Triassic sauropodomorph dinosaurs from South America: The origin and diversification of dinosaur dominated herbivorous faunas

Sauropodomorpha is the first major dinosaurian group that radiated during the Triassic. During this time the group underwent major changes in body plan, including the acquisition of features related to herbivory, large body size, and quadrupedality. By the end of the Late Triassic, approximately 30 million years after the origin of dinosaurs, sauropodomorphs predominated the niches of large herbivores in continental ecosystems throughout the world. The Triassic sauropodomorph diversity includes diverse lineages with great disparity in body size, feeding biomechanics, and locomotion types, ranging from small (similar to 10 kg) bipedal taxa to the large (>5 tons) quadrupedal lessemsaurids. The South American record has provided key information to understand certain stages of this evolutionary radiation. We review here the diversity and composition of sauropodomorph faunas throughout the Late Triassic of South America and highlight their contribution for understanding the evolution of this group.