The book “Peixes da planície de inundação do alto rio Paraná e áreas adjacentes” represents the most cohesive data compilation for the rio Paraná floodplain. However, considering the dynamicity of the taxonomy of freshwater fishes, several new records and taxonomic changes occurred along the past years. Therefore, the results of that publication were revisited, providing an update of the species list, their taxonomic status, records and geographic distribution, and also new keys for genera and species. The species included were those recorded in the rio Paraná basin, from the mouth of the rio Paranapanema to the Itaipu Reservoir, following the general methodology presented in the book. A total of 10 orders, 41 families, 126 genera, and 211 species were registered, with an increase of one order, six families, 14 genera, and 29 species when compared to the book. Additionally, four new genera recently described, five synonymization proposals, 14 new identifications, four new combinations, 12 new species recently described, 34 new records, and nine misidentified species were recorded. These results are associated with the redirection of human and financial resources to that area, which enabled monitoring and intensive exploration of its watercourses; as well as training of taxonomists, and new taxonomic resolutions.

We performed an analysis of the descriptions of new species of Neotropical Siluriformes (catfishes) to estimate the number of new species that remain to be described for a complete knowledge on biodiversity of this order, to verify the effectiveness of taxonomic support, and to identify trends and present relevant information for future policies. We conducted a literature review of species descriptions between January 1990 and August 2014. The following metadata were recorded from each article: year of publication, number of species, journal and impact factor, family(s) of the described species, number of authors, age of the authors and coauthors, country of the first author’s institution and ecoregion of the type-locality. From accumulation of descriptions, we built an estimate model for number of species remaining to be described. We found 595 described species in 402 articles. The data demonstrated that there has been an increased understanding of the diversity of Siluriformes over the last 25 years in the Neotropical region, although 35% of the species still remain to be described. The model estimated that with the current trends and incentives, the biodiversity will be known in almost seven decades. We have reinforced the idea that greater joint efforts should be made by society and the scientific community to obtain this knowledge in a shorter period of time through enhanced programs for promoting science, training and the advancement of professionals before undiscovered species become extinct. The model built in this study can be used for similar estimates of other groups of animals.

We investigated the potential effects of an invasive alien Poaceae (Urochloa arrecta) on the abundance, richness, and composition of native macrophytes and fish. Samples were collected in patches of macrophytes dominated by the invasive species and in others dominated by a native macrophyte (Eichhornia azurea). We assessed the potential effects of these two species on macrophyte and fish abundance and richness, as well as in fish assemblage composition. The effects of both macrophytes did not differ when they were in similar, low biomasses. Consistent with our expectations, however, the abundance of native macrophytes and fish decreased with increasing U. arrecta biomass, and both assemblages were eliminated at the extreme high levels of biomass attained by this species. In contrast, E. azurea did not affect the assemblages because this native species never reached levels of biomass as high as those recorded for the invasive species. Competition for space and light most likely determines the elimination of macrophytes in patches that are extensively colonized by U. arrecta, whereas fish assemblages do not occupy these patches due most likely to the limited space available for movement and foraging. Thus, U. arrecta is a source of concern for biodiversity conservation because it has negative influences on both assemblages when it is well developed, which is true in the later stages of the invasion process.

