Body length
InferredAbout 10 m (museum genus reference)
This rounded profile value is not a measured G. monumentensis individual, a maximum or a range for every species. [D1]
EXHIBIT 78
Gryposaurus
Gryposaurus monumentensis
Gryposaurus was a duck-billed dinosaur with an arched nose; its species differ in skull construction.
TWO WAYS TO PICTURE THE PAST
Science & the silver screen
Compare the evidence with the familiar movie image. The illustrations are not to a shared scale.
01 / SCIENTIFIC RECONSTRUCTION
An animal, reconstructed
Image unavailableLife reconstruction of Gryposaurus monumentensis with a deep skull and rounded nasal arch.The exhibit and its credited image source remain available.
Life reconstruction of Gryposaurus monumentensis by TotalDino. This species has a particularly robust skull; the full body, missing anatomy, soft tissues and coloration include reconstruction. [2]
Gryposaurus TD.png · TotalDino. CC BY 4.0. Commons-listed 1280px current preview resized proportionally for the thumbnail and converted to WebP; no anatomical edits. Same source license applies.
Scientific reconstruction is an interpretation; source credit does not certify every anatomical detail.
02 / MOVIE-STYLE INTERPRETATION
A cinematic imagination
Image unavailableIllustrative reconstruction of Gryposaurus monumentensis.The exhibit and its credited image source remain available.
Original cinematic interpretation of Gryposaurus monumentensis. Coloration, soft tissues and scenery are artistic choices; reconstructed proportions do not establish a measured individual. Lighting, coloration and scenery are artistic choices. This image does not document a fossil locality or behavior.
Original artwork · artistic interpretation.
Scientific view: source-informed reconstruction, credited paleoart or specimen-based imagery. Movie-style view: Original artistic interpretation. Reconstructions involve uncertainty.
PERIODLate Cretaceous[2]
DIETHerbivoreEvidence and uncertainty in the dossier
TOTAL LENGTHSee the dossierEstimate scope matters
FOSSILS FOUNDCanada, USA[2]
MEET THE ANIMAL
Meet Gryposaurus
Gryposaurus was a plant-eating dinosaur from Late Cretaceous North America. The genus includes more than one species, so a single size reference cannot describe all its animals. A museum figure of about ten metres gives a broad introduction, while individual fossils belong to particular species and growth stages. Keeping those differences visible prevents several animals from being blended into one. [D1]
A study of Gryposaurus notabilis compared its reconstructed jaw muscles and feeding mechanics with those of Corythosaurus. The results suggest differences in how the jaws worked, but larger muscles alone do not establish a stronger bite. Such models help explain feeding equipment without revealing a precise meal or a favorite kind of vegetation. [D3]
A separate bonebed from the Oldman Formation contains juvenile Gryposaurus in two age groups. Researchers interpret the collection as evidence of young animals gathering, while also recognizing that the bones moved a short distance before burial. It is a local interpretation of a particular fossil group. It should not become a claim that every Gryposaurus species lived in identical adult herds. [D4]
PREHISTORIC ANIMAL DOSSIER
A life in profile.
The animal, the evidence, and the questions still open.
The gallery features G. monumentensis; feeding models and juvenile associations concern other material.
Profile scope: Genus — Gryposaurus; species-specific findings are identified below.
- Time
- Late Cretaceous
- Fossil locations in this exhibit
- Canada, USA
How to read the evidence
Source supported identifies a description documented by the cited source. Inferred marks a reconstruction or functional estimate. Debated marks competing interpretations. Not established means the sources reviewed for this dossier do not support a firm conclusion; it does not mean a behavior never occurred.
A size reference is an estimate, not a population range. Nesting evidence does not by itself establish courtship, mate choice, or lifelong pairing.
Body mass
InferredAbout 405 kg for a juvenile individual
Mallon estimates G. notabilis CMN 8784 by developmental mass extrapolation, scaling femur length against adult AMNH 5350 (reference estimate 4,312 kg). This is not an adult genus average or a G. monumentensis estimate. [D5]
Diet and feeding
InferredPlant-eating; feeding mechanics varied
Models of G. notabilis suggest different jaw mechanics from Corythosaurus, including possible size-related food partitioning. They do not identify a preserved diet or test G. monumentensis. [D3]
Habitat and setting
Source supportedNorth American continental deposits
G. monumentensis comes from Utah’s Kaiparowits Formation; other species occur in Alberta and Montana. Its type skull was recovered from a river point-bar deposit. [D2]
Movement
InferredAdults probably mainly used four legs
Comparative limb anatomy supports predominantly quadrupedal adult hadrosaurids. This is broader-family evidence; precise gait and speed for each Gryposaurus species remain uncertain. [D6]
Recognizable anatomy
Source supportedArched nasal bones; robust skull in G. monumentensis
The deep nasal arch distinguishes the genus. The Utah species has especially robust jaws and skull proportions; these traits should not be copied unchanged to all Gryposaurus. [D2]
Reproduction & life together
Reproduction and nesting
Not establishedNot established here
The reviewed sources establish juvenile remains but do not establish Gryposaurus nest construction, clutch size, egg incubation or parental care.
