The pygmy short-tailed opossum, (''Monodelphis kunsi)'', is an

opossum 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 A ...

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

from

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

. ''M. kunsi'' is a

marsupial Marsupials are a diverse group of mammals belonging to the infraclass Marsupialia. They are natively found in Australasia, Wallacea, and the Americas. One of marsupials' unique features is their reproductive strategy: the young are born in a r ...

from the family Didelphidae of the order

Didelphimorphia 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 A ...

. Although it is a marsupial, it lacks the characteristic pouch that is often associated with this order.Hannibal, Wellington, Vlaquiria V. Figueiredo, Paulo Landgref Filho, and Mauricio N. Godoi. "New Records of Monodelphis Kunsi (Didelphimorphia, Didelphidae) from Brazil." ''Mastozoología Neotropical'' 19.2 (2012): 317-20. Web. 10 Nov. 2016. It is found in

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

Bolivia Bolivia, officially the Plurinational State of Bolivia, is a landlocked country located in central South America. The country features diverse geography, including vast Amazonian plains, tropical lowlands, mountains, the Gran Chaco Province, w ...

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

and

Paraguay Paraguay, officially the Republic of Paraguay, is a landlocked country in South America. It is bordered by Argentina to the Argentina–Paraguay border, south and southwest, Brazil to the Brazil–Paraguay border, east and northeast, and Boli ...

. ''M. kunsi'' is considered a smaller species within the family ''Didelphidae'', which is why it is named a pygmy opossum.Anderson, Sydney. "Monodelphis Kunsi." ''Mammalian Species'' 190 (1982): 1. Web. 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 An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching, inv ...

in 2001, but has since been moved to least concern by the

International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the stat ...

Morphological characteristics

''Monodelphis kunsi'' is a relatively small opossum with short, warm-brown hair on its dorsal side. The ventral side of this pygmy opossum is a lighter color with pale, ivory patches of fur mixed throughout. In addition to fur, vibrissae can be found in three locations on the face, including the nose, above the eyes and near the ears, and under the chin. ''M. kunsi'' lacks a mid-sagittal crest; however, it does have a throat gland present. Compared to other opossums, the

rostrum Rostrum may refer to: * Any kind of a platform for a speaker: **dais **pulpit ** podium * Rostrum (anatomy), a beak, or anatomical structure resembling a beak, as in the mouthparts of many sucking insects * Rostrum (ship), a form of bow on naval ...

of ''M. kunsi'' is less protruded than some other opossums, but it is still recognizable as a character of the genera ''Monodelphis'' and ''Didelphis''. ''M. kunsi'' has an approximate body mass of 19 grams, with a body length ranging from 71–94 mm long, and a relatively short tail from 41–42 mm in length. The tail is, to at least some degree, prehensile, and it is covered with very small hairs. The tail is hairless at the tip, which is seen in many members of the Short-tailed opossum genus. It is also thought to be used for tactile purposes.Anderson, Sydney. Monodelphis Kunsi. Digital image. Clark Science Center. Smith College, 1982.

Distribution and habitat

''Monodelphis kunsi'' is a terrestrial marsupial that inhabits a wide range of habitats within South America.Gettinger, D., Modesto, T.C., Bergallo, H.G., Martins-Hatano, F., 2011. Mammalia, Didelphimorphia, Didelphidae, Monodelphis kunsi Pine, 1975: distribution extension and first record for eastern Amazonia. Check List 7, 585–588 It has been documented in southern and eastern parts of Bolivia, eastern Paraguay, western, central and southeastern Brazil, and in the northern parts of Argentina.Caceres, Nilton Carlos, Maurício Neves Godoi, Wellington Hannibal, and Vanda Lúcia Ferreira. "Effects of Altitude and Vegetation on Small-mammal Distribution in the Urucum Mountains, Western Brazil." ''J. Trop. Ecol. Journal of Tropical Ecology'' 27.03 (2011): 279-87. Web.Bueno, Adriana De Arruda, and José Carlos Motta-Junior. "Behavioural and Morphological Strategies by Small Savannah Rodents to Avoid Predation." ''Mammalian Biology - Zeitschrift für Säugetierkunde'' 80.5 (2015): 401-08. Web. It is thought that due to the species wide and fragmented distribution that the specimens documented as ''M. kunsi'' may actually be a complex of species. A study conducted by Caceres et al. from the year 2000 to 2008 documented ''M. kunsi'' at all altitudes of two designated localities in the Urucum Mountains of western Brazil. The study monitored altitudes ranging from 150 meters to over 1000 meters. The findings suggested that while the opossum was found at all altitudes, it is a grassland specialist in that region. ''M. kunsi'' is also found in the Rio Lipeo department of

Tarija Tarija or San Bernardo de la Frontera de Tarixa is a city in southern Bolivia. Founded in 1574, Tarija is the largest city and capital and municipality within the Tarija Department, with an airport ( Capitán Oriel Lea Plaza Airport, (TJA)) of ...

, Bolivia, which is between 200 m and 640 m in elevation. They are generally encountered in shrub forests of 6–12 m in height in

. ''M. kunsi'' is found in a variety of habitats ranging from forested or wooded areas, to dry Cerrado savannahs, and even Amazonian rain forest.

Ecology and behavior

''Monodelphis kunsi'' is still a relatively unknown species with few publications on its behavior and ecology. The species is thought to be insectivorous due to their occlusal dentition, general skull shape, and skull size. ''M. kunsi'' lacks enlarged canines, and their posterior incisors are bigger than their first upper pair of

incisor Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, wher ...

s. When it comes to being preyed upon, one study documented ''M. kunsi'' as a lesser choice of prey by the maned wolf - '' Chrysocyon brachyurus,'' the barn owl - '' Tyto alba,'' and the burrowing owl - '' Athene cunicularia'' in a savannah preserve located in southeastern Brazil. Little is known about the reproductive behaviors in ''M. kunsi''; however, other ''Monodelphis'' species are known to be

semelparous Semelparity and iteroparity are two contrasting reproductive strategies available to living organisms. A species is considered ''semelparous'' if it is characterized by a single reproduction, reproductive episode before death, and ''iteroparous ...

breeders, so it possible that this species is as well.Feldhamer, George A., Lee C. Drikamer, Stephen H. Vessey, Joseph F. Merritt, and Carey Krajewski. ''Mammalogy: Adaptation, Diversity, Ecology''. 4th ed. Baltimore: Johns Hopkins UP, 2007. Print. More research is needed to understand the basic reproductive behavior of ''M. kunsi'' before any assumptions can be made.

References

Olivia the Opossum
{{Taxonbar, from=Q194473 Short-tailed opossums Fauna of the Amazon Fauna of the Cerrado Marsupials of Argentina Marsupials of Bolivia Marsupials of Brazil Mammals of Paraguay Mammals described in 1975