Amargasaurus

Amargasaurus was an unmistakable sauropod that lived in Early Cretaceous South America. Unlike most giant long-necked dinosaurs, Amargasaurus was relatively compact, stretching roughly nine to ten metres from snout to tail tip. Its most striking feature was two parallel rows of long, backward-pointing bony spines running along its neck and forward back. Researchers continue to debate whether these remarkable structures supported a fleshy sail, carried keratinous sheaths like horns for defense and display, or served as attachment sites for heavy neck musculature. Its downward-angled skull and low neck position suggest that Amargasaurus specialized in grazing low-growing ferns and horsetails. Known from a remarkably complete skeleton, it provides crucial insights into the unusual dicraeosaurid lineage.

It bore a parallel row of tall, paired spines projecting upward from its neck vertebrae.

Where and when

Amargasaurus lived in the Early Cretaceous, from 125 to 122 million years ago (Barremian-Aptian age). Its remains come from Argentina, in the La Amarga Formation.

The numbers

Length 9.5 m (estimates run from 9 to 10 m). Mass about 2.4 t. Hip height about 1.9 m. That is 5.6 human-lengths, or 0.85 of a double-decker bus. These are estimates from partial skeleton; fields marked estimated by the site are length, mass, hip height.

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