STEGOSAUR EVOLUTION

Genasauria show derived ornithchain characteristics and the mark the evolutionary split of the ornithchia into cerapoda and thyreophora. The derived characteristics of genasauria (which are all displayed in stegosaurs ) are, they all have muscular cheeks (as indicated by the position of the tooth rows away from the sides of the face ); a snout-shaped front to the mandibles and reduction in the size of the opening on the outside of the lower jaw (the external manibular foramen).


general dinosaur anatomy

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