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 water opossum, also locally known as the yapok, is a marsupial of the family Didelphidae. It is the only monotypic species of its genus, Chironectes. This semiaquatic creature is found in and near freshwater streams and lakes from Mexico through Central and South America to Argentina and is the most aquatic living marsupial. It is also the only extant marsupial species in which both sexes have a pouch. The thylacine, commonly referred to as the Tasmanian tiger, also exhibited this trait, but it is now extinct.
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.
Monodelphis is a genus of marsupials in the family Didelphidae, commonly referred to as short-tailed opossums. They are found throughout South America. As of January 2019, the most recently described species is M. vossi.
Lutreolina is a genus of opossum found in South America. Both extant species in this genus are known as lutrine opossums. They have an otter-like body plan and occasionally semiaquatic tendencies, hence the genus name Lutreolina, which is Latin for "otter-like".
The nine species in the genus Philander, commonly known as gray and black four-eyed opossums, are members of the order Didelphimorphia. Mature females have a well-developed marsupium. The tail appears to be hairless except for the proximal 5 or 6 cm, which has a few long hairs. The tail is slightly longer than the head-and-body length, and it is black for the proximal one half to two thirds of its length. The genus is closely related to Didelphis but the species of Philander are smaller than those of Didelphis. The genus formerly included Metachirus nudicaudatus, but this species lacks a pouch and so is now considered a separate genus. The common name comes from the white spots above the eyes, which can appear from a distance to be another set of eyes.
The fat-tailed dunnart is a species of mouse-like marsupial of the Dasyuridae, the family that includes the little red kaluta, quolls, and the Tasmanian devil.
The northern red-sided opossum or the Guianan short-tailed opossum, Monodelphis brevicaudata, is an opossum species from South America. It is found in Bolivia, Brazil. French Guiana, Guyana, Suriname and Venezuela.
The yellow-sided opossum is an opossum species from South America. It is found in Argentina, Brazil and Uruguay. They have grey or black fur on their dorsal side with yellowish fur on the lateral side that continues down to the feet. They are the most mysterious of all the Monodelphis that is found specifically in the Pampean region or Pampa of Argentina. It is suspected to be a once-in-a-lifetime breeder as seen in a three-year observational study of one population in the marshy grasslands of the Pampean region. Maintaining their native grasslands is important for them to keep a stable population. They show sexual dimorphism in overall size: adult males are typically 100-150 g whereas adult females are 30-70 g.
The pygmy short-tailed opossum, scientifically named Monodelphis kunsi, is an opossum species from South America. M. kunsi is a marsupial from the family Didelphidae of the order Didelphimorphia. Although it is a marsupial, it lacks the characteristic pouch that is often associated with this order. It is found in Argentina, Bolivia, Brazil and Paraguay. M. kunsi is considered a smaller species within the family Didelphidae, which is why it is named a pygmy opossum. The young are referred to as 'joeys'. The females are referred to as 'Jill,' and the males 'jack'. It was thought to have been endangered in 2001, but has since been moved to least concern by the International Union for Conservation of Nature.
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 genus, Tlacuatzin, although some sources disagree with this.
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 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 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. While the American Society of Mammalogists maintains this as a distinct species, mitochondrial DNA sequence analysis does not support the population being distinct from T. cinderella.
Massoia's lutrine opossum is a species of opossum native to South America.
