Planetetherium

Planetetherium Temporal range: 56.8–55.4 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Dermoptera
Family:	†Plagiomenidae
Genus:	†Planetetherium Simpson, 1928
Species:	†P. mirabile
Binomial name
†Planetetherium mirabile Simpson, 1928

Planetetherium is an extinct genus of herbivorous gliding mammal endemic to North America during the Paleogene living from 56.8 to 55.4 mya, existing for approximately 1.4 million years.^[1]

Fossils have been discovered in strata formed from ancient cypress forests, suggesting that this was the animal's preferred habitat.

Morphology

Plantetherium is estimated to reach around 25 centimetres (10 in) in length, and its known materials closely resembled that of its modern relatives. Its teeth already included the comb-like structure distinctive to modern colugos. Since no postcranial materials have been described for any plagiomenid,^[2] there is no direct evidence that Planetetherium had the membrane of skin that allows modern colugos to glide, but this was likely the case.^[3]

References

1. PaleoBiology Database: Planetetherium, basic info
2. Rose, Kenneth D. (2008-01-01), "Plagiomenidae and Mixodectidae", Evolution of Tertiary Mammals of North America: Volume 2: Small Mammals, Xenarthrans, and Marine Mammals, Cambridge University Press, pp. 198–206, retrieved 2025-02-24
3. Palmer, D., ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. p. 210. ISBN 1-84028-152-9.