Darwin's fishes: phylogeography of Galápagos Islands reef fishes

AbstrAct.—Working in the Galápagos Islands and surrounding areas, we examined the relationship between population structure, a precursor to allopatric speciation, in species of reef fishes that exhibit different life history traits and three types of distributions in a nested setting: endemic (restricted to the Galápagos Islands), insular (Galápagos and neighboring islands), and Panamic (tropical eastern Pacific). We used a combination of population structure and coalescent approaches to assess the degree of genetic population structure in the three groups of fish species. In addition, we evaluated the level of inter-island genetic diversity in endemic species to determine if Galápagos fishes, like their terrestrial counterparts, could be used as a system to study allopatric speciation in the sea. We found that in general, there was no correlation between distribution