Binomial Allosaurus fragilis · AL-oh-SOR-us
Late Jurassic · 155-145 Ma
AI reconstructionAllosaurus fossil records in Fossil Atlas are mapped as selected modern discovery locations, with 205 source-backed records currently shown. Known especially from the Morrison Formation of the western United States, with additional reported Jurassic records from Portugal. Key mapped formations in the current dataset include Morrison Formation, Morrison Fm, Morrison. These pins are fossil record locations, not a complete ancient habitat map.
This remains a specimen profile: the reconstruction, measurements, field account, and evidence sections stay intact. The fossil-map answer is surfaced here so visitors from search can orient themselves before reading the full dossier.
Allosaurus was a large meat-eating theropod from the Late Jurassic. Fossil Atlas treats it as a Morrison Formation anchor animal: a predator whose records make the classic western North American Jurassic ecosystem feel more complete. The page maps selected modern fossil discovery records and separates those locations from ancient habitat reconstructions.
Drawn true to scale on a metre ruler.
Length
measured8.5 m · 28 ft
Largest known specimens
Height
measured3.2 m · 10.5 ft
Body mass
estimate2,000 kg · 4,400 lb
Typical adult
Top speed
estimate34 km/h · 21 mph
Modelled, debated
Bite force
estimate3,500 lbf
Teeth
measured≈ 70
Brain : body (EQ)
estimate1.5
Encephalization quotient
Position of this animal’s known range across 252 million years of the Mesozoic and beyond.
155-145 million years ago
Allosaurus is one of the anchor predators of the Morrison Formation.
Several Morrison quarries preserve multiple Allosaurus individuals.
Its skull was lighter and more flexible than a tyrannosaur skull.
Allosaurus helps connect Stegosaurus and sauropod records into one Jurassic ecosystem.
Pins show selected fossil records for Allosaurus; 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 the AI reconstruction. Only media with clear open or reusable rights is displayed by default.
USNM PAL 530086_6
Steve Jabo
USNM PAL 530086_5
Steve Jabo
USNM PAL 530086_7
Steve Jabo
USNM PAL 530086_4
Steve Jabo
Allosaurus is represented here by selected fossil records from known especially from the morrison formation of the western united states, with additional reported jurassic records from portugal. 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 Formation. Formation coverage depends on the selected dataset and may not be complete.
Yes. Use the expedition card generator to turn the Allosaurus map and specimen profile into a shareable card.
Selected fossil records from PBDB and museum biodiversity aggregators. 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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