Pantolambda

Pantolambda is an extinct genus of Paleocene pantodont mammal. Pantolambda lived during the middle Paleocene, and has been found both in Asia and North America. A generalized early mammal, it had a vaguely cat-like body, heavy head, long tail, and five-toed plantigrade feet ending in blunt nails that were neither hooves nor sharp claws. The foot bones articulated in a similar way to the feet of hoofed mammals, and the feet were probably not very flexible. The teeth had a selenodont structure; enamel ridges with crescent-shaped cusps. Selenodont teeth are found in modern grazers and browsers such as cattle and deer, but Pantolambda's teeth were low-crowned and indicate a not very specialized diet.^[1] Pantolambda probably ate a mix of shoots, leaves, fungi, and fruit, which it may have supplemented with occasional insects, worms, or carrion.

Cretaceous mammals, which had to compete with dinosaurs, were generally small insect eaters. Pantolambda was one of the first mammals to expand into the large-animal niches left vacant by the extinction of the dinosaurs. It was large for a Paleocene mammal, about the size of a sheep. Pantolambda and other early pantodonts would quickly evolve into heavy animals such as Barylambda and Coryphodon. These were the first large browsers, pioneering styles of life later followed by many unrelated groups of mammals: rhinos, tapirs, hippos, ground sloths, and elephants.^[2]

Pantodonts such as Pantolambda were definitely not tree dwellers. Fossils of the species of this genus have been found in these locations:

Pantolambda bath modon San Juan Basin, San Juan County, New Mexico San Juan County, Sandoval County, New Mexico

Pantolambda cavirictum San Juan Basin, San Juan County, New Mexico Fort Union Formation, Fremont County, Wyoming

Pantolambda intermedium Gidley Quarry, Montana