Freshwater fishes from Paraná State, Brazil: an annotated list, with comments on biogeographic patterns, threats, and future perspectives.

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.

Encephalon gross morphology of the cichlid Geophagus sveni (Cichlidae: Geophagini): Comparative description and ecological perspectives.

The encephalon gross morphology of Geophagus sveni is described, compared between male and female specimens and discussed in relation to evolutionary, ecological and behavioural aspects. The Student's t-test revealed that there are no sexual dimorphism regarding the volume or linear measurements obtained from the main encephalon subdivisions (telencephalon, tectum mesencephali, cerebellum, gustative lobes, hypothalamus and hypophysis) in proportion to encephalon length, which is congruent with the absence of external dimorphic characters and presence of biparental care behaviour. In all specimens examined, the tectum mesencephali is the largest structure of the encephalon, which may be explained by feeding habit and by the importance of the vision center in a social context (i.e., brood guarding and territory defence, which are common behaviours in cichlids). Also, the lobus vagi is more developed than usual for other teleosts, which may be explained by the presence, in G. sveni as well as in other Geophagini species, of a differentiated pharyngeal apparatus, probably an adaptation to winnowing, a specialized feeding habit. The little intraspecific variation in neuroanatomical characters observed herein indicates a possible source of morphological characters to be explored in cichlid phylogeny.

Areas of endemism for Anablepidae (Teleostei: Cyprinodontiformes): A monophyletic family of freshwater fishes in the Neotropics.

Knowledge on the hydrological evolution of the Neotropical region was used along with the current distribution of the anablepid species to investigate the historical biogeography of this family. Areas of endemism were delimited by endemicity analysis resulting in seven individual areas of endemism and three consensus areas located in northwestern Argentina, southern Brazil, and northern South America. These areas were discussed in the context of anablepid species diversification, especially for the genus Anableps and the subgenera Jenynsia and Plesiojenynsia. The existence of areas of endemism for the family analyzed reveals an intimate association with historical events that occurred in the geological evolution of South America, which can be associated with the main diversification patterns and historical hypotheses in the context of Neotropical freshwater fishes biogeography.

Redescription of Astyanax gymnogenys Eigenmann, 1911 (Characiformes: Characidae), a senior synonym of Astyanax longirhinus Garavello amp; Sampaio, 2010.

Astyanax gymnogenys Eigenmann was described from the middle rio Iguaçu basin, based on two specimens and A. longirhinus Garavello Sampaio was described from the upper, middle and lower rio Iguaçu, based on several specimens. Due to their morphological similarity, including overlapping diagnostic characters between the two nominal species, allied to their occurrence in the same basin, doubts of their validity as independent taxa emerged. The validity of both taxa was analysed through the examination of type-material of both nominal species and additional material from the rio Iguaçu basin. The present study failed to support the recognition of A. longirhinus as a valid species and consequently, the latter species is herein considered a junior synonym of A. gymnogenys. The type-series of A. longirhinus was found to be composed of several Astyanax species. Astyanax gymnogenys can be differentiated from its congeners occurring at the rio Iguaçu basin by a combination of characters, including presence of vertically-elongated dark humeral blotch, margin of the third infraorbital distant from the margin of preopercle, leaving a broad naked area between these bones more than 25% of the depth of third infraorbital, body deepest at dorsal-fin origin or slightly ahead, and seven to 10 gill rakers on lower arch. We also examined all paratypes of A. scabripinnis paranae from the rio Iguaçu and conclude that they are not conspecific with the holotype, and consequently, that the species does not occur in the rio Iguaçu basin.

Neotropical Siluriformes as a Model for Insights on Determining Biodiversity of Animal Groups.

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.

Basic cytogenetics and physical mapping of ribosomal genes in four Astyanax species (Characiformes, Characidae) collected in Middle Paraná River, Iguassu National Park: considerations on taxonomy and systematics of the genus.

Karyotypes and chromosomal characteristics of both minor and major rDNAs in four fish species known popularly as "lambaris", namely Astyanaxabramis (Jenyns, 1842), Astyanaxasuncionensis Géry, 1972, Astyanaxcorrentinus (Holmberg, 1891) and Astyanax sp. collected from downstream of the Iguassu Falls (Middle Paraná River basin), preservation area of the Iguassu National Park, were analyzed by conventional and molecular protocols. Astyanaxabramis had diploid chromosome number 2n=50 (4m+30sm+8st+8a) and single AgNORs (pair 22), Astyanaxasuncionensis had 2n=50 (8m+24sm+6st+12a) and single AgNORs (pair 20), Astyanax sp. had 2n=50 (4m+26sm+8st+12a) and single AgNORs (pair 25), and Astyanaxcorrentinus had 2n=36 (12m+16sm+2st+6a) and multiple AgNORs (pairs 12, 15, 16, 17). FISH with 18S rDNA showed a single site for Astyanaxabramis, Astyanaxasuncionensis and Astyanax sp. and multiple for Astyanaxcorrentinus (14 sites). FISH with 5S rDNA showed single 5S-bearing loci chromosome pair only for Astyanaxasuncionensis and multiple for Astyanaxabramis (four sites), Astyanaxcorrentinus (five sites) and Astyanax sp. (four sites). Distinct distribution patterns of heterochromatin were observed for karyotypes of all species, with the exception of the first acrocentric chromosome pair characterized by centromeric, interstitial-proximal and telomeric blocks of heterochromatin on the long arm, which may represent homeology between karyotypes of Astyanaxabramis and Astyanaxasuncionensis. Our study showed species-specific characteristics which can serve in diagnosis and differentiation between Astyanaxabramis and Astyanaxasuncionensis, considered cryptic species, as well as strengthening the occurrence of a species of Astyanax not yet described taxonomically. In addition, the data obtained from first cytogenetic studies in Astyanaxcorrentinus suggest a high similarity with Astyanaxschubarti Britski, 1964, suggesting that these species may belong to the same morphological group and that can be phylogenetically related.