Temporal range: Upper Triassic, 233 mya
Description[change | change source]
At just 2.25 metres (7.4 ft), 80 centimetres tall (31 in), and weighing just 30 kilograms (66 lb), Staurikosaurus was small in comparison to later theropods like Megalosaurus. Staurikosaurus and the related Herrerasaurus are definitely theropods and evolved after the sauropod line had split from the theropods.
The fossil record of Staurikosaurus is poor, but the skeletal structure of the legs is known. Staurikosaurus was a quick runner for its size. It also had just two vertebrae joining the pelvis to the spine, a distinctly primitive arrangement.
The available teeth for Staurikosaurus strongly suggest a carnivorous diet.
Tail[change | change source]
The tail of Staurikosaurus was relatively long (with more than 40 vertebrae) compared to the rest of its body and was held straight and off the ground as it ran. The rear part of Staurikosaurus's tail is stiffened by features of the tail vertebrae. Ostrom thought this was a dynamic stabilizer to help balance while leaping and running.
References[change | change source]
- Nesbitt S.J. et al. 2009. A complete skeleton of a late Triassic saurischian and the early evolution of dinosaurs. Science 326:1530-1533.
- Staurikosaurus. In: Dodson, Peter et al. The age of dinosaurs. Publications International, p45 ISBN 0-7853-0443-6.
- Grillo O.N. and Azevedo S.A.K. 2011. Recovering missing data: estimating position and size of caudal vertebrae in Staurikosaurus pricei Colbert, 1970. Annals of the Brazilian Academy of Sciences,
- Ostrom J.H. 1969. Osteology of Deinonychus antirrhopus, an unusual theropod from the Lower Cretaceous of Montana. Peabody Museum Bulletin 30:1-165