Kingdom Animalia Class Reptilia Order Saurischia | Phylum Chordata Clade Dinosauria Suborder Theropoda | |
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Piatnitzkysauridae is an extinct family of dinosaurs composed of megalosauroid tetanurans. The family was coined by Carrano et al. in 2012, and contains three known dinosaur genera: Condorraptor, Marshosaurus, and Piatnitzkysaurus. This last genus gives the family its name. It is sister taxa to Megalosauria.
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Discovery
They were found in Jurassic deposits in Argentina (Middle Jurassic) and the United States (Late Jurassic).
Synapomorphies
There are many synapomorphies of Piatnitzkysauridae. The first is two parallel rows of nutrient foramina on the surface of the maxilla (also found in Eocarcharia and Shaochilong). Another is the vertically striated or ridged paradental plates (also found in Abelisauridae, Megalosaurus and Proceratosaurus.) The third is the reduced parapophyses (also found in Coelophysoidea, Eustreptospondylus and Afrovenator). The fourth is the anteriorly inclined posterior dorsal neural spines (in parallel with Allosauroidea). The fifth is the canted distal humerus condyles (also in Poekilopleuron, Allosauridae and Fukuiraptor). In addition, these specialized Tetanurans show reversal to the primitive condition for the following features. The first is a short or absent anterior maxillary ramus, a moderate development of axial diapophyses, and no pleurocoels.
Definition
The definition of Piatnitzkysauridae is: All Megalosauroidea more closely related to Piatnitzkysaurus than to either Spinosaurus or Megalosaurus.