Abstract

Triassic dinosaurs of Brazil are found in Santa Maria and Caturrita formations, Rio Grande do Sul state, Brazil. There are three species known from the Santa Maria Formation (Staurikosaurus pricei, Saturnalia tupiniquim and Pampadromaeus barberenai), and two from Caturrita Formation (Guaibasaurus candelariensis and Unaysaurus tolentinoi). These dinosaur materials are, for the most part, well preserved and allow for descriptions of musculature and biomechanical studies. The lateral rotation of the Saturnalia femur is corroborated through calculations of muscle moment arms. The enhanced supracetabular crest of Saturnalia, Guaibasaurus, Staurikosaurus, Herrerasaurus ischigualastensis, Efraasia minor and Chormogisaurus novasi suggests that basal dinosaurs may have maintained an inclination of the trunk at least 20º on the horizontal axis. The pectoral girdle articulation of basal sauropodomorphs (Saturnalia and Unaysaurus) was established using a new method, the Clavicular Ring, and the scapular blade remains near 60º on the horizontal axis. This is a plesiomorphic condition among sauropodomorphs and is also seen in the articulated plateosauridae Seitaad ruessi. The Brazilian basal dinosaurs were lightweight with a body mass estimated around 18.5 kg for Staurikosaurus, 6.5 kg for Saturnalia, and 17 kg for Guaibasaurus. Pampadromaeus probably weighed 2.5 kg, but measures of its femur are necessary to confirm this hypothesis. The Triassic dinosaurs from Brazil were diversified but shared some functional aspects that were important in an evolutionary context.

Highlights

  • Knowledge of Brazilian dinosaurs increased substantially with the description of new species, and referred materials have been registered annually (Bittencourt & Langer, 2011; Cabreira et al, 2011; Delcourt & Grillo, 2011; Kellner et al, 2011; Santucci & Arruda-Campos, 2011; Zaher et al, 2011)

  • Triassic dinosaurs of Brazil were found in the Santa Maria and Caturrita formations in central Rio Grande do

  • The Clavicular Ring methodology provides a new approach for reconstructing the scapular blade orientation relative to the horizontal axis

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Summary

Introduction

Knowledge of Brazilian dinosaurs increased substantially with the description of new species, and referred materials have been registered annually (Bittencourt & Langer, 2011; Cabreira et al, 2011; Delcourt & Grillo, 2011; Kellner et al, 2011; Santucci & Arruda-Campos, 2011; Zaher et al, 2011). Sul, belonging to the Rosário do Sul Group (Langer et al, 2007a; Bittencourt & Langer, 2011). They represent the oldest Brazilian strata in which dinosaur remains were found. We aim to enrich the current state of knowledge on the biomechanics of Triassic dinosaurs from Brazil, with comments on sauropodomorph pectoral girdle articulation and mass prediction

Objectives
Conclusion

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