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 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.
Tschudi's slender opossum is an opossum species from South America, named after Swiss naturalist Johann Jakob von Tschudi. It is found in Bolivia, Brazil, Colombia, Ecuador, Paraguay, Peru and Venezuela.
The neblina slender opossum is an opossum species from South America. It is found in Brazil, Ecuador, Venezuela, and perhaps Peru.
The white-bellied slender opossum is a species of opossum from South America. It is found in Bolivia, Brazil, Ecuador and Peru.
The Brazilian slender opossum is an opossum species from South America. It is found in moist montane forest in the Atlantic Forest region of southeastern Brazil, including the states of Minas Gerais, Rio de Janeiro, São Paulo and Paraná. Its breeding may be fully semelparous, which is unusual for a mammal.
Pinheiro's slender opossum is an opossum species from South America. It is found in Brazil, French Guiana, Guyana, Suriname and Venezuela.
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 narrow-headed slender opossum is a species of opossum in the family Didelphidae. It is endemic to Venezuela.
Dorothy's slender opossum is a species of opossum in the family Didelphidae. It is found in Brazil and Bolivia. It is threatened by habitat loss.
The dusky slender opossum is a species of opossum in the family Didelphidae. It is found in Colombia, Trinidad and Tobago, and Venezuela. It is threatened by habitat loss.
Handley's slender opossum is a species of opossum in the family Didelphidae. It is endemic to Colombia.
The Panama slender opossum, also known as the slaty slender mouse opossum, is a species of opossum in the family Didelphidae. It is endemic to Panama, where it has been found in tropical rainforest habitats, including disturbed areas, at elevations from 500 to 1500 m. This opossum is mostly terrestrial in its habits, and feeds on plants and insects. It is vulnerable to deforestation.
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.
Bishop's slender opossum is a small, arboreal marsupial opossum native to Brazil, Peru, and Bolivia. It somewhat resembles a placental rat or shrew.
The Junin slender opossum is a species of South American opossum in the family Didelphidae. It is known only from the valley of the Chanchamayu in Peru where it lives in Andean montane forests at elevations between 1460 and 2200 m. The species is threatened by destruction of its forest habitat as the area under cultivation in the region increases.
The spectacled slender opossum, also known as little spotted slender opossum is a species in the marsupial genus Marmosops from South America.
