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Temporal range: Middle Jurassic
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Sauropsida
Superorder: Dinosauria
Order: Saurischia
Suborder: Theropoda
(unranked): Tetanurae
Superfamily: Megalosauroidea[1]
Genus: Piatnitzkysaurus
Species: P. floresi
Binomial name
Piatnitzkysaurus floresi
Bonaparte, 1979

Piatnitzkysaurus (pron.:"PEA-at-NITS-key-SORE-us") 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 4.3 m (14.1 ft) long.

Classification and Description[edit]

Skeleton cast in Argentina

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,[2] it may instead be a megalosauroid.[1] 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 4.3 metres (14 ft) long and around 450 kilograms (990 lb) in mass, though such estimates apply to the holotype, which is a subadult.[3] It had robust arms and powerful hind legs with four toes on each foot. Its ischium is 423 millimetres (16.7 in) long.[4] Its braincase resembles that of another megalosauroid, the megalosaurid Piveteausaurus from France.[5] A general resemblance to the theropod Allosaurus was also noted by Benton (1992).[6]

The type species, Piatnitzkysaurus floresi, was described by Jose Bonaparte in 1979.


  1. ^ a b Benson, R.B.J. (2010). "A description of Megalosaurus bucklandii (Dinosauria: Theropoda) from the Bathonian of the UK and the relationships of Middle Jurassic theropods". Zoological Journal of the Linnean Society 158 (4): 882–935. doi:10.1111/j.1096-3642.2009.00569.x. 
  2. ^ Bonaparte, 1979. Dinosaurs: A Jurassic assemblage from Patagonia. Science. 205, 1377–1379.
  3. ^ 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.
  4. ^ 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
  5. ^ Rauhut, 2004. Braincase structure of the Middle Jurassic theropod dinosaur Piatnitzkysaurus. Canadian Journal of Earth Science. 41, 1109–1122.
  6. ^ Benton, M. (1992). Dinosaur and other prehistoric animal factfinder. 1st American ed. New York: Kingfisher Books. Chicago / Turabian - Author Date Citation