Abstract: Twig girdlers have a short adult life and a long larval stage (up to one year in some species). This fact, together with lack of morphological traits to identify the species from the larval stage, poses obstacles for the taxonomic identification and characterization of the many twig girdlers found in the wild. To solve this matter, Random Amplified Polymorphic DNA (RAPD) molecular markers have been applied to identify some insect species and to determine species boundaries. The aim of this study was to identify three species of Oncideres using the RAPD technique. Adults and larvae of O. saga, O. ocularis and O. ulcerosa were collected in Minas Gerais, Brazil. Two RAPD primers were used (OPA-05 and OPB-13), which produced different electrophoretic profiles that were used to construct a UPGMA phenogram. Three groups identified in the analyses accurately separated the three species, based on individuals in two different stages of development (adults and larvae): I: O. saga, II: O. ulcerosa, and III: O. ocularis. Molecular markers, such as RAPD, are valuable tools that help taxonomists in species identification.

ABSTRACT The objective of this study was to compare ecohydrological simulations from a one-dimensional model (PHABSIM - Physical Habitat Simulation System) and a two-dimensional model (River2D) in order to indicate a reliable tool that could be used to determine public policies for the sustainable management of the water resources of the FormosoRiver basin(MG). The results from the calibration of hydraulic variables, namely, water depth and velocity, as well as habitat predictions for three fish species of the river were compared. The results showed that River 2D was best suited to simulate ecohydrological features for the studied river stretch. Although PHABSIM presented a better fit of the hydraulic variables at the calibration process, the use of only three monitoring cross sections to compose the biotic model database compromised its habitat modeling. PHABSIM model was not able to accurately assess the actual characteristics of the physical habitat in the segments of the river located between the monitoring cross sections.

ABSTRACT This paper aimed at determining the environmental flow regime in a 1 km stretch of the Formoso River, MG, using River2D model. To carry out the ecohydrological modeling, the following information was used: bathymetry, physical and hydraulic features, and the Habitat Suitability Index for species of the Hypostomus auroguttatus. In the River2D, the Weighted Usable Areas were determined from the average long-term streamflows with percentage from 10% to 100%. Those streamflows were simulated for the later construction of optimization matrices that maximize the habitat area throughout the year. For H. auroguttatus Juvenile, higher values of Weighted Usable Area were associated with the percentage of 60% and 70% of the average long-term streamflows in October and September, respectively. For H. auroguttatus Adult, the highest value of Weighted Usable Area was associated with the percentage of 100% of the average long-term streamflow in September. The environmental flows found for this stretch of the Formoso River varied over the year. The lowest environmental flow was observed in December (2.85 m3 s-1), while the highest was observed in May (4.13 m3 s-1). This paper shows the importance of ecohydrological studies in forming a basis for water resources management actions.

Uma nova espécie de caracídeo, Hyphessobrycon vinaceus é descrita para o alto rio Pardo, Minas Gerais, Brasil. A nova espécie distingue-se das demais espécies de Hyphessobrycon pela combinação dos seguintes caracteres: coloração avermelhada do corpo em vida, uma mancha umeral preta e conspícua verticalmente alongada seguida de uma segunda mancha umeral fracamente pigmentada, 5 dentes na série interna do pré-maxilar, 2-3 dentes pentacuspidados no maxilar, 15-17 raios ramificados na nadadeira anal, 4-5 escamas acima e 3-4 escamas abaixo da linha lateral, 10-26 escamas perfuradas na linha lateral, 32-34 escamas em uma série longitudinal e menor comprimento da cabeça em relação ao comprimento padrão (23,9-26,7%).

A new species of characid, Hyphessobrycon vinaceus, is described from the upper rio Pardo, Minas Gerais, Brazil. The new species is distinguished from all other Hyphessobrycon species by the combination of the following characters: the body red or reddish pigmented in live specimens, an anterior and conspicuous vertically elongate black humeral spot followed by a second faint humeral spot, 5 teeth in the inner series of premaxilla, maxilla with 2-3 pentacuspidate teeth, 15-17 branched anal-fin rays, 4-5 scale rows above and 3-4 scale rows below lateral line, lateral line with 10-26 perforated scales, 32-34 scales in a longitudinal series, and by a smaller head length in relation to standard length (23.9-26.7%).

In the Rio Doce basin of southeastern Brazil, the freshwater fish Hoplias malabaricus (trahira) is a widespread predatory characin and one of the few resilient native fishes in a highly impacted lake system. In order to test for genetic differentiation in populations within this basin and for biogeographic relationships among populations of this species in other basins, a study was conducted using RAPD-PCR analysis of Rio Doce samples (N = 63) and phylogeographic analyses with mitochondrial DNA (mtDNA) haplotypes, including the Rio Grande and Macacu river basins. In the Rio Doce basin, the patterns of genetic similarity of RAPD-PCR markers (individual fingerprinting and Nei’s genetic distance) suggest the existence of two genetically different groups, one composed of the lacustrine populations Carioca and Dom Helvécio, and the other of riverine and the remaining lacustrine populations. The differences in the RAPD-PCR patterns may be explained by the existence of sub-basins within this lacustrine system. A maximum parsimony tree of cytochrome b fragment (383 base pairs) supports the view that trahiras of the Rio Doce share a complex biogeographic history with those of neighboring basins. The phylogeographic patterns may be explained by a common history of the watersheds of the Rio Doce, Paraíba do Sul, and Rio Grande basins, corroborating the hypothesis of a Plio-Pleistocene separation of these drainage systems, forming the Mantiqueira "divortium aquarium".

Hoplias malabaricus, a traíra, colonizou o Rio Iguaçu nas últimas décadas. Numa tentativa de determinar os níveis de diferenciação genética deste taxon nominal em bacias vizinhas, assim como a origem da população colonizadora, foram analisados os padrões de similaridade de marcadores genômicos do tipo randomly amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) de amostras dos rios Paraná, Iguaçu, e Tibagi. As amostras do Paraná e do Tibagi apresentaram elevados índices de diversidade genética, os quais sugerem a ocorrência de espécies diferentes nestes rios. Todos os alelos presentes na população da cabeceira do rio Tibagi ocorreram também na amostra do rio Iguaçu. Esta semelhança permite-nos sugerir que a população da cabeceira do rio Tibagi (ou alguma população com características genéticas semelhantes) possa ser a origem da população amostrada no rio Iguaçu.

Hoplias malabaricus, the common trahira, extended its range into the Iguaçu River sometime in the last decades. To determine levels of genetic differentiation in neighboring basins of this nominal taxon, as well as to unveil the source of the invading population, we analyzed patterns of similarity of RAPD-PCR genomic markers of samples from Paraná, Iguaçu and Tibagi Rivers. The high genetic diversity of samples from the Paraná and Tibagi Rivers suggested strong population structuring or even the occurrence of undescribed species. All alleles of the sample from the headwaters of Tibagi River were present in the sample from the Iguaçu River, which suggests that the former population or another population with similar genetic makeup, may be the source of the trahiras of the Iguaçu River.