''Oligoryzomys'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

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 n ...

s in the tribe

Oryzomyini Oryzomyini is a tribe of rodents in the subfamily Sigmodontinae of the family Cricetidae. It includes about 120 species in about thirty genera,Weksler et al., 2006, table 1 distributed from the eastern United States to the southernmost parts of ...

of 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 h ...

. Many species are known as pygmy rice rats or colilargos.Musser and Carleton, 2005 The genus is found from

Mexico Mexico (Spanish language, Spanish: México), officially the United Mexican States, is a List of sovereign states, country in the southern portion of North America. It is borders of Mexico, bordered to the north by the United States; to the so ...

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 ...

and includes approximately 17 species. 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 List of South American countries by area, second-largest ...

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 eas ...

, ''

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 ...

'' and other members of the genus represent the reservoir for the

hantavirus ''Orthohantavirus'' is a genus of single-stranded, enveloped, negative-sense RNA viruses in the family '' Hantaviridae'' within the order ''Bunyavirales''. Members of this genus may be called orthohantaviruses or simply hantaviruses. Orthohantav ...

strain

Andes virus ''Andes orthohantavirus'' (ANDV), a species of '' Orthohantavirus,'' is a major causative agent of hantavirus cardiopulmonary syndrome (HCPS) and hantavirus pulmonary syndrome (HPS) in South America. It is named for the Andes mountains of Chile ...

(ANDV) (Wells et al., 1997; Levis et al., 1998; Cantoni et al., 2001).

Taxonomy

The genus ''Oligoryzomys'' is included in the subfamily

Sigmodontinae The rodent subfamily Sigmodontinae includes New World rats and mice, with at least 376 species. Many authorities include the Neotominae and Tylomyinae as part of a larger definition of Sigmodontinae. When those genera are included, the species c ...

of the family

. The genus is placed in the

tribe, first proposed by

Oldfield Thomas Michael Rogers Oldfield Thomas (21 February 1858 – 16 June 1929) was a British zoologist. Career Thomas worked at the Natural History Museum on mammals, describing about 2,000 new species and subspecies for the first time. He was appo ...

in the early 20th century. It includes genera that have certain dental features of the upper and lower molars and a long palate which extends past the third molars. More recently, molecular analysis and morphological data has placed the genus in Clade C, alongside ''

Neacomys The genus ''Neacomys'', also known as bristly mice because of their spiny fur, includes several species of rodents in the tribe Oryzomyini of family Cricetidae. It is most closely related to ''Oligoryzomys'', ''Oreoryzomys'', and ''Microryzomys'' ...

'', ''

Microryzomys ''Microryzomys'' is a genus of rodent in the tribe Oryzomyini of family Cricetidae. It is closely related to '' Oreoryzomys'', '' Oligoryzomys'', and '' Neacomys''.Weksler, 2006 It contains two species, both restricted to the Andes: '' M. altiss ...

'' and ''

Oreoryzomys ''Oreoryzomys balneator'', also known as the Peruvian rice rat or Ecuadoran oryzomys, is a species of rodent in the tribe Oryzomyini of family Cricetidae. It is found in Ecuador and northern Peru in cloud forest at elevations from 1500 to 1800 m. ...

''.

Characteristics

Characteristics that identify this group are broad rostrum, a tail that is longer than its head, and short broad hind feet. Pygmy rice rats are very small rodents, with a head-and-body length of between and a tail length of between . They are greyish-brown or reddish-brown animals that resemble members of the genus ''

Oryzomys ''Oryzomys'' is a genus of semiaquatic rodents in the tribe Oryzomyini living in southern North America and far northern South America. It includes eight species, two of which—the marsh rice rat (''O. palustris'') of the United States an ...

'' in appearance. They differ from ''Oryzomys'' in being mostly terrestrial rather than semi-aquatic and in having longer tails in proportion to their body size. The females have four pairs of

mammary gland A mammary gland is an exocrine gland in humans and other mammals that produces milk to feed young offspring. Mammals get their name from the Latin word ''mamma'', "breast". The mammary glands are arranged in organs such as the breasts in ...

s. The snout is pointed, the ears are rounded and the long slender tail is hairless.

Ecology

Pygmy rice rats occupy a range of habitats including tropical forests, dry forests, plantations, scrubland, mountain grassland, agricultural land, gardens and houses. They are nocturnal and solitary and feed mainly on seeds, insects and fruits. They are mostly found on the ground but can climb into the undergrowth. They can be agricultural pests, particularly in rice fields. Some species such as '' O. flavescens'' and '' O. longicaudatus'' are the principal reservoir host of certain

es which are harmless to rodents but can cause disease in humans.

References

Literature cited

*IUCN. 2009. 2009

IUCN Red List of Threatened Species The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biologi ...

IUCN 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 ...

. Version 2009.2. Retrieved on December 8, 2009. *Musser, G.G. and Carleton, M.D. 2005
Superfamily Muroidea
Pp. 894–1531 in Wilson, D.E. and Reeder, D.M. (eds.)
Mammal Species of the World: a taxonomic and geographic reference. 3rd ed
Baltimore: The Johns Hopkins University Press, 2 vols., 2142 pp. *Weksler, M. 2006
Phylogenetic relationships of oryzomyine rodents (Muroidea: Sigmodontinae): separate and combined analyses of morphological and molecular data
Bulletin of the American Museum of Natural History 296:1–149.

External links

* * {{Taxonbar, from=Q244303 Rodent genera Taxa named by Outram Bangs