Origen de ranas de alta montaña: Un estudio filogenético del género Pristimantis en la Cordillera Oriental de Colombia.

Abstract

Mountain ecosystems currently contain half of the biodiversity "hotspots", specifically tropical mountains are home to an extraordinary and surprising wealth of species, even though they cover only 27% of the Earth’s surface. The Eastern Cordillera is a complex mountain system that has presented an extensive orogenic history in addition to being influenced by paleoclimatic events, which have facilitated the diversification and accumulation of endemic species in this Andean region. We used a phylogenetic framework to evaluate the possible diversification processes that have occurred in frogs of the genus Pristimantis present in the Eastern Cordillera based on 6 genetic regions, four mitochondrial genes (IOC,16s, 12s and Cytb) and two nuclear genes (Rag-1 y Tyr). We carry out a phylogenetic reconstruction and estimation of the divergence times to evaluate by means of the time scale the possible historical processes that have promoted the diversification of high mountain frogs taking into account two main historical events: the rise of the Eastern Range and the climatic oscillations in the Pleistocene. Additionally, we evaluated the effect of the elevation gradient on the distribution of species and the possible speciation process that has been generated within this group of vertebrates in the Andean mountains. The species of Pristimantis present in the Eastern Cordillera originated in the Miocene which is associated with the times of greater construction of Andean mountains, however, the diversification of the genus extended to the Pleistocene indicating that the oscillations that occurred in the glacial-interglacial period could have influenced the diversification of the youngest species. The species of Pristimantis present in the Eastern Cordillera occur mainly in alopatria. Although the hypothesis that some elevation replacements evidenced in Pristimantis may reflect parapathic speciation along mountain slopes cannot be completely rejected, It is concluded that speciation in these frogs occurs predominantly in allopatry within elevation zones, with most elevation replacements resulting from secondary contact of formerly allopathic lineages.