Taxonomia e ecologia dos parasitos branquiais de Serrasalmus marginatus Valenciennes, 1837 (Characiformes: Serrasalminae) da planície de inundação do alto rio Paraná, PR/MS, Brasil.

Serrasalmus marginatus Valenciennes, 1837, is one of the most abundant fish species in the Upper Paraná River floodplain, where the region has to occur after the flooding of the Seven Falls for the construction of the Itaipu reservoir in 1983. To the knowledge of gill parasite fauna this fish were analyzed 61 specimens. Fish were collected in February 2008, in the upper Paraná River floodplain, in ponds of Paraná subsystems, Ivinheima and Baia. Parasites of 15 taxa were collected, these three groups of metazoans: Monogenea, Digeneans and Acarina. This fish includes a variety of species belonging to monogenetic Dactylogyridae family and representatives of two subfamilies - Anacanthorinae and Ancyrocephalinae differentiated mainly by morphological characteristics of sclerotized structures (sclerites haptor and the copulatory complex). host of features as standard length (LS), sex and relative condition factor (Kn) of the host, in general, did not influence the prevalence, wealth, abundance and diversity of parasites. abundance patterns, wealth, dominance, Brillouin diversity and co-occurrence of the parasites, as well as ordering gradients based on the abundance indicated differences between infracommunities of gill parasites of subsystems, primarily highlighting the differences between infracommunities parasites of Paraná and Baia subsystems. The subsystem Ivinheima presented an intermediate position to the other, as the gill parasites of S. marginatus. The absence of interspecific associations between species most prevalent parasites in different subsystems analyzed and the lack of correlation between infrapopulations of parasites with the characteristics of each host demonstrates the important role of habitat features in the structure of S. gill parasites infracommunities marginatus of the subsystems of the Upper Paraná river floodplain.