Later he and de Queiroz redefined it as an apomorphy-based clade more in keeping with Haeckel's original usage, including the first pan-avian with a "bird tail" homologous with that of Vultur gryphus, and all of its descendants.

They included Aves (which they defined as the "crown group" of modern birds), Ichthyornis, Hesperornithes, and Apsaravis in Ornithurae.

Gauthier and de Queiroz, therefore, consider Neornithes a junior synonym of Ornithurae,[4] though many other scientists use Neornithes to refer to the much more restrictive crown group consisting only of modern birds (a group for which Gauthier uses the name Aves).

Alternately, some researchers have used Ornithurae to refer to a more restrictive node-based clade, anchored on Hesperornis and modern birds.

[6] †Hesperornithes †Ichthyornis dispar †Ornithurine D †Iaceornis marshi †Maaqwi cascadensis †Vegavis iaai †Cimolopteryx minima †Cimolopteryx petra †Cimolopteryx rara †Ornithurine A †Ornithurine E †Ceramornis major †Cimolopteryx maxima †Ornithurine B †Ornithurine C †Ornithurine F Aves