Hesperornis
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 Hesperornis regalis skeleton at the NMNH
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Extinct (fossil)
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Hesperornis is an extinct genus of flightless aquatic birds that lived during the Coniacian to Maastrichtian sub-epochs of the Late Cretaceous (89-65 mya).
Hesperornis were very large birds, reaching up to 1.50 metre (5 feet) in length. They had virtually no wings and hunted in the waters of the North American Inland Sea (Hills et al, 1999), swimming with powerful hind legs (the feet were probably lobed (not webbed!) as in today's grebes). Like other Mesozoic birds such as Ichthyornis, Hesperornis had teeth in its beak which were used to hold prey (probably mainly fish), although in the hesperornithiform lineage they were of a different arrangement than in any other known bird with the teeth sitting in a longitudinal groove rather than in individual sockets (Marsh, 1880).
On land, Hesperornis was unable to walk. Indeed, the leg skeleton of the hesperornithids was so much adapted to diving that their mode of locomotion while ashore, as well as where it layed its eggs and how it cared for its young, is a matter of much speculation. Some have even pointed out[citation needed] that it cannot be completely ruled out that these birds were ovoviviparous instead of incubating their eggs. In any case, youg Hesperornis grew fairly quickly and continuously to adulthood, as is the case in modern birds, but not Enantiornithes (Chinsamy et al. 1998).
Hesperornis was featured in the last episode of the 2003 BBC documentary series Sea Monsters, a spin-off of the famous Walking With Dinosaurs (1999).
[edit] References
- Chinsamy, A.; Martin, Larry D. & Dobson, P. (1998): Bone microstructure of the diving Hesperornis and the volant Ichthyornis from the Niobrara Chalk of western Kansas. Cretaceous Research 19(2): 225-235. DOI:10.1006/cres.1997.0102 (HTML abstract)
- Hills, L. V.; Nicholls, E. L.; Núñez-Betelu, L. "Koldo" M. & McIntyre, D. J. (1999): Hesperornis (Aves) from Ellesmere Island and palynological correlation of known Canadian localities. Canadian Journal of Earth Sciences 36(9): 1583-1588. HTML abstract
- Marsh, Othniel Charles (1880): Odontornithes, a Monograph on the Extinct Toothed Birds of North America. Government Printing Office, Washington DC.
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