Profile view of Ceratosaurus nasicornis
Kingdom Animalia
Phylum Chordata
Superclass Tetrapoda
Class Reptilia
Subclass Diapsida
Superorder Dinosauria
Order Saurischia
Suborder Theropoda
Family Ceratosauridae
Genus Ceratosaurus
1st Species Ceratosaurus nasicornis
Other attributes
Time Range 155-150 mya
Location United States of America, Portugal
Name Meaning Horned reptile
Physical Dimensions 6.9 meters long
Weight 1 tonne
Dietary Classification Carnivore
Ceratosaurus is a ceratosaurid theropod dinosaur from the Late Jurassic of the United States of America and Portugal. It was named in 1884 by Othniel Charles Marsh. It is one of the more well-known Jurassic dinosaurs of the Western United States, notable for the large, horn-like crests atop its head.


Ceratosaurus was a theropod with a semi-bulky body, moderately long legs, a long, laterally-flattened tail, short arms with 3 fingers on each hand, and a large head with a mouth containing lots of big teeth. Perhaps the most defining traits of Ceratosaurus were the 3 large, horn-like crests atop its head (two of them were above the eyes, while the other was on top of its nose). Its body would have been covered in scaly skin, with a row of osteoderms running down its back.


Ceratosaurus was a predator, preying on ornithopods, small sauropods, stegosaurians, small ankylosaurs, small crocodylomorphs, and smaller theropods. Its teeth had knife-like serrations from back to back, and were used to cut into the hides of large prey.


The use of the horn-like crests atop Ceratosaurus' head has been open to debate for a long time, with a prevalent theory being that its nasal crest was used as a weapon against predators and prey alike; however, this theory no longer holds up (especially since other theropods such as Dilophosaurus and Guanlong have large crests that do not serve as weapons), and the most widely-accepted theory is that it was used for display (whether it was used for attracting mates or for recognition by other members of its species is unknown). Another unique trait of Ceratosaurus is the row of osteoderms running down its back; it is very likely that they evolved for defensive purposes (like they do in most cases), as larger theropods like Allosaurus would have a harder time biting into armored hide rather than regular scales. As well as this, Ceratosaurus had a long, flexible body and a laterally-flattened tail (similar to that of a crocodile); this has caused people to speculate that it lived a lot like a crocodile, swimming around in large bodies of water and feeding on aquatic prey. Even if this theory is partially baseless, it would be assumed that Ceratosaurus occupied an ecological niche different from that of its larger counterparts, as it was too small to prey on gigantic herbivores such as Brontosaurus.

In popular cultureEdit

Ceratosaurus was first introduced to the public in the 1914 silent film Brute Force, where it tries to eat a tribe of cave people that reside in the prehistoric times. Since then, it has appeared in major pieces of media such as Fantasia, One Million Years B.C, and Jurassic Park; in most of those pieces of media, it is depicted in a similar manner to Allosaurus and Tyrannosaurus, being a terrible, hungry brute willing to chase prey for miles in fantasy films, and behaving more realistically in documentaries. Due to the sudden emergence of Carnotaurus in popular culture, Ceratosaurus has started to suffer a fall from grace, slowly becoming just as unpopular as dinosaurs such as Megalosaurus.

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