus.

The Tyrannosaurus jaw is on permanent exhibit in the Hall of Geology and Paleontology.