Styracosaurus (Sty-rack-oh-soar-us) was a horned dinosaur that lived in western North America during the Late Cretaceous Period. It was somewhat smaller than its more famous cousin, Triceratops, being approximately 18 feet in length.
Styracosaurus is distinguished from other horned dinosaurs by the large spikes that extended from the frill. There were also small horns located on the cheeks and a large, rhinoceros-like horn (up to two feet in length) that protruded from the nose. Very small brow horns appear to have been present in juveniles, but were absent in the adults.
The frill of Styracosaurus featured two large window-like openings, believed to mark the attachment sites of powerful jaw muscles. The frill also probably served a protective function - evidenced not only by the large, protruding spikes, but also by the fact that the frill projected backwards from the head to cover the otherwise vulnerable neck.