The Stegosaurus was an herbivorous dinosaur from the Upper Jurassic period. It had a distinctive alternating double row of plates down its back and tail. These would have stiffened the tail which was also armed with four large spikes.
Fossils of the genus have been found in the western United States and in Portugal. They were large, heavily built, herbivorous quadrupeds with rounded backs, short fore limbs, long hind limbs, and tails held high in the air. Due to their distinctive combination of broad, upright plates, and tail tipped with spikes, the Stegosaurus is one of the most recognizable kinds of dinosaurs.