Body length
InferredAbout 9 m; museum reference
The current museum profile gives 9 m. It is a rounded body reconstruction, with no life stage or biological range specified. [D1]
EXHIBIT 68
Amargasaurus
Amargasaurus cazaui
Amargasaurus cazaui was an Early Cretaceous sauropod from Argentina with paired elongated neck spines. Bone histology supports connected soft tissue rather than separate horn sheaths.
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 / SKELETAL RECONSTRUCTION
A framework from the fossils
Image unavailablePhotograph of an Amargasaurus skeletal mount, showing paired tall neck spines.The exhibit and its credited image source remain available.
Photograph of a reconstructed Amargasaurus cazaui skeletal mount. Mounts include restored parts and do not preserve living colours or soft tissues; the bare bones do not establish separate horn sheaths. [2]
Amargasaurus skeleton.jpg · Jeffrey. CC BY-SA 2.0. Resized proportionally and converted to WebP; no anatomical edits. Same source license applies.
Skeletal mounts and drawings may restore missing parts; the caption identifies the displayed material.
02 / MOVIE-STYLE INTERPRETATION
A cinematic imagination
Image unavailableArtistic reconstruction of Amargasaurus; colors and soft tissues are illustrative.The exhibit and its credited image source remain available.
Original cinematic interpretation of Amargasaurus. Anatomy, soft tissues and colors are reconstructed choices. 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 Cretaceous[1]
DIETHerbivoreEvidence and uncertainty in the dossier
TOTAL LENGTHSee the dossierEstimate scope matters
FOSSILS FOUNDArgentina, Patagonia, Neuquén[1]
MEET THE ANIMAL
Meet Amargasaurus
Amargasaurus cazaui was a plant-eating sauropod from Early Cretaceous Argentina. Sauropods are the long-necked dinosaurs familiar from many giant skeletons, but this animal had a particularly unusual neck outline. Its double row of bony spines makes it recognizable within that wider group, rather than just another dinosaur with a long neck. [S1]
The spines rose from the vertebrae, the bones of the backbone, and were especially elongated along the neck. A twin sail of skin has been proposed as a covering. That proposal is a reconstruction of missing tissues, while the bony structures supply the physical evidence. Picturing a complete living animal therefore involves more than simply drawing the bones. [S1]
Its classification places it in the dicraeosaurid branch of sauropods, and the named type species is cazaui. Those labels help organize comparisons with relatives. They do not record its exact colors or show how its striking neck was used during daily life. An unusual outline can identify a dinosaur clearly while leaving the purpose and complete appearance of its outer covering open to investigation. [S1]
Overview sources
- AmargasaurusNatural History Museum, London · Accessed 2026-10-04Inspected: page
PREHISTORIC ANIMAL DOSSIER
A life in profile.
The animal, the evidence, and the questions still open.
Amargasaurus is a relatively small sauropod distinguished by paired, tall neural spines. Their preserved bone structure helps evaluate alternative reconstructions of the neck's soft tissues.
Profile scope: Species: Amargasaurus cazaui. Rounded museum size and mass figures are educational reconstructions; they do not specify an adult population range.
- Time
- Early Cretaceous
- Fossil locations in this exhibit
- Argentina, Patagonia, Neuquén
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
InferredRoughly 2.5 tonnes; museum reference
The museum's facts list roughly 2.5 tonnes without naming a method or life stage. This is not a measured fossil individual's live weight. [D1]
Diet
Source supportedPlant-eating sauropod
The museum identifies herbivory. The reviewed evidence does not establish a preferred plant species. [D1]
Habitat & fossil setting
Source supportedLa Amarga Formation, Neuquén, Argentina
The original description places the holotype in the lower La Amarga Formation. The museum identifies an Early Cretaceous northern Patagonian setting. [D2] [D1]
Movement
InferredQuadrupedal sauropod
The holotype's forelimbs and hind limbs support a four-legged reconstruction. Exact running speed is not inferred from its short limb proportions here. [D2]
Distinctive anatomy
Source supportedPaired tall neck spines; sail favored
The spines are preserved bone. A 2022 histological study supports interspinous ligaments and a cervical sail, and finds no support for separate keratin horn sheaths. [D2] [D3]
Reproduction & life together
Reproduction & nesting
Not establishedNot established here
The reviewed sources do not establish species-specific nests, clutch size or parental care.
Courtship & mating
Not establishedNot established here
Spine and sail reconstructions do not establish a courtship sequence or mating system. A display interpretation is a hypothesis, not direct behavior. [D3]
Social behavior
Not establishedNot established here
The reviewed sources do not establish herd structure, pair bonds or cooperative behavior.
Dossier research & sources
Sources and inspection notes for the claims in this profile.
- Amargasaurus cazauiWestern Australian Museum; updated January 2026 · Accessed 2026-10-02Museum profile and indexed facts: 9 m length, approximately 2.5 tonnes, herbivory and La Amarga provenance; life stage and method unspecified. · Inspected: excerpt
- A new dicraeosaurid sauropod, Amargasaurus cazaui, from the La Amarga FormationAmeghiniana; Salgado & Bonaparte (1991), English translation by Harris & Lamanna · Accessed 2026-10-02Original description in English translation; locality, holotype, skeletal proportions and elongated spines inspected. · Inspected: excerpt
- Osteohistology of the hyperelongate hemispinous processes of Amargasaurus cazauiJournal of Anatomy; Cerda et al. (2022), abstract via PubMed · Accessed 2026-10-02Original research abstract: holotype spine microanatomy, interspinous ligaments and evidence favoring a cervical sail over keratinized horn sheaths. · Inspected: abstract
THE STORY IN THE FOSSILS
Meet Amargasaurus.
Amargasaurus came from Early Cretaceous Patagonia. Its comparatively compact sauropod body carried remarkable paired spines extending from the neck vertebrae. [1] [2]
Artists have given those spines several different soft-tissue coverings. A 2022 study examined their internal structure and favored ligaments connecting neighboring spines within a cervical sail. It did not support separate keratin horn sheaths. The animal's living appearance remains a reconstruction. [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.
- Amargasaurus cazauiWestern Australian Museum; updated January 2026 · Accessed 2026-10-02Museum profile and indexed facts: 9 m length, approximately 2.5 tonnes, herbivory and La Amarga provenance; life stage and method unspecified. · Inspected: excerpt
- A new dicraeosaurid sauropod, Amargasaurus cazaui, from the La Amarga FormationAmeghiniana; Salgado & Bonaparte (1991), English translation by Harris & Lamanna · Accessed 2026-10-02Original description in English translation; locality, holotype, skeletal proportions and elongated spines inspected. · Inspected: excerpt
- Osteohistology of the hyperelongate hemispinous processes of Amargasaurus cazauiJournal of Anatomy; Cerda et al. (2022), abstract via PubMed · Accessed 2026-10-02Original research abstract: holotype spine microanatomy, interspinous ligaments and evidence favoring a cervical sail over keratinized horn sheaths. · Inspected: abstract
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