Figure 1.

Consensus cladogram depicting phylogenetic relationships among select bird-line archosaurs based on refs. 2 and 32–35, showing stem along which proposed frame shift is hypothesized to have occurred. Archosauria, node-based name for the crown clade stemming from the last common ancestor Aves shared with Crocodylia; Ornithosuchia, stem-based name for Aves plus all other archosaurs more closely related to Aves than to Crocodylia; Dinosauria, node-based name for the clade stemming from the last common ancestor shared by Aves and Ornithischia; Theropoda, stem-based name for the clade including Aves and all dinosaurs more closely related to Aves than to Sauropoda; Maniraptora, stem-based name for the clade including Aves and all theropods more closely related to Aves than to Ornithomimidae; Avialae, node-based name for the clade stemming from the last common ancestor shared by Archaeopteryx and Aves; Aves, node-based name for the crown clade stemming from the last common ancestor shared by Palaeognathae and Neognathae.