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This study assessed the feeding strategies of nine fish species in their native (Cuiaba River) and in an invaded basin (upper Parana River) to identify trophic variables that may explain the success of these species in the new basin, over 30 years. The following predictions were analyzed: (i) species that display omnivorous or piscivorous diets in the native basin are favored in the invasion process over the long term, and (ii) specialist feeders are favored in the invasion process provided that their food items are highly available in the invaded area. These predictions were supported by the data; the species that were successful invaders had high trophic plasticity (omnivores), consumed a wide variety of food items from specific trophic guilds (piscivores), or if a species had a specialized diet, the resources demanded are abundant (detritivores). Thus, in a long-term perspective, the food resources used by these species are rarely limiting in aquatic ecosystems, and these feeding characteristics should be one of the key factors determining the colonization success of fishes. Understanding the factors that determine the success of invasive species in new areas is critical for developing management policies aimed at minimizing the impacts of biological invasions.

A new species of Moenkhausia is described from the upper rio Tocantins basin, States of Goiás and Tocantins, Brazil. Moenkhausia goya, new species, can be distinguished from its congeners by the shape of the humeral blotch in combination with a uniform dark pigmentation covering the interradial membranes of the dorsal and anal fins. Among congeners, the new