Temporal range: Late Jurassic
An interpretation of Ceratosaurus nasicornis by Mario Lanzas.
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Sauropsida
clade: Dinosauria
Order: Saurischia
Suborder: Theropoda
Family: †Ceratosauridae
Genus: Ceratosaurus
Marsh, 1884
Referred species
  • ?Ceratosaurus dentisulcatus
    (Madsen & Welles, 2000)
  • ?Ceratosaurus magnicornis
    (Madsen & Welles]], 2000)
  • ?Ceratosaurus nasicornis
    (Marsh, 1884) (type)
  • Megalosaurus nasicornis Marsh, 1884 (originally Ceratosaurus)

Ceratosaurus (ce·rat·o·saur·us) (meaning horned lizard) was a genus of medium-sized carnivorous dinosaur with a unique horny crest protruding out of the end of its skull. It was one of the earliest dominant predators. It was named by Othniel Charles Marsh in 1884. It grew to 6-7 meters long and 2 meters (6.5 feet) tall on average. Some species may have grown larger than this.

It hunted as well as scavenged small to medium sized prey; such as Dryosaurus. It could potentially eat other prey items from various sources as well.


Ceratosaurus was a primitive medium-sized theropod that was an ancestor of Carnotaurus and other abelisaurids. It had short forelimbs with five fingers, signs of it being more primitive than its main rival Allosaurus. Its legs were so long and muscular, with three toes with sharp talons on the end, designed for fast running. Its skull was double-hinged like a snake, and could open very wide to swallow prey bigger than its head. Ceratosaurus is most distinguishable by the horns above its eyes and the one on its nose. Its tail was somewhat short, and is some of the reason why this dinosaur itself wasn't very long. Its teeth were thin and blade-like, designed to slice through flesh. Ceratosaurus was relatively a medium-sized dinosaur in terms of Jurassic ecosystem, despite its strong build Ceratosaurus were quite likely nimble and able run to speeds of 20-30mph. Each 3 described species varied size, relatively sporting a radical morphological change in the design of the nasal horn (for example, C. magnicornis had more rounder horn than the other species), adjacent in comparison to the Allosaurus and Torvosaurus subspecies. Ceratosaurus measures around 6-7 meters at an average, and roughly stood about 2 meters (6.5 ft) at the hips. Ceratosaurus weighed around 1 metric ton. Interestingly enough it was also had the weak protective armor/ scutes on the back similar to the armor of the genus Carnotaurus.


In his original description of the Ceratosaurus nasicornis holotype and subsequent publications, Marsh noted a number of characteristics that were unknown in all other theropods known at the time. Two of these features, the fused pelvis and fused metatarsus, were known from modern-day birds, and according to Marsh, clearly demonstrate the close relationship between the latter and dinosaurs. To set the genus apart from Allosaurus, Megalosaurus, and coelurosaurs, Marsh made Ceratosaurus the only member of both a new family, the Ceratosauridae, and a new infraorder, the Ceratosauria. This was questioned in 1892 by Edward Drinker Cope, Marsh's rival in the Bone Wars, who argued that distinctive features such as the nasal horn merely showed that C. nasicornis was a distinct species, but were insufficient to justify a distinct genus. Consequently, he assigned C. nasicornis to the genus Megalosaurus, creating the new combination Megalosaurus nasicornis.

Although Ceratosaurus was retained as a distinct genus in all subsequent analyses, its relationships remained controversial during the following century. Both the Ceratosauridae and Ceratosauria were not widely accepted, with only few and poorly known additional members identified. Over the years, separate authors classified Ceratosaurus within the Deinodontidae, the Megalosauridae, the Coelurosauria, the Carnosauria, and the Deinodontoidea. In his 1920 revision, Gilmore argued that the genus was the most basal theropod known from after the Triassic, so not closely related to any other contemporary theropod known at that time; it thus warrants its own family, the Ceratosauridae. It was not until the establishment of cladistic analysis in the 1980s, however, that Marsh's original claim of the Ceratosauria as a distinct group gained ground. In 1985, the newly discovered South American genera Abelisaurus and Carnotaurus were found to be closely related to Ceratosaurus. Gauthier, in 1986, recognized the Coelophysoidea to be closely related to Ceratosaurus, although this clade falls outside of Ceratosauria in most recent analyses. Many additional members of the Ceratosauria have been recognized since.

The Ceratosauria split off early from the evolutionary line leading to modern birds, thus is considered basal within theropods. Ceratosauria itself contains a group of derived (nonbasal) members of the families Noasauridae and Abelisauridae, which are bracketed within the clade Abelisauroidea, as well as a number of basal members, such as Elaphrosaurus, Deltadromeus, and Ceratosaurus. The position of Ceratosaurus within basal ceratosaurians is under debate. Some analyses considered Ceratosaurus as the most derived of the basal members, forming the sister taxon of the Abelisauroidea. Oliver Rauhut, in 2004, proposed Genyodectes as the sister taxon of Ceratosaurus, as both genera are characterized by exceptionally long teeth in the upper jaw. Rauhut grouped Ceratosaurus and Genyodectes within the family Ceratosauridae, which was followed by several later accounts.

Shuo Wang and colleagues, in 2017, concluded that the Noasauridae were not nested within the Abelisauroidea as was previously assumed, but instead were more basal than Ceratosaurus. Because noasaurids had been used as a fix point to define the clades Abelisauroidea and Abelisauridae, these clades would consequently include many more taxa per definition, including Ceratosaurus. In a subsequent 2018 study, Rafael Delcourt accepted these results, but pointed out that, as a consequence, the Abelisauroidea would need to be replaced by the older synonym Ceratosauroidea, which was hitherto rarely used. For the Abelisauridae, Delcourt proposed a new definition that excludes Ceratosaurus, allowing for using the name its traditional sense. Wang and colleagues furthermore found that Ceratosaurus and Genyodectes form a clade with the Argentinian genus Eoabelisaurus. Delcourt used the name Ceratosauridae to refer to this same clade, and suggested to define the Ceratosauridae as containing all taxa that are more closely related to Ceratosaurus than to the abelisaurid Carnotaurus.

Paleoenvironment and Paleobiogeography[]

The Ceratosaurus lived in both western North America, but also parts of Africa. It's most likely that the Ceratosaurus (both species) lived in an environment where there were only two season, the dry and the wet. The Ceratosaurus may have been one of the more medium-sized predators, so it may have needed less food than its counterpart predators.

In the Media[]

  • Ceratosaurus appears briefly in Jurassic Park 3 when the main characters are looking for a satellite phone in a pile of Spinosaurus dung. Like all of InGen's cloned theropods, Ceratosaurus had pronated wrists and a thin frame. The clones also had small horns over the eyes like a Ceratosaurus juvenile and was slightly larger than the original with the most notable difference in size being that it was 3 meters in height rather than 2 meters. This was originally supposed to be Carnotaurus, but it was changed to Ceratosaurus.
  • Ceratosaurus appeared in two episodes of Jurassic Fight Club. In the first episode, Bloodiest Battle, it killed a baby Stegosaurus trapped in mud, but later gets killed by a trio of Allosaurus. In the second episode, Hunter Becomes Hunted, a mated pair are hunting prey, when the female is killed by an Allosaurus. The male Ceratosaurus and the Allosaurus fight for a long time before the Allosaurus kills the male.
  • A pack of Ceratosaurus attacks a group of Diplodocus and Stegosaurus that got stuck in mud in the film Fantasia.
  • A preserved body of the Ceratosaurus can be seen in an episode of Disney's Gravity Falls.

Jurassic Park 3 Ceratosaurus

  • Two Ceratosaurs appear in The Animal World where they fight over the corpse of a Stegosaurus and fall off the cliff and die.
  • A Ceratosaurus battles a Giant Sloth in Unknown Island.
  • Ceratosaurus appeared on Dinosaur King.
  • A Ceratosaurus battles a Triceratops in the film One Million Years B.C.
Cerato saurus

When Dinosaurs Roamed America Ceratosaurus

  • Ceratosaurus appears in the film Brute Force.
  • A Ceratosaurus makes an appearence in the Anime show, Dinosaur King, as a Wind-type Dinosaur, and is slightly larger than 8 meters.
  • Ceratosaurus makes an appearance in the Discovery Channel show Prehistoric in the episode Washington D.C, where it is inaccurately called Allosaurus. “Footage taken from When Dinosaurs Roamed America”.
  • Greymon from Digimon strongly resembles Ceratosaurus.
  • Ceratosaurus was added to Jurassic World: The Game on January 22, 2016 as a limited tournament dinosaur. It is a legendary carnivore. It has three long finger rather than the four short ones the real animal had.
  • Ceratosaurus is one of the available dinosaurs in the IOS application, Jurassic Park: Builder.
  • The Ceratosaurus also appears in Jurassic World: Evolution, seen in the second in-game trailer footage. It looks a lot like the Jurassic Park III movie version, with a red at the head with black marks and white body. However, it takes more after its real-life counterpart, including a thinner skull with more prominent brow horns.
  • Ceratosaurus is featured in the DVD game Jurassic Park: Explorer. A player earns the dinosaur when he/she wins a minigame. It is stated that Ceratosaurus was a cousin to Allosaurus, when actually both dinosaurs are distantly related.
  • Ceratosaurus is available as a two-star, small carnivore in the game Jurassic Park: Operation Genesis. Its appearance is based on the movie. However, Ceratosaurus‘ upper jaw is actually smaller than the movie's design. Ceratosaurus hunts larger herbivores in packs or even by itself for that matter. It is known to posses cannibalism when no other food is around. Ceratosaurus can coexist with the Albertosaurus, Dilophosaurus and Allosaurus (though they do fear it and flee when it is near) and even with smaller carnivores like Velociraptor, but this only occurs when they are not hungry or attacking each other. However with the smaller carnivores like Velociraptor the Ceratosaurus coexists either way and can even share its meals among the smaller theropods.
  • Ceratosaurus can be created in Jurassic Park III: Park Builder.
  • Ceratosaurus skeleton can be in Betty Boop's Museum.
  • Ceratosaurus can be resembled to Barney in Robot Chicken.
  • Ceratosaurus appears as a playable dinosaur in the ROBLOX game "Era of Terror: Remastered", like the other dinosaurs in the game, it starts off as a juvenile before growing into a sub adult before becoming an adult, with each growth stage taking around 20 real life minutes to complete.
  • Ceratosaurus skeleton can seen in Toy Story 3.
  • The Dragonsaurus in Dazzle the Dinosaur strongly resembles the Ceratosaurus.
  • Ceratosaurus appear in the second, third, fourth and fifth season of Jurassic World: Camp Cretaceous.
  • Ceratosaurus appear in the game Jurassic World: Alive in the 2,23 Update after being requested by fans for a long time. It is one of the two unique non-hybrid dinosaur alongside Dracovenator.

Other Wikis[]