Deinonychosauria

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Deinonychosauria Colbert & Russell, 1969 sensu Gauthier, 1986 emended Currie & Padian, 1997

Common ancestor of all forms closer to Deinonychus than Neornithes and all descendants. Autapomorphies of Deinonychosauria, non sensu Sereno, include:

a)Cranium large, pterygoids slender

bEctopterygoids triradiate, with a dorsally oriented fossa

c)Maxilla deep, pariticpating in all antorbital fenestrae

d)Forelimb proportionately long, with tridigitate manus bearing raptorial claws

e)Semilunate proximal carpal element

f)Pes functionally didactyl

g)Ilium deep, short, with pubic peduncle angled caudoventrally

h)Ischium short, thin, tapering distally, bears a large, triangular obturator process

i)Distal 80% of the caudal series possesses extremely elongated prezygapophyseal elements which stiffen the tail into a single dynamic stabilizer