Golden viscacha rat | |
---|---|
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | Rodentia |
Family: | Octodontidae |
Genus: | Pipanacoctomys Mares, Braun, Barquez, and Díaz, 2000 |
Species: | P. aureus |
Binomial name | |
Pipanacoctomys aureus Mares, Braun, Barquez, and Díaz, 2000 | |
The golden viscacha rat or golden vizcacha rat (Pipanacoctomys aureus) is the single species of the genus Pipanacoctomys of the rodent family Octodontidae. [2] It has 92 chromosomes and has been regarded as tetraploid (4x = 2n). [3] 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), [3] (2x = 2n = 56) 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. [4]
The golden viscacha rat grows to a head-and-body length of about 170 millimetres (7 in) with a tufted tail of about 140 millimetres (6 in). The dorsal fur is golden-blond and the underparts are white. [5]
The species is known from Catamarca Province of northwestern Argentina, 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 plants growing there. [6] The genus is named after the locale, with “octo” being a reference to the figure-eight ridge on its cheek tooth.
The golden viscacha rat is only found within a very restricted area totalling less than 100 square kilometres (39 sq mi) 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 has rated its conservation status as "critically endangered". [1]
Ploidy is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Here sets of chromosomes refers to the number of maternal and paternal chromosome copies, respectively, in each homologous chromosome pair—the form in which chromosomes naturally exist. Somatic cells, tissues, and individual organisms can be described according to the number of sets of chromosomes present : monoploid, diploid, triploid, tetraploid, pentaploid, hexaploid, heptaploid or septaploid, etc. The generic term polyploid is often used to describe cells with three or more sets of chromosomes.
Kirchner, a surname of German origin, from the Middle High German word, 'kirchenaere'. Kirchner originated as an occupational surname for a church worker, such as a priest, church assistant or a church property administrator. Notable people with the name include:
Los Chalchaleros were an Argentine musical folkloric ensemble consisting of four men, and one of the most famous folk singers in the history of Latin America. The group was established in 1948 in the northern province of Salta. It was named after a local song-bird, the chalchalero. They left the stages and recording in 2003.
Pittier's crab-eating rat is a species of semiaquatic rodent in the family Cricetidae. It is endemic to Venezuela. The natural habitats of this species are rivers and swamps. Its karyotype has 2n = 92 and FNa = 98. This was previously thought to be the highest chromosome number known for a mammal, but it has since been found that the plains viscacha rat or red viscacha rat has 4x = 2n = 102.
The Ethiopian forest brush-furred rat or golden-footed brush-furred rat, is a species of rodent in the family Muridae. It is endemic to Ethiopia where its natural habitat is subtropical or tropical moist montane forests. It is threatened by habitat loss.
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.
Nephelomys auriventer, also known as the golden-bellied oryzomys or Ecuadorian rice rat, is a species of rodent in the genus Nephelomys of family Cricetidae. Oldfield Thomas originally described it, in 1899, as a species of Oryzomys, Oryzomys auriventer, and considered it most similar to Oryzomys aureus. In 1926, a subspecies was described from an Ecuadorian locality, Oryzomys auriventer nimbosus, and it was suggested that O. auriventer was closely related to O. albigularis. This proposal was formalized in 1961 by including O. auriventer within the species O. albigularis, but by 1976 O. auriventer was recognized again as a separate species. In 2006, Oryzomys albigularis and related species, including O. auriventer, were transferred to the new genus Nephelomys. Simultaneously, the former subspecies nimbosus was recognized as a separate species, Nephelomys nimbosus.
The chisel-toothed kangaroo rat is a species of rodent in the family Heteromyidae.
The mountain viscacha rat or mountain vizcacha rat, historically viscacha rat or vizcacha rat, is a species of rodent in the family Octodontidae. It is endemic to Argentina.
The plains viscacha rat, plains vizcacha rat, red viscacha rat, or red vizcacha rat is a species of rodent in the family Octodontidae native to Argentina. It is one of three species in the genus Tympanoctomys.
Tympanoctomys is a genus of rodent in the family Octodontidae. There are three extant species in the genus: T. barrerae, T. kirchnerorum and T. loschalchalerosorum. T. loschalchalerosorum was formerly considered to be monotypic within the genus Salinoctomys, but has been shown by genetic analysis to nest within the variation of T. barrerae.
Viscacha rats are a group of rodents in the family Octodontidae. All species are found in Argentina. They are placed in the following genera:
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.
The delicate salt flat mouse is a sigmodontine rodent species in the family Cricetidae from South America. It is the only species in the genus Salinomys. Its habitat is scrublands bordering salt flats in the Monte Desert area of central western Argentina at elevations around 400 m. The closest relatives of the species are the chaco mice (Andalgalomys).
The Chalchalero viscacha rat or Chalchalero vizcacha rat is a species of caviomorph rodent in the family Octodontidae. It was formerly considered to be monotypic within the genus Salinoctomys, but has been shown by genetic analysis to nest within Tympanoctomys, and in particular, within the variation of T. barrerae. The species is endemic to a small area of northwestern Argentina, where it lives in shrublands bordering the salt flats of the Salinas Grandes. Its diet consists of halophyte plants. It is named after an Argentine musical group, Los Chalchaleros, whose songs were popular with its discoverers.
The Tokunoshima spiny rat is a rodent found only on the island of Tokunoshima in the Satsunan Islands of Japan. Due to its small habitat, it is considered endangered. It is commonly found in the secondary and primary subtropical moist broadleaf forests of this island. The karyotype has an odd diploid number, 2n = 45. Like its relative T. osimensis, it is one of the few mammals that lack a Y chromosome and SRY gene.
The 2000s witnessed an explosion of genome sequencing and mapping in evolutionarily diverse species. While full genome sequencing of mammals is rapidly progressing, the ability to assemble and align orthologous whole chromosomal regions from more than a few species is not yet possible. The intense focus on the building of comparative maps for domestic, laboratory and agricultural (cattle) animals has traditionally been used to understand the underlying basis of disease-related and healthy phenotypes.
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.
The High Monte is a montane grasslands and shrublands ecoregion in Argentina.
The Saharan halophytics ecoregion covers a series of low-lying evaporite depressions and wetlands spread across North Africa. The depressions are characteristically saline, variously chotts or sabkhas. The plants of the areas are highly specialized to survive in the harsh environment, with many being xerophytes (drought-tolerant) and halophytes (salt-tolerant). The biodiversity of the areas has been relatively protected by their isolation, and unsuitability of alkaline soil for farming.