The common fat-tailed mouse opossum (''Thylamys pusillus'') is a species of opossum in the family Didelphidae. It occurs in

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...

, Bolivia,

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

, and

Paraguay Paraguay (; ), officially the Republic of Paraguay ( es, República del Paraguay, links=no; gn, Tavakuairetã Paraguái, links=si), is a landlocked country in South America. It is bordered by Argentina to the south and southwest, Brazil to th ...

in chaco and

Andean The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S l ...

foothill habitats. Its head-and-body length is about 75 to 120 (mean 94.3) mm, and its tail length is about 90 to 134 (mean 103.6) mm. Its

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage * Dorsal c ...

fur Fur is a thick growth of hair that covers the skin of mammals. It consists of a combination of oily guard hair on top and thick underfur beneath. The guard hair keeps moisture from reaching the skin; the underfur acts as an insulating blanket t ...

is brownish gray, and its

ventral Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

fur is yellowish to white. The legs and cheeks are the same color as the

surface. Its tail is sharply bicolored (divided into two colors). A ring of faintly darker fur surrounds each eye. Its tail often lacks fat deposits, but does not always.

References

Opossums Marsupials of South America Marsupials of Argentina Mammals of Bolivia Mammals of Uruguay Mammals described in 1804 Taxonomy articles created by Polbot {{marsupial-stub