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017

Stegosaurus stenops

OLogy Series
extinct animal
card
017

Stegosaurus stenops

OLogy Series
extinct animal

Because its back was covered with diamond-shaped plates, Stegosaurus was given a name that means "roof lizard." Its back legs were about twice as long as its front legs. This plant eater's jaw was toothless in front and had small, leaf-shaped teeth in back. Nice tail spikes, huh?

A Two-Brained Beast?
When Stegosaurus was discovered in the late 1800s, paleontologists were surprised to find that it had a tiny brain, about the size of a walnut. How could such a small brain control its bulky body? Some scientists thought this dinosaur had a "second brain" near its hips that controlled the back half of the body. But fossil evidence doesn't support this idea. As it turns out, Stegosaurus had only one brain. What scientists thought was a second brain was actually an enlargement of the spinal cord in the hip area. This large nerve center may have helped to control its hind legs and tail.

We know that Stegosaurus' plates were covered with skin because plates have been found with:

skin impressions

grooves for blood vessels

fossilized tattoos

Are you right?

Correct!

The fossilized plates are crisscrossed with grooves for blood vessels. These plates must have been covered with skin.

As of the year 2000, over 100 Stegosaurus skeletons have been found.

Fact
or
Fiction
?

Fiction

Despite their fame, fewer than a dozen Stegosaurus skeletons have been found so far.

When Stegosaurus lived, Earth's climate was so warm there were no ice caps. Sea levels were much higher than they are today.

Fact
or
Fiction
?

Fact

The climate during the late Jurassic Period, about 150 million years ago, was much warmer and moister than the global climate today.

Scientific Name: Stegosaurus stenops
Pronunciation: steg-uh-SAW-rus STEN-ops
Meaning: "roof lizard"
Locality Found: United States
Age: Late Jurassic, 140 million years ago
Length: 8.5 meter (28 feet) long
Weight: 2,720 kilograms (6,000 pounds)
Characteristics: The large triangular plates that lined the back of this herbivorous dinosaur may have helped regulate its body temperature.

Image credits: Rick Spears.