Class Mammalia Linnaeus, 1758 - mammals Order Rodentia Bowdich, 1821 - rodents Suborder Hystricognathi Tullberg, 1899 see Infraorder Hystricognathi Tullberg, 1899 Family Chinchillidae Bennett, 1833 - viscachas and chinchillas Genus Lagostomus Brookes, 1828 - plains viscacha Lagostomus maximus (Desmarest, 1817) - plains viscacha