Opossums are members of the marsupial order Didelphimorphia endemic to the Americas. The largest order of marsupials in the Western Hemisphere, it comprises 126 species in 18 genera. Opossums originated in South America and entered North America in the Great American Interchange following the connection of North and South America.
The Chacoan pygmy opossum is a recently described genus and species of didelphimorph marsupial. The only species in Chacodelphys, C. formosa, was known until 2004 from only one specimen collected in 1920 in the Chaco of Formosa Province, Argentina. The species is gaining popularity as a pocket pet.
The bushy-tailed opossum is an opossum from South America. It was first described by English zoologist Oldfield Thomas in 1912. It is a medium-sized opossum characterized by a large, oval, dark ears, fawn to cinnamon coat with a buff to gray underside, grayish limbs, and a furry tail. Little is known of the behavior of the bushy-tailed opossum; less than 25 specimens are known. It appears to be arboreal (tree-living), nocturnal and solitary. The diet probably comprises insects, eggs and plant material. This opossum has been captured from heavy, humid, tropical forests; it has been reported from Bolivia, Brazil, Colombia, Ecuador and Peru. The IUCN classifies it as least concern.
The southeastern four-eyed opossum is an opossum species native to South America. It is found in Atlantic Forest ecoregions, in Brazil, Paraguay and Argentina.
The 27 species in the genus Marmosa are relatively small Neotropical members of the family Didelphidae. This genus is one of three that are known as mouse opossums. The others are Thylamys and Tlacuatzin, the grayish mouse opossum. Members of the genus Marmosops used to be called "slender mouse opossums", but are now just called "slender opossums". The thirteen members of the Marmosa subgenus Micoureus, known as woolly mouse opossums, were formerly considered to be a separate genus, but were moved into Marmosa in 2009. Based on a comparison of sequences of one mitochondrial and three nuclear genes, three new subgenera, Eomarmosa, Exulomarmosa and Stegomarmosa, were recognized by Voss et al. in 2014. Eomarmosa and Exulomarmosa, as well as Marmosa and Micoureus, are thought to be sister taxa, while Stegomarmosa is viewed as sister to Marmosa plus Micoureus. Exulomarmosa is a mostly trans-Andean clade.
The Patagonian opossum(Lestodelphys halli) is the sole species in genus Lestodelphys.
Marmosops is a genus of Neotropical opossums of the family Didelphidae. The genus was originally treated as a subgenus from the genus Marmosa rather than having their own classification. This was changed in 1989 by Gardner and Crieghton, who officially separated the group and made them their own genus. The mix-up between to genera Marmosa and Marmosops was common due to the similar appearances including size and other external features. However, the two groups differ significantly in their integument and in the arrangement of their skull and dentition. The dentition is similar in morphology between the two groups, with the exception of the deciduous lower third premolar varying from one genus to the next. The similarity between the two continues to cause the genus Marmosops to be frequently misidentified due to the lack of knowledge regarding the species along with the overlooked traits that help separate them from other opossums. The Marmosops are also commonly confused with the genus Gracilinanus, but this is quickly ruled out by a large number of differing characteristics. These differences include the arrangement of their digits, caudal scales, and the central hair on the scales changing from a three hairs per follicle to many more. This causes the hair of the Gracilinanus to be thicker and has also found to be heavily pigmented. The last group commonly confused with Marmosops is known as the genus Thylamys. These animals have a contrasting dorsal body pelage and the taxa are actually quite different.
The grayish or gray mouse opossum is a diminutive species of opossum in the family Didelphidae, endemic to Mexico. It is the sole species of its monotypic genus, Tlacuatzin.
The elegant fat-tailed mouse opossum, also known as the Chilean mouse opossum, is an opossum from central Chile. The type species of Thylamys, it was first described by English naturalist George Robert Waterhouse in 1839. This medium-sized opossum is characterized by black rings around the eyes, white limbs, gray to light brown coat, lighter flanks and underbelly and a thick 12.7–14.6 centimetres (5.0–5.7 in) long tail covered with hairs. It is crepuscular and lives in nests in tree hollows or under rocks and roots. This opossum feeds mainly on arthropods and larvae apart from fruits. Litter size is typically between 11 and 13. The elegant fat-tailed opossum can occur in a variety of habitats – from cloud forests to chaparrals. The IUCN classifies the opossum as least concern.
The Paraguayan fat-tailed mouse opossum is a species of opossum in the family Didelphidae. It is found in forested areas of Brazil and Paraguay. It is known only from a few specimens. For two listed specimens, one had a head-and-body length of about 135 mm and a tail length of about 140 mm, while the other had a head-and-body length of about 120 mm and a tail length of about 155 mm. Most of its fur is gray, but the shoulder areas are reddish gray, and the ventral fur is pure white or creamy white. There is also a ring of black fur surrounding each eye. The ventral surface of the tail is white. The dorsal surface of the tail is gray for the first one third to one half of its length ; the remainder of the dorsal surface of the tail is white. The tail is hairless except for about its first ten mm. Although the genus Thylamys is characterized by fat storage in the tail, there is no evidence that this species stores fat in its tail.
The white-bellied fat-tailed mouse opossum is a species of opossum in the family Didelphidae. It is found in Argentina, Bolivia, Chile and Peru.
The common fat-tailed mouse opossum is a species of opossum in the family Didelphidae. It occurs in Argentina, Bolivia, and Paraguay in chaco and Andean foothill habitats. Its head-and-body length is about 75 to 120 mm, and its tail length is about 90 to 134 mm. Its dorsal fur is brownish gray, and its ventral fur is yellowish to white. The legs and cheeks are the same color as the ventral surface. Its tail is sharply bicolored. A ring of faintly darker fur surrounds each eye. Its tail often lacks fat deposits, but does not always.
The Didelphinae are a subfamily of opossums consisting of 15 genera and 123 species. Specimens have been collected throughout the Americas, but are predominant in South and Central America.
The Cinderella fat-tailed mouse opossum is a species of opossum in the family Didelphidae. It is found in northern Argentina and southern Bolivia, in the eastern foothills of the Andes. 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. sponsorius by the well-developed postorbital ridges of the latter, but mitochondrial DNA sequence analysis does not support separate species status for sponsorius.
The Argentine fat-tailed mouse opossum was formerly considered a species of opossum in the family Didelphidae. It is found in the eastern foothills of the Andes in northern Argentina and southern Bolivia. Typically reach around 10-13 cm in body length, with a bushy tail adding another 12-15 cm. 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 postorbital ridges. T. cinderella has well-developed postorbital ridges in both juveniles and adults that extend laterally behind the eye sockets. Only adults of T. sponsorius have fully developed postorbital ridges, and these do not extend laterally behind the eye sockets. However, mitochondrial DNA sequence analysis does not support the population being distinct from T. cinderella.
Tate's fat-tailed mouse opossum is a species of opossum in the family Didelphidae, named after American zoologist George Henry Hamilton Tate. It is found at elevations of 300 to 3,000 m along the coast of central Peru. The species has the northernmost range of any member of its genus. It has white ventral fur and short condylobasal and zygomatic lengths. T. pallidior is very similar.
Cryptonanus is a genus of opossums from South America. It includes five species found from Bolivia to Uruguay and eastern Brazil, one of which is now extinct. Although the first species were discovered in 1931, the genus was not recognized as distinct from Gracilinanus until 2005. It includes small opossums with generally grayish, sometimes reddish, fur that are mainly distinguished from other opossums by characters of the skull.
The Isthmian mouse opossum is a species of opossum in the family Didelphidae found in Colombia, Ecuador, and Panama.
