Mountain viscacha rat

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Mountain viscacha rat
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Rodentia
Family: Octodontidae
Genus: Octomys
Thomas, 1920
Species:
O. mimax
Binomial name
Octomys mimax
Thomas, 1920

The mountain viscacha rat or mountain vizcacha rat (Octomys mimax), historically viscacha rat or vizcacha rat, is a species of rodent in the family Octodontidae. [2] It is endemic to Argentina. [1]

Contents

It is the only living species within the genus Octomys. [3] This diploid genus (2n = 56) may be ancestral to the two unusual suspected tetraploid species Tympanoctomys barrerae and Pipanacoctomys aureus . [4] However, some genetic studies have rejected any polyploidism in mammals as unlikely, and suggests that amplification and dispersion of repetitive sequences best explain the large genome size. [5]

Description

The mountain viscacha rat is a rat-like animal with a head-body length of about 11 to 18 centimetres (4.3 to 7.1 in) and weighing from 85 to 121 grams (3.0 to 4.3 oz). The feet are relatively long, while the tail measures 12 to 16 centimetres (4.7 to 6.3 in). It has light brown fur with white underparts and a bushy tail. [3]

Unusual features of the viscacha rat include greatly enlarged auditory bullae, and the presence of numerous whiskers on the roof of the mouth behind the incisor teeth. The exact function of the whiskers is unclear, but they may enable the animal to sense the position of food inside the mouth. [6]

Distribution and habitat

Mountain viscacha rats are found only in the Monte Desert region of northwestern Argentina, [1] specifically in the provinces of Catamarca, La Rioja, San Luis, San Juan. They inhabit rocky desert and semidesert environments up to 800 metres (2,600 ft) above sea level. [3]

Behaviour

Mountain viscacha rats are nocturnal and solitary, spending the day sheltering in rock crevices. Although it does not construct burrows, it may place pieces of cactus close to crevice entrances to help protect against predators. [3] Individuals occupy large home ranges of around 12,300 square metres (3.0 acres), often overlapping with those of their neighbours. [7] They are herbivorous, feeding on the leaves and seeds of shrubland vegetation. During the dry season, their diet consists largely of the leaves of Prosopis trees, supplemented by caperbushes and alkaliweeds. During the wet season, they eat more seeds and fruit, including those from plants such as Maytenus and boxthorn shrubs. [3]

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<i>Abrocoma</i> Genus of rodents

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The golden viscacha rat or golden vizcacha rat is the single species of the genus Pipanacoctomys of the rodent family Octodontidae. It has 92 chromosomes and has been regarded as tetraploid. This octodontid and its sister-species, the plains viscacha rat, may have arisen from the diploid mountain viscacha rat, as a result of the doubling and subsequent loss of some chromosomes. However, some genetic studies have rejected any polyploidism in mammals as unlikely, and suggest that amplification and dispersion of repetitive sequences best explain the large genome size.

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<i>Tympanoctomys</i> Genus of rodents

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Kirchner's viscacha rat or Kirchner's vizcacha rat is a species of rodent in the family Octodontidae described in 2014. It is one of three species in the genus Tympanoctomys. That species is endemic to Chubut Province in the central western Argentina, where it has a fragmented range. Its natural habitat is desert scrubland, dunes and salt flats, where it eats halophyte plants. It is a solitary, nocturnal rodent that constructs large mounds with complex burrows. The species was named in honor of both Cristina Fernández de Kirchner and Néstor Kirchner, presidents of Argentina.

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References

  1. 1 2 3 Roach, N. (2016). "Octomys mimax". IUCN Red List of Threatened Species . 2016: e.T15093A78321632. doi: 10.2305/IUCN.UK.2016-2.RLTS.T15093A78321632.en . Retrieved 11 November 2021.
  2. ↑ Woods, C.A.; Kilpatrick, C.W. (2005). "Infraorder Hystricognathi". 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. 1572. ISBN   978-0-8018-8221-0. OCLC   62265494.
  3. 1 2 3 4 5 Sobrero, R.; et al. (2010). "Octomys mimax (Rodentia: Octodontidae)". Mammalian Species. 42 (1): 49–57. doi: 10.1644/853.1 .[ dead link ]
  4. ↑ Gallardo, M.H. (2006). "Molecular cytogenetics and allotetraploidy in the red vizcacha rat, Tympanoctomys barrerae (Rodentia, Octodontidae)]". Genomics. 88 (2): 214–221. doi: 10.1016/j.ygeno.2006.02.010 . PMID   16580173.
  5. ↑ Svartman, Marta; Stone, Gary; Stanyon, Roscoe (2005). "Molecular cytogenetics discards polyploidy in mammals". Genomics. 85 (4): 425–30. doi:10.1016/j.ygeno.2004.12.004. PMID   15780745.
  6. ↑ Berman, S.L. (2003). "A desert octodontid rodent, Tympanoctomys barrerae, uses modified hairs for stripping epidermal tissue from leaves of halophytic plants". Journal of Morphology. 257 (1): 53–61. doi:10.1002/jmor.10115. PMID   12740896. S2CID   25765293.
  7. ↑ Ebensperger, L.A.; et al. (2008). "Activity, range areas, and nesting patterns in the viscacha rat, Octomys mimax". Journal of Arid Environments. 72 (7): 1174–1183. Bibcode:2008JArEn..72.1174E. doi:10.1016/j.jaridenv.2008.02.003.
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