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Piatnitzkysaurus brancaise


New paper:

Braincase structure of the Middle Jurassic theropod dinosaur Piatnitzkysaurus

Oliver W.M. Rauhut

Abstract: The braincase of the Middle Jurassic basal tetanuran theropod
Piatnitzkysaurus floresi is described in detail. It exhibits several probable
autapomorphic characters of this taxon, including the extremely shortened and
basipterygoid processes, the presence of parasphenoid recesses that seem to
communicate with each other, and basipterygoid recesses that are approximately 
long anteroposteriorly as they are high. The braincase of Piatnitzkysaurus shows
two possible synapomorphies with the enigmatic European Middle Jurassic theropod
Piveteausaurus, a subrectangular pituitary fossa that is wider than high and the
transverse span between the basipterygoid processes being smaller than the 
width of
the basal tubera. A noteworthy aspect of the braincase of Piatnitzkysaurus is 
high number of accessory pneumatic recesses, which indicates that the presence 
an anterior and dorsal tympanic recess, and possibly also of subcondylar and
basipterygoid recesses is plesiomorphic for tetanurans. In contrast, the bones
enclosing the brain (e.g., laterosphenoid, prootic, supraoccipital) are very
massive and lack internal pneumatic chambers, as they are present in later

Can. J. Earth Sci. 41: 1109?1122.