Pantolambda

Pantolambda Temporal range: Paleocene, 63–57 Ma PreЄ Є O S D C P T J K Pg N
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	†Cimolesta
Suborder:	†Pantodonta
Family:	†Pantolambdidae
Genus:	†Pantolambda Cope, 1882
Type species
†Pantolambda bathmodon Cope, 1882
Species[1][2]
P. bathmodon Cope, 1882 P. cavirictum Cope, 1883 P. intermedium Simpson, 1935

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.

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. 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.^[3] Pantodonts such as Pantolambda were definitely not tree dwellers.

Description

P. bathmodon fore and hind foot casts at the Museum für Naturkunde, Berlin

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 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 Pantolambda's teeth were low-crowned and indicate a not very specialized diet.^[4] Pantolambda probably ate a mix of shoots, leaves, fungi, and fruit, which it may have supplemented with occasional insects, worms, or carrion.

Discovery and species

P. bathmodon by Robert Bruce Horsfall.

Fossils of this genus have been found in these Torrejonian-Tiffanian formations at the following localities of the United States:

• Pantolambda bathmodon
  • Sandoval County, New Mexico (35°42′N 107°00′W / 35.7°N 107.0°W, paleocoordinates 42°06′N 87°06′W / 42.1°N 87.1°W)^[5]
• Pantolambda cavirictum
  • Park County, Wyoming^[6]
  • San Juan County, New Mexico^[7]
  • Sandoval County, New Mexico^[8]
  • Carbon County, Wyoming^[9]
  • Fremont County, Wyoming^[10]
• Pantolambda intermedium
  • Hot Springs/Washakie County, Wyoming^[11]
  • San Juan County, New Mexico^[12]
  • Sweet Grass County, Montana^[13]

References

1. Pantolambda in the Paleobiology Database. Retrieved July 2013.
2. "Pantodonta". After McKenna & Bell (1997) and Alroy (2002). Retrieved 2 November 2013.
3. Halstead, L.B., The Evolution of the Mammals, Peter Lowe, 1978.
4. E. D. Cope (November 1884), "The Amblypoda", The American Naturalist, Vol. 18, No. 11
5. Alamito Arroyo (Paleocene of the United States) in the Paleobiology Database. Retrieved July 2013.
6. Rock Bench Quarry (Paleocene of the United States) in the Paleobiology Database. Retrieved July 2013.
7. 44 Store (High) (Paleocene of the United States) in the Paleobiology Database. Retrieved July 2013.
8. East Flank Torreon Wash (Upper) (Paleocene of the United States) in the Paleobiology Database. Retrieved July 2013.
9. Boulder Quarry (UW V-94027) (Paleocene to of the United States) in the Paleobiology Database. Retrieved July 2013.
10. Shotgun (Paleocene of the United States) in the Paleobiology Database. Retrieved July 2013.
11. MPG (Paleocene of the United States) in the Paleobiology Database. Retrieved July 2013.
12. Chico Springs (Paleocene of the United States) in the Paleobiology Database. Retrieved July 2013.
13. Gidley Quarry (Paleocene of the United States) in the Paleobiology Database. Retrieved July 2013.