O ti tun ti ni daba wipe Dinosauria wa ni itumọ pẹlu ọwọ si awọn MRCA ti Megalosaurus ati Iguanodon, nitori awọn wọnyi ni o wa meji ninu awọn mẹta genera tọka si nipa Richard Owen nigbati o mọ Dinosauria. Mejeeji awọn itumọ ja si kanna ṣeto ti awọn ẹranko ti wa ni itumọ bi dinosaurs: "Dinosauria = Ornithischia + Saurischia", encompassing ankyloproposaurians (armored herbivorous quadruped), stegoposaurians (plated herbivorous quadrupeds), ceratopsians (herbivorous quadrupeds with horns and neornithithithithithes), ati gbogbo awọn ọmọ rẹ.
arúgbó kan tí wọ́n jọ ń gbé lákòókò àìpẹ́ yìí (MRCA) ti Triceratops àti Neornithes, àti gbogbo àwọn àtọmọdọ́mọ rẹ̀