Table 3 Character matrix on the differences in the described development mode of elements (Fig. 13a). Character 1: origin of the fenestra basicranialis posterior: 0 = absent; 1 = primary origin; 2 = secondary origin;? = no information. Character 2: formation of trabecula communis: 0 = by fusion with intertrabecula; 1 = by fusion of trabeculae;? = no information. Character 3: chondrification centres of otic capsule: 0 = centre in cochlear portion; 1 = centre in cochlear and canalicular portion; 2 = centre in canalicular portion;? = no information. Character 4: cartilaginous metotic cartilage: 0 = not independent, but unclear to which part of the chondrocranium they are fused; 1 = independent; 2 = fused to basal plate; 3 = fused to otic capsule;? = no information. Character 5: development of anterior orbital cartilage: 0 = independent origin; 1 = from trabeculae; 2 = from trabecula communis; 3 = in continuity with interorbital septum;? = no information. Character 6: base of interorbital septum: 0 = intertrabecula; 1 = trabecula communis;? = no information. Character 7: base of prenasal process: 0 = nasal septum; 1 = trabecula communis;? = no information. Character 8: base of nasal septum: 0 = intertrabecula; 1 = trabecula communis;? = no information

From: Evolution and development of the bird chondrocranium