Drainage Network Morphology Influences Population Structure and Gene Flow of the Andean Water Frog Telmatobius pefauri (Anura: Telmatobiidae) of the Atacama Desert, Northern Chile.

Abstract

Desert aquatic species tend to show isolated and disconnected populations due to the fragmented nature of their environment; however, the morphology of the hydrographic basins, added to humid climatic conditions, can allow dispersion between populations in a desert environment. The aim of this study was to examine the influence of drainage morphology on the phylogeographic structure and gene flow (using a fragment of the mitochondrial control region and seven microsatellite markers) of an endemic taxon of the Andean Precordillera in the Atacama Desert, the aquatic frog species Telmatobius pefauri. We detected three genetic clusters, one cluster present in the Lluta basin and two clusters in the Azapa basin. The results suggest that the genetic structure of T. pefauri is influenced by the morphology of the drainage network formed by the Lluta and Azapa basins: localities present in the same drainage, Tignamar River, were less differentiated and showed higher gene flow levels among them than to their conspecifics belonging to the other drainage in the same basin, Seco River, and those belonging to the other basin, Lluta basin. Gene flow patterns and genetic structure to populations Atacama Andean aquatic taxa would be influenced by basin morphology, with dispersion being stimulated in dendritic hydrological systems, and eventually by humid climatic (regional) events.