ˌiːəsˈʌkiə wʌz ɪnˈɪʃəli dᵻfˈaɪnd tʊ ɪŋklˈuːd ˈɔːl "ðəkoʊdˈɔnʃən" ɹˈɛptaɪlz wˌɪtʃ dɪdnˌɑːt hæv ɐn ˈæntoːɹbˌɪɾəl fˈɛnɛstɹə bˌʌt dˈɪd ɹᵻtˈeɪn tˈæbjʊlɚz, pˈoʊstpɐɹˌaɪəɾəlz ænd ɐ lˈɑːɹdʒ pˈɪniəl fˈɔːɹeɪmˌɛn bɹˈuːm, nˈaɪntiːnhˈʌndɹɪd fˈoːɹtiːn.
Eosuchia was initially defined to include all "thecodontian" reptiles which did not have an antorbital fenestra but did retain tabulars, postparietals and a large pineal foramen (Broom, 1914).