Oklahoma State Fossil

Theropod Dinosaur

(Saurophaganax maximus)

Adopted on April 14, 2000.

The governor signed Senate Bill 1185 on April 14, 2000 designating the Theropod Dinosaur, Saurophaganax maximus, the state fossil.

Description of the Oklahoma State Fossil

The first bones of Saurophaganax were found in the late 1930s by a WPA crew under the supervision of a University of Oklahoma paleontologist. Since that time, discoveries have been rare and fragmentary. However, a very nice restoration is on display at the Sam Noble Museum in Norman, which has an entire hall devoted to prehistoric life.

The theropod (meaning "beast-footed") dinosaurs are a diverse group of bipedal saurischian dinosaurs. They include the largest terrestrial carnivores ever to have made the earth tremble.

Geologic Time

145 to 150 million years ago (Late Jurassic)

Geographic Range

Wyoming, Montana, Colorado, New Mexico, South Dakota, Utah, and Oklahoma

Characteristics:

Allosaurus was the most common large carnivore of the Late Jurassic in North America. It was a smaller predecessor of the Cretaceous Tyrannosaurus. Strong forelimbs with sharp claws, powerful hind legs and recurved, dagger-like teeth are evidence that Allosaurus was a formidable predator. Although it was much smaller than sauropods like Apatosaurus (Brontosaurus), which were also common at the time, quite possibly Allosaurus hunted in packs to bring down larger prey. Like many meat eaters, it may also have been a scavenger.

Many Allosaurus specimens representing individuals of different ages have been recovered in exposures of the Morrison Formation in the Rocky Mountain West. This specimen is interpreted as a subadult.

Adult Weight: 1.5 - 2 tons

Adult Length: 30 - 40 ft long

Habitat: Plains and lowlands

Diet: Meat

Several characteristics that typify a theropod:

• They were all carnivores (meat-eaters)
  - Most theropods had sharp, recurved teeth useful for eating flesh, and claws were present on the ends of all of the fingers and toes.
• - They all used their back legs for walking and each foot had three toes
  - The fourth and fifth digits are reduced;
  - Most walked exclusively on two legs
  - They had hollow limb bones
  - The humerus (upper arm bone) is less than half as long as the femur (upper leg bone)