I have read on Osteology of the reptiles of Alfred S.Romer that some dinosaurs have two coronoids in the mandible, this seems to me a fact in contrast to all the other amniotes (except synapsids).
If some dinosaurs (protoceratops? sauropoda?) have a second coronoid, have they inherited it from ancient amphibians as the synapsids or is a secondarily developped
Alberto Arisi - Italy