Its karyotype has 2n = 18 and FN = 32 in females[7] but has 2n = 19 in males.[8] Due to an X-autosometranslocation, S. delicatus has an XY1Y2sex chromosome system, rare in mammals.[8] During meiotic prophase, a male's X and two Y chromosomes form a trivalent.[8] 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.[8]
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."[1]
^Braun, Janet K.; Mares, Michael A. (May 1995). "A new genus and species of phyllotine rodent (Rodentia: Muridae: Sigmodontinae: Phyllotini) from South America". Journal of Mammalogy. 76 (2). American Society of Mammalogists: 504–521. doi:10.2307/1382359. JSTOR1382359.
^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