Cinderella fat-tailed mouse opossum

The Cinderella fat-tailed mouse opossum (Thylamys cinderella) is a species of opossum in the family Didelphidae.^[2] It is found in northern Argentina and southern Bolivia, in the eastern foothills of the Andes.^[1] Its dorsal fur is gray brown to dark brown. Its ventral fur is gray-based, except for the white to yellowish chest hairs.

Cinderella fat-tailed mouse opossum
Conservation status
Least Concern  (IUCN 3.1)[1]
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Infraclass:	Marsupialia
Order:	Didelphimorphia
Family:	Didelphidae
Genus:	Thylamys
Species:	T. cinderella
Binomial name
Thylamys cinderella Thomas, 1902
Cinderella fat-tailed mouse opossum range

Argentine fat-tailed mouse opossum

The Argentine fat-tailed mouse opossum (Thylamys sponsorius) was formerly considered a species of opossum in the family Didelphidae.^[3] However, mitochondrial DNA sequence analysis does not support separate species status from T. cinderella.^[1][4]

It is found in the eastern foothills of the Andes in northern Argentina and southern Bolivia.^[5] Typically reach around 10-13 cm (4-5 inches) in body length, with a bushy tail adding another 12-15 cm (5-6 inches). Its dorsal fur is gray brown to dark brown. Its ventral fur is gray-based except for the white to yellowish chest hairs. It has been distinguished from T. cinderella by its well-developed postorbital ridges in both juveniles and adults that extend laterally behind the eye sockets.^[6] Only adults of T. sponsorius have fully developed postorbital ridges, and these do not extend laterally behind the eye sockets.^[6] While the American Society of Mammalogists maintains this as a distinct species,^[7] mitochondrial DNA sequence analysis does not support the population being distinct from T. cinderella.^[8][4]