The delicate salt flat mouse, ''Salinomys delicatus'', (in Spanish, el ratón delicado de los salares) is a sigmodontine

rodent Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are roden ...

species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...

in the family

Cricetidae The Cricetidae are a family of rodents in the large and complex superfamily Muroidea. It includes true hamsters, voles, lemmings, muskrats, and New World rats and mice. At almost 608 species, it is the second-largest family of mammals, a ...

from

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the souther ...

. It is the only species in the genus ''Salinomys''. Its habitat is

scrubland Shrubland, scrubland, scrub, brush, or bush is a plant community characterized by vegetation dominated by shrubs, often also including grasses, herbs, and geophytes. Shrubland may either occur naturally or be the result of human activity. It ma ...

s bordering salt flats (such as those of the

Salinas Grandes The Salinas Grandes ('Salina' is a spanish word for salt flat) is a large salt flat in central-northern Argentina, spanning the borders of four provinces (Córdoba, Catamarca, La Rioja and Santiago del Estero), at an average altitude of above s ...

) in the

Monte Desert The Monte Desert is a South American desert, lying entirely within Argentina and covering approximately the submontane areas of Catamarca, La Rioja, San Juan, San Luis and Mendoza Provinces, plus the western half of La Pampa Province and the ext ...

area of central western

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, t ...

at elevations around 400 m. The closest relatives of the species are the chaco mice (''Andalgalomys'').Steppan, S.J.; Ramirez, O.; Banbury, J.; ''et al.'' 2007. A molecular reappraisal of the systematics of the leaf-eared mice ''Phyllotis'' and their relatives. In: Kelt, D.A., E.P. Lessa, J. Salazar-Bravo & J.L. Patton (eds.), The Quintessential Naturalist: Honoring the Life and Legacy of Oliver P. Pearson. University of California Publications in Zoology. Volume 134, pp. 799–826. University of California Press, Berkeley. http://escholarship.org/uc/item/9g62053v#page-812

Karyotype

Its

karyotype A karyotype is the general appearance of the complete set of metaphase chromosomes in the cells of a species or in an individual organism, mainly including their sizes, numbers, and shapes. Karyotyping is the process by which a karyotype is disce ...

has 2n = 18 and FN = 32 in females but has 2n = 19 in males. Due to an X- autosome

translocation Translocation may refer to: * Chromosomal translocation, a chromosome abnormality caused by rearrangement of parts ** Robertsonian translocation, a chromosomal rearrangement in pairs 13, 14, 15, 21, and 22 ** Nonreciprocal translocation, transfer ...

, ''S. delicatus'' has an XY₁Y₂ sex chromosome system, rare in mammals. During meiotic prophase, a male's X and two Y chromosomes form a trivalent. The female value of 18 is the lowest diploid number of any species in the tribe Phyllotini. Given that close relative '' Andalgalomys pearsoni'' has the highest known diploid number (78) of the tribe, it appears that major chromosome restructuring occurred during the evolution of the ''Andalgalomys''-''Salinomys'' clade.

Conservation status

While not formally assessing its conservation status, the IUCN has stated, "This species occurs in a very narrow range of ecological requirements (salt flats) which are severely fragmented and which could be threatened by human disturbance."

References

Mammals of Argentina Phyllotini Mammals described in 1995 {{Cricetidae-stub