What makes Amargasaurus scientifically significant?

Amargasaurus provides critical insights into the evolutionary radiation of Sauropodomorpha. Holotypes and fossil evidence indicate: Nearly complete skeleton with intact skull, cervical spine, and postcrania at MACN, Buenos Aires.

Amargasaurus (Amargasaurus cazaui Salgado & Bonaparte, 1991) - Size, Diet & Cretaceous Period Facts

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Amargasaurus (Amargasaurus cazaui Salgado & Bonaparte, 1991) - Size, Diet & Cretaceous Period Facts | DinoOrigin

Evolutionary Taxonomy & Cladistics

View Dinosaur Phylogeny

Phylogenetic classification of Amargasaurus cazaui Salgado & Bonaparte, 1991 based on peer-reviewed cladistic analyses of diagnostic skeletal synapomorphies.

Taxonomic Rank	Taxon / Clade	Diagnostic Context
Kingdom	Animalia	Monophyletic prehistoric clade
Phylum	Chordata	Monophyletic prehistoric clade
Clade	Dinosauria	Monophyletic prehistoric clade
Order	Saurischia (Lizard-Hipped Dinosaurs)	Characterized ancestrally by a triradiate pelvis with an anteriorly pointing pubis.
Suborder	Sauropodomorpha	Herbivorous saurischians characterized by elongated necks, columnar limbs, and enormous body volumes.
Genus	Amargasaurus	Monophyletic prehistoric clade
Species	Amargasaurus cazaui Salgado & Bonaparte, 1991	Specific authority designation

Anatomy & Physical Characteristics

Amargasaurus is instantly recognizable by the extraordinary parallel rows of long, backward-curving spines projecting from its cervical and anterior dorsal vertebrae. Inhabiting Early Cretaceous Patagonia, this compact, nine-meter sauropod displayed one of the most flamboyant spinal adaptations in dinosaur history.

Whether these twin rows of spines were covered in keratinous horns for defense or supported double skin sails for display remains one of paleontology's most intriguing debates.

Diagnostic Morphological Traits

Compact sauropod with a relatively short neck crowned with two parallel rows of long, curved spines.

Comparative Scale & Biometrics

Anatomical dimensions relative to an average adult human (1.8 m / 6 ft tall)

Approx. 5.6× human length

Amargasaurus (Length)8.5–10 m (27.9–32.8 ft)

Adult Human1.8 m (6.0 ft)

Length

8.5–10 m (27.9–32.8 ft)

Height

2.2–2.7 m (7.2–8.9 ft)

Estimated Mass

2.5–4.0 metric tons (5,512–8,818 lbs)

Diet & Feeding Ecology

All Herbivore Species

Trophic Guild: Herbivore

Low-growing ferns, cycads, and horsetails stripped with pencil-shaped peg teeth.

Paleobiology & Behavior

Low-browsing sauropod that used its neck spines for visual signaling, defense, or sexual display. Phylogenetically allied with the Late Jurassic African Dicraeosaurus, Amargasaurus represents a specialized South American branch of short-necked dicraeosaurids adapted to low-tier foraging.

Habitat & Ecological Biome

Prehistoric Depositional Setting

Braided river basins, conifer-fern floodplains, and semi-arid inland valleys.

Fossil Evidence & Specimen Records

Preserved Skeletal Material & Bonebeds

Nearly complete skeleton with intact skull, cervical spine, and postcrania at MACN, Buenos Aires.

Discovery & Taxonomic Naming History

Year of Discovery / Description1984

Type Specimen Locality & FormationLa Amarga Formation, Neuquén, Argentina

Discovered by paleontologist José Bonaparte and named by Leonardo Salgado and Bonaparte in 1991.

Geological Era & Chronostratigraphy

Explore All Cretaceous Period Fauna

Cretaceous Period PeriodTemporal Interval: 129–122 Ma (million years ago)

The longest and final period of the Mesozoic Era, characterized by the rise of flowering plants, ceratopsians, hadrosaurs, tyrannosaurids, and concluding with the Chicxulub asteroid impact.

Where It Lived & Paleoenvironment

South America Dinosaurs

During the Mesozoic Era, continental drift progressively reconfigured land bridges, atmospheric currents, and regional precipitation regimes. Fossils of Amargasaurus evidence its adaptation to the paleoenvironments of South America.

Paleogeographic RealmSouth America (South America)

Preserved within the Huincul, Candeleros, and Ischigualasto formations, hosting colossal titanosaurs and specialized abelisaurid and carcharodontosaurid apex predators.

Fossil Discovery Locality

Scientific Significance & Evolutionary Impact

The anatomical architecture of Amargasaurus serves as a crucial benchmark in vertebrate paleontology, illustrating key adaptive radiations within Sauropodomorpha.

Phylogenetic Placement: Informs cladistic debates concerning the divergence, skull biomechanics, and skeletal evolution of Cretaceous Period fauna.
Paleoecological Guild: Documents trophic specialization (Herbivore) and predator-prey dynamics across its regional ecosystem.
Taphonomic Record: Nearly complete skeleton with intact skull, cervical spine, and postcrania at MACN, Buenos Aires.

Frequently Asked Questions About Amargasaurus

Scientifically verified answers based on peer-reviewed paleontological evidence.

Q1.When did Amargasaurus live?

Amargasaurus lived during the Cretaceous Period Period, approximately 129–122 Ma (million years ago). This places it within the Mesozoic Era.

Q2.How big was Amargasaurus?

Paleontological estimates place Amargasaurus at a length of 8.5–10 m (27.9–32.8 ft), a hip/standing height of 2.2–2.7 m (7.2–8.9 ft), and a body mass of 2.5–4.0 metric tons (5,512–8,818 lbs).

Q3.What was the diet of Amargasaurus?

Classified as a herbivore, Amargasaurus specialized in consuming Low-growing ferns, cycads, and horsetails stripped with pencil-shaped peg teeth..

Q4.Where were Amargasaurus fossils discovered?

Fossil specimens of Amargasaurus have been recovered from La Amarga Formation, Neuquén, Argentina, with notable historic specimens documented in 1984. Discovered by paleontologist José Bonaparte and named by Leonardo Salgado and Bonaparte in 1991.

Academic Literature & Peer-Reviewed References

Authoritative citations establishing the factual taxonomy, biometrics, and anatomy of Amargasaurus.

AmeghinianaView Publication
Salgado, L., & Bonaparte, J. F. (1991). Un nuevo sauropodo Dicraeosauridae, Amargasaurus cazaui gen. et sp. nov., de la Formacion La Amarga, Neocomiano de la provincia del Neuquen, Argentina. Ameghiniana, 28(3-4), 333-346.
Curated & Verified: 2026-09-24

Amargasaurus

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