Morphological and molecular support for nonmonophyly of the Galloanserae

This paper discusses morphological and molecular data bearing on the earliest evolution of the Neornithes. Phylogenetic analyses of basal neornithine groups frequently result in poorly resolved trees, most likely caused by rapid branching events in the Cretaceous and early Tertiary. Although data that efficiently resolve the earliest history of modern birds are few, a consensus opinion about their basal phylogeny has emerged in recent years. Two major splits within Neornithes are postulated. The first occurs when the palaeognathous birds branch off from the rest (the Neognathae), and the second when the Anseriformes and Galliformes split from all other neognaths. Morphological data presented by Livezey (1997) supporting this second dichotomy are combined with additional data from Ericson (1997) and re-analyzed. In addition, a new data set consisting of nucleotide sequences from the nuclear, single-copy gene c-myc is analyzed separately and in combination with the morphological data. Neither analyses support the suggested anseriform‐galliform relationship. Instead, the Anseriformes group with the Ciconiiformes, Phoenicopteriformes and Charadriiformes, that is, a clade of wading birds.