Sauropodomorphs are a group of dinosaurs that include both the long-necked sauropods and their smaller, bipedal ancestors. They lived during the Triassic, Jurassic, and Cretaceous periods, evolving from early herbivorous dinosaurs. These creatures are characterized by their long necks, large bodies, and, in many cases, long tails. The group is divided into two main categories: prosauropods, which were generally smaller and more primitive, and the larger sauropods, known for their massive size and long necks. Sauropodomorphs were primarily herbivorous, feeding on plants, and played a significant role in their ecosystems.