AmargasaurusArticle | Updated 10 years ago  Amargasaurus Image Peter Schouten Amargasaurus lived 130 million years ago in what is now Argentina, and represents a unique group of dwarfed, short-necked sauropods. Amargasaurus belongs to a peculiar group of sauropods from Gondwana, known from the Late Jurassic to the Early Cretaceous. They are related to Diplodocus, a giant, long-necked sauropod from the Late Jurassic of North America. However they went down a different evolutionary path to their ancestors and evolved a much shorter neck and a drastically reduced overall body size. SOUTH AMERICA (130 million years ago) Long and short of it Sauropods followed several evolutionary paths (often combined) to increase or decrease the length of their necks. Some evolved more vertebrae in the neck, others had the original number of vertebrae but each one became either longer or shorter, and a few had the most forward of their body vertebrae transform into neck vertebrae. The size of the spines on the neck vertebrae and the way they are arranged, prevented these dinosaurs from raising their necks vertically. This restricted movement, as well as the short length of their neck, limited these dinosaurs to feeding on understory plants. It is possible that the small size of these sauropods was linked to their more limited food source. Spine speculationThis illustration shows how the spine on each of the neck and back vertebrae of Amargasaurus is greatly elongated and divided into two. Some scientists think the spines supported a sail, however we have shown an alternate view, that each spine had an individual covering. It is possible that the spines were used for defence. By bending the neck, Amargasaurus would be able to direct the spines towards an approaching predator. Amargasaurus cazaui NAMED BY SALGADO & BONAPARTE, 1991. Diet Plants Height 2.5m Length 10.0m Width 1.2m ‹ Styracosaurus Fight to the Death ›