A synthesis concerning fishes from Upper Paraná River basin is presented, based on data from fish-collections, literature, and new field samples. Three hundred and ten species, pertaining to 11 orders and 38 families, are referred to the drainage, elevating anterior estimates. Concerning total species, 236 (76.1%) are autochthonous, 67 (21.6%) are allochthonous, and seven (2.3%) are exotic. Principal causes of occurrence of non-native species are: a) dispersal from the Lower Paraná, after the construction of Itaipu dam, and b) escapes from aquaculture farms. Most species (65%) are small-sized, having less than 21 cm of length, and the great majority occurs only in headwaters and small streams. One of the best known and most studied in Brazil, Upper Paraná ichthyofauna richness is far from reaching actual numbers, considering the exponential elevation of species presented herein. Indeed, in the last years various new species have been described and around 50 other species, already recognized as new, are now under description. The improvement on the knowledge about Upper Paraná ichthyofauna is proportional to the number of researchers involved with studies in the area and, unequivocally, reflects recent initiatives stimulating and incrementing taxonomic research, and also improving access to fish collections and to poor or never-sampled areas. However, if we are going to maintain the number of species descriptions per year of last decade, the 50 new species already recognized, will be described only in the next ten years, a period too long. In consequence it is very important that scientific community and grant agencies find and offer initiatives in order to elevate the number of new taxa descriptions per year.Keywords: fishes, freshwater, southeasten Brazil, inventory, transposition. É apresentada uma síntese sobre os peixes do Alto Paraná, com base em dados de coleções, dados de literatura e novas coletas. Trezentas e dez espécies, de 11 ordens e 38 famílias, são referidas para a drenagem, aumentando significativamente números anteriores. Dentre as espécies da área, 236 (76,1%) são autóctones, 67 (21,6%) alóctones e sete (2,3%) exóticas. As principais causas de ocorrência de espécies não nativas (alóctones e exóticas) foram a dispersão a partir do baixo Paraná, após a construção do Reservatório de Itaipu e o escape de pisciculturas. A maior parte das espécies referidas (65%) tem porte pequeno, sendo menor que 21 cm de comprimento; dentre essas, a maioria

This study investigates whether (1) structural configuration (considering substrate composition, wood debris, marginal and riparian vegetation) of streams suggests habitat simplification on a basin scale and (2) fish assemblage structure follows stream habitat configurations. Ninety-five sites in two pasture basins in southeastern Brazil were randomly selected. Two passes of electro-fishing were done in a 75-m reach at each site. Ten habitat descriptors related to in-stream and riparian physical structures were evaluated at each stream reach. Two groups of streams were identified by principal component analysis: a grassy and a non-grassy group. In comparison to non-grassy sites, grass-dominated streams exhibited a more homogenous fish fauna due to lower species diversity and higher dominance, especially by the guppy Poecilia reticulata, a highly generalist exotic species. The grassy group had not only the most simplified habitat but also the most simplified fish fauna, and the combination of grassdominated, completely deforested, heavily silted conditions with recent land use conversion may cause a future habitat homogenization followed by a fish fauna homogenization on a regional scale.

In the present investigation we studied the feeding habits of the fishes associated with aquatic macrophytes in the Rosana Reservoir, southeastern Brazil. Twenty fish species were collected during four field trips, regularly distributed across the dry and wet seasons. Focal snorkeling observations of the fishes were made over a total of six hours. Nine species were present in abundances of more than 1% and, therefore, had their feeding habits analyzed. Hemigrammus marginatus, Roeboides paranensis, Hyphessobrycon eques, Astyanax altiparanae, Serrasalmus spilopleura, and Bryconamericus stramineus were predominantly invertivores, with predominance of aquatic insects (Diptera, Ephemeroptera, and Trichoptera immatures) among their food items. The predominantly algivores were Apareiodon affinis, Serrapinnus notomelas, and Satanoperca pappaterra, with high frequency of filamentous blue-green algae, diatoms, clorophyts, and periderm. The different microhabitat exploitation plus diet composition suggests partitioning of resources and absence of food competition among the most representative fish species in the studied community, indicating the importance of the naturalistic approach to fish ecology studies.Key words: aquatic macrophytes, fishes, feeding, Rosana Reservoir, Paranapanema River. RESUMO

