Fagner de Souza

Ecomorphological differences between Rhamdia (Bleeker, 1858) populations from the Iguaçu River basin

Morphological and genetic evidences suggest that Rhamdia branneri and Rhamdia voulezi, currently considered synonymous of Rhamdia quelen, are in fact two valid species. Furthermore, in the taxonomic revision of R. quelen, no exemplars from the Iguacu River were examined, which makes the synonymy doubtful. Considering the two species as valid, it was hypothesized that R. branneri and R. voulezi have ecomorphological differences, with the objective to verify if they can be considered ecologically distinct. Ecomorphological characterization was conducted using ecomorphological indices. For statistical analysis, a Principal Component Analysis (PCA), a Multiresponse Permutation Procedure (MRPP), and a Discriminant Analysis (DA) were performed. The ordination provided by the PCA evidenced ecomorphological separation, with R. branneri having morphological aspects related to benthic fishes, and R. voulezi having morphological characteristics related to pelagic and lentic habitats. The DA results confirmed the morphological tendencies found in the PCA, and the MRPP showed significant statistical differences between the ecomorphology of Rhamdia species. In this way, the initial hypothesis can be corroborated. These results allied to information about diet, genetics, and reproduction can be helpful for the elucidation of the taxonomic status of R. branneri and R. voulezi.

Widening the geographical distribution of Pimelodus mysteriosus Azpelicueta 1998 (Siluriformes: Pimelodidae) to the upper Paraná River, with diagnosis for syntopic congeners

Pimelodus mysteriosus Azpelicueta 1998, previously known only from the lower Paranaand Paraguay River basins, has been also recorded in the upper ParanaRiver floodplain. The only congeners occurring in syntopy with P. mysteriosus in the upper ParanaRiver basin are P. maculatus and P. ornatus. New diagnostic characters between P. mysteriosus and P. maculatus are provided.

Intraspecific ecomorphological variations in Poecilia reticulata (Actinopterygii, Cyprinodontiformes): comparing populations of distinct environments

Morphological variations, according to the principles of ecomorphology, can be related to different aspects of the organism way of life, such as occupation of habitats and feeding behavior. The present study sought to examine the intraspecific variation in two populations of Poecilia reticulata Peters, 1859, that occur in two types of environments, a lotic (Maringa Stream) and a lentic (Jaboti Lake). Due to a marked sexual dimorphism, males and females were analyzed separately. Thus, the proposed hypotheses were that the populations that occur in distinct environments present morphological differences. The morphological variables were obtained using morphometric measurements and the ecomorphological indexes. The data were summarized in a Principal Component Analysis (PCA). A Multivariate Analysis of Variance (Manova) was made to verify significant differences in morphology between the populations. Males and females showed similar ecomorphological patterns according to the environment they occur. In general the population from Maringa Stream had fins with major areas, and the Jaboti Lake population eyes located more dorsally. Additionally, others morphological differences such as wider mouth of the males from Maringa Stream, wider heads on Jaboti Lake females and more protractible mouths on males from Jaboti Lake suggest a set of environmental variables that can possibly influence the ecomorphological patterns of the populations, as the water current, availability of food resources and predation. In summary, the initial hypotheses could be confirmed, evidencing the occurrence of distinct ecomorphotypes in the same species according to the environment type.

Variação espacial na estrutura da ictiofauna em Dois Riachos na Bacia do Rio Pirapó / Spatial variation in the structure of ichthyofauna on Two Streams in Pirapó River Basin

Varios fatores podem influenciar na estrutura espacial de uma assembleia ictiofaunistica, que podem ser de origem natural ou de origem antropica. Os impactos de origem antropicas sao de extrema importância pois afetam de forma intermitente os ambientes aquaticos. Neste sentido,testamos a hipotese de que corregos mais proximos a areas urbanas sofrem mais impactos do que os mais distantes, os quais influenciam negativamente os parâmetros ecologicos de diversidade de especies. Nossos objetivos foram de realizar um levantamento rapido da assembleia de peixes em dois corregos na bacia do alto rio Pirapo, relacionando-o com os impactos antropicos causados em uma dimensao espacial. Para isso, realizamos um levantamento com tres pontos de amostragem (montante, medio curso e jusante). Em cada corrego e realizamos comparacoes estruturais entre os parâmetros biometricos, de biomassa e bioticos. Foram coletados 357 individuos, pertencentes a 11 especies. Os maiores valores biometricos e de biomassa, nas especies que co-ocorrem entre os corregos, foram no corrego Indaia, exceto para duas especies. O corrego Ipigua apresentou maiores valores na riqueza e nos indices de diversidade de especies. Estes valores podem estar relacionados aos impactos antropicos gerados nos locais mais proximos as areas urbanas, influenciando a disponibilidade de habitats e a biodiversidade. Foram constatados impactos negativos na comparacao entre os corpos d’agua, sugerindo que estes ambientes devem receber uma atencao dos orgaos governamentais e da sociedade.