Mating and courtship
Not establishedNot established here
No reviewed source demonstrates a mating display or sex-specific nasal arch. A prominent nose alone does not establish courtship behavior.
Social behavior
InferredJuvenile aggregations inferred
A 2022 taphonomic study interprets two juvenile age classes in an Oldman Formation Gryposaurus sp. bonebed as a segregated group. Short-distance transport occurred; this does not establish adult herds or G. monumentensis behavior. [D4]
Dossier research & sources
Sources and inspection notes for the claims in this profile.
- GryposaurusNatural History Museum, London · Accessed 2026-10-02Museum profile; rounded reference size, diet, identity and geographic occurrence. Life stage and individual basis of size values are not specified. · Inspected: page
- A new species of Gryposaurus (Dinosauria: Hadrosauridae) from the late Campanian Kaiparowits Formation, southern Utah, USAZoological Journal of the Linnean Society / Wiley · Accessed 2026-10-02Original species description; inspected taxonomic comparisons, holotype, diagnostic skull anatomy and North American stratigraphic occurrences. · Inspected: page
- Disparate feeding mechanics between two hadrosaurid dinosaurs support the potential for resource partitioningProceedings of the Royal Society B / PubMed · Accessed 2026-10-02Original research abstract inspected through PubMed; G. notabilis and Corythosaurus casuarius muscle reconstructions and finite-element feeding comparison. · Inspected: abstract
- Taphonomy of a monodominant Gryposaurus sp. bonebed from the Oldman Formation (Campanian) of Alberta, CanadaUniversity of Bologna Research Repository / Canadian Journal of Earth Sciences · Accessed 2026-10-02Original authors’ peer-reviewed abstract in institutional repository; short-distance transport, overbank burial and two juvenile age classes. DOI 10.1139/cjes-2020-0200. · Inspected: abstract
- Rare juvenile material constrains estimation of skeletal allometry in Gryposaurus notabilis (Dinosauria: Hadrosauridae)The Anatomical Record / Wiley · Accessed 2026-10-02Original full text inspected; juvenile CMN 8784 reconstruction and developmental mass extrapolation using adult AMNH 5350 as a scaling reference. · Inspected: page
- Osteological correlates for quadrupedality in ornithischian dinosaursActa Palaeontologica Polonica · Accessed 2026-10-02Original comparative study abstract; adult hadrosaurid locomotor inference is broader-group evidence, not species-specific tracks. · Inspected: abstract
THE STORY IN THE FOSSILS
One nose, several species.
The skull that anchors G. monumentensis came from southern Utah. Comparisons with Canadian and Montanan species show why a genus profile must preserve species differences rather than combine every measurement and trait into one animal. [2]
A separate feeding study tests G. notabilis. Its jaw muscles and leverage differ from Corythosaurus, but the comparison yields similar bite forces at similar body sizes. Larger muscles alone do not prove a stronger bite. [3]
A note on scale and time
The dossier identifies the scope of each reference estimate. A mount, an individual fossil and a species-wide adult range are different measurements. Comparison metrics remain unavailable where adult scope has not been established. Unknown does not mean zero.
Sources & editorial notes
Sources support the stated claims and scopes. Refer to the evidence notes for uncertainty.
- GryposaurusNatural History Museum, London · Accessed 2026-10-02Museum profile; rounded reference size, diet, identity and geographic occurrence. Life stage and individual basis of size values are not specified. · Inspected: page
- A new species of Gryposaurus (Dinosauria: Hadrosauridae) from the late Campanian Kaiparowits Formation, southern Utah, USAZoological Journal of the Linnean Society / Wiley · Accessed 2026-10-02Original species description; inspected taxonomic comparisons, holotype, diagnostic skull anatomy and North American stratigraphic occurrences. · Inspected: page
- Disparate feeding mechanics between two hadrosaurid dinosaurs support the potential for resource partitioningProceedings of the Royal Society B / PubMed · Accessed 2026-10-02Original research abstract inspected through PubMed; G. notabilis and Corythosaurus casuarius muscle reconstructions and finite-element feeding comparison. · Inspected: abstract
- Taphonomy of a monodominant Gryposaurus sp. bonebed from the Oldman Formation (Campanian) of Alberta, CanadaUniversity of Bologna Research Repository / Canadian Journal of Earth Sciences · Accessed 2026-10-02Original authors’ peer-reviewed abstract in institutional repository; short-distance transport, overbank burial and two juvenile age classes. DOI 10.1139/cjes-2020-0200. · Inspected: abstract
- Rare juvenile material constrains estimation of skeletal allometry in Gryposaurus notabilis (Dinosauria: Hadrosauridae)The Anatomical Record / Wiley · Accessed 2026-10-02Original full text inspected; juvenile CMN 8784 reconstruction and developmental mass extrapolation using adult AMNH 5350 as a scaling reference. · Inspected: page
- Osteological correlates for quadrupedality in ornithischian dinosaursActa Palaeontologica Polonica · Accessed 2026-10-02Original comparative study abstract; adult hadrosaurid locomotor inference is broader-group evidence, not species-specific tracks. · Inspected: abstract
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