Sauropodomorpha
Sauropodomorpha is a major dinosaur lineage that includes the giant, long-necked sauropods and their mostly bipedal, often smaller early relatives.
Sauropoda: A group of mostly quadrupedal, herbivorous dinosaurs with long necks and tails, including the largest land animals. This is the branch of sauropodomorphs that evolved the familiar giant, long-necked body plan.
Dinosaur locomotion: The ways dinosaurs moved, shaped by limb posture, anatomy, body size, and habitat. Changes in limb posture track the transition from bipedal early forms to quadrupedal sauropods.
Late Triassic: The final epoch of the Triassic Period, spanning approximately 237 to 201 million years ago. The earliest known sauropodomorphs lived during this interval, near the beginning of dinosaur diversification.
Jurassic: A geologic period lasting from about 201 to 145 million years ago, marked by diverse dinosaur faunas. Sauropods became widespread and ecologically prominent during much of this period.
Plateosaurus: A genus of large, mostly bipedal herbivorous sauropodomorphs that lived in Europe during the Late Triassic. Its anatomy illustrates the relatively early, non-sauropod body plan.
Vertebral column: The series of vertebrae forming the backbone and supporting the trunk, neck, and tail. Elongated neck vertebrae helped sauropods reach vegetation without moving their massive bodies.
Eoraptor: A small dinosaur from Late Triassic Argentina, known from fossils in the Ischigualasto Formation. Its early dinosaur fauna provides context for the emergence of sauropodomorphs, though its precise affinities have been debated.
Cretaceous: The final geologic period of the Mesozoic Era, lasting from about 145 to 66 million years ago. Several sauropod lineages persisted and diversified through the end of this period.
Prosauropoda: An obsolete grouping once used for early sauropodomorphs, now recognized as an unnatural assemblage rather than a natural clade. Its changing status shows why early sauropodomorph relationships are described with revised classifications.
Pneumatic bone: Bone containing air spaces connected to respiratory air sacs, reducing skeletal mass in some vertebrates. Air-filled spaces in sauropod vertebrae helped lighten their exceptionally long necks.