Biomechanical comments about Triassic dinosaurs from Brazil

Authors

  • Rafael Delcourt Universidade de São Paulo; Museu de Zoologia Author
  • Sergio Alex Kugland de Azevedo Universidade Federal do Rio de Janeiro Author
  • Orlando Nelson Grillo Universidade Federal do Rio de Janeiro Author
  • Fernanda Oliveira Deantoni Universidade Federal do Rio de Janeiro Author

DOI:

https://doi.org/10.1590/S0031-10492012002900001

Keywords:

Dinosaurs, Triassic, Biomechanics, Articulation, Mass

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.

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Published

2012-01-01

Issue

Section

naodefinida

How to Cite

Biomechanical comments about Triassic dinosaurs from Brazil. (2012). Papéis Avulsos De Zoologia, 52(29), 341-347. https://doi.org/10.1590/S0031-10492012002900001