Amphibia, Anura, Bufonidae, Rhinella atacamensis : altitudinal distribution extension, new records and geographic distribution map

Amphibian distribution patterns in Chile have been strongly influenced by the formation of physiographic and climatic barriers, mainly the Atacama desert in the north, the Andes mountains in the east, and cold Patagonian steppes in the southeast (Cei 1962; Veloso and Navarro 1988). Other fundamental factor that has influenced the distribution of these organisms in Chile, as well as that of other groups of plants and animals is a climatic gradient characterized by a sustained increment of precipitation level from north to south (Di Castri 1968; Veloso 2006). Along this gradient, the highest degree of species richness among the amphibians is concentrated between 38° and 46° S (Veloso and Navarro 1988; Ortiz and Diaz-Paez 2006), a zone dominated by humid temperate forests (Gajardo 1995). Northward, temperate forests give way to the sclerophyllic forests and shrublands of central Chile, which gradually gives way to the Atacama desert at about 28° S. The vegetational changes mentioned may be directly related to the gradual decrease in the richness of the amphibian fauna progressing northward, both in the coast and in the interior of the country (Cei 1962; Veloso 2006). The situation is different in the Andes, since northward from 23°47' S, the region corresponding to the Chilean Altiplano, where populations of Rhinella spinulosa, Pleurodema marmorata and various species of the genus Telmatobius may be found (Veloso et al. 1982; Formas et al. 2005). In contrast, there are no records of amphibian populations above 2000 m between 23°47' S (Tilomonte, which is known to be the southern limit of the Altiplano populations of R. spinulosa in Chile, Mendez et al., unpublished data) and 31°45' S (Vega Piuquenes, a locality where P. thaul was recently recorded, Correa et al. 2007).