Body length
Not establishedNot established here
No total body length adopted. The incomplete skeleton does not yield a securely specimen-bound length or an established adult range. [D3]
EXHIBIT 258
Yuxisaurus
Yuxisaurus kopchicki
Dinosaur
A stocky early armored dinosaur from Yunnan that helps document the early spread of shield-bearing dinosaurs. [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 Yuxisaurus 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 Yuxisaurus kopchicki; 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.
PERIODEarly Jurassic[1]
DIETHerbivoreEvidence and uncertainty in the dossier
TOTAL LENGTHSee the dossierEstimate scope matters
FOSSILS FOUNDChina[1]
MEET THE ANIMAL
Meet Yuxisaurus
Yuxisaurus lived in southwestern China during the Early Jurassic, long before the best-known giant armored dinosaurs. Its discovery helped show that early shield-bearing dinosaurs were already spreading and developing different body shapes. It was a stocky animal with spiked armor, and its fossils added another plant eater to a region better known for long-necked dinosaurs and their relatives. [D2]
Researchers identified it from one incomplete skeleton containing skull pieces, vertebrae, limb bones and many armor elements. More than 120 pieces of bony armor were recovered. These remains provide real identifying features, but they do not reveal the complete original arrangement of every plate. A drawing must therefore combine what was found with clearly limited reconstruction of the missing parts. [D1]
Its heavy build suggests it usually moved on four legs. Some researchers also consider occasional movement on two legs possible, although this is an interpretation of its anatomy. We do not have assigned eggs, nests or a recorded courtship display for this specimen. The find is valuable because it explains part of armored-dinosaur history, while leaving many details of everyday life open. [D3]
PREHISTORIC ANIMAL DOSSIER
A life in profile.
The animal, the evidence, and the questions still open.
Yuxisaurus lies near the early radiation of armored dinosaurs; its discovery adds regional evidence without identifying a direct ancestor. [D2]
Profile scope: The exhibit concerns the incomplete holotype CVEB 21701 of Yuxisaurus kopchicki. [D1]
- Time
- Early Jurassic
- Fossil locations in this exhibit
- China
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 dependable body mass adopted. Reviewed descriptions provide skeletal anatomy, rather than a calibrated complete-body mass estimate. [D3]
Diet and feeding
InferredPlant feeding inferred.
Its triangular, denticulate, ridged tooth crown is consistent with herbivory; exact foods and a preserved meal are unavailable. [D1]
Habitat and setting
InferredTerrestrial Fengjiahe Formation in Yunnan.
The fossil is from Early Jurassic strata in a sauropodomorph-dominated fauna; a detailed preferred habitat remains unresolved. [D2] [D1]
Movement
InferredPrimarily quadrupedal movement is inferred.
The robust skeleton favors four-legged posture; possible two-legged movement is an interpretation, not observed behavior. [D3]
Recognizable anatomy
InferredStocky body with numerous armor elements.
More than 120 osteoderms were recovered; their complete arrangement and missing body outline remain partly reconstructed. [D1]
Reproduction & life together
Reproduction and nesting
Not establishedNot established here
Assigned eggs and nests are unknown here. The reviewed single incomplete skeleton and focused searches do not establish taxon-specific reproductive remains. [D3]
Mating and courtship
Not establishedNot established here
No established courtship display. Armor alone does not identify a sex difference, breeding signal or mating ritual. [D2]
Social behavior
Not establishedNot established here
Group organization remains unknown. Sociality discussed for other early armored dinosaurs cannot be transferred to this single Yuxisaurus individual. [D1]
Dossier research & sources
Sources and inspection notes for the claims in this profile.
- Yao et al. (2022), A new early-branching armoured dinosaur from the Lower Jurassic of southwestern ChinaeLife · Accessed 2026-10-08Full original description inspected via its PMC copy: incomplete skeleton, age correlation, ridged tooth crown, armor and alternative phylogenies. · Inspected: page
- New species is earliest armoured dinosaur described from Asia (2022)Natural History Museum, London · Accessed 2026-10-08Complete indexed institutional article inspected for regional significance, stocky build and early-diversification context. · Inspected: excerpt
- Early Jurassic armoured dinosaur discovered in southwestern China (2022)Natural History Museum, London · Accessed 2026-10-08Press release inspected, including partial-skeleton scope and cautiously proposed facultative quadrupedality. · Inspected: page
THE STORY IN THE FOSSILS
Evidence behind Yuxisaurus
The specimen preserves skull portions, limb bones and many separate armor pieces. Their combination, including distinctive skull features, allowed researchers to diagnose a new genus from southwestern China. [3]
The discovery broadens the geographic picture of early armored dinosaurs. It shows that this body plan was already varied, while leaving the group's exact place of origin unsettled. [2]
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.
- Yao et al. (2022), A new early-branching armoured dinosaur from the Lower Jurassic of southwestern ChinaeLife · Accessed 2026-10-08Full original description inspected via its PMC copy: incomplete skeleton, age correlation, ridged tooth crown, armor and alternative phylogenies. · Inspected: page
- New species is earliest armoured dinosaur described from Asia (2022)Natural History Museum, London · Accessed 2026-10-08Complete indexed institutional article inspected for regional significance, stocky build and early-diversification context. · Inspected: excerpt
- Early Jurassic armoured dinosaur discovered in southwestern China (2022)Natural History Museum, London · Accessed 2026-10-08Press release inspected, including partial-skeleton scope and cautiously proposed facultative quadrupedality. · Inspected: page
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