U fiirso qoraalka hoose ka dibna ka jawaab su'aasha kadib isla luqadda qoraalka:  Gelitaanka: Sida ku cad magacyada taranka, dinosaur waxaa badanaa lagu qeexaa koox ka kooban awoowegii ugu dambeeyay ee caadiga ahaa (MRCA) ee Triceratops iyo Neornithes, iyo dhammaan faraciisa. Waxaa sidoo kale la soo jeediyay in Dinosauria lagu qeexo iyadoo la tixraacayo MRCA ee Megalosaurus iyo Iguanodon, maxaa yeelay kuwani waxay ahaayeen laba ka mid ah saddexda nooc ee uu soo xigtay Richard Owen markii uu aqoonsaday Dinosauria. Labada qeexitaanba waxay keenaan in xayawaan isku mid ah loo qeexo dinosaur: "Dinosauria = Ornithischia + Saurischia", oo ay ku jiraan ankylosaurians (xayawaan afar lugood leh oo geela cunaya), stegosaurians (xayawaan afar lugood leh oo geela cunaya), ceratopsians (xayawaan afar lugood leh oo geela cunaya oo leh geesaha iyo xarkaha), ornithopods (xayawaan laba lugood leh ama afar lugood leh oo geela cunaya oo ay ku jiraan "duck-bills"), theropods (inta badan laba lugood leh oo hilib cunaya iyo shimbiraha), iyo sauropodomorphs (inta badan afar lugood leh oo geela cunaya oo leh qoorta iyo dabada dheer). Shimbiraha ayaa hadda loo aqoonsan yahay inay yihiin safka kaliya ee badbaaday ee dinosaur theropod. Sida caadiga ah, shimbiraha waxaa loo tixgeliyaa inay yihiin nooc gaar ah oo ka soo jeeda dinosaur, oo ah nooc ka sarreeya. Si kastaba ha noqotee, inta badan paleontologists-ka casriga ah ee ka walaacsan dinosaurs-ka waxay diidaan qaabka caadiga ah ee kala soocida iyagoo doorbidaya taxonomy phylogenetic; habkani wuxuu u baahan yahay, in kooxda ay dabiici tahay, dhammaan faracyada xubnaha kooxda waa in sidoo kale lagu daro kooxda. Shimbiraha waxaa loo arkaa inay yihiin Daayeesoor, sidaa darteedna Daayeesoorku ma ahan kuwo dabar go'ay. Shimbiraha waxaa loo kala saaraa inay ka tirsan yihiin hoosaadka Maniraptora, kuwaas oo ah coelurosaurs, kuwaas oo ah theropods, kuwaas oo ah saurischians, kuwaas oo ah dinosaurs. Cilmi baaris ay sameeyeen Matthew Baron, David B. Norman, iyo Paul M. Barrett sanadkii 2017 waxay soo jeediyeen dib u eegis xagjir ah oo ku saabsan nidaamka dinosaur. Falanqaynta phylogenetic ee Baron et al. waxay dib u soo ceshatay Ornithischia inay u dhowdahay Theropoda marka loo eego Sauropodomorpha, taas oo ka soo horjeedda midowgii caadiga ahaa ee theropods iyo sauropodomorphs. Waxay dib u soo nooleeyeen kooxda Ornithoscelida si ay ugu tilmaamaan kooxda ay ku jiraan Ornithischia iyo...  Suaal: Maxaa diinoosaaradu ka kooban yihiin?
awoowayaashii ugu dambeeyay ee Triceratops iyo Neornithes (MRCA), iyo dhammaan faracooda