The golden viscacha rat or golden vizcacha rat (''Pipanacoctomys aureus'') is the single species of the genus ''Pipanacoctomys'' of the rodent

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Octodontidae Octodontidae is a family of rodents, restricted to southwestern South America. Fourteen species of octodontid are recognised, arranged in seven genera. The best known species is the common degu, ''Octodon degus''. Octodontids are medium-sized ...

. It has 92

chromosome A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are ...

s and has been regarded as

tetraploid Polyploidy is a condition in which the cells of an organism have more than one pair of ( homologous) chromosomes. Most species whose cells have nuclei (eukaryotes) are diploid, meaning they have two sets of chromosomes, where each set contains ...

( 4x = 2n).Gallardo, M. H. ''et al.'' (2004).
Whole-genome duplications in South American desert rodents (Octodontidae)
. ''Biological Journal of the Linnean Society, 82'', 443-451. This octodontid and its sister-species, the plains viscacha rat (''Tympanoctomys barrerae'') (2n = 102), may have arisen from the diploid mountain viscacha rat (''Octomys mimax''), (2x = 2n = 56) as a result of the doubling and subsequent loss of some chromosomes. However, some genetic studies have rejected any

polyploid Polyploidy is a condition in which the cells of an organism have more than one pair of ( homologous) chromosomes. Most species whose cells have nuclei ( eukaryotes) are diploid, meaning they have two sets of chromosomes, where each set contain ...

ism in mammals as unlikely, and suggest that amplification and dispersion of repetitive sequences best explain the large genome size.

Description

The golden viscacha rat grows to a head-and-body length of about with a tufted tail of about . The dorsal fur is golden-blond and the underparts are white.

Distribution and habitat

The species is known from Catamarca Province of northwestern

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 ...

, where specimens are known only from the Salar de Pipanaco, a salt flat. This habitat consists largely of low, salt-loving shrubs, and the soil consists of sand with high levels of salt. It feeds on the

halophytic A halophyte is a salt-tolerant plant that grows in soil or waters of high salinity, coming into contact with saline water through its roots or by salt spray, such as in saline semi-deserts, mangrove swamps, marshes and sloughs and seashores. ...

plants growing there. The genus is named after the locale, with “octo” being a reference to the figure-eight ridge on its cheek

tooth A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, t ...

Status

The golden viscacha rat is only found within a very restricted area totalling less than and it actually occupies only about one tenth of that area. It lives among the salt-loving plants that live between the salt pans and the desert. It is threatened by conversion of its very restricted habitat to agricultural use, for the growing of olives, and its population trend is downwards. 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 nat ...

has rated its conservation status as " critically endangered".

References

{{Taxonbar, from=Q984226 Octodontidae Mammals described in 2000 Mammals of Argentina Endemic fauna of Argentina Taxobox binomials not recognized by IUCN High Monte