Ceratosaurus
- Pronunciation: sih-RAT-uh-SAWR-us
- Translation: Horned Lizard
- Order: Saurischia
- Suborder: Theropoda
- Infraorder: Ceratosauria
- Family: Ceratosauridae
- Height: 13 feet (4.0 meters)
- Weight: 3,000 lbs (1,360 kg)
- Length: 20 feet (6.1 meters)
- Period: Late Jurassic
- Description: Carnivore, Bipedal
- Notes: Ceratosaurus was found in western North America.It has horns above and forward of its eyes, resembling those of Allosaurus, but it Ceratosaurus derives its name from itsextremely unusual, rather large nose horn. Because Ceratosauruswas a very large predator, it is not likely that the horn was aweapon. Possibly it was a secondary sex characteristic, identifying males or females; perhaps it was used in ritual mating battlesbetween males. It has also been suggested that the horn was usedby hatchlings to break out of their eggs.