Sauropodomorphs

Sauropodomorpha is a clade of saurischian dinosaurs that includes the early, often smaller, herbivorous forms known as prosauropods and the later, giant long-necked sauropods. First appearing in the Late Triassic, sauropodomorphs diversified into a wide range of forms and widely occupied herbivorous niches before the group persisted in various lineages into the Jurassic and, in some classifications, into the Cretaceous.

Anatomy and lifestyle evolved through a trend from modestly sized, often bipedal or facultatively bipedal ancestors to large, obligate quadrupeds in many lineages. Early sauropodomorphs, such as Plateosaurus and Massospondylus, typically had long necks, beaked mouths, and leaf-shaped or simple teeth, with hind limbs longer than the forelimbs and a relatively light build. In the later, true sauropods, the skeleton became more robust and columnar, the forelimbs and hind limbs were more equal in length, and the necks became extremely long. The teeth of sauropods were generally peg-like and widely spaced, with some groups developing dental batteries suited to processing plant material. They also possessed large air-filled bones and sophisticated respiratory systems linked to air sacs, aiding in weight reduction and potentially supporting high respiratory efficiency.

Ecology and evolution: Sauropodomorphs were among the dominant herbivores of their ecosystems. Their sheer size in many lineages led to distinctive feeding strategies, such as high-browsing using very long necks. The group's success relates to their adaptive radiation, skeletal innovations, and the expansion of sauropod lineages across prehistoric continents.