Taxonomic revision of Galeocharax (Characiformes: Characidae: Characinae)

Abstract

The taxonomy of Galeocharax, a genus of freshwater fishes distributed in most South American cis-Andean river systems, except the rio Negro, rio São Francisco and rio Xingu basins and the eastern drainages of Brazil, is herein revised. A total of 1229 specimens were examined from which 680 had meristic and morphometric data taken. Osteological and morphological features were also examined through radiographs, scanning electron microscopy and in cleared and stained specimens. Three of the four species previously considered as valid are herein recognized: Galeocharax humeralis from rio Paraguay and lower rio Paraná basins; Galeocharax goeldii, from rio Madeira basin, with records of geographical distribution expanded to the río Madre de Dios, río Beni, rio Mamoré and rio Guaporé basins and Galeocharax gulo, which is widespread throughout rio Amazonas, río Orinoco, rio Tocantins, and upper rio Paraná basins. Galeocharax knerii is herein considered a junior synonym of Galeocharax gulo. A key to species of Galeocharax is presented.Keywords: Key of identification, Ostariophysi, Systematics, Widespread species.A taxonomia de Galeocharax, um gênero de peixes de água doce distribuído nos principais sistemas hídricos da América do Sul cisandina, com exceção da bacia do rio Negro, do rio São Francisco, do rio Xingu e das drenagens litorâneas do leste, é aqui revisada. Foram examinados 1229 exemplares, dos quais 680 tiveram dados merísticos e morfométricos tomados. Características osteológicas e morfológicas também foram examinadas por meio de radiografias, microscopia eletrônica de varredura e exemplares diafanizados. Três das quatro espécies previamente consideradas válidas são reconhecidas: Galeocharax humeralis das bacias do rio Paraguai e baixo rio Paraná; Galeocharax goeldii da bacia do rio Madeira, com registros de distribuição geográfica ampliados para as bacias dos rios Madre de Dios, Beni, Mamoré e Guaporé, e Galeocharax gulo amplamente distribuída nas bacias dos rios Amazonas, Orinoco, Tocantins e alto rio Paraná. Galeocharax knerii foi considerada sinônimo júnior de Galeocharax gulo. Uma chave de identificação para as espécies de Galeocharax é apresentada.Palavras-chave: Chave de identificação, Espécies amplamente distribuídas, Ostariophysi, Sistemática.

The Fishes of the Amazon: Distribution and Biogeographical Patterns, with a Comprehensive List of Species

“…Wallace (1889) was the first to note that water type influenced the composition of fish assemblages in the Amazon (Dagosta and de Pinna, 2018), an observation repeatedly confirmed in subsequent studies (see Roberts, 1972;Kullander, 1986;Goulding et al, 1988;Vari, 1988;Araujo-Lima and Goulding, 1997;Saint-Paul et al, 2000;Lima and Ribeiro, 2011). The extremely acidic water of the Rio Negro, in particular, may be a deterrent to many Pinna, 2017; Reis, 1989), the genera Galeocharax (see Giovannetti et al, 2017) and Hypoptopoma (see Aquino and Schaefer, 2010), and several species such as Anostomus ternetzi (see Lima and Ribeiro, 2011), Brachyplatystoma juruense, Cheirocerus goeldii (see Stewart and Pavlik, 1985), Copella stigmasemion (see Marinho and Menezes, 2017), Curimatella dor¬ salis (see Vari, 1992a), Hemiodus microlepis (see Langeani, 1996) (Grande, 1985;Hunn and Upchurch, 2001;Morrone, 2009) expected outside: 9.5; observed outside: 0; X2 = 19. X2 >3.841, rejects the null hypothesis, i.e., the species is not randomly distributed.…”

Peixes da planície de inundação do alto rio Paraná e áreas adjacentes: revised, annotated and updated

“…Distribution. Río Orinoco, rio Oyapok, rio Araguaia-Tocantins, upper rio Paraná and Amazon (except the rio Negro and rio Xingu) basins (Giovannetti et al, 2017).…”

“…Galeocharax gulo was identified as G. knerii by . Giovannetti et al (2017), in a revisionary study of Galeocharax Fowler, 1910, proposed the new synonym.…”

Checklist and key for the identification of fish fauna of the Uberaba River, Upper Paraná River system, Brazil

“…Ota et al (2018) suggested that the occurrence of Hoplerythrinus unitaeniatus in the Upper Paraná River can be associated with its introduction as a live bait or after inundation of the Sete Quedas Falls after the construction of the Itaipu dam. Galeocharax gulo is widely distributed in almost all Upper Amazon River systems, also in the Orinoco, Oyapok, Araguaia-Tocantins, and Paraná rivers (Giovannetti et al 2017). The occurrence of this species in the Upper Paraná system may be a result of natural dispersion.…”