Ceratosaurus, meaning "Horned Lizard" in reference to the large bony protrusion on its nose, was a medium-sized theropod dinosaur from the Late Jurassic Period.
Three Ceratosaurus made an appearance near of the end of the segment, attacking a group of Brontosaurus and Stegosaurus trapped in the mud pit, likely with the intention of eating them. One Ceratosaurus made a cameo walking with a Parasaurolophus after the Tyrannosaurus Rex collapsed of dehydration. It was one of many starving and dehydrated at the end of the scene, forced to extinction by the endless drought.
- The Ceratosaurs seen in Fantasia strangely did not have any teeth (though they may have been too small to be visibly seen). They also did not have horns over their eyes like the real Ceratosaurus.
- Ceratosaurus was a distant relative of Carnotaurus, as they shared a common ancestor and they are both members of a group called Ceratosauria.
- Ceratosaurus is known from both North America and Portugal in the Morrison and Lourinha formations, respectively.
- Stegosaurus and Ceratosaurus, having lived at the same time and in the same place during the Jurassic, were natural enemies.
- Ceratosaurus is believed by some to have been an excellent swimmer, thanks to its strong tail.