''Oligoryzomys magellanicus'', also known as the Patagonian colilargo and the Magellanic pygmy rice rat, is a species of

rodent Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are na ...

in the genus ''

Oligoryzomys ''Oligoryzomys'' is a genus of rodents in the tribe Oryzomyini of family Cricetidae. Many species are known as pygmy rice rats or colilargos.Musser and Carleton, 2005 The genus is found from Mexico to Tierra del Fuego and includes approximately 1 ...

'' of the family

Cricetidae The Cricetidae are a family of rodents in the large and complex superfamily Muroidea. It includes true hamsters, voles, lemmings, muskrats, and New World rats and mice. At almost 608 species, it is the second-largest family of mammals, and has m ...

. It is found in the southernmost parts of

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 ...

and

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

, including

Tierra del Fuego Tierra del Fuego (, ; Spanish for "Land of the Fire", rarely also Fireland in English) is an archipelago off the southernmost tip of the South American mainland, across the Strait of Magellan. The archipelago consists of the main island, Isla G ...

and other outlying islands. Its

karyotype A karyotype is the general appearance of the complete set of metaphase chromosomes in the cells of a species or in an individual organism, mainly including their sizes, numbers, and shapes. Karyotyping is the process by which a karyotype is disce ...

has 2n = 54 and FNa = 66.

Taxonomy

There has been discussion as to whether ''Oligoryzomys magellanicus'' should be regarded as a full species or whether it should be considered to be a subspecies of ''

Oligoryzomys longicaudatus ''Oligoryzomys longicaudatus'', also known as the long-tailed colilargo or long-tailed pygmy rice rat, is a species of rodent in the genus '' Oligoryzomys'' of the family Cricetidae. It is found in the southern Andes of Chile and Argentina, with ...

''. Milton H. Gallardo and Eduardo Palma (1990) recognised it as a valid species, basing their findings on "phallic morphology and karyotypic and morphometric data".

Description

The Magellanic pygmy rice rat has a head-and-body length about equal to the length of its tail. The ears are moderately large, and are rounded with hairs on both surfaces. The dorsal pelage is greyish-buff and the underparts are whitish. The upper surface of both fore and hind feet is white. Tufts of white hairs extend beyond the tips of the claws. The tail is slender and naked.

Ecology

Like other members of the genus, the Magellanic pygmy rice rat probably feeds on seeds, fruits and insects. Where it occurs in forests, it co-exists with the

olive grass mouse ''Abrothrix olivacea'', also known as the olive grass mouse or olive akodont,Musser and Carleton, 2005, p. 1090 is a species of rodent in the genus ''Abrothrix'' of family Cricetidae. It is found from northern Chile into southern Chile and A ...

(''Abrothrix olivaceus'') but not on the open pampas or in scrubland. One of the places where this pygmy rice rat can be found is the

Torres del Paine National Park Torres del Paine National Park ( es, Parque Nacional Torres del Paine) is a national park encompassing mountains, glaciers, lakes, and rivers in southern Chilean Patagonia. The Cordillera del Paine is the centerpiece of the park. It lies in a tr ...

in the southern part of Chilean

Patagonia Patagonia () refers to a geographical region that encompasses the southern end of South America, governed by Argentina and Chile. The region comprises the southern section of the Andes Mountains with lakes, fjords, temperate rainforests, and gl ...

Status

''O. magellanicus'' is common on

but is more localised further north. It faces no specific threats, has a wide range and occurs in a number of protected areas, so 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 ...

has assessed its conservation status as being of "

least concern A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. T ...

References

Literature cited

* *Pardinas, U., D'Elia, G., Patterson, B. and Teta, P. 2008. . In IUCN. IUCN Red List of Threatened Species. Version 2009.2.
www.iucnredlist.org
. Downloaded on November 28, 2009. {{Taxonbar, from=Q1764219 Mammals of Argentina Mammals of Chile Oligoryzomys Mammals described in 1836 Taxa named by Frederick Debell Bennett Taxonomy articles created by Polbot