Three fishes in one: cryptic species in an Amazonian floodplain forest specialist

摘要: Accurately describing biodiversity in tropical regions such as Amazonia is difficult because of insufficient morphological inventories and the lack studies on distribution genetic diversity. Aquatic organisms from Amazonian flooded forests are generally expected to move laterally along during annual inundation cycle, a behaviour that should promote admixture populations reduce within-drainage speciation. We used an unprecedented fine-scale sampling effort multiple DNA markers quantify region-wide population differentiation floodplain forest specialist, black-wing hatchet fish Carnegiella marthae (Myers, 1927). Our study revealed three previously unsuspected ancient cryptic species Rio Negro (RNF), central Amazonia. Two produce occasional first-generation hybrids. The third rarer species, although found extreme sympatry with another appears be reproductively isolated, also differs external morphology dentition. findings have important implications for guiding conservation management C. harvested commercially RNF ornamental fishery. They suggest diversity ichthyofauna vastly underestimated, including landscapes lacking contemporary barriers account divergence © 2011 Linnean Society London, Biological Journal Society, 2011, 102, 391‐403.