The Casiquiare river acts as a corridor between the Amazonas and Orinoco river basins: biogeographic analysis of the genus Cichla |
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Authors: | S. C. WILLIS M. NUNES C. G. MONTAÑA I. P. FARIAS G. ORTÍ N. R. LOVEJOY |
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Affiliation: | 1. School of Biological Sciences, 348 Manter Hall, University of Nebraska‐Lincoln, Lincoln, NE 68588, USA;2. Laboratório de Evolu??o e Genética Animal, ICB, Universidade Federal do Amazonas, Estrada do Contorno 3000, Manaus, AM, Brazil;3. Museo de Ciências Naturales, Universidad Nacional de Los Llanos, 3310 Mesa de Cavacas, Guanare, Venezuela;4. Department of Biology, The George Washington University, 2023?G St. NW Suite 340, Washington, DC 20052, USA;5. Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON, Canada M1C 1A4 |
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Abstract: | The Casiquiare River is a unique biogeographic corridor between the Orinoco and Amazonas basins. We investigated the importance of this connection for Neotropical fishes using peacock cichlids (Cichla spp.) as a model system. We tested whether the Casiquiare provides a conduit for gene flow between contemporary populations, and investigated the origin of biogeographic distributions that span the Casiquiare. Using sequences from the mitochondrial control region of three focal species (C. temensis, C. monoculus, and C. orinocensis) whose distributions include the Amazonas, Orinoco, and Casiquiare, we constructed maximum likelihood phylograms of haplotypes and analyzed the populations under an isolation‐with‐migration coalescent model. Our analyses suggest that populations of all three species have experienced some degree of gene flow via the Casiquiare. We also generated a mitochondrial genealogy of all Cichla species using >2000 bp and performed a dispersal‐vicariance analysis (DIVA) to reconstruct the historical biogeography of the genus. This analysis, when combined with the intraspecific results, supports two instances of dispersal from the Amazonas to the Orinoco. Thus, our results support the idea that the Casiquiare connection is important across temporal scales, facilitating both gene flow and the dispersal and range expansion of species. |
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Keywords: | Cichla Neotropics peacock bass phylogeography vicariance |
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