What is Hesperornis?
{{Taxobox |name = ''Hesperornis'' |fossil_range = <small>89–65 million years ago: </small>[[Upper Cretaceous]] |image = Hesperornis regalis.jpg |image_width = 250px |image_caption = ''H. regalis'' skeleton in swimming pose; <br/>note feet pointing sideways. |regnum = [[Animal]]ia |phylum = [[Chordata]] |classis = [[Aves]] |subclassis = [[Hesperornithes]] |familia = [[Hesperornithidae]] |genus = '''''Hesperornis''''' |genus_authority = [[Othniel Charles Marsh|Marsh]], 1872}} '''''Hesperornis ''''' is an extinct [[genus]] of flightless [[aquatic]] [[bird]]s that lived during the [[Upper Cretaceous]] (89–65 million years ago). ''Hesperornis'' was an important early find in the history of [[avian]] [[paleontology]]. It was discovered by the paleontologist [[Othniel Charles Marsh|O.C. Marsh]] in the late 19th century [[Bone Wars]]. Famous locations for ''Hesperornis'' are the Upper Cretaceous [[Ocean|marine]] [[limestone]]s from [[Kansas]] and the marine [[shale]]s from [[Canada]]. The genus probably had a [[Holarctic]] distribution. == Anatomy and life style == [[File:Animals of the past - an account of some of the creatures of the ancient world (1929) (18012757429).jpg|thumb|right|200px|J.M. Gleeson's restoration of ''Hesperornis'' swimming, 1902]] ''Hesperornis'' was a large bird, reaching up to 1.5 meters (5&nbsp;feet) in length. It had virtually no wings, and swam with its powerful hind legs. Like many other [[Mesozoic]] birds such as ''[[Ichthyornis]]'', ''Hesperornis'' had [[teeth]] in its [[beak]] which were used to hold prey (most likely [[fish]]).<ref> Marsh, Othniel Charles 1880. ''Odontornithes, a monograph on the extinct toothed birds of North America''. Government Printing Office, Washington DC.</ref><ref>Gregory, Joseph T. 1952. The jaws of the Cretaceous toothed birds, ''Ichthyornis'' and ''Hesperornis''. ''Condor'' '''54''' (2): 73–88. [http://sora.unm.edu/sites/default/files/journals/condor/v054n02/p0073-p0088.pdf]</ref> ''Hesperornis'' hunted in the waters of such contemporary [[Continental