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.
Paucituberculata is an order of South American marsupials. Although currently represented only by the seven living species of shrew opossums, this order was formerly much more diverse, with more than 60 extinct species named from the fossil record, particularly from the late Oligocene to early Miocene epochs. The earliest paucituberculatans date to the late Paleocene. The group went through a pronounced decline in the middle Miocene epoch, which resulted in the extinction of all families of this order except for the living shrew opossums (Caenolestidae). Extinct families of Paucituberculatans include Pichipilidae, Palaeothentidae, and Abderitidae.
The family Caenolestidae contains the seven surviving species of shrew opossum: small, shrew-like marsupials that are confined to the Andes mountains of South America. The order is thought to have diverged from the ancestral marsupial line very early. They were once included in the superorder but it is now known that Ameridelphia is paraphyletic, having given rise to Australidelphia, and thus could be considered an evolutionary grade. Genetic studies indicate that they are the second most basal order of marsupials, after the didelphimorphs. As recently as 20 million years ago, at least seven genera were in South America. Today, just three genera remain. They live in inaccessible forest and grassland regions of the High Andes.
Kitti's hog-nosed bat, also known as the bumblebee bat, is a near-threatened species of bat and the only extant member of the family Craseonycteridae. It occurs in western Thailand and southeast Myanmar, where it occupies limestone caves along rivers.
Sangay National Park is a national park located in the Morona-Santiago, Chimborazo, Tungurahua, Cañar, and Azuay provinces of Ecuador. The park contains two active volcanoes, one extinct volcano El Altar. Protecting a range of elevations from 900 to 5,319 meters above sea level, Sangay National Park contains a wide variety of habitats, including glaciers, volcanic landscapes, tropical rainforests, cloud forests, wetlands, grasslands, and one of the largest regions of páramo in Ecuador. 327 lakes feed into a vast wetland system covering 31.5 square kilometers (12.2 sq mi).
The dusky caenolestid, also known as Tate's shrew opossum, is a shrew opossum from South America. The dusky caenolestid is characterized by a dark brown coat with a lighter underbelly, soft and thick fur, and a loosely haired tail. A nocturnal animal, the dusky caenolestid lives on trees and feeds on insects and small invertebrates and vertebrates. It occurs in alpine and páramo forests in northern and western Colombia, Ecuador, and western Venezuela. The IUCN classifies this shrew 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 common shrew opossums are members of the family Caenolestidae. They are found in Colombia, Ecuador, Peru, and Venezuela. The most recently discovered species is C. sangay.
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 gray-bellied caenolestid, or grey-bellied shrew opossum, is a shrew opossum found in humid, temperate forests and moist grasslands of western Ecuador and northwestern Peru. It was first described by American zoologist Harold Elmer Anthony in 1921. Little is known about the behavior of the gray-bellied caenolestid. It appears to be terrestrial (land-living) and crepuscular or nocturnal. Diet consists of invertebrate larvae, small vertebrates and plant material. The IUCN classifies the gray-bellied caenolestid as near threatened.
The northern caenolestid, also known as the blackish shrew opossum, is a shrew opossum found in Colombia and Ecuador. It is listed as Vulnerable by the IUCN.
The Incan caenolestid, also known as the Incan shrew opossum or Peruvian caenolestid, is a caenolestid found in the southern Peruvian Andes. It was first described by English zoologist Oldfield Thomas in 1917. The head-and-body length ranges from 9 to 11.5 centimetres, and the weight is between 25 and 32 grams. It is brown on the back, and lighter on the underside. Little is known about the behaviour of the Incan caenolestid; it appears to be terrestrial and nocturnal. It feeds on small invertebrates and insects. This caenolestid inhabits elfin and secondary forests. The IUCN classifies it as least concern.
The Andean caenolestid, also known as the Andean shrew opossum or Condor caenolestid, is a shrew opossum known only from Cordillera del Cóndor (Ecuador), its type locality. It was first described by zoologists Bruce D. Patterson and Luis Albuja in 1996. It is the largest caenolestid. The IUCN classifies it as vulnerable. As of 2015, the population is estimated at less than 1,000.
The eastern caenolestid is a shrew opossum found on the eastern slopes of the Andes in southern Ecuador.
