Looking to the past and the future: were the Madeira River rapids a geographical barrier to the boto (Cetacea: Iniidae)?

  title={Looking to the past and the future: were the Madeira River rapids a geographical barrier to the boto (Cetacea: Iniidae)?},
  author={Waleska Gravena and Izeni Pires Farias and Maria Nazareth Ferreira da Silva and Vera M.F. da Silva and Tom{\'a}{\vs} Hrbek},
  journal={Conservation Genetics},
In the present study we tested if a series of 18 rapids on the upper Madeira River form an effective barrier to gene flow, and in particular if they delimit the distribution of the boto Inia boliviensis—which it is believed to occurs only in the Bolivian sub-basin, above the rapids—and I. geoffrensis, which occurs throughout the Amazon basin and below the upper Madeira River rapids. We analyzed 125 individuals from the Madeira River basin sampled from upstream and downstream of the rapids. As… 

Living between rapids: genetic structure and hybridization in botos (Cetacea: Iniidae: Inia spp.) of the Madeira River, Brazil

A large number of dolphins collected in the rapids region above the Teotonio waterfall belong to a management unit (MU) distinct from the I. boliviensis MU occupying Bolivian rivers, and population structuring between these localities is investigated.

On the brink of isolation: Population estimates of the Araguaian river dolphin in a human-impacted region in Brazil

The findings suggest that the Araguaian boto population has been impacted by the construction of the Tucuruí dam, the world’s fifth largest hydropower dam.

Four decades of research on distribution and abundance of the Bolivian river dolphin Inia geoffrensis boliviensis

The Bolivian river dolphin, known locally as the bufeo, is one of 4 species of river dolphin in South America. Endemic to the upper basin of the Madeira in the Bolivian Amazon region, the species is

The biosonar of the boto: evidence of differences among species of river dolphins (Inia spp.) from the Amazon

Differences in acoustical parameters of clicks are mainly related to the animal’s internal morphology, thus this study may potentially support with information for the species-level classification mostly of I. araguaiaensis (the Araguaian boto).

Population genetic structure of the Amazonian black flannelmouth characin (Characiformes, Prochilodontidae: Prochilodus nigricans Spix & Agassiz, 1829): contemporary and historical gene flow of a migratory and abundant fishery species

The results of the analysis of molecular variance revealed that a large part of the genetic variation occurred within the populations analyzed, and suggested that the upper Madeira River and Purus Rivers had diverged genetically from the other samples, indicating restricted gene flow among these areas, while sites within the remaining range exhibited relatively little population structure.

New genetic data extend the range of river dolphins Inia in the Amazon Delta

The northernmost records of Inia araguaiaensis, a newly described river dolphin that occurs in the Araguaian and Tocantins Rivers, in central-eastern Brazil, are reported to establish the actual distribution limits of this aquatic mammal for conservation purposes.

Risks of dam construction for South American river dolphins: a case study of the Tapajós River

Low abundances of river dolphins compared to other Amazon rivers are identified and boto may not be sustainable at a population level, due primarily to population fragmentation which would result from the construc- tion of the proposed dams.

Population estimate and identification of major conservation threats for the river dolphin (Inia geoffrensis humboldtiana) at the Colombian Orinoquia

South American sub-continent, housed the largest diversity of river dolphins on the planet, here there are two species in the genus Sotalia and three species in the genus Inia. Tonina, present on the

A Multilocus Approach to Understanding Historical and Contemporary Demography of the Keystone Floodplain Species Colossoma macropomum (Teleostei: Characiformes)

Demographic analyzes of mitochondrial genes indicated population expansion in the Brazilian and Bolivian Amazon basins during the Pleistocene, and microsatellite data indicated a population reduction during the Holocene shows that the historical demography of C. macropomum is highly dynamic.

Aquatic Mammals of the Amazon: A Review of Gene Diversity, Population Structure and Phylogeography Applied to Conservation

There are five types of aquatic mammals in the Amazon river basin. Two are semi-aquatic: the giant river otter (Pteronura brasiliensis) and the Neotropical otter (Lontra longicaudis); and three are



Molecular identification of evolutionarily significant units in the Amazon River dolphin Inia sp. (Cetacea: Iniidae).

The results support the proposal to subdivide the Inia genus into at least two evolutionarily significant units: one confined to the Bolivian river basin and the other widely distributed across the Amazon and Orinoco basins.

The Amazon River system as an ecological barrier driving genetic differentiation of the pink dolphin (Inia geoffrensis)

Both mtDNA and microsatellite data indicate a major demographic collapse within Brazil in the late Pleistocene, and it is estimated that the diversification of the Inia sp.

Population, density estimates, and conservation of river dolphins (Inia and Sotalia) in the Amazon and Orinoco river basins

This study is part of an on-going effort to evaluate and monitor river dolphin populations in South America. It comprises the largest initiative to estimate population size and densities of Inia and

A New Species of River Dolphin from Brazil or: How Little Do We Know Our Biodiversity

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, is reported, which is diagnosable by a series of molecular and morphological characters and diverged from its Amazonian sister taxon 2.08 million years ago.

Evolution of river dolphins

It is suggested that ancestors of the four extant river dolphin lineages colonized the shallow epicontinental seas that inundated the Amazon, Paraná, Yangtze and Indo–Gangetic river basins, subsequently remaining in these extensive waterways during their transition to freshwater with the Late Neogene trend of sea–level lowering.

Simultaneous delimitation of species and quantification of interspecific hybridization in Amazonian peacock cichlids (genus cichla) using multi-locus data

While several instances of introgressive hybridization were observed in anthropogenically altered habitats, most were found in undisturbed natural habitats, suggesting that introgression is a natural but ephemeral part of the evolution of many tropical species.

First human-caused extinction of a cetacean species?

The Yangtze River dolphin or baiji is likely to be extinct, probably due to unsustainable by-catch in local fisheries, which represents the first global extinction of a large vertebrate for over 50 years.

Effects of natural rapids and waterfalls on fish assemblage structure in the Madeira River (Amazon Basin)

–  Habitat connectivity is considered a central factor shaping ecological communities, and the effects of waterway barriers such as natural waterfalls on fish movements are expected to produce

Estimating population structure under nonequilibrium conditions in a conservation context: continent‐wide population genetics of the giant Amazon river turtle, Podocnemis expansa (Chelonia; Podocnemididae)

Overall, the DNA data show that P. expansa populations lack a long history of genetic differentiation, but that each major tributary currently forms a semi‐isolated reproductive population and should be managed accordingly.