Fossils of the best-known species, the Shasta ground sloth (N. shastensis), have been found throughout western North America, especially in the American Southwest. The most famous specimen was recovered from a lava tube at Aden Crater in New Mexico and was found to still have hair and tendon preserved. This nearly complete specimen is on display at the Yale Peabody Museum of Natural History in New Haven, CT. Numerous dung boluses belonging to this sloth have also been found throughout the soutwestern United States and have provided an insight into the diet of these extinct animals.

References

• List of prehistoric species
• Family tree of Megatheriidae
• M. C. McKenna & S. K. Bell (eds.) (1997): Classification of mammals, above the species level. New York: Columbia University Press.
• SDNHM Fossil Mysteries Field Guide, "Ground Sloths"