Piatnitzkysaurus (pron.:"Template:Respell") is an extinct genus of megalosaurid theropod dinosaur that lived approximately 164 to 161 million years ago during the middle part of the Jurassic Period in what is now Argentina. It was named to honor Alejandro Mateievich Piatnitzky (1879–1959), a Russian-born Argentine geologist. Piatnitzkysaurus was a moderately large, lightly built, bipedal, ground-dwelling carnivore, that could grow up to Template:Convert long.
Classification and description
The holotype specimen of Piatnitzkysaurus, PVL 4073, was collected during expeditions in 1977, 1982, 1983 at the Canadon Asfalto Formation in sediments that were deposited during the Callovian stages of the Jurassic period, approximately 164 to 161 million years ago. Once thought to be a basal carnosaur, it may instead be a megalosauroid. In total two partial skeletons are known (a fractured skull and parts of two postcranial skeletons, among which paratype MACN CH 895) and show that Piatnitzkysaurus was a relatively lightly built medium-sized bipedal carnivore that was around Template:Convert long and around Template:Convert in mass, though such estimates apply to the holotype, which is a subadult. It had robust arms and powerful hind legs with four toes on each foot. Its ischium is Template:Convert long. Its braincase resembles that of another megalosauroid, the megalosaurid Piveteausaurus from France. A general resemblance to the theropod Allosaurus was also noted by Benton (1992).
The type species, Piatnitzkysaurus floresi, was described by Jose Bonaparte in 1979.
- Bonaparte, 1979. Dinosaurs: A Jurassic assemblage from Patagonia. Science. 205, 1377–1379.
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- Mazzetta, G. V., Fariiia, R. A., & Vizcaino, S. F. 2000. On the palaeobiology of the South American homed theropod Carnotaurus sastrei Bonaparte. In: B. Perez-Moreno, T.R. Holtz Jr., J.L. Sanz, & J.J. Moratalla (eds.), Aspects of Theropod Paleobiology, Special Volume - Gaia 15, 185-192. Lisbon.
- Brusatte, S. L., Benson, R. B. J., and Xu, X. 2010. The evolution of large-bodied theropod dinosaurs during the Mesozoic in Asia. Journal of Iberian Geology, 36, 275-296
- Rauhut, 2004. Braincase structure of the Middle Jurassic theropod dinosaur Piatnitzkysaurus. Canadian Journal of Earth Science. 41, 1109–1122.
- Benton, M. (1992). Dinosaur and other prehistoric animal factfinder. 1st American ed. New York: Kingfisher Books. Chicago / Turabian - Author Date Citation