''Pantolambda'' (Greek: "all" (pantos), "lambda" (lambda), in a reference to the shape of upper premolars, similar to the Greek letter lambda) is an extinct genus of

Paleocene The Paleocene, ( ) or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), E ...

pantodont mammal. ''Pantolambda'' lived during the middle Paleocene, and has been found both in Asia and North America.

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...

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. ''Pantolambda'' and other early pantodonts would quickly evolve into heavy animals such as ''

Barylambda ''Barylambda'' (Greek: "heavy" (baros), "lambda" (lambda) in a reference to larger size than that of '' Pantolambda'') is an extinct genus of pantodont mammal from the middle to late Paleocene, well known from several finds in the Wasatchian ( N ...

'' 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. Pantodonts such as ''Pantolambda'' were definitely not tree dwellers.

Description

''Pantolambda'' was large for a Paleocene mammal, about the size of a sheep. A generalized early mammal, it had a vaguely cat-like body, heavy head, long tail and five-toed

plantigrade 151px, Portion of a human skeleton, showing plantigrade habit In terrestrial animals, plantigrade locomotion means walking with the toes and metatarsals flat on the ground. It is one of three forms of locomotion adopted by terrestrial mammals. T ...

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.

Teeth

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 ''Pantolambdas teeth were low-crowned and indicate a not very specialized diet. ''Pantolambda'' probably ate a mix of shoots, leaves, fungi, and fruit, which it may have supplemented with occasional worms or eggs.

Discovery and species

Fossils of this genus have been found in these

Torrejonian The Torrejonian North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 63,300,000 to 60,200,000 years BP lasting . It is usually ...

- Tiffanian formations at the following localities of the United States: * ''Pantolambda bathmodon'' **

Sandoval County, New Mexico Sandoval County is located in the U.S. state of New Mexico. As of the 2010 census, the population was 131,561, making it the fourth-most populous county in New Mexico. The county seat is Bernalillo. Sandoval County is part of the Albuquerque m ...

(, paleocoordinates ) * ''Pantolambda cavirictum'' **

Park County, Wyoming Park County is a county in the U.S. state of Wyoming. As of the 2020 United States Census, the population was 29,624. The county seat is Cody. Park County is a major tourism destination. The county has over 53 percent of Yellowstone National Pa ...

** San Juan County, New Mexico ** Sandoval County, New Mexico **

Carbon County, Wyoming Carbon County is a County (United States), county in the U.S. state of Wyoming. As of the 2020 United States Census, the population was 14,537. Its county seat is Rawlins, Wyoming, Rawlins. Its south border abuts the north line of Colorado. ...

** Fremont County, Wyoming * ''Pantolambda intermedium'' **

Hot Springs A hot spring, hydrothermal spring, or geothermal spring is a spring produced by the emergence of geothermally heated groundwater onto the surface of the Earth. The groundwater is heated either by shallow bodies of magma (molten rock) or by circ ...

Washakie County, Wyoming Washakie County is a county in the U.S. state of Wyoming. As of the 2020 United States Census, the population was 7,685. Its county seat is Worland. History Washakie County was created on February 21, 1911, as Hanover County with land detached ...

** San Juan County, New Mexico ** Sweet Grass County, Montana. Retrieved July 2013.

References

Pantodonts Paleocene mammals Natural history of San Juan County, New Mexico Paleocene mammals of Asia Fossil taxa described in 1882 Prehistoric mammal genera {{Paleo-mammal-stub