We sequenced mitochondrial genes of otter (Lontra longicaudis and Pteronura brasiliensis) and dolphin (Inia sp.) species to provide new systematics data and to test hypotheses that offer explanations as to the Amazon’s biodiversity. Four of the 11 hypotheses tested --Paleogeography (PH), Recent Lagoon (RLH), Hydrogeological Recent Change (HRCH), and Refugia (RH)-- support the evolution of these three species. As part of this comparative phylogenetic study, we also considered the degree of water dependence of each species. For the least water dependent of the three species, L. longicaudis, only HRCH and RH had an influence on genetic structure, although it was relatively minor. For the more water dependent otter species, P. brasiliensis, our analyses stressed the significance of a single PH event along with two lesser important PH events. However, its gene diversification basically occurred during the Pleistocene and our analyses did detect a relatively small influence of HRCH and RH. For the completely water dependent species, Inia, we detected two significant PH events. Its genetic structure was considerably more developed than in either otter species, although the Pleistocene was a very important period of genetic diversification for the pink river dolphins (HRCH and RLH). Each species has ancestors with different geographical origins and genomes with different capacities to colonize—making it difficult to rely on a generalized hypothesis to understand the origins of the Amazon’s extremely rich biodiversity.
Bibliographical noteFunding Information:
Economic resources to carry out this study were obtained from Colciencias (Grant 1203-09-11239; Geographical population structure and genetic diversity of two river dolphin species, Inia boliviensis and Inia geoffrensis , using molecular markers) and the Fondo para la Accion Ambiental (US-Aid) (120108-E0102141; Structure and Genetic Conservation of river dolphins, Inia and Sotalia , in the Amazon and Orinoco basins). Many thanks go to Dr. Diana Alvarez (Colombia), Luisa Castellanos (Colombia), Ariel Rodriguez (Colombia), Esteban Pay?n (Colombia), Carlos Vergara (Colombia), Maria Fernanda G?mez (Colombia), Nathal? Romero (Colombia), Mariana Escovar (La Paz, Bolivia), Juanito, and Angelito (Iquitos, Peru), and to Isaias, and his sons (Requena, Peru), who participated in the capture of the pink river dolphins herein studied. Also, diverse Peruvian Indian communities collaborated with our pink river dolphin and otter captures throughout the Peruvian rivers (Bora, Ocaina, Shipigo-Comibo, Capanahua, Angoteros, Orej?n, Cocama, Kishuarana, and Alamas) and also to diverse Bolivian communities, who helped to capture dolphins and otters throughout the Mamor? river and other Bolivian Amazon tributaries (Sirion?, Canichana, Cayubaba and Chacobo). Dr. Fernando Trujillo (Omacha Foundation) gently offered some dolphin samples from the Colombian Orinoco, and Amazon. Additional thanks go to Hugo G?lvez (Iquitos, Per?), and Armando Castellanos (Quito, Ecuador) to collaborate in collection permits in both countries. Similarly, many thanks go to the Bolivian, Peruvian and Ecuadorian Ministry of Environment, to the Direcci?n General de Biodiversidad and CITES from Bolivia, PRODUCE, Direcci?n Nacional de Extracci?n and Procesamiento Pesquero and to the Instituto Nacional de Recursos Naturales (INRENA) from Per? for their role in facilitating the obtainment of the collection permits. Special thanks goes to the Colecci?n Boliviana de Fauna (Dr. Julieta Vargas) in La Paz (Bolivia). Thanks also to the Fundaci?n Sociedad Portuaria de Santa Marta (Colombia) for its logistical support.
- Amazon biodiversity
- Mitochondrial markers