Biogeography, habitat transitions and hybridization in a radiation of South American silverside fishes revealed by mitochondrial and genomic RAD data.
Hughes, L. C., Cardoso, Y. P., Sommer, J. A., Cifuentes, R., Cuello, M., Somoza, G. M., Gonzalez-Castro, M., Malabarba, L. R., Cussac, V., Habit, E. M., Betancur, R. R. and Orti, G.
Department of Biological Sciences, George Washington University, Washington, DC, USA.
Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Laboratorio de Sistematica y Biologia Evolutiva-CONICET, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Argentina.
Vice Chancellor for Research Office, University of Nebraska Medical Center, Omaha, NE, USA.
Departmento de Sistemas Acuaticos, Facultad de Ciencias Ambientales y Centro EULA, Universidad de Concepcion y Centro de Investigaciones en Ecosistemas Patagonicos, Concepcion, Chile.
Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata-CONICET, Buenos Aires, Argentina.
Instituto Tecnologico de Chascomus (CONICET-UNSAM), Chascomus, Buenos Aires, Argentina.
Grupo de Biotaxonomia Morfologica y molecular de peces, IIMyC-CONICET, Universidad Nacional de Mar del Plata, Argentina.
Departamento de Zoologia, Instituto de Biociencias, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
Centro Cientifico Tecnologico CONICET Patagonia Norte - Universidad Nacional del Comahue, Bariloche, Rio Negro, Argentina.
Department of Biology, University of Oklahoma, Norman, OK, USA.
Rivers and lake systems in the southern cone of South America have been widely influenced by historic glaciations events, carrying important implications on the evolution of aquatic organisms including prompting transitions between marine and freshwater habitats and by triggering hybridization among incipient species via waterway connectivity and stream capture events. Silverside fishes (Odontesthes) in the region comprise a radiation of 19 marine and freshwater species that have been hypothesized on the basis of morphological or mitochondrial DNA data to have either transitioned repeatedly into continental waters from the sea or colonized marine habitats following freshwater diversification. New ddRAD data presented here provide a robust framework to investigate biogeographic history and habitat transitions in Odontesthes. We show that Odontesthes silversides originally diversified in the Pacific but independently colonized the Atlantic three times, producing three independent marine-to-freshwater transitions. Our results also indicate recent introgression of marine mitochondrial haplotypes into two freshwater clades, with more recurring instances of hybridization among Atlantic- versus. Pacific-slope species. In Pacific freshwater drainages, hybridization with a marine species appears to be geographically isolated and may be related to glaciation events. Substantial structural differences of estuarine gradients between these two geographic areas may have influenced the frequency, intensity, and evolutionary effects of hybridization events.
Molecular Ecology : en prensa (2020)