Body length
InferredAbout 7 m (museum display reference)
The roughly23-foot museum reconstruction is a reference, not one complete measured fossil or a species maximum. [D2]
EXHIBIT 239
Peloroplites
Peloroplites cedrimontanus
Dinosaur
Peloroplites was a large armored plant eater with a broad beak and powerful jaws. [2]
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 / SOURCE-INFORMED RECONSTRUCTION
A life reconstruction from the evidence
Image unavailableIllustrative life reconstruction of Peloroplites in a period-appropriate environment; coloration and missing anatomy are interpretations.The exhibit and its credited image source remain available.
An illustrative reconstruction. Compare its anatomy with the evidence and limitations in the dossier. [1]
Source-informed reconstruction. Appearance evidence [1]. Original illustration; missing anatomy, coloration and scenery include interpretation.
Fossils constrain this life reconstruction. Missing anatomy, coloration and the environmental scene include interpretation; the dossier explains the evidence limits.
02 / MOVIE-STYLE INTERPRETATION
A cinematic imagination
Image unavailableIllustrative reconstruction of Peloroplites cedrimontanus; missing anatomy, pose, skin and colors are hypotheses.The exhibit and its credited image source remain available.
An illustrative reconstruction. Compare its anatomy with the evidence and limitations in the dossier. 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[3]
DIETHerbivoreEvidence and uncertainty in the dossier
TOTAL LENGTH7–7 mEstimate scope matters
FOSSILS FOUNDUnited States[1]
MEET THE ANIMAL
Meet Peloroplites
Peloroplites was a large, four-legged armored dinosaur from Utah. Its museum reconstruction is about seven meters long, but that display length is not the measurement of one complete fossil animal. A broad beak and powerful jaws helped it process vegetation. Those features suggest plant feeding, possibly including tougher material, while its exact menu remains beyond what the display and bones can tell us. [D2]
The fossil-bearing Mussentuchit Member now falls within the Cenomanian part of the Late Cretaceous. This updates the Early Cretaceous wording found in the original description's title and some older exhibits. Scientists refine dates by investigating rock layers and dating suitable minerals. A regional age framework helps place the dinosaur in time without pretending that each individual fossil has received its own direct numerical date. [D3]
Researchers have also compared the hand bones with those of other armored dinosaurs. The Peloroplites metacarpals were separate when found, but they fit a curved arrangement that may have helped support body weight. This is a careful anatomical inference rather than a preserved footprint from that exact animal. It shows why a complete museum reconstruction can include useful ideas while some details remain uncertain. [D4]
PREHISTORIC ANIMAL DOSSIER
A life in profile.
The animal, the evidence, and the questions still open.
The museum reconstruction combines a broad, low armored body with four weight-bearing limbs and an unclubbed tail. [D2]
Profile scope: Genus — Peloroplites cedrimontanus; type skull CEUM 26331 and referred Utah material. [D1]
- Time
- Late Cretaceous
- Fossil locations in this exhibit
- United States
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
Not establishedNot established here
No comparable maturity-qualified numerical body mass is adopted from the exhibit account. [D2]
Diet and feeding
InferredPlant feeding inferred
Broad beak and robust teeth and jaws suggest cropping vegetation, possibly tougher material; no particular meal is demonstrated. [D2]
Habitat and setting
Source supportedUtah Mussentuchit setting
Later regional dating places this member in the Cenomanian Late Cretaceous, updating the original paper's historical age label. [D3]
Movement
InferredQuadrupedal reconstruction
Comparative metacarpal evidence suggests a semicircular, supporting hand arrangement; direct articulated hands were not tested. [D4]
Recognizable anatomy
Source supportedLow skull; small rear horns
Referred armor positions require restoration. [D1]
Reproduction & life together
Reproduction and nesting
Not establishedNot established here
No assigned nest in reviewed material. [D1]
Mating and courtship
Not establishedNot established here
No mating display in reviewed material. [D1]
Social behavior
Not establishedNot established here
A multi-individual quarry does not establish herds. [D1]
Dossier research & sources
Sources and inspection notes for the claims in this profile.
