Oligoryzomys microtis

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Oligoryzomys microtis
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Rodentia
Family: Cricetidae
Subfamily: Sigmodontinae
Genus: Oligoryzomys
Species:
O. microtis
Binomial name
Oligoryzomys microtis
Allen, 1916

Oligoryzomys microtis, also known as the small-eared colilargo [2] [3] or small-eared pygmy rice rat, [1] is a species of rodent in the genus Oligoryzomys of family Cricetidae. It is found in western Brazil, eastern Peru, Bolivia, and northern Paraguay. [1]

Contents

Description

Oligoryzomys microtis has a total length of 188 mm (7.4 in) including a tail of 106 mm (4.2 in). It weighs about 18 g (0.63 oz) and is the smallest species in the genus. In proportion to the head and body length, the hind feet are relatively long, being 28.5% of their length. This compares with the rather similar Oligoryzomys nigripes where the proportion is 24.5%. The ears are small and densely furred inside. The cheeks may be grey or orangeish-brown. The back is brownish and the underparts are whitish or greyish, sometimes tinged with buff. The tail is rather darker on the upper surface than the lower surface. [4]

Its karyotype has 2n = 64 and FNa = 66. [5]

Distribution and habitat

O. microtis is native to South America, its range extending from northwestern Brazil, south of the Solimões River and Amazon River, to the adjoining lowlands of Peru and Bolivia, northern Argentina, eastern Paraguay and the Gran Chaco plain. Its typical habitat is marshes and wet grassland, but in Brazil it is more associated with forest borders, gallery woodland and secondary forest. In the Paraguayan Chaco it is associated with both dry and wet marshland, and has been reported from floating masses of vegetation. [1] [4]

Ecology

Breeding starts at a young age, even while still in juvenile coat, and pregnancy rates are high. In Bolivia, pregnant females have been found in March, May, August and September, and the number of embryos varied from two to eight. [3] The Rio Mamore virus has been isolated from this species in Bolivia. [6]

Status

This is a common species over much of its wide range. It is an adaptable species, able to tolerate some habitat degradation. No particular threats have been recognised and the population seems to be stable, so the International Union for Conservation of Nature has rated its conservation status as being of least concern. [1]

Related Research Articles

<span class="mw-page-title-main">Sigmodontinae</span> Subfamily of rodents

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 count numbers at least 508. Their distribution includes much of the New World, but the genera are predominantly South American, such as brucies. They invaded South America from Central America as part of the Great American Interchange near the end of the Miocene, about 5 million years ago. Sigmodontines proceeded to diversify explosively in the formerly isolated continent. They inhabit many of the same ecological niches that the Murinae occupy in the Old World.

<i>Euryoryzomys nitidus</i> Species of rodent

Euryoryzomys nitidus, also known as the elegant oryzomys or elegant rice rat, is a rodent species in the family Cricetidae. Previously it was known as Oryzomys nitidus, but it is not closely related to Oryzomys as that genus is now constructed. Its range includes Bolivia, Brazil and Peru to the east of the Andes, in lowland tropical rainforest as well as forest in the eastern foothills of the mountains, at elevations from 50 to 2,000 m.

<i>Euryoryzomys russatus</i> Species of mammal (rodent)

Euryoryzomys russatus, also known as the russet oryzomys, russet rice rat, or big-headed rice rat, is a species of rodent in the family Cricetidae. It is a member of the genus Euryoryzomys, which was split off from Oryzomys in 2006. It was first described by Johann Andreas Wagner in 1848. It is found in southern Brazil, eastern Paraguay and northeastern Argentina. It is considered a large species in its genus, with a reddish-brown coat, long tail length, and large skull. It is a terrestrial rodent, spending its time foraging for seeds, fruits, and insects. It is listed by the IUCN as least concern, although studies have shown it to be influenced by anthropogenic disturbances. Predators consist of small members of the order Carnivora.

Oligoryzomys chacoensis, also known as the Chacoan colilargo or Chacoan pygmy rice rat, is a rodent species from South America. It is found in the Gran Chaco region of southeastern Bolivia, southwestern Brazil, Paraguay, and northeastern Argentina. Its karyotype has 2n = 58 and FNa = 74.

<i>Oligoryzomys flavescens</i> Species of rodent

Oligoryzomys flavescens, also known as the flavescent colilargo or yellow pygmy rice rat is a species of rodent in the genus Oligoryzomys of family Cricetidae. It is found in southern South America, occurring in southern Brazil, Paraguay, Uruguay, and northeastern Argentina. Its karyotype has 2n = 64-66 and FNa = 66–70.

<i>Oligoryzomys fulvescens</i> Species of rodent

Oligoryzomys fulvescens, also known as the fulvous colilargo, fulvous pygmy rice rat, or northern pygmy rice rat, is a species of rodent in the genus Oligoryzomys of family Cricetidae. It is found from southern Mexico through Central America into South America, where it occurs south into Peru and Brazil, and includes numerous synonyms, including the type species of the genus, Oryzomys navus Bangs, 1899. The taxonomy of this species is unresolved, and it may be found to contain more than one species. Its karyotype has 2n = 54-60 and FNa = 68–74.

<i>Oligoryzomys nigripes</i> Species of rodent

Oligoryzomys nigripes, also known as the black-footed colilargo or the black-footed pygmy rice rat, is a rodent in the genus Oligoryzomys of family Cricetidae. Oligoryzomys nigripes is a species that has been further divided into different sister taxa throughout history. It is found in different countries in South America. It is a large species with long ears, dark yellow to dark brown upperparts, sharply delimited from the whitish underparts, and often a pink girdle on the chest. This species of rat spends much of its life among the trees. The karyotype is 2n = 62, FNa = 78–82.

Oligoryzomys stramineus, also known as the straw-colored colilargo or straw-colored pygmy rice rat, is a species of rodent in the genus Oligoryzomys of the family Cricetidae. It occurs only in the cerrado and caatinga ecoregions of northeastern Brazil. Its karyotype has 2n = 52 and FNa = 68-70.

<i>Oligoryzomys</i> Genus of rodents

Oligoryzomys is a genus of rodents in the tribe Oryzomyini of family Cricetidae. Many species are known as pygmy rice rats or colilargos. The genus is found from Mexico to Tierra del Fuego and includes approximately 17 species.

Oligoryzomys andinus, also known as the Andean colilargo or Andean pygmy rice rat, is a species of rodent in genus Oligoryzomys of family Cricetidae. It is found in the Andes of southern Peru and western Bolivia, but may in fact include more than one species. Its karyotype has 2n = 60 and FNa = 70.

Oligoryzomys destructor, also known as Tschudi's colilargo or the destructive pygmy rice rat, is a species of rodent in the genus Oligoryzomys of family Cricetidae. It is found along the eastern Andes from southern Colombia, through Ecuador, Peru, and Bolivia into northern Argentina. Its karyotype has 2n = 60 and FNa = 76.

Oligoryzomys griseolus, also known as the grizzled colilargo or the grayish pygmy rice rat, is a species of rodent in the genus Oligoryzomys of family Cricetidae. It is found in the Andes of Venezuela and nearby Colombia. Its karyotype has 2n = 62 and FNa = 74–76.

<i>Oligoryzomys longicaudatus</i> Species of rodent

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 an outlying population in eastern Argentina. As a common species with a wide range and a stable population, the International Union for Conservation of Nature has rated this rodent as being of "least concern".

Oligoryzomys magellanicus, also known as the Patagonian colilargo and the Magellanic pygmy rice rat, is a species of rodent in the genus Oligoryzomys of the family Cricetidae. It is found in the southernmost parts of Argentina and Chile, including Tierra del Fuego and other outlying islands. Its karyotype has 2n = 54 and FNa = 66.

Oligoryzomys fornesi, also known as Fornes' colilargo, is a species of rodent in the genus Oligoryzomys of family Cricetidae. It is found from northeastern Brazil via Paraguay into northeastern Argentina. Its karyotype has 2n = 62 and FNa = 64.

Oligoryzomys moojeni is a species of rodent from South America in the genus Oligoryzomys of family Cricetidae. It is known only from central Brazil, where it is found in the cerrado and gallery forests. It is named after twentieth-century Brazilian zoologist João Moojen. Its karyotype has 2n = 70 and FNa = 84.

Oligoryzomys rupestris is a species of rodent in the genus Oligoryzomys of family Cricetidae. It is known only from eastern Brazil, where it has been found in several localities in the campos rupestres montane savanna ecoregion. This is a small Oligoryzomys species with a gray head, a yellow-brown back and gray belly and tail. Of the two karyotypic forms described by Silva & Yonenaga-Yassuda in 1998, species 1 is probably identical to O. rupestris, while the other is closely related. Its karyotype has 2n = 46 and FNa = 52.

References

  1. 1 2 3 4 5 Patton, J.; Weksler, M.; Bonvicino, C.; Percequillo, A. (2008). "Oligoryzomys microtis". IUCN Red List of Threatened Species . 2008. Retrieved 2015-08-31.
  2. ↑ Musser, G.G.; Carleton, M.D. (2005). "Superfamily Muroidea". In Wilson, D.E.; Reeder, D.M (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. p. 1143. ISBN   978-0-8018-8221-0. OCLC   62265494.
  3. 1 2 Patton, James L.; Pardiñas, Ulyses F.J.; D'Elía, Guillermo (2015). Mammals of South America, Volume 2: Rodents. University of Chicago Press. pp. 432–433. ISBN   978-0-226-16957-6.
  4. 1 2 Eisenberg, John F.; Redford, Kent H. (2000). Mammals of the Neotropics, Volume 3: Ecuador, Bolivia, Brazil. University of Chicago Press. p. 391. ISBN   978-0-226-19542-1.
  5. ↑ Weksler, M.; Bonvicino, C. R. (2005-01-03). "Taxonomy of pygmy rice rats genus Oligoryzomys Bangs, 1900 (Rodentia, Sigmodontinae) of the Brazilian Cerrado, with the description of two new species" (PDF). Arquivos do Museu Nacional, Rio de Janeiro. 63 (1): 113–130. ISSN   0365-4508. Archived from the original (PDF) on 2012-03-26. Retrieved 2012-04-22.
  6. ↑ Richter, M. H.; Hanson, J. D.; Cajimat, M. N.; Milazzo, M. L.; Fulhorst, C. F. (2010-08-05). "Geographical Range of Rio Mamoré Virus (Family Bunyaviridae, Genus Hantavirus) in Association with the Small-Eared Pygmy Rice Rat (Oligoryzomys microtis)". Vector-Borne and Zoonotic Diseases. 10 (6): 613–620. doi:10.1089/vbz.2009.0115. PMC   2979329 . PMID   20687859.
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