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 white-bellied woolly mouse opossum is a small pouchless marsupial of the family Didelphidae. It was formerly assigned to the genus Micoureus, which was made a subgenus of Marmosa in 2009. The specific epithet was given in honour of Constance Sladen, wife of the naturalist Percy Sladen. She funded the 1902 expedition which collected the type specimen.
Linnaeus's mouse opossum, also known as the common or murine mouse opossum, is a South American marsupial of the family Didelphidae.
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 bare-tailed woolly opossum is an opossum from South America. It was first described by Swedish zoologist Carl Linnaeus in 1758. The bare-tailed woolly opossum is characterized by a gray head, brown to gray coat, orange to gray underside and a partially naked tail. It is nocturnal and solitary; there is hardly any social interaction except between mother and juveniles and in mating pairs. The opossum constructs nests in tree cavities, and its litter size ranges from one to seven. Gestation lasts 25 days, and the juveniles exit the pouch after three months; weaning occurs a month later. The bare-tailed woolly opossum inhabits subtropical forests, rainforests, secondary forests, and plantations; its range extends from northern Venezuela to northeastern and southcentral Brazil. The IUCN classifies this opossum as least concern.
The brown-eared woolly opossum, also known as the western woolly opossum, is an opossum from South America. It was first described by German naturalist Ignaz von Olfers in 1818. The opossum is characterized by a brown to reddish brown coat and similarly colored limbs, yellow to orange underbelly, hairless, brown ears with a hint of pink, and a tail furred on the back for up to half of its length. The brown-eared woolly opossum is nocturnal, solitary and omnivorous. The IUCN lists it as least concern.
The black-shouldered opossum, also known as the white-eared opossum, is an opossum known from western Brazil and southeastern Peru. It was first described by Colin Campbell Sanborn, curator of Field Museum of Natural History, in 1951. The black-shouldered opossum is characterized by a gray coat, gray underbelly, and broad black stripes that extend from the forefeet, meet on the shoulders, run along the midline of the back and then split into parallel stripes that run down the hind feet. Little is known of the behavior of the black-shouldered opossum. It is nocturnal and arboreal. It is known to feed on fruits and rodents. The opossum inhabits humid forests. The IUCN classifies it as least concern.
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 heavy-browed mouse opossum, or Anderson's mouse opossum, is a species of opossum in the family Didelphidae. It is endemic to a restricted range in southern Peru. This opossum inhabits forests; it is nocturnal and probably arboreal.
The Mexican mouse opossum is a species of North American opossum in the family Didelphidae.
Thylamys is a genus of opossums in the family Didelphidae. The premaxillae are rounded rather than pointed. The females lack a pouch. The females' nipples are arranged in two symmetrical rows on the abdomen. All species but T. macrurus store fat in their tails., although this is not necessarily true for all species in the genus. Fossils belonging to the genus date back to the Miocene, with the oldest specimens being found in the Cerro Azul Formation of Argentina and the Honda Group of Colombia. Genetic studies indicate that the genus may have originated around 14 million years ago.
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.
Gracilinanus is a genus of opossum in the family Didelphidae. It was separated from the genus Marmosa in 1989, and has since had the genera Cryptonanus, Chacodelphys, and Hyladelphys removed from it.
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.
Karimi's fat-tailed mouse opossum is a species of opossum in the family Didelphidae. It is endemic to central and northeast Brazil, where it is found in the cerrado and caatinga at elevations from 300 to 1100 m. This opossum is crepuscular and mostly terrestrial; its omnivorous diet includes leaves, insects and small vertebrates. Its head-and-body length is about 95 millimeters, and its tail length is about 72 millimeters. It is very similar to T. pallidor. Its tail may be nonprehensile. The species is named after Iranian epidemiologist Y. Karimi. It is threatened by habitat destruction and fragmentation due to agriculture and ranching.
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.
The buff-bellied fat-tailed mouse opossum is a species of opossum in the family Didelphidae. It is found in the transitional and humid forests of northern Argentina and southern Bolivia. Its dorsal fur is cinnamon brown. Most of its ventral fur is gray-based, but its chest, throat, and the thoracic midline are not gray-based. The postorbital ridges are absent in the young and weakly developed in adults.
