Introduction. Material and Methods. Results and Discussion.

Neotropical freshwater fishes (NFFs) constitute the most diverse continental vertebrate fauna on Earth, with more than 6,200 named species compressed into an aquatic footprint <0.5% the total regional land-surface area and representing the greatest phenotypic disparity and functional diversity of any continental ichthyofauna. Data from the fossil record and time-calibrated molecular phylogenies indicate that most higher taxa (e.g., genera, families) diversified relatively continuously through the Cenozoic, across broad geographic ranges of the South American platform. Biodiversity data for most NFF clades support a model of continental radiation rather than adaptive radiation, in which speciation occurs mainly in allopatry, and speciation and adaptation are largely decoupled. These radiations occurred under the perennial influence of river capture and sea-level oscillations, which episodically fragmented and merged portions of adjacent river networks. The future of the NFF fauna into the Anthropocene is uncertain, facing numerous threats at local, regional, and continental scales. Expected final online publication date for the Annual Review of Ecology, Evolution, and Systematics, Volume 51 is November 2, 2020. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Biogeography of Amazonian fishes (2,500 species in vastly disjunct lineages) is complex and has so far been approached only partially. Here, we tackle the problem on the basis of the largest database yet on geographical distribution and phylogenetic relationships of Amazonian fishes, including all information available. Distributions of 4,095 species (both Amazonian and outgroups) and 84 phylogenetic hypotheses (comprising 549 phylogenetically-informative nodes) were compiled, qualified and plotted onto 46 areas (29 Amazonian and 17 non-Amazonian). The database was analyzed with PAE, CADE, BPA and BPA 0 , yielding largely congruent results and indicating that biogeographic signal is detectable on multiple dimensions of fish distribution, from single species ranges to cladistic congruence. Agreement is especially pronounced in deeper components, such as Trans-Andean, Cis-Andean, Western Amazon and Orinoco basins. Results show that all major Amazonian tributaries, as well as the Amazon basin itself, are non-monophyletic and constitute hybrid sets of heterogeneous biotic partitions. Amazonian drainages should not be assumed a priori as historically cohesive areas, contrary to widespread practice. Our hypothesis allows reevaluation of broader issues in historical biogeography, such as the predictive power of biogeographic hypotheses, the vicariant/ dispersal duality, the significance of widely distributed taxa, and the need for temporal dimension in biogeographic patterns. A biogeografia dos peixes amazônicos (2.500 espécies de diferentes linhagens) é complexa e até agora foi abordada apenas parcialmente. Aqui abordamos o problema com base no maior banco de dados já feito sobre a distribuição geográfica e as relações filogenéticas dos peixes amazônicos, incluindo todas as informações disponíveis. A distribuição de 4.095 espécies (tanto amazônicas como de grupos-externos) e 84 hipóteses filogenéticas (que incluíam 549 nós filogeneticamente informativos) foram compiladas e qualificadas em 46 áreas (29 amazônicas e 17 não-amazônicas). O banco de dados foi analisado a partir das metodologias PAE, CADE, BPA e BPA0, resultando em topologias amplamente congruentes e indicando que o sinal biogeográfico é detectável em múltiplas dimensões, desde a simples distribuição de peixes até em congruência cladística. A concordância topológica é especialmente pronunciada em componentes mais profundos, como as bacias Trans-Andina, Cis-Andina, Amazonas Ocidental e Orinoco. Os resultados demonstram que todos os principais afluentes amazônicos, bem como a própria bacia amazônica, não são monofiléticos e constituem conjuntos híbridos formados a partir de parcelas bióticas heterogêneas. As drenagens amazônicas não devem ser consideradas a priori como áreas historicamente coesas, contrariamente à prática generalizada. Nossa hipótese permite a reavaliação de questões mais amplas na biogeografia histórica, como o poder preditivo de hipóteses biogeográficas, a dualidade vicariante/dispersão, significância de táxons amplamente distribuídos e a n...

The Brazilian Cerrado, one of the most threatened biomes of our planet, illustrates the challenges and opportunities of reconciling economic development with conservation of land and water ecosystems. Here, we assess the state of the art of and present new information on the impacts of agricultural expansion, dams, and water use, and make recommendations for basin management, conservation, and restoration of water-related Cerrado ecosystems and rivers. The conservation of the Cerrado requires not only the preservation of remnants of its vegetation but also the ability to keep the hydro-geomorphological and ecological functionality of its rivers, particularly the Araguaia River, the last large well preserved and unregulated system. If business as usual continues, the Cerrado riverine ecosystems may never rebound.

Freshwater ecosystems represent less than 0.01% of Earth's surface water but proportionately encompass the most species‐rich environment on the planet, including nearly one‐third of all vertebrate species. Even though inland continental waters are widely regarded as highly endangered ecosystems, their species assemblages are mostly ignored in conservation plans, largely because spatial patterns of freshwater species remain poorly understood. This is particularly severe throughout the Neotropics, most notably in the Amazon superbasin, where the sheer biotic diversity is coupled with a severe lack of biodiversity knowledge at several levels. Spatial patterns of Neotropical freshwater fishes focusing mainly on the Amazon superbasin were investigated. First, Endemic Amazonian Fish Areas (EAFAs) representing central units for the conservation of continental fishes were delimited. Interpolated maps were then analysed using alternative methodologies to delimit spatial patterns of diversity and endemicity across the Amazon superbasin. Several biogeographical analyses used a comprehensive dataset of species and geographical coordinates of Amazonian fishes. The results reveal well‐defined spatial patterns of species richness and endemicity in the Amazonian fish fauna, showing that most protected areas are concentrated in a single bioregion (Amazon lowlands). Those areas are incongruent and insufficient to protect endemic and threatened species, which are mostly distributed in upland regions. Effective conservation of the Amazonian fish fauna should include EAFAs within protected areas, especially those undergoing deforestation and hydropower development pressure and containing a high concentration of threatened species. The following EAFAs should be considered as conservation priorities: Upper Araguaia, Upper Tocantins, Lower Teles Pires/Serra do Cachimbo, Chapada dos Parecis and Upper Marañon. These regions should be urgently protected to avert the loss of important trophic relationships and unique elements of the Amazonian fish fauna.

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A new species of Hyphessobrycon Durbin is described from tributaries of the rio Grande (rio São Francisco basin) draining east to the Serra Geral de Goiás, of the rio São Domingos (upper rio Tocantins basin) and rio do Sono basins (middle rio Tocantins basin). Hyphessobrycon diastatos can be diagnosed from its congeners by the absence of humeral spot, 15-18 branched analfin rays, 1-3 maxillary conical to tricuspid teeth, a relatively well-defined dark caudal-peduncle spot, and elongation of dorsaland anal-fin rays in mature males. The biogeographical significance of the distribution of the new species is evaluated and discussed.Uma espécie nova de Hyphessobrycon Durbin é descrita dos tributários do rio Grande (bacia do rio São Francisco) que drenam a leste a Serra Geral de Goiás, das bacias dos rios São Domingos (bacia do alto rio Tocantins) e rio do Sono (bacia do médio rio Tocantins). Hyphessobrycon diastatos pode ser diagnosticada de seus congêneres pela ausência de mancha umeral, 15-18 raios ramificados na nadadeira anal, 1-3 dentes maxilares cônicos ou tricuspidados, uma mancha escura relativamente bem definida no pedúnculo caudal e alongamento das nadadeiras dorsal e anal em machos maduros. O significado biogeográfico da distribuição da espécie nova é avaliado e discutido.

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