-The trophic structure of a fish assemblage in a first order stream in the upper Paraná River basin was investigated using standard methods of diet analysis and underwater observations utilizing snorkeling. Three stretches of the Córrego São Carlos were studied. Eighteen fish species belonging to five orders and ten families were captured. The stomach analysis of 299 fishes revealed that 70% of the food items are autochthonous, 24% allochthonous, and 6% material of unidentifiable origin. Eighteen pairs of species (33%) showed significant feeding overlap, though this overlap does not necessarily indicate competition given the temporal and spatial segregation during foraging. Three feeding guilds were found. The invertivores included Astyanax altiparanae, Moenkhausia sanctaefilomenae, and Oligosarcus pintoi, whose diet demonstrated a predominance of allochthonous items, and Rhamdia quelen, Trichomycterus sp., Corydoras aeneus, and Crenicichla britskii, that had a predominance of autochthonous items in their diets. In this group, A. altiparanae and M. sanctaefilomenae are drift feeders, R. quelen is a benthic opportunistic predator, Trichomycterus sp. and C. aeneus are grubbers, and O. pintoi and C. britskii are ambush predators. The omnivore with a tendency to herbivory is represented by Phalloceros caudimaculatus, which feeds mainly on algae. The periphitivores included Hisonotus sp., Hypostomus nigromaculatus, and H. ancistroides that are grazers with a diet composed mostly of diatoms, clorophyts, and organic matter. The results indicated that the fish assemblage in the Córrego São Carlos is structured at spatial, temporal, and trophic levels, and shows partitioning of the food resources. The addition of the fish species in each trophic guild along the stream is possibly due to the longitudinal increase of microhabitats that makes available more feeding sites. Key words: stream fishes, feeding, spatial segregation, trophic segregation, resource partitioningResumo -Neste estudo foi investigada a estrutura trófica de uma comunidade de peixes de um riacho de primeira ordem na bacia do Alto Rio Paraná, empregando métodos habituais de análise da dieta combinados com observações naturalísticas. Três trechos do Córrego São Carlos foram estudados. Foram coletadas 18 espécies de peixes, pertencentes a cinco ordens e dez famílias. A análise de 299 estômagos mostrou que 70% dos itens alimentares são autóctones, 24% alóctones e 6% material de origem não identificada. Dezoito pares de espécies (33%) apresentaram sobreposição alimentar significativa, porém esta sobreposição não necessariamente indica competição em razão da segregação espacial e temporal observada na captura do alimento. Três guildas alimentares foram determinadas. Os invertívoros incluíram Astyanax altiparanae, Moenkhausia sanctaefilomenae e Oligosarcus pintoi, que apresentaram predominância de itens alóctones, e Rhamdia quelen, Trichomycterus sp., Corydoras aeneus e Crenicichla britskii, com predominância de itens autóctones. Neste grupo A. altipara...

The ecomorphology of 14 fish species resident in a headwater riffles area of the São Francisco river, southeastern Brasil, was analyzed and combined with diet and feeding behavior data, previously obtained by us. The three larger species groups formed in the ecomorphological analysis were found to reflect primarily microhabitat occupation in the following manner: a) nektonic characids with compressed bodies, lateral eyes and lateral pectoral fins, with diurnal and opportunistic feeding habits (Astyanax rivularis, Bryconamericus stramineus, and Bryconamericus sp.); b) nektobenthic characiforms and siluriforms with fusiform bodies and expanded pectoral fins, including sit-and-wait characidiins, predators of aquatic insect larvae (Characidium fasciatum and Ch. zebra), as well as the algae grazing parodontids (Apareiodon ibitiensis and Parodon hilarii), and also the heptapterid and trichomycterid catfishes that practice substrate speculation and feed on benthic aquatic insect larvae (Cetopsorhamdia iheringi, Imparfinis minutus, Rhamdia quelen, and Trichomycterus sp.); c) benthic species with depressed bodies, suctorial oral discs, dorsal eyes, and horizontal pectoral fins, represented by the periphytivorous loricariid catfishes (Hisonotus sp., Harttia sp., and Hypostomus garmani). Correlation between diet and general morphology was not significant in our analysis, unless when the analyzed set included only nektonic and benthic species, indicating that the lack of correlation between these factors is most pronounced in the group of nektobenthic species. The unequivocal case of morphological convergence found between the nektobenthic Characidiinae and Parodontidae is a clear example of the integration between phylogenetic information and ecomorphology, and provides a way to objectively identify cases of morphological and adaptive convergence and divergence. Furthermore, the general congruence between the ecomorphological results and the independently obtained ecological data about the analyzed fish species in their natural environment seems to be strong evidence in favor of the proposed predictive capabilities of the ecomorphological hypothesis.A ecomorfologia de 14 espécies de peixes residentes em um trecho de corredeiras do curso superior do rio São Francisco, sudeste do Brasil, foi analisada e combinada com dados de comportamento alimentar e dieta, previamente obtidos por nós. Os três principais agrupamentos ecomorfológicos de espécies identificados refletem a ocupação espacial de micro-hábitats da seguinte forma: a) caracídeos nectônicos com corpos comprimidos, olhos laterais e nadadeiras peitorais laterais, com hábitos noturnos e oportunistas alimentares (Astyanax rivularis, Bryconamericus stramineus e Bryconamericus sp.); b) nectobentônicos com corpos fusiformes e nadadeiras peitorais expandidas, que incluem os caracidiíneos predadores de espreita que se alimentam principalmente de larvas aquáticas bentônicas de insetos (Characidium fasciatum e Characidium zebra), parodontídeos pastadores de epilíton (Apareiodon...