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    Dinosaur

    National Monument CO,UT

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Allosaurus fragilis

Allosaurus fragilis reconstruction at the Carnegie Museum is one of the most terrifying specimens of the Jurassic Hall
The Allosaurus fragilis at the Carnegie Museum is one of the most terrifying specimens of the Jurassic Hall.
 

About Allosaurus fragilis:

Allosaurus, meaning "different delicate reptile," is a theropod (meat-eating dinosaur) that probably ate other smaller dinosaurs. Its teeth were up to 3 in (7.6 cm) long and serrated like steak knives for cutting flesh. Adults hunted by overpowering their prey, possibly in small groups. Juvenile Allosaurus relied on their longer limb bones that were better adapted to running in order to hunt smaller vertebrates. Even though Allosaurus grew up to 30 ft (8.5 m) in length, it was not the largest predator of the time. Its sharp teeth and hook-shaped claws did, however, make Allosaurus a nightmare for many creatures of the Jurassic.

 
Allosaurus fragilis is one of the largest predators in the Morrison. Notice how large even just the skull is in comparison to a human!

Allosaurus fragilis is one of the largest predators in the Morrison. Notice how large even just the skull is in comparison to a human!

Why is Allosaurus fragilis a superstar?

The Allosaurus fragilis skeleton found at Dinosaur National Monument has one of the best skulls of any Late Jurassic predatory dinosaur in the world! Dinosaur skulls are rarely preserved because they are made of very thin bone that is easily crushed. Skulls are mostly hollow to hold soft tissues that cannot be preserved. Fine sediments compress the skull to flatten it the way you might step on an empty tin can. These skulls may be preserved, but some of the three-dimensional structure is lost. The sand-sized sediments in the Carnegie Quarry are fine enough to preserve bone in great detail but coarse enough to resist compression of the skulls.

This specimen of Allosaurus fragilis has attracted the attention of paleontologists around the world and has been referenced in many scientific studies. You don't, however, have to be a scientist to marvel at this beautiful specimen. The real skull is on display at the Quarry Exhibit Hall.

 

Jurassic Fact: Almost 75% of all theropods (meat-eating dinosaurs) found in the Morrison Formation are Allosaurus!

For more information: Visit the Carnegie Museum of Natural History in Pittsburgh, Pennsylvania where another Allosaurus fragilis from Dinosaur National Monument is on display.

Did You Know?

Photo of paleontologist Earl Douglass.

Paleontologist Earl Douglass first came to Utah looking for mammal fossils. He returned in 1909 and discovered an immense deposit of dinosaur bones, now protected at Dinosaur National Monument. Although made famous by dinosaurs, Douglass died preferring his beloved mammal fossils over dinosaurs.