1000 resultados para Upper Rio Paraná


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Potamotrygon boesemani, new species, is described from the Corantijn river drainage in Surinam. The species has a diagnostic dorsal color pattern formed by deep orange to red ocellated spots of irregular form, encircled by relatively broad black rings. Potamotrygon boesemani is distinguished from other ocellated congeners (P. motoro, P. henlei and P. leopoldi) by the more intensely colored ocelli, which are usually yellow in the latter species. From P. motoro it is also distinguished by the darker dorsal background coloration, by the broader black contour of the dorsal ocelli, and by the irregular form of the ocelli as compared to the more rounded shape in the latter species. From P. henlei and P. leopoldi, it is distinguished by the lack of ocelli on tail. From the tentatively identified specimen of P. ocellata, which also has dark orange ocelli, the irregular contour of the ocelli in the new species is also distinctive. The teeth are relatively smaller and in greater number than in P. motoro and P. ocellata, with up to 45 rows in the upper jaw.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The harvestmen subfamily Hernandariinae is reviewed and a new classification is proposed based on cladistic analysis using 67 morphological characters. The subfamily is composed of six genera and 23 species and occurs in south-southeastern Brazil, Paraguay, and northeastern Argentina. Fourteen new combinations are proposed: Hernandaria armatifrons (Roewer, 1917); H. una (Mello-Leitão, 1927); Acrogonyleptes granulatus (H. Soares, 1966); A. pectinifemur (Soares & Soares, 1947); Acanthogonyleptes alticola (Mello-Leitão, 1922); A. editus (Roewer, 1943); A. fallax (Mello-Leitão, 1932); A. fulvigranulatus (Mello-Leitão, 1922); A. marmoratus (Mello-Leitão, 1940); A. pictus (Piza, 1942); A. singularis (Mello-Leitão, 1935); A. soaresi (Mello-Leitão, 1944); A. variolosus (Mello-Leitão, 1944). Seven synonymies are proposed: Proweyhia Mello-Leitão, 1927 and Metaxundarava Mello-Leitão, 1927 = Hernandaria Sørensen, 1884; Apembolephaenus calcaratus Soares & Soares, 1945 = H. armatifrons (Roewer, 1917); Sphaerobunus Rower, 1917 and Paraproweyhia Soares & Soares, 1947 = Acrogonyleptes Roewer, 1917; Paraproweyhia curitibae Soares & Soares, 1947 = Acrogonyleptes exochus (Mello-Leitão, 1931); and Melloleitaniana curitibae B. Soares, 1943 = Acrogonyleptes spinifrons Roewer, 1917. Three species are revalidated: Acrogonyleptes granulatus (H. Soares, 1966), A. pectinifemur (Soares & Soares, 1947), and A. spinifrons Roewer, 1917. Seven new species are described: Hernandaria sundermannorum sp. nov. (São Paulo State, Brazil), Hernandaria anitagaribaldiae sp. nov. (Santa Catarina State, Brazil), Hernandaria zumbii sp. nov. (Santa Catarina State, Brazil), Hernandaria chicomendesi sp. nov. (Santa Catarina State, Brazil), Acrogonyleptes cheguevarai sp. nov. (Rio Grande do Sul State, Brazil), Pseudotrogulus pagu sp. nov. (São Paulo State, Brazil), Pseudotrogulus trotskyi sp. nov. (Paraná State, Brazil).

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Collections were made every two months in Ilha Grande Bay, Rio de Janeiro, for 21 months (August/2004-May/2006) to study the gametogenesis of Madracis decactis Lyman, 1859. A total of 1800 polyps were examined using standard histological techniques. Madracis decactis is a hermaphroditic species whose male and female gametes develop within different mesenteries. Oogenesis begins in October, while spermatogenesis begins at the end of February, both reaching maturity at the end of April. The peak of reproductive activity occurred between February and April, when all the polyps were fertile, containing mainly stage III oocytes. Examination of fertile polyps indicated the simultaneous presence of stages I, II and III for oogenesis and I, II, III and IV for spermatogenesis. No embryos or planulae were observed in the histological sections. The gametes or planulae spawning may occur between April and May.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A assembléia de abelhas (Hymenoptera, Apidae) de uma área restrita de campos naturais do Parque Estadual de Vila Velha, Paraná e comparações com áreas de campos e cerrado. Foram realizadas coletas sistemáticas de abelhas em uma área restrita no Parque Estadual de Vila Velha, Paraná, no período de outubro de 2003 a setembro de 2004. Essa amostragem visou gerar subsídios para comparações entre áreas de campo dentro do Parque e com outras áreas de vegetação aberta brasileiras. A área de estudo possui cerca de quatro hectares e foi subdividida em quatro subáreas contínuas e com o mesmo perímetro. As abelhas em flores e em vôo foram capturadas com auxílio de rede entomológica. Foram coletados 1.459 espécimes pertencentes a 122 espécies de abelhas. Estas espécies estão distribuídas em 51 gêneros, 20 tribos e cinco subfamílias. As plantas visitadas correspondem a 93 espécies, pertencentes a 62 gêneros e 29 famílias. Neste estudo e em outro estudo realizado anteriormente em outra área do Parque foram coletadas 222 espécies sendo 74 espécies em comum as duas áreas e uma soma de 148 espécies restritas a uma ou outra área. Ainda, registros históricos de abelhas para Vila Velha elevam a riqueza conhecida para 261 espécies. O índice de similaridade de Morisita entre as áreas foi de 0,50 quando utilizadas as plantas como variáveis e 0,88 quando utilizados gêneros e espécies de abelhas, revelando uma notável heterogeneidade. Comparações entre as áreas do Parque Estadual de Vila Velha e áreas de campos e cerrado foram realizadas através do índice de similaridade e da análise de correspondência. Foram observados dois agrupamentos fortemente evidentes, referentes aos campos e ao cerrado. A análise de correspondência sugere que alguns gêneros podem ser relacionados a determinadas formações vegetais. Esse estudo indica que a fauna de abelhas de Vila Velha é composta principalmente por gêneros relacionados às áreas de campos, porém com presença de elementos de cerrado.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The Paraná-Paraguay basin encompasses central western Brazil, northeastern Paraguay, eastern Bolivia and northern Argentina. The Pantanal is a flooded plain with marked dry and rainy seasons that, due to its soil characteristics and low declivity, has a great water holding capacity supporting abundant fish fauna. Piaractus mesopotamicus, or pacu, endemic of the Paraná-Paraguay basin, is a migratory species economically important in fisheries and ecologically as a potential seed disperser. In this paper we employ eight microsatellite loci to assess the population structure of 120 pacu sampled inside and outside the Pantanal of Mato Grosso. Our main objective was to test the null hypothesis of panmixia and to verify if there was a different structuring pattern between the Pantanal were there were no physical barriers to fish movement and the heavily impounded Paraná and Paranapanema rivers. All loci had moderate to high levels of polymorphism, the number of alleles varied from three to 18. The average observed heterozygosity varied from 0.068 to 0.911. After the Bonferroni correction three loci remained significant for deviations from Hardy-Weinberg, and for those the frequency of null alleles was estimated. F ST and R ST pairwise comparisons detected low divergence among sampling sites, and differentiation was significant only between Paranapanema and Cuiabá and Paranapanema and Taquari. No correlation between genetic distance and the natural logarithm of the geographic distance was detected. Results indicate that for conservation purposes and for restoration programs small genetic differences detected in the Cuiabá and Paranapanema rivers should be taken in consideration.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Hemiancistrus cerrado is described from the tributaries of rio Araguaia, rio Tocantins basin. Hemiancistrus cerrado has external similarities with H. megalopteryx and H. punctulatus from coastal streams of southern Brazil, and can be distinguished by having a larger internarial width, 15.9-21.1% of head length (vs. 11.2-14.0% in H. megalopteryx and 11.2-13.9% in H. punctulatus) and, with little overlap, by the larger adipose-fin spine length, 9.4-13.6% of standard length (vs. 7.1-8.7% in H. megalopteryx and 7.4-10.0% in H. punctulatus). Hemiancistrus cerrado further differs from H. megalopteryx by having the pectoral-fin spine reaching maximally to the middle of the pelvic-fin spine when adpressed in adult males (vs. reaching tip). Hemiancistrus cerrado differs from other members of Hemiancistrus by color and numerous morphometric and meristic data.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Este estudo teve o objetivo de relatar a ocorrência de Trypanosoma vivax no Sul do Brasil. O protozoário foi diagnosticado em esfregaço sanguíneo de um bovino e a identificação baseada na morfologia das formas tripomastigotas e confirmada pela técnica de reação em cadeia de polimerases (PCR). O animal infectado apresentou sintomatologia compatível com a forma nervosa da infecção por T. vivax. Outros bovinos que compartilhavam o mesmo ambiente apresentaram resultados negativos para T. vivax por PCR. Este é o primeiro registro de T. vivax no Estado do Rio Grande do Sul e na região Sul do Brasil.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Structural analysis carried out on a segment of the Neoproterozoic Ribeira Belt, southeastern Brazil, show that it represents part of the transpressive dextral orogen related to the Central Mantiqueira Province. NNE-trending and steeply dipping regional mylonitic belts form anastomosed geometry, and describe a map-scale, S-C-like structure that is characterized by their deflection towards NE near the Além Paraíba Lineament. Lithological and structural control related to deformation partition were responsible for the formation of felsic mylonitic granulites with S-type granites lenses developed in ductile shear zones, alternated with less deformed intermediate to basic granulites associated with charnockites. The dextral shear sense indicators are consistent with transpressive deformation in the region and are common especially at the border of the main shear zones. The presence of S-type leucogranite may lead to variations of linear and planar relationships, which result in local extension zones. These elements are consistent with oblique continental collision considering the São Francisco Craton as a stable block.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The study assessed heavy metal concentrations in the tissue samples of Corbiculafluminea, by ICP-OES. In the tissues, average levels of 23.99 µg/g of Cu, 144.21 µg/g of Zn, 0.71 µg/g of Cd, 7.10 µg/g of Cr and 2.41 µg/g of Pb were detected ahowing that this last value is high and above the ANVISA reference (2.00 µg/g) for fish and other products. The results suggest that natural processes occuring in the Ribeira de Iguape River are not sufficient for purification so that metals remain in the water and can accumulate in the trophic chain.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The capacity of natural zeolites and its host rock (dacite) to remove Pb2+ and Cr3+ from aqueous solutions has been investigated. Results showed that both samples prefer to remove Pb2+ instead of Cr3+. Almost 100% of Pb2+ was removed from solutions with concentration until 50 mg L-1 and 100 mg L-1 of this metal, respectively by dacite and zeolite. The equilibrium of metals adsorption process was reached during the first 30 min by both materials. Na+ can be used to recover Pb2+, but not to remove Cr3+ from the treated samples. The Sips model showed a good fit for experimental data of this study.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Sediment samples from Tietê river were submitted to chemical and sequential extractions of heavy metals (Cd, Cr, Cu, Ni, Pb and Zn). It was followed a single extraction by using 0.1 mol L-1 hydrochloric acid and a sequential procedure to evaluate possible chemical associations described as exchangeable, carbonate, reducible oxides, sulfide, organic matter and residual fractions. High concentrations of heavy metals were determined at Pirapora reservoir, which is closer to the Metropolitan Area of São Paulo while for Barra Bonita reservoir, the results showed low concentrations for such elements. Acid volatile sulfides, grain size distribution and carbon contents were also determined.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Concrete modules were deployed on the bottom of the 11, 18 and 30 meters isobaths along a cross-shelf hydrographic gradient off Paraná State, Southern Brazil, with the purpose of studying the colonization of sessile epilithic macroinvertebrates on artificial surfaces. After one year of submersion a total of 63 species of epilithic organisms were identified, dominated by Ostrea puelchana, Chthamalus bisinuatus, Balanus cf spongicola, Astrangia cf rathbuni, Didemnum spp, poryphers and bryozoans. Diversity index and percent cover at reef stations placed at 11, 18 and 30 meters isobaths were respectively 2.28 and 66.7%, 2.79 and 96.6% and 1.66 and 77.4%. Differences of general community structure among the three assemblages were not clearly related to the general environmental conditions at the bottom layers near the reef stations. Turbidity and larval abundance are discussed as important factors affecting colonization processes. Results indicate that depths between 15-20 meters are more suitable for the implementation of large scale artificial reef systems in the inner shelf off Paraná and, possibly, throughout the inner shelves off southern Brazil with similar hydrographic conditions.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Desembocaduras são ambientes bastante dinâmicos e sujeitos à complexa interação entre fatores estabilizadores e desestabilizadores. Dependendo dessa interação, desembocaduras podem apresentar a tendência de migração ao longo de barreiras arenosas. Um dos mecanismos mais eficientes de transporte de sedimento paralelo à costa, e consequentemente migração de canais, são as correntes longitudinais geradas pelas ondas se aproximando obliquamente à costa. A motivação do presente trabalho é entender o comportamento morfodinâmico do sistema de desembocadura do rio Itapocú, localizado no centro-norte de Santa Catarina (SC), frente aos processos forçantes que atuam na sua migração ao longo da linha de costa. A morfologia dos pontais arenosos foi obtida a partir de levantamentos morfológicos com o uso de DGPS. Para analisar a refração de ondas foi utilizado o modelo numérico MIKE 21 SW, sendo considerados como condições de contorno os dados de ondas referentes ao ano de 2002 e os dados de ondas previstos referentes ao período de coleta. Os dados de saída do modelo foram utilizados para estimar a deriva litorânea potencial na região. Os resultados morfológicos obtidos demonstraram uma migração da desembocadura para o norte durante o período analisado, sendo mais intenso durante o inverno e o verão. Ondas incidentes do quadrante sul sofreram mais o fenômeno da refração e as ondas de leste apresentaram menor variação angular ao se aproximarem à costa. A deriva litorânea potencial anual para os dados de ondas de 2002 apresentou sentido norte-sul, com inversão de sentido durante o outono. Utilizando os dados de ondas previstas para o período dos levantamentos, a deriva litorânea potencial estimada apresentou sentido sul-norte, concordando com a migração observada. Na região próxima a desembocadura, nos pontais arenosos, a deriva potencial apresentou direção para o norte durante todas as estações. Os dados de descarga fluvial não apresentaram influência na migração do canal, porém apresentaram uma relação com a largura do mesmo sazonalmente.Os dados de morfologia juntamente com os dados de deriva litorânea referentes às ondas de 2004/2005 mostraram claramente a migração do canal para o norte sendo a deriva a principal contribuinte para a migração da desembocadura.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Changes in the Brazilian continental margins oceanic productivity and circulation over the last 27,000 years were reconstructed based on sedimentological and microfaunal analyses. Our results suggest that oceanic paleoproductivity and the supply of terrigenous sediments to the Brazilian continental margin were higher during the Last Glacial Maximum (LGM) than during the Holocene. These changes may have been primarily influenced by significant sea level fluctuations that have occurred since the late Pleistocene. During the LGM, the lower sea level, higher productivity and lower sea-surface paleotemperatures may have been the result of the offshore displacement of the main flow of the Brazil Current. However, during the Holocene, the warm waters of the Brazil Current were displaced toward the coast. This displacement contributed to the increase in water temperature and prevented an increase in oceanic productivity. The decrease in terrigenous supply since the LGM could be related to the increase of the extension of the continental shelf and/or drier climatic conditions.