Abstract
True river dolphins are some of the rarest and most endangered of all vertebrates. They comprise relict evolutionary lineages of high taxonomic distinctness and conservation value, but are afforded little protection. We report the discovery of a new species of a river dolphin from the Araguaia River basin of Brazil, the first such discovery in nearly 100 years. The species is diagnosable by a series of molecular and morphological characters and diverged from its Amazonian sister taxon 2.08 million years ago. The estimated time of divergence corresponds to the separation of the Araguaia-Tocantins basin from the Amazon basin. This discovery highlights the immensity of the deficit in our knowledge of Neotropical biodiversity, as well as vulnerability of biodiversity to anthropogenic actions in an increasingly threatened landscape. We anticipate that this study will provide an impetus for the taxonomic and conservation reanalysis of other taxa shared between the Araguaia and Amazon aquatic ecosystems, as well as stimulate historical biogeographical analyses of the two basins.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Biodiversity*
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Brazil
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Cytochromes b / genetics
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DNA, Mitochondrial / chemistry
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DNA, Mitochondrial / genetics
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Dolphins / classification
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Dolphins / genetics*
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Dolphins / growth & development*
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Electron Transport Complex IV / genetics
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Endangered Species*
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Genetic Variation
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Geography
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Microsatellite Repeats / genetics
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Molecular Sequence Data
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Phylogeny
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Principal Component Analysis
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Rivers
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Sequence Analysis, DNA
Substances
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DNA, Mitochondrial
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Cytochromes b
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Electron Transport Complex IV
Grants and funding
Financial support for fieldwork and laboratory analyses was provided by grants CNPq-483408/2009-3 and 482253/2012-6, CNPq/CT Amazônia-575603/2008-9 and CNPq/FAPEAM SISBIOTA-563348/2010-0 to IPF, and the Scott Neotropical Fund and the Society for Marine Mammalogy to WG. TH and IPF were supported by a Bolsa de Pesquisa scholarship from CNPq during the study, ND by a CAPES fellowship and WG by a CNPq fellowship. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.