A new species of Hyphessobrycon Durbin (Characiformes: Characidae) from the middle rio São Francisco and upper and middle rio Tocantins basins, Brazil, with comments on its biogeographic history

Abstract

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.

Ichthyofauna of streams from the lower Iguaçu River basin, Paraná State, Brazil

“…Although others studies had shown that geologic processes provide the capture of headwaters by adjacent basins (Ribeiro 2006;Dagosta et al 2014), this seems not to be the case of this study. So, the main insight of our study is related to fact that differentiation has occurred in species composition between streams up and downstream and that these follow a similar pattern for the registered to the fish fauna of the principal channel.…”

Biogeography of Amazonian fishes: deconstructing river basins as biogeographic units

“…1.6; Dagosta et al, 2014). The area upstream of the diversion is then separated from its original watershed and starts to drain into a new watershed.…”

“…Amazonian river drainages have evolved by numerous events of reticulation (cf. Hubert, Renno, 2006;Lima, Ribeiro, 2011;Ribeiro et al, 2013;Dagosta et al, 2014). Géry (1962) was perhaps the first ichthyologist to recognize the great dynamism of South American drainages and the evanescence of their limits as biogeographic barriers to fish: "The Characoids (at least) have shown that they can pass readily from one basin to another in a very short time, geologically speaking" (Géry, 1962: page 67).…”

“…But evidence of faunistic mixing in shield rivers have accumulated in recent years as well. For the most part, they involve adjacent drainages: Tapajós and Paraguay (Shibatta, Pavanelli, 2005;Lima et al, 2007;Birindelli, Britski, 2009;Tapajós, Xingu (Campos-da-Paz, 1999;Birindelli et al, 2008;Menezes et al, 2009);Tapajós, Madeira (Netto-Ferreira, Vari, 2011;Varella et al, 2012); Xingu, Paraguay (Vari, 1991;da Graça et al, 2008;Aquino, Schaefer, 2010;Netto-Ferreira, Vari, 2011); Xingu, Tocantins (Zawadzki et al, 2008;Ingenito et al, 2013); Tocantins, Paraguay (Lucinda, 2005;); Tocantins, São Francisco (Vari, Harold, 2001;Lima, Caires, 2011;Dagosta et al, 2014;Freitas et al, 2015); Tocantins, Upper Paraná (Britski,1997;Lima, Caires, 2011); Madeira, Paraguay (Kullander, 1982;Reis, Malabarba, 1988;Kullander, 2003;Vari et al, 2005;Vera-Alcaraz et al, 2012;Ota et al, 2014); Madeira and Juruena (Dagosta et al, 2016). In all such examples, the hypothesis that ancestral populations of trans-basin taxa were once widespread in the two basins concerned can be refuted because the current watershed divide between them dates from the Precambrian and vastly predate the radiations of Teleostei in the Upper Cretaceous (c. 100-66 Ma) and predate also the origin of the basins themselves .…”

“…This means that all such basins are historically (and compositionally) hybrid. It seems certain that the ichthyofaunal composition of Amazonian basins are mosaics of divergent elements of different origins, recruited in the course of separate and differently-aged events (Hubert, Renno, 2006;Lima, Ribeiro, 2011;Ribeiro et al, 2013;Dagosta et al, 2014).…”