Triceratops (trĪsĕrˈətŏps) [key] [Gr., = three-horn face], genus of ornithischian quadruped dinosaurs of the late Cretaceous period. Because of some variations in sample fossils, it was thought at one time that there were as many as 16 different species, but only one species, Triceratops horridus is currently recognized. It is characterized by its three horns, one on the nose and one over each eye, and a large bony frill projecting backward from the skull, which probably served to protect the neck and fore part of the body. The head was large (about 8 ft/2.4 m long), the body (about 20 ft/6 m long) was bulky and barrel shaped, and the limbs were massive and of equal length. Fossil specimens have been found in the W United States and Canada. It belongs to the group of horned dinosaurs, the ceratopsians.