Dina nomenklatur filogenetik, dinosaurus biasana dihartikeun salaku kelompok anu diwangun ku karuhun umum panganyarna (MRCA) tina Triceratops sareng Neornithes, sareng sadaya turunanana. Éta ogé disarankeun yén Dinosauria didefinisikeun kalayan hormat ka MRCA tina Megalosaurus sareng Iguanodon, sabab ieu mangrupikeun dua tina tilu genera anu dikutip ku Richard Owen nalika anjeunna mikawanoh Dinosauria. Duanana definisi ngahasilkeun sakumpulan sato anu sami anu diartikeun salaku dinosaurus: "Dinosauria = Ornithischia + Saurischia", ngawengku ankyloproposaurians (armored herbivorous quadrupod), stegoposaurians (plated herbivorous quadrupod), ceratopsians (herbivorous quadrupod sareng tanduk sareng frog), atanapi frognitopods (frognitopods), atanapi frognitopods (frognitopods) sareng frognitopods.
karuhun umum panganyarna (MRCA) Triceratops jeung Neornithes, sarta sakabeh turunanana