- Ankylosaurs from the Price River Quarries, Cedar Mountain Formation, Lower Cretaceous, East-Central Utah (Carpenter et al., 2008)Journal of Vertebrate Paleontology 28(4):1089–1101; doi:10.1671/0272-4634-28.4.1089 · Accessed 2026-10-06Original author-uploaded type/systematic, skull, limbs, armor and discussion passages inspected. Type CEUM26331 partial skull, PR2 base Mussentuchit. Referred bones/armor include multiple individuals; not all articulated. Old Early Cretaceous assignment superseded by later member dating. Already used by prior catalog; total shared source prose is budgeted, not reset. · Inspected: page
- Peloroplites cedrimontanus — museum exhibit handoutUtah State University Eastern Prehistoric Museum · Accessed 2026-10-06Institutional handout and indexed exhibit account inspected: broad beak, robust teeth/jaws, plant-feeding interpretation, four legs, no tail club, missing hindfoot. Display reference about23ft/7m is a mounted reconstruction, not a complete fossil measurement. Five-ton label has no individual or maturity qualification, so mass remains null. Older100Ma/EarlyCretaceous wording not adopted. Current HTML URL returned404; accessible handout retained instead. · Inspected: page
- A refined temporal framework for newly discovered fossil assemblages of the upper Cedar Mountain Formation (Mussentuchit Member), Mussentuchit Wash, Central Utah (2020)Cretaceous Research 110:104384 · Accessed 2026-10-06Original abstract and introduction inspected: localized Cenomanian LA-ICP-MS/CA-TIMS detrital-zircon framework, with two volcaniclastic phases no older than96Ma and94Ma. Earlier98.39±0.07Ma results are historical40Ar/39Ar dates. Regional/member dating does not directly date a Peloroplites individual. · Inspected: abstract
- Evidence for a sauropod-like metacarpal configuration in stegosaurian dinosaurs (Senter, 2010)Acta Palaeontologica Polonica 55(3):427–432; doi:10.4202/app.2009.1105 · Accessed 2026-10-06Full original PDF retained and comparative Peloroplites paragraph inspected. Main direct tests concern stegosaur hands; disarticulated Peloroplites metacarpals fit a semicircular arc, suggesting a semitubular support arrangement. This is comparative inference, not a direct articulated Peloroplites hand experiment. · Inspected: page
THE STORY IN THE FOSSILS
Evidence behind Peloroplites
The hands illustrate how careful comparisons can suggest posture while leaving details of a particular animal uncertain. [4]
Rock dating changes the chronology; the original article's title retains its historical age assignment. [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.
- Ankylosaurs from the Price River Quarries, Cedar Mountain Formation, Lower Cretaceous, East-Central Utah (Carpenter et al., 2008)Journal of Vertebrate Paleontology 28(4):1089–1101; doi:10.1671/0272-4634-28.4.1089 · Accessed 2026-10-06Original author-uploaded type/systematic, skull, limbs, armor and discussion passages inspected. Type CEUM26331 partial skull, PR2 base Mussentuchit. Referred bones/armor include multiple individuals; not all articulated. Old Early Cretaceous assignment superseded by later member dating. Already used by prior catalog; total shared source prose is budgeted, not reset. · Inspected: page
- Peloroplites cedrimontanus — museum exhibit handoutUtah State University Eastern Prehistoric Museum · Accessed 2026-10-06Institutional handout and indexed exhibit account inspected: broad beak, robust teeth/jaws, plant-feeding interpretation, four legs, no tail club, missing hindfoot. Display reference about23ft/7m is a mounted reconstruction, not a complete fossil measurement. Five-ton label has no individual or maturity qualification, so mass remains null. Older100Ma/EarlyCretaceous wording not adopted. Current HTML URL returned404; accessible handout retained instead. · Inspected: page
- A refined temporal framework for newly discovered fossil assemblages of the upper Cedar Mountain Formation (Mussentuchit Member), Mussentuchit Wash, Central Utah (2020)Cretaceous Research 110:104384 · Accessed 2026-10-06Original abstract and introduction inspected: localized Cenomanian LA-ICP-MS/CA-TIMS detrital-zircon framework, with two volcaniclastic phases no older than96Ma and94Ma. Earlier98.39±0.07Ma results are historical40Ar/39Ar dates. Regional/member dating does not directly date a Peloroplites individual. · Inspected: abstract
- Evidence for a sauropod-like metacarpal configuration in stegosaurian dinosaurs (Senter, 2010)Acta Palaeontologica Polonica 55(3):427–432; doi:10.4202/app.2009.1105 · Accessed 2026-10-06Full original PDF retained and comparative Peloroplites paragraph inspected. Main direct tests concern stegosaur hands; disarticulated Peloroplites metacarpals fit a semicircular arc, suggesting a semitubular support arrangement. This is comparative inference, not a direct articulated Peloroplites hand experiment. · Inspected: page
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