ɪn nˈaɪntiːnhˈʌndɹɪd nˈaɪnti wˈʌn, pˈɔːl sɛɹˈɛnoʊ ɹˌiːdᵻfˈaɪnd dˌɪnəsˈɔːɹəmˌoːɹfə æz ɐ nˈoʊdbˈeɪst klˈeɪd, dᵻfˈaɪnd baɪ ɐ lˈæst kˈɑːmən ˈænsɛstɚ ænd ɪts dᵻsˈɛndənts.
In 1991, Paul Sereno redefined Dinosauromorpha as a node-based clade, defined by a last common ancestor and its descendants.