Ceratosaurus, or "horned lizard," was a theropod dinosaur similar to Allosaurus, but only about half as big. It may have been a vicious predator and was named for the bump on its snout, which was probably not really a horn but instead a small crest covered with skin. Unlike later theropods, which had three fingers with a long second finger, or just two fingers, Ceratosaurus had four fingers on each "hand."