Amargasaurus cazaui

Amargasaurus navigated Early Cretaceous river plains, using a downturned neck and peg-like teeth to crop ferns, horsetails, and cycads close to the ground. Its most striking feature was a double row of elongate, upward-pointing neural spines along the neck and back, which likely supported defensive keratin sheaths or a visual display structure. Unlike long-necked titanosaurs, this compact sauropod relied on low-browse foraging and nimble herd movements within seasonal Patagonian scrublands.