Dinosaurs in Their Time

DinoGuide: Stegosaurus ungulatus

Stegosaurus was a common plant-eating dinosaur in western North America during the Late Jurassic Period. It had small, simple teeth, and probably fed on vegetation close to the ground.

Stegosaurus also had weak jaw muscles, implying that it could not chew its food very effectively. It may have required a method similar to the one used by sauropods such as Diplodocus and Apatosaurus. These dinosaurs ripped away huge amounts of plant matter which they barely chewed before swallowing. The food would then ferment in the stomach, ground up by small rocks which the dinosaurs swallowed just for that purpose.

Tall bony plates on its back and paired spikes on its tail give Stegosaurus a very distinctive appearance. The spiked tail was almost certainly used for defense against large predators like Allosaurus. In addition to protecting the dinosaur's back, the bony plates were full of channels for blood vessels, and probably also conducted heat to and from the animal's body.

StegosaurusCARNEGIE SPECIMEN NUMBER:
CM 11341

SCIENTIFIC NAME MEANING:
"Clawed plated reptile"

CLASSIFICATION:
Ornithischia : Thyreophora : Stegosauria : Stegosauridae

LENGTH:
Up to 25 feet (7.6 meters)

GEOLOGICAL FORMATION & LOCALITY:
Morrison Formation; Dinosaur National Monument, Uintah County, Utah

COLLECTOR:
Earl Douglass and field crew, 1920–1922

TIME PERIOD:
Late Jurassic, 145–150 million years ago

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