Odontoanserae

The Odontoanserae is a clade that includes Odontopterygiformes (pseudo-toothed birds) and Anseriformes (waterfowls). It is the sister taxon of Neoaves. The Odontoanserae are most probably the first major group of modern birds that has developed adaptations to aquatic life. Webbed feet and functional salt glands, for instance, are most likely derived characters of this clade, although the degree of development of these structures are known to vary among waterfowls. Similar adaptations have appeared later in the evolution of modern birds, in various neoavian groups.^[1]

References

1. Bourdon, Estelle (2005) Osteological evidence for sister group relationship between pseudo-toothed birds (Aves: Odontopterygiformes) and waterfowls (Anseriformes), Naturwissenschaften, 92, 586-591