Class Mammalia Linnaeus, 1758 - mammals
Order Rodentia Bowdich, 1821 - rodents
Suborder Sciurognathi (Tullberg, 1899)
see Suborder Sciuromorpha Brandt, 1855
Family Muridae Batsch, 1788 - rats, mice, hamsters, voles, lemmings, and gerbils
Subfamily Sigmodontinae Wagner, 1843
Genus Sigmodon Say & Ord, 1825 - cotton rats
Sigmodon alstoni Thomas, 1880[1881]