Two new genera and species of halophytic desert mammals from isolated salt flats in Argentina

Abstract

Two new genera and species of rodents are described from isolated salt pans in far northwestem Argentina. Both are members of the hystricognath family, Octodontidae. The two new genera are both specialized for life in zones of high salinity with halophytic vegetation growing at the periphery of saline flats. The new taxa are most closely related to Tympanoctomys barrerae, the Red Vizcacha Rat, which occurs in salt flats in central Argentina further to the south. One of the new mammals is restricted to an isolated salt flat lying within an enclosed bolsón in Catamarca Province. The other is limited to habitat islands that occur within the vast Salinas Grandes (great salt flat) ofLa Rioja Province in central Argentina. Taxonomic descriptions are included, as is information on relationships within the family Octodontidae. The biogeographic history of the group, and an evolutionary scenario for the evolution ofthe two new genera, are also discussed.