An annotated checklist for the freshwater fishes from Paraná State, Brazil is provided. A total of 440 freshwater fish species are recorded for the state, distributed across five ecoregions: Upper Parana, Lower Parana, and Iguassu, all within the rio Paraná basin, and corresponding to the state’s Inland Slope, and Southeastern Mata Atlantica and Ribeira de Iguape, corresponding to the Atlantic Slope, encompassing minor coastal drainages emptying in the Baía de Paranaguá or in the Baía de Guaratuba, and the rio Ribeira de Iguape basin, respectively. The Upper Parana ecoregion ocuppies the larger in area in the state, and is divided into the following sub-ecoregions: Floodplain, Paranapanema, Piquiri, and Ivaí. Species richness for each ecoregion is as follows: 273 species for the Upper Parana (Paranapanema sub-ecoregion, 217 species; Floodplain sub-ecoregion, 193 species; Piquiri sub-ecoregion, 154 species; Ivaí sub-ecoregion, 132 species), 154 species in the Lower Parana, 127 species in the Iguassu, 68 species in the Southeastern Mata Atlantica, and 50 species in the Ribeira de Iguape. We recorded 42 putatively undescribed species and 117 endemic species from specific ecoregions (except Upper Parana) or sub-ecoregions in the state. Ninety-eight species recorded are non-native from at least one of the state’s ecoregions. Thirty-three species are considered threatened. The ecoregions in the Atlantic Slope share many more species with each other than with ecoregions in the Inland Slope. The Iguassu ecoregion is the only one located in Inland Slope that shares more species with the Atlantic Slope than with the remaining ecoregions from the Inland Slope. The Ivaí sub-ecoregion lacks several species that are common to all other sub-ecoregions of the Upper Parana ecoregion. Comments on the historical development of taxonomic knowledge, biogeography, threats, and conservation strategies for the fish fauna from the Paraná State are provided.

A taxonomic review of the Hyphessobrycon panamensis species-group is presented, with recognition of six valid species. In Central America, H. panamensis was restricted to the drainages of both Atlantic and Pacific coasts of Panama; H. savagei was recorded at the río Pírris and río Térraba, Pacific coast of Costa Rica, and Hyphessobrycon bussingi, new species, described from the río Sixaola basin, Atlantic coast of Costa Rica, and from the río Changuinola, río Guarumo and río San San, Atlantic coast of Panama. At trans-andean South America, H. columbianus was recorded at the río Acandí, Colombia, and its geographical distribution was extended into the coastal drainages in San Blas province, Panama; H. condotensis was recorded at the río Atrato, río Baudó, lower río Magdalena and río San Juan basins, Colombia, while H. sebastiani was considered as its junior synonym. Hyphessobrycon daguae was revalidated, erected to the specific level, considered as senior synonym of H. chocoensis, and recorded from the río Dagua, río Patía and río Telembí basins, in Colombia, the río Mira, at the border between Colombia and Ecuador, and the río Cayapas, río Mataje, and río Santiago, in Ecuador. Color pattern and secondary sexual characters (e.g. number, arrangement and shape of hooks in mature males) suggest that the Hyphessobrycon panamensis species-group is a putatively monophyletic lineage.

The rio das Cinzas and rio Itararé basins are important tributaries of the rio Paranapanema, a major left-bank tributary of the upper rio Paraná basin. The upper reaches of both drainages intersect the northern portion of the APA Escarpa Devoniana (Devonian Escarpment Environment Protection Area, EPA), an area considered crucial for the preservation of biodiversity. This study aimed to provide an ichthyofaunistic inventory for headwater streams of the rio das Cinzas and rio Itararé basins, both within and off of the borders of the EPA, increasing the knowledge about the species already known from streams in the rio Paranapanema system. We found 32 fish species, representing five orders and 12 families. Siluriformes was the richest order followed by Characiformes. Ten species presented high abundance of sampled individuals, contributing with 85.0% of all specimens. Most species were classified as occasional (captured in less than 25% of the samples) and only two species were classified as constant (captured in more than 50% of samples), which may reflect the altitudinal gradient. We did not record any introduced species in the sampled streams, reinforcing the need of, at least, maintaining the original area of the EPA. We expanded the geographic distribution of Astyanax bifasciatus to the upper rio Paraná system, confirming the cases of faunal exchange among several drainage systems in the limits of the Ponta Grossa Arch. Finally, we identified three putatively undescribed species that show a large biodiversity knowledge shortfall for the region studied.

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Pimelodus mysteriosus Azpelicueta 1998, previously known only from the lower Paraná and Paraguay River basins, has been also recorded in the upper Paraná River floodplain. The only congeners occurring in syntopy with P. mysteriosus in the upper Paraná River basin are P. maculatus and P. ornatus. New diagnostic characters between P. mysteriosus and P. maculatus are provided.