“The Horned Hunter of the Late Jurassic”
Binomial Ceratosaurus nasicornis · seh-RAT-oh-SORE-us
Late Jurassic - 153-145 Ma
IllustrationCeratosaurus fossil records in Fossil Atlas are mapped as selected modern discovery locations, with 24 source-backed records currently shown. Late Jurassic records from the Morrison Formation plus selected international records that connect Portugal, Tanzania, and Uruguay context in the source mix. Key mapped formations in the current dataset include Morrison Fm, Morrison, Tacuarembó. These pins are fossil record locations, not a complete ancient habitat map.
Ceratosaurus was a medium to large Late Jurassic theropod with a distinctive horned skull. Fossil Atlas uses selected records to connect the Morrison Formation with other Jurassic localities, while treating international pins as source-backed discovery records rather than a complete range map.
Drawn true to scale on a metre ruler.
Length
measured6.7 m · 22 ft
Largest known specimens
Height
measured2.1 m (7 ft)
Body mass
estimate700 kg · 1,540 lb
Typical adult
Top speed
estimate40 km/h · 25 mph
Modelled, debated
Ceratosaurus was a medium-sized theropod that occupied a predator niche below Allosaurus in the Morrison ecosystem. Its nasal horn and brow ridges set it apart visually from every other Morrison theropod. The horn was probably used in display or intraspecific rivalry rather than as a weapon against prey. Ceratosaurus had more tail flexibility and slightly different limb proportions from Allosaurus, suggesting a somewhat different hunting style.
The horn
A single horn on the nasal bones, flanked by smaller ridges above the eyes. No evidence supports its use against prey; it was most likely a display structure for recognising or competing with other Ceratosaurus.
The teeth
Large, blade-like, and serrated, similar to Allosaurus in function. Ceratosaurus could tackle substantial prey but was not built for the largest Morrison prey items.
Distribution
Known from the Morrison Formation in North America and from Late Jurassic deposits in Portugal, Tanzania, and possibly Uruguay, making it the most geographically widespread Morrison-era predator.
Build
A longer relative tail and slightly different limb proportions from Allosaurus. Some researchers have suggested an affinity for wetter habitats based on its distribution and anatomy.
Position of this animal’s known range across 252 million years of the Mesozoic and beyond.
153-145 million years ago
Ceratosaurus had a distinctive nasal horn and bony ornaments above the eyes.
Its record appears in both North American and European Late Jurassic fossil contexts.
Fossil Atlas uses its records to make the Jurassic predator set less Allosaurus-only.
Marshall Parker Felch collected the first good Ceratosaurus skeleton at Garden Park, Colorado in 1883 and Marsh described it the same year. The discovery provided one of the first near-complete Morrison theropod skeletons and helped establish what a large Jurassic predator looked like before Allosaurus was equally well understood. Ceratosaurus material from Portugal and Tanzania has since helped researchers trace the distribution of the group across the Late Jurassic landmasses.
Animals known from the same deposits and time as Ceratosaurus.
Allosaurus
The larger, dominant predator of the Morrison Formation. Ceratosaurus probably occupied a slightly different predatory niche to avoid direct competition.
Stegosaurus
A potential prey animal at smaller individual sizes.
Diplodocus
The long-necked Morrison sauropod, probably too large for Ceratosaurus to challenge as an adult.
Other members of Ceratosauridae.
Carnotaurus
A Cretaceous abelisaurid in the same ceratosaur branch of the family tree, with much more elaborate skull ornamentation.
Dilophosaurus
An earlier, crested ceratosaur from the Early Jurassic, showing the group's deep history.
Abelisaurus
The namesake of the abelisaurid group that dominated large predator niches across the Cretaceous southern continents.
Pins show selected fossil records for Ceratosaurus; use them as modern discovery evidence, not a complete range map. Modern fossil discovery map: pins show where selected fossil and specimen records were found today, not ancient Earth positions. What does this mean?
Specimen evidence
These are sourced specimen assets, separate from reconstruction artwork. Only media with clear open or reusable rights is displayed by default.
Ceratosaurus sp. (YPM VP 000319). Digital Image: Yale Peabody Museum; photo by Division of Vertebrate Paleontology, Yale Peabody Museum 2016
Division of Vertebrate Paleontology, Yale Peabody Museum
Ceratosaurus is represented here by selected fossil records from late jurassic records from the morrison formation plus selected international records that connect portugal, tanzania, and uruguay context in the source mix. Fossil Atlas maps those records as modern discovery locations.
No. The map shows modern fossil discovery locations from selected records. Ancient habitat and paleogeographic reconstructions are separate questions.
The current Fossil Atlas records include Morrison Fm. Formation coverage depends on the selected dataset and may not be complete.
Yes. Use the expedition card generator to turn the Ceratosaurus map and specimen profile into a shareable card.
Selected fossil records from PBDB and museum biodiversity aggregators. This is not a complete fossil count by country; source labels and confidence notes help distinguish canonical paleobiology records from specimen-media records.
Reconstruction images are labeled illustrations and do not represent fossil evidence. Size, speed, and bite-force figures are typical published estimates and remain subject to revision as new specimens are described.
Maps use curated PBDB, museum, and specimen-source records with visible caveats.
Pins show where fossils were found or reported today, not exact ancient habitat positions.
Artwork is labeled separately from specimen photos, maps, and source records.
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