taxa to seriemas, phorusrhacids and idiornithids, sometimes even as a polyphyletic group.

It is usually considered the sister clade to Paracrax, and several authorities consider Neocathartes and several other taxa to be nested with it (see below). However, at least one phylogenetic study recovers Bathornis (and its synonyms) as more closely related to phorusrhacids than to Paracrax, though this is considered premature and based