Using phylogenies to trace the geographical signal of diversification

Editor: Franc ois Guilhaumon Abstract Aim: Current geographical distributions in conjunction with species-level phylogenies have been viewed as offering an enormous potential for investigating the causes of speciation. However, many authors have concluded that species ranges are too dynamic to retain the historical signal of the speciation processes. We develop an approach to explore the extent to which range changes have erased the geographical signal of speciation in the current distribution of species lineages, and whether phylogenetic relationships among species and their current distributions can provide information regarding the geography of diversification. As case studies we used different lineages of aquatic Coleoptera. Location: Western Palaearctic. Methods: We first assessed the persistence of a geographical signal in the current distribution of a clade from the association between evolutionary relationships and geography using Mantel tests. We then tested two potential scenarios of diversification using bivariate plots of the geographical distance between the centroids of the species ranges and phylogenetic distances, and an assessment of the match between the observed geographical distribution and the phylogenetic topology. We used as a study system a set of 10 monophyletic lineages of water beetles with different ecological characteristics (either standing water, running water or a mixture of both habitat types). Results: Our results point to a common pattern of geographically conserved ranges where current species seem to have originated through range fragmentation of formerly more widespread species. Exclusive standing water clades showed a much weaker signal, as expected from their higher mobility, which erases the geographical signal at much shorter temporal scales. Main conclusions: Overall, our findings show that for at least some lineages it is possible to obtain strong evidence of stasis of the geographical ranges of species, as well as information regarding the diversification process, through the study of their current distributions and phylogenetic relationships.