Three partial skeletons allow a nearly complete description of the sacrum, pelvic girdle, and
hind limb of the stemsauropodomorph Saturnalia tupiniquim, from the Late Triassic Santa
Maria Formation, South Brazil. The new morphological data gathered from these specimens
considerably improves our knowledge of the anatomy of basal dinosaurs, providing the
basis for a reassessment of various morphological transformations that occurred in the early
evolution of these reptiles. These include an increase in the number of sacral vertebrae, the …

Although less clear than previously suggested, some traits of S. tupiniquim, such as a long
deltopectoral crest and a broad distal humeral end, are indicative of its sauropodomorph
affinity. The taxon also bears several features previously regarded as autapomorphic of
Herrerasaurus ischigualastensis, alluding to their broader distribution among basal
dinosaurs. Variations within S. tupiniquim are mainly robustness-related and do not
necessarily imply taxonomic distinctions.