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Cytogenetic and comparative morphology of two allopatric populations of Astyanax altiparanae Garutti & Britski, 2000 (Teleostei: Characidae) from upper rio Paraná basin

The recently described fish species, Astyanax altiparanae (tetra) is common in the upper rio Parana basin, and has been reported in the Iguacu basin. However, its natural origin in the rio Iguacu is questionable. In the present work, karyotypical and morphological features of two populations of Astyanax altiparanae from the upper rio Tibagi and upper rio Iguacu were compared. Both populations showed 2n=50 chromosomes and differences in their karyotype formula, NOR-bearing chromosomes and location of heterochromatin. Morphometric data from both populations were analyzed through free-size canonical variables. Cytogenetic and morphological results were mostly coincident showing exclusive markers that reflect their degree of populational isolation. In addition to other geographic, morphological and molecular data for A. altiparanae populations from the lower rio Iguacu and rio Parana tributaries upstream from the Itaipu Dam (South Brazil), the present results indicate that the two populations analyzed in this study belong to different stocks. The presence of this species along the rio Iguacu basin would be a consequence of a complex and poorly understood evolutionary history.

Fishes of the Atlantic Rain Forest Streams: Ecological Patterns and Conservation

Fishes constitute more than one half of the species of vertebrates, with around 32,000 living species (Froese & Pauly, 2011). Approximately 40% of this global fish diversity lives in freshwater environments, which represents less than 1% of the surface of the Earth (Dudgeon et al., 2006). In the Neotropical Region, freshwater fishes constitute a taxonomically distinct fauna that extends throughout the continental waters from Central Mexico to the southernmost tip of South America. This zoogeographical region is known to harbor the richest and most diverse freshwater fish fauna of the whole planet (Gery, 1969; Vari & Malabarba, 1998; Lundberg et al., 2000; Albert et al., 2011). The Atlantic Rain Forest is one of the richest biomes in the Neotropics mainly due to the variety of habitats throughout the range of the forest types and subtypes, which originally covered a wide stripe of the Brazilian coastline (Morellato & Haddad, 2000). Considering the fact that the definition of the limits and forest types of the Brazilian Atlantic Rain Forest is controversial and beyond the scope of this study, this vegetation domain was considered here in a narrower sense, comprising the coastal forest formations between 6–300 S, with elevations from sea level to approximately 1,000 meters. In this sense, this forest is dispersed along degraded landscapes, embracing some of the largest and oldest Brazilian urban areas, where more than 150 million people live. The Atlantic Rain Forest constitutes one of Brazil s most important vegetation domains, because of its historical relationship with the colonization of the country, and also in view of the role that it plays in the conservationist scenario (Silva, 2003). In the broadest and most generic sense of the forest formations, this biome is one of the most biodiverse and endangered ecosystems in the world (Myers et al., 2000). The region bounded by this forest has a high percentage of fish species with restricted distribution, as a result of the great number of independent coastal drainages (or groups of basins), and the isolating effect of mountain ranges and seawater among coastal rivers (Bizerril, 1994; Menezes et al., 2007). In fact, according to our survey a great amount (70%) of the freshwater fishes can be considered exclusive to the coastal drainages of this vegetation domain The high rate of speciation and high degree of geographic endemism is an important factor that needs to be considered in the conservation policies of the Atlantic Rain Forest remains, as this biome is located in the most populated regions of the country,

Spatial, seasonal and ontogenetic variation in the diet of Astyanax aff. fasciatus (Ostariophysi: Characidae) in an Atlantic Forest river, Southern Brazil

Este estudo descreveu os habitos alimentares do lambari Astyanax aff. fasciatus. Foram comparadas as composicoes alimentares de especimes de dois sitios (A e B) de um rio no sul do Brasil de acordo com o tamanho dos individuos e do periodo sazonal. As coletas foram realizadas mensalmente de marco de 2005 a fevereiro de 2006, sendo o conteudo estomacal de 290 exemplares analisado. A dieta de A. aff. fasciatus foi composta basicamente por plantas e insetos, especialmente fragmentos de folhas, sementes, frutos, algas filamentosas, insetos aquaticos e terrestres e fragmentos de insetos. No sitio A, os itens de maior importância foram fragmentos de insetos e plantas. Ao contrario no sitio B, fragmentos de plantas foram mais representativos. Em geral, todos os itens de origem animal apresentaram os maiores valores do indice alimentar no sitio A, enquanto que no sitio B detritos e gramineas foram mais abundantes. A composicao dos itens ingeridos variou sazonalmente, sendo a maior diversidade registrada durante o periodo da primavera para ambos os sitios. Individuos pequenos preferiram itens de origem animal enquanto que os maiores consumiram principalmente itens de origem vegetal. De acordo com seu tamanho A. aff. fasciatus neste estudo pode ser considerada uma especie com tendencias a insetivoria quando imaturo, ou a herbivoria quando adulto. No entanto, seu habito alimentar pode ser flexivel de acordo com a disponibilidade de recursos, mostrando ampla variacao tanto ontogenetica quanto espacial e temporal.

Feeding ecology and trophic comparisons of six shark species in a coastal ecosystem off southern Brazil.

The diets of six shark species, Sphyrna lewini, Sphyrna zygaena, Carcharhinus obscurus, Carcharhinus limbatus, Rhizoprionodon lalandii and Galeocerdo cuvier, were investigated in a subtropical coastal ecosystem of southern Brazil. Stomach content data were obtained to assess foraging niche segregation and ontogenetic shifts in the diets of these sharks. Five of the shark species off the Paraná coast were ichthyophagous, with the exception of S. zygaena, which was teutophagous. With the exception of G. cuvier, which had a generalist diet, the other five species displayed specialization in their feeding. Ontogenetic shifts were observed in C. obscurus and S. lewini with large individuals consuming elasmobranchs. Owing to the diet overlap between C. obscurus and S. lewini, C. obscurus and C. limbatus and R. lalandii and C. limbatus, future studies on the spatial and temporal distributions of these species are needed to understand the extent of competitive interactions.

Elasmobranchs of the Paraná Coast, southern Brazil, south-western Atlantic

The present study provides a check list of elasmobranchs from the Parana State coast, southern Brazil. Information from fish collections, literature data, field surveys and personal communications were included. Results indicated that 83 species from seven orders and 28 families were recorded. According to the results 51 species belonging to six orders and 17 families of sharks; and 32 species belonging to one order and eleven families of rays occur in this region. The most species-rich families were Carcharhinidae (14 species) and Arhynchobatidae (eight species).

Astyanax totae, a new characid species (Teleostei: Characidae) from the upper rio Iguaçu basin, southeastern Brazil

A new species of characid fish, Astyanax totae, is described from a small tributary in the upper drainage of the rio Iguacu, Parana basin, Brazil. The new species is distinct from most species of Astyanax by the vertically elongated humeral spot, slightly expanded above the lateral line to posterodorsal margin of opercle, followed by a midlateral dark stripe expanded from the humeral region to the median caudal-fin rays, maxilla with 2 to 5 teeth (usually 3) and 15 to 18 branched anal-fin rays.

Feeding ecology of Rivulus luelingi (Aplocheiloidei: Rivulidae) in a Coastal Atlantic Rainforest stream, southern Brazil

collected in a black water stream of the Coastal Atlantic Rainforest in southern Brazilwere investigated. Eight samplings were made between April 2003 and January 2004. The diet, assessed through a similarity matri xwith the estimated contribution values of food items, included microcrustaceans, aquatic immature insects (larvae and pupae),aquatic adult insects, terrestrial insects, insect fragments, spiders, and plant fragments. Differences in the diet according totemporal variations (months) were registered, but changes related with size classes evaluated and high/low precipitation periodwere not observed. The species presented an insectivorous feeding habit, and its diet in the studied stream was composed ofautochthonous (mainly aquatic immature insects) and allochthonous (mainly insect fragments) material.Neste estudo foram investigados os habitos alimentares do peixe anual

A multibiomarker evaluation of urban, industrial, and agricultural exposure of small characins in a large freshwater basin in southern Brazil

Iguaçu River is the second most polluted river of Brazil. It receives agrochemicals and contaminants of urban and industrial sources along its course. A multibiomarker approach was employed here to evaluate the health of a small characin (Astyanax spp.) at two sites along the river, sampled during a dry (autumn) and a rainy (spring) season. Biomarkers were condition factor and somatic indices (gonads and liver); genetic damage (comet assay and micronucleus test); enzyme activities such as hepatic catalase (CAT) and glutathione S-transferase (GST), lipoperoxidation (LPO), branchial and renal carbonic anhydrase (CA), acetylcholinesterase (AChE) in the muscle and the brain, histopathology of the liver and gills, and concentrations of polycyclic aromatic hydrocarbons (PAHs) in bile. There were no consistent differences in biomarker responses between the two study sites. Some biomarkers revealed greater potential impact in the rainy season, when increased amounts of contaminants are washed into the river (combined CAT inhibition and LPO increase, CA upregulation). Other biomarkers, however, revealed potential greater impact in the dry season, when contaminants potentially concentrate (GST induction, AChE inhibition, and liver histopathological alterations). Although of a complex nature, field experiments such as this provide rich data for monitoring protocols and assessment of general risk of exposure to pollutants of river systems.

Feeding ecology of Lutjanus analis (Teleostei: Lutjanidae) from Abrolhos Bank, Eastern Brazil

Diet and feeding ecology of the mutton snapper Lutjanus analis were investigated in the Abrolhos Bank, Eastern Brazil, the largest and richest coral reefs in the South Atlantic, where about 270 species of reef and shore fishes occur. To evaluate seasonal and ontogenetic shifts in the diet, specimens of L. analis were obtained through a fish monitoring program in four cities in southern Bahia State, from June 2005 to March 2007. Stomachs from 85 mutton snappers that ranged in size from 18.1 to 74.0 cm TL were examined. Prey were identified to the lowest possible taxon and assessed by the frequency of occurrence and volumetric methods. Variations in volume prey consumption were evaluated using non-metric multi-dimensional scaling ordination, analysis of similarity, and similarity percentage methods. Significant differences in diet composition among size classes were registered, whereas non significant differences between seasons were observed. Considering size-classes, food items consumption showed important variations: juveniles ( 50.1 cm TL) consumed basically fish, mostly Anguiliformes. Lutjanus analis is an important generalist reef predator, with a broad array of food resources and ontogenetic changes in the diet. This snapper species plays an important role on the trophic ecology of the Abrolhos Bank coral reefs.

Two new species of Rineloricaria (Siluriformes: Loricariidae) from the rio Iguaçu basin, southern Brazil

is distinguishable from all other congeners by the shape and extension of the naked area of the ventralregion of pectoral girdle and other morphological characters. The presence of a naked region on the abdominal surface isshared with other species from the rio Parana and rio Uruguay basins and coastal drainages from southeastern and southernBrazil. This may indicate a close phylogenetic relationship among these species. Similarities between the two new species andspecies from the aforementioned drainages also suggest close biogeographic relationship between the Parana basin and otherBrazilian coastal Atlantic drainages throughout the rio Iguacu basin.