Pedro De Podestà Uchôa de Aquino

Trophic structure of a fish community in Bananal stream subbasin in Brasília National Park, Cerrado biome (Brazilian Savanna), DF

O presente estudo foi desenvolvido com o objetivo de determinar a estrutura trofica da comunidade de peixes da sub-bacia do ribeirao Bananal pertencente a uma area bem preservada de Cerrado no Parque Nacional de Brasilia. Alem disso, buscou-se verificar a influencia das variacoes ambientais na dieta das especies. Em cada trecho de 30 m de extensao foram realizadas quatro amostragens, duas no periodo seco e duas no periodo chuvoso. Foram analisados 1050 estomagos pertencentes as 13 especies mais abundantes encontradas. No total, foram consumidos 36 itens alimentares sendo 24 autoctones, oito aloctones e quatro de origem indeterminada. A analise de escalonamento multidimensional nao-metrico (NMDS), juntamente com os resultados dos graficos de frequencia de ocorrencia e abundância, agrupou as especies em quatro guildas: detritivoros, onivoros (com tendencia a herbivoria e invertivoria), invertivoros e piscivoros. Cerca de 69% dos recursos consumidos pelos individuos foram de origem aloctone, o que evidencia a importância dos recursos advindos das matas de galeria. A contribuicao de presas autoctones e aloctones na dieta diferiu, de acordo com a estacao para Aspidoras fuscoguttatus, Astyanax sp., Characidium xanthopterum, Hyphessobrycon balbus, Kolpotocheirodon theloura, Moenkhausia sp., Phalloceros harpagos e Rivulus pictus. Apesar das caracteristicas climaticas do bioma Cerrado, nao houve influencia significativa da variacao sazonal na dieta. A ausencia de variacao sazonal e a predominância de itens aloctones na dieta provavelmente estao associadas a presenca de matas ciliares, que atuam como zonas de amortecimento e zonas provedoras de recursos para a biota aquatica. O presente estudo demonstra a importância de estudos em regioes integras para fornecer conhecimentos sobre a biologia das especies e permitir o direcionamento de acoes publicas para o manejo dos recursos aquaticos, para a recuperacao de areas degradadas e para a determinacao de areas prioritarias para a conservacao.

Amazonian freshwater habitats experiencing environmental and socioeconomic threats affecting subsistence fisheries

Matching the trend seen among the major large rivers of the globe, the Amazon River and its tributaries are facing aquatic ecosystem disruption that is affecting freshwater habitats and their associated biodiversity, including trends for decline in fishery resources. The Amazon’s aquatic ecosystems, linked natural resources, and human communities that depend on them are increasingly at risk from a number of identified threats, including expansion of agriculture; cattle pastures; infrastructure such as hydroelectric dams, logging, mining; and overfishing. The forest, which regulates the hydrological pulse, guaranteeing the distribution of rainfall and stabilizing seasonal flooding, has been affected by deforestation. Flooding dynamics of the Amazon Rivers are a major factor in regulating the intensity and timing of aquatic organisms. This study’s objective was to identify threats to the integrity of freshwater ecosystems, and to seek instruments for conservation and sustainable use, taking principally fish diversity and fisheries as factors for analysis.

Structure and integrity of fish assemblages in streams associated to conservation units in Central Brazil

This study aims to characterize the spatial and seasonal distribution of the fish assemblage and evaluate the integrity of streams in a sustainable use area that includes integral protection conservation units in Distrito Federal, Central Brazil (Cerrado biome). For the study, 12 stretches of 8 streams were sampled in 2008 (dry season) and 2009 (wet season). For that evaluation was estimated the Physical Habitat Index (PHI), vegetation cover (VC), pH, dissolved oxygen, turbidity, and conductivity. We recorded 22 species, about eight undescribed species, by a total of 2,327 individuals. The most representative families in number of species were Characidae (31.8%), Loricariidae (31.8%), and Crenuchidae (13.6%). Knodus moenkhausii was the most abundant species with 1,476 individuals, added to Astyanax sp., Phalloceros harpagos, and Hasemania sp. they represent over 95% of the total abundance. The species Astyanax sp. (occurring in 79.2% of the stretches) and K. moenkhausii (50.0%) were considered constant in both seasons. The longitudinal gradient (River Continuum) exerts a strong influence on the studied assemblage. According to CCA, the variables that structure the fish assemblage are based on aspects related to water volume and habitat complexity. No seasonal variation in richness, diversity, abundance, and mass were detected. A cluster analysis suggests a separation of species composition between the stretches of higher and lower orders, which was not observed for seasonality. The streams were considered well preserved (mean PHI 82.9±7.5%), but in some stretches were observed anthropogenic influence, detected in the water quality and, mainly, on the riparian vegetation integrity. The exotic species Poecilia reticulata was sampled in the two stretches considered most affected by anthropogenic activities by PHI, conductivity, and VC.

Ictiofauna dos córregos do Parque Nacional de Brasília, bacia do Alto Rio Paraná, Distrito Federal, Brasil Central

The aims of this study were to survey the stream fishes of Parque Nacional de Brasilia, Federal District, and identify its community structure variation. We sampled streams in the Bananal and Santa Maria/Torto sub-basins at Upper Parana River. Lotic systems in this region are well preserved, as indicated by environmental integrity and the maintenance of native biological components. A total of 8,614 individuals were collected belonging to four orders, nine families, and twenty-eight species (being 11 new to science). The predominant order was Characiformes, followed by Siluriformes. Poecilia reticulata was the only nonnative fish specie found. Astyanax sp. and Hyphessobrycon balbus displayed widest spatial distribution. The most abundant species was Knodus moenkhausii with 64.5% of individuals. Highest fish richness and abundance were found in the wider and deeper stretches.

A new species of Ituglanis (Siluriformes: Trichomycteridae) from the Tocantins and Paranaiba river basins, central Brazil, with remarks on the systematics of the genus

Ituglanis goya, new species, is described from the Paranaíba and Tocantins river drainages, central Brazil. This is the first species of the genus described for the Upper Paraná system and the second epigean Ituglanis for the Tocantins basin. The new species is distinguished from its congeners by the combination of a color pattern formed by longitudinal stripes and spots, absence of the anterior cranial fontanel, pattern of the cephalic laterosensory system and several fin-ray counts. Ituglanis goya exhibits morphological features that oppose the traditional hypotheses of alignment of the genus with the TSVSG clade of Trichomycteridae. These and other issues concerning the systematics of Ituglanis and the Trichomycterinae are critically discussed.

Pisces, Teleostei, Characiformes, Characidae, Hasemania crenuchoides Zarske and Géry, 1999, Hyphessobrycon balbus Myers, 1927 and Oligosarcus planaltinae Menezes and Géry, 1983: new records in Distrito Federal, Central Brazil

Herein we present new records of three freshwater fish species ( Hasemania crenuchoides , Hyphessobrycon balbus and Oligosarcus planaltinae ) considered restricted to Central Brazil and previously known only for the upper Rio Sao Bartolomeu sub-basin. Our data expand their range to other sub-basins in the Distrito Federal, including Sobradinho, Bananal, Santa Maria-Torto, Gama and Ribeirao Santana sub-basins.

Cytogenetic studies in Hasemania crenuchoides (Characiformes: Characidae) and molecular investigations into kinship relationships of the genus

ABSTRACT The genus Hasemania is considered incertae sedis from the family Characidae which possesses nine fish species. Hasemania crenuchoides is endemic to the Federal District of Brazil and is under threat of extinction. The objective of this work was to characterize the Hasemania crenuchoides karyotype and investigate phylogenetic relationships using the 5ʹ region of the COI gene. Our results showed a chromosome number of 2n = 50, with a fundamental number equal to 82 and a karyotype formula of 32m/sm+ 18st/a. C banding evidenced that constitutive heterochromatin is not only present in pericentromeric regions, but also in telomeric and interstitial regions. Ag-NOR marking occurred in the short arm of pair 6. DAPI staining revealed that few bands were rich in A/T. The diploid number observed is in accordance with previous findings in Characidae, including the presence of a long metacentric pair, and is considered a plesiomorphic character. Based on the literature, together with cytogenetic and molecular data, it is suggested that Hasemania is possibly not monophyletic, composed of two groups: (1) a basal group with H. hanseni and H. nana; and (2) a derived group with H. crenuchoides, H. kalunga, and H. uberaba. Therefore, the molecular and cytogenetic data presented may contribute to understanding phylogenetic relationships within the family.