Synonyms: Coniornis Marsh 1893, Hargeria Lucas 1903, Lestornis Marsh 1876
Full reference: O. C. Marsh. 1872. Preliminary description of Hesperornis regalis, with notices of four other new species of Cretaceous birds. The American Journal of Science and Arts, series 3 3(13-18):360-365
Parent taxon: Ornithurae according to L. M. Chiappe 2002
Sister taxa: Ambiortus, Apatornis, Apsaravis, Archaeovolans, Carinatae, Chaoyangia, Chaoyangiformes, Chaoyangornithiformes, Gansus, Gobipterygiformes, Guildavis, Iaceornis, Jianchangornis, Liaoningornithiformes, Odontoholcae, Odontoholomorphae, Otogornis, Qinornis, Schizooura, Songlingornithidae, Yanornithiformes, Yixianornithiformes
Subtaxa: Hesperornis altus, Hesperornis crassipes, Hesperornis gracilis, Hesperornis montana, Hesperornis regalis, Hesperornis rossicus
Type: Hesperornis regalis
Ecology: aquatic piscivore