Archosauria: Avemetatarsalia to Neornithes
2° Nominal Author
Inactive Taxon Status
Chiappe (2001:126) defined Chatterjee’s taxon Pygostylia as a node-based definition that is very similar in content to Ornithurae (
Sereno, 1998), a stem-based taxon that includes all birds closer to Neornithes than to
. Pygostylia is node-based and so is not a junior synonym. If there are taxa that fall between Archaeopterygidae and Confuciusornithidae, Pygostylia would define a node at a less inclusive level than Ornithurae. Chiappe (2001:fig. 1) placed
in this position, although other authors have placed it elsewhere. There seems little utility in using Pygostylia at present, if one accepts Ornithurae as a stem of a node-stem triplet centered on the traditional content of Aves.
Current Age Range
Basis for Range
Definitional History #1
The common ancestor of Confuciusornithidae and Neornithes (modern birds) plus all its descendants.