Hesperornis
| Hesperornis Temporal range: Late Cretaceous
| |
|---|---|
| |
| Hesperornis regalis skeleton at the NMNH | |
Fossil
| |
| Scientific classification | |
| Kingdom: | |
| Phylum: | |
| Class: | |
| Order: | |
| Family: | |
| Genus: | Hesperornis |
| Species | |
| |
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). One of the lesser known discoveries of Marsh in the late 19th century Bone Wars, it was an important early find in the history of avian paleontology.
Description
Hesperornis were very large birds, reaching up to 2 meters (6.5 feet) in length. They had virtually no wings and hunted in the waters of the North American Inland Sea,[1] swimming with powerful hind legs; the feet were probably lobed rather than being 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 (most likely 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.[2]
Paleobiology
On land, Hesperornis may or may not have been able 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 laid 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, young Hesperornis grew fairly quickly and continuously to adulthood, as is the case in modern birds, but not Enantiornithes.[3]
Hesperornis were preyed upon by large marine carnivores. Tylosaurus proriger specimen SDSMT 10439 contains the bones of a Hesperornis in its gut, for example.
References
- ^ 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 OC (1880): Odontornithes, a Monograph on the Extinct Toothed Birds of North America. Government Printing Office, Washington DC.
- ^ 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)
