Table 1 A selection of chondrocranial features typical for birds listed by de Beer [11]

Distinctive features of birds and crocodilians (de Beer 1937:463):

“(i) The presence of a median prenasal process.“

“(ii) The formation of infrapolar processes.“

“(iii) The formation of subcapsular process or metotic cartilages.“

Features that birds share with crocodilians and chelonians (de Beer1937:463):

“(i) The intraparachordal course of the notochord.“

Features shared by reptilians in general (de Beer 1937:463):

“(ii) The formation of the supratrabecular bar (except Ophidia).“

“(iii) The disposition of the orbital cartilage (planum supraseptale) and pila antotica.“