The Plains Viscacha Rat or Red Vizcacha Rat (Tympanoctomys barrerae) is a species of rodent

Rodent

Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....

 in the family Octodontidae

Octodontidae

The Octodontidae are a family of rodents, restricted to south-western South America. Thirteen species of octodontid are recognised, arranged in nine genera. The best known species is the Degu, Octodon degus....

. It is monotypic

Monotypic

In biology, a monotypic taxon is a taxonomic group with only one biological type. The term's usage differs slightly between botany and zoology. The term monotypic has a separate use in conservation biology, monotypic habitat, regarding species habitat conversion eliminating biodiversity and...

 within the genus Tympanoctomys. It is endemic to central western Argentina

Argentina

Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...

, where it has a fragmented range. Its natural habitat

Habitat

* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...

 is desert scrubland

Deserts and xeric shrublands

Deserts and xeric shrublands is a biome characterized by, relating to, or requiring only a small amount of moisture.-Definition and occurrence:...

, dunes and salt flats, where it eats halophyte

Halophyte

A halophyte is a plant that grows where it is affected by salinity in the root area or by salt spray, such as in saline semi-deserts, mangrove swamps, marshes and sloughs, and seashores. An example of a halophyte is the salt marsh grass Spartina alterniflora . Relatively few plant species are...

 plants. It is a solitary, nocturnal rodent that constructs large mounds with complex burrows. This species of rodent is unusual because it is tetraploid (4x

Ploidy

Ploidy is the number of sets of chromosomes in a biological cell.Human sex cells have one complete set of chromosomes from the male or female parent. Sex cells, also called gametes, combine to produce somatic cells. Somatic cells, therefore, have twice as many chromosomes. The haploid number is...

 = 2n = 102). Scientists think that this species may have arisen when an ancestor (very possibly the Mountain Vizcacha Rat

Viscacha Rat

The viscacha rat , or mountain viscacha rat, is a species of rodent in the family Octodontidae. It is endemic to Chile and Argentina.It is the only living species within the genus Octomys...

, Octomys mimax, chromosome count 2x = 2n = 56) doubled its chromosome number, presumably by errors in mitosis or meiosis within the animal's reproductive organs.
Research has found another closely related species Pipanacoctomys aureus

Pipanacoctomys

The Golden Vizcacha Rat ' is the single species of the genus Pipanacoctomys of the rodent family Octodontidae. This animal is tetraploid and has 4x = 2n = 92 chromosomes...

which is also tetraploid and appears to be the sister species of T. barrerae.

The species is threatened by destruction of its fragmented and restricted habitat.