Coryphodon

Template:Infobox MammalCoryphodon (meaning "peaked tooth") is an extinct genus of mammal. It was widespread in North America between 59 and 51 million years ago. It is regarded as the ancestor of the genus Hypercoryphodon of Mid Eocene Mongolia.

Coryphodon was a pantodont, a member of the world's first group of large browsing mammals. It migrated across what is now northern North America, replacing Barylambda, an earlier pantodont. At about 1 metre (3.3 ft) at shoulder height and 2.25 metres (7.4 ft) in body length, Coryphodon was the biggest known mammal of its time. It had a semi-aquatic lifestyle, likely living in swamps and marshes like a hippopotamus, although it was not closely related to modern hippos or any other animal known today.

Restoration by Charles R. Knight

Fossils found on Ellesmere Island, near Greenland, show that Coryphodon once lived there in warm swamp forests of huge trees, similar to the modern cypress swamps of the American South. Though the climate of the Eocene was much warmer than today, plants and animals living north of the Arctic Circle still experienced months of complete darkness and 24-hour summer days. Chemical studies of fossil bone show that in the summer, Coryphodon ate flowers, leaves, and swamp plants. In the winter dark, they survived on pine needles, dead leaves, and fungi. This flexible diet allowed the species to spread widely across the Eocene world.

Coryphodon had very strong neck muscles and short tusks that were probably used to uproot swamp plants. As in most pantodonts, the tusks were larger in males. The creature was very slow, with long upper limbs and short lower limbs, which were needed to support its weight. Coryphodon had one of the smallest brain/body ratios of any mammal, living or extinct, possessing a brain weighing just 90 grams (3.2 oz) and a body weight of around 500 kilograms (1,100 lbs).

Coryphodon was an extinct genus of pantodont that resembles other representatives of members of the pantodont family, were widely distributed in the lower Eocene, at the end of which they sadly died. Coryphodon appeared in Asia in the Paleocene epoch, and then migrated to the territory of modern North America, which probably drove the evolution to the aboriginal pantodont Barylambda. Its height was about a meter and weighed approximately 500 kg. It was a dense, tightly folded animal with very strong neck muscles. Both sexes have large canine teeth, among which were the upper hypertrophied.

Canines of males, which is typical for pantodonts were larger. The skull had a pronounced sagittal crest, which carries the powerful temporal muscles. The limbs were pretty strong, but short. At each extremity were on hand. Finger phalanges ended in small hooves. The brain was relatively one of the smallest among the known mammalian brain weight, which was only about '90. According to constitution, they were rather slow and clumsy animals. These animals probably prefer to settle in the woods or near water bodies.

Restoration by Heinrich Harder

The basis of their diet consisted of leaves, young shoots, flowers and all sorts of marsh vegetation.

Coryphodon-like animals, with very little brain, and characterized by highly imperfect structure of the teeth and limbs, could not longly coexist with new, more advanced ungulates that have taken their place.

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