Name: Coryphodon (Peaked tooth).
Phonetic: Cor-e-foe-don.
Named By: Richard Owen - 1845.
Synonyms: Bathmodon, Ectacodon, Lefalophodon, Loxolophodon, Manteodon, Metalophodon.
Classification: Chordata, Mammalia, Cimolesta, Pantodonta, Coryphodontidae.
Species: C. eocaenus (type), C. dabuensis, C. lobatus, C. oweni, C. proterus, C. ryani.
Diet: Herbivore.
Size: Around 2.25 meters long, 1 meter tall at the shoulder.
Known locations: Across North America but particularly well known in the USA.
Time period: Selandian of the Paleocene through to Ypresian of the Eocene.
Fossil representation: Multiple individuals.
Coryphodon is one of the best known genera of pantodont, one of the earliest major groups of large herbivorous mammals. Usually interpreted as being similar to a modern hippopotamus,
Coryphodon were heavily built with squat legs, the upper portion of which were longer than the lower. This indicates that the legs were there for supporting a heavy body rather than fast running.
Coryphodon does not seem to have been in need of much in the way of defences however since most known predators of the time seem to have been much smaller than
Coryphodon.
Coryphodon had an enlarged pair of tusks in the upper jaw that were probably used for rooting up plants, although they may have also been used for display since male specimens have larger tusks. The other teeth in the mouth were suited for processing plants that had been grabbed by browsing. Popular opinion of
Coryphodonhowever suggests that it was not an intelligent animal with the cranial cavity for the brain suggesting the total brain size relative to the total body size was one of the proportionately smallest known.
A 2009 paper authored by Jaelyn Eberle, Henry Fricke and John Humphrey in conjunction with the University of Colorado discussed the potential diet of
Coryphodon in the June, 2009 issue of Geology. This study was focused upon the fossils of
Coryphodon that that had been recovered from Ellesmere Island that lies west of northern Greenland. Ellesmere Island is situated within the Arctic Circle, and although it was much warmer and covered in forests back in the Eocene, it would still have experienced periods of constant daylight in the summer and constant nigh time in the winter.
The study which was centred around the isotopic study of tooth enamel revealed that during the summer period of extended daylight
Coryphodon would eat soft vegetation such as flowering plants, aquatic plants and leaves. However during the extended periods of darkness when plant photosynthesis was impossible,
Coryphodon would switch to a diet of leaf litter, twigs, evergreen needles and most revealingly fungi, an organism and food source that does not require light to grow. Not only does this study reveal the dietary range of
Coryphodon, but it also reveals the behaviour of the northern populations living within the Arctic Circle. In this respect
Coryphodon did not migrate south or hibernate, it simply switched between two seasonal food sources.
When
Coryphodon fossils are compared to those of other pantodont genera in terms of size and relationship a scenario can be developed where the pantodont
Barylambda was replaced by
Coryphodon, while
Coryphodonitself was ancestral to
Hypercoryphodon.
