The pygmy short-tailed opossum, scientifically named ''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 93 species in 18 genera. Opossums originated in South America and entered North ...

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

from

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...

. ''M. kunsi'' is a

marsupial Marsupials are any members of the mammalian infraclass Marsupialia. All extant marsupials are endemic to Australasia, Wallacea and the Americas. A distinctive characteristic common to most of these species is that the young are carried in a po ...

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.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 ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...

Bolivia , image_flag = Bandera de Bolivia (Estado).svg , flag_alt = Horizontal tricolor (red, yellow, and green from top to bottom) with the coat of arms of Bolivia in the center , flag_alt2 = 7 × 7 square p ...

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

and

Paraguay Paraguay (; ), officially the Republic of Paraguay ( es, República del Paraguay, links=no; gn, Tavakuairetã Paraguái, links=si), is a landlocked country in South America. It is bordered by Argentina to the south and southwest, Brazil to th ...

. ''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 and inva ...

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; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

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 Vibrissae (; singular: vibrissa; ), more generally called Whiskers, are a type of stiff, functional hair used by mammals to sense their environment. These hairs are finely specialised for this purpose, whereas other types of hair are coarser ...

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 * 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 ships * Ros ...

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 ''Monodelphis'' is a genus of marsupials in the family Didelphidae, commonly referred to as short-tailed opossums. They are found throughout South America. , the most recently described species is ''M. vossi''. Species * Sepia short-tailed o ...

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)) offe ...

, 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, whe ...

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 maned wolf (''Chrysocyon brachyurus'') is a large canine of South America. It is found in Argentina, Brazil, Bolivia, Peru, and Paraguay, and is almost extinct in Uruguay. Its markings resemble those of foxes, but it is neither a fox nor a w ...

,'' the barn owl - ''

Tyto alba The barn owl (''Tyto alba'') is the most widely distributed species of owl in the world and one of the most widespread of all species of birds, being found almost everywhere except for the polar and desert regions, Asia north of the Himalay ...

,'' and the burrowing owl - ''

Athene cunicularia The burrowing owl (''Athene cunicularia''), also called the shoco, is a small, long-legged owl found throughout open landscapes of North and South America. Burrowing owls can be found in grasslands, rangelands, agricultural areas, deserts, or any ...

'' 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 reproductive episode before death, and iteroparous if it is characteri ...

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 Opossums Mammals of Bolivia Mammals of Brazil Mammals described in 1975