Geographical isolation governs Neotropical fishes diversification

YAMILA P. CARDOSO; JUAN I. MONTOYA-BURGOS

Lausanne, Suiza

Conferencia; The annual meeting of the Swiss Botanical, Mycological, Systematics and Zoological Societies; 2008

Universidad de Lausanne (UNIL)

Tropical South America hosts the greatest freshwater fish diversity in the world. However, the evolutionary forces that gave rise to this high diversity are not well understood yet. Here, we assessed the role played by two evolutionary forces - geographical isolation and ecological specialization - in shaping the diversification history of the catfish Pseudancistrus brevispinis species complex (Siluriformes). Our phylogenetic analyses, based on a mitochondrial (Dloop) and two nuclear markers, included specimens coming from all the distribution range of this species complex, which is the Guiana Shield. We found several monophyletic lineages which we assign to species rank. Each of these species inhabits different, non-overlapping basins or river systems. This distribution pattern is the expected outcome of speciation via geographical isolation; finding sister species in the same river system would have supported diversification via ecological specialization. Our results are in accordance with the eventful history of Neotropical river systems which likely promoted speciation by vicariance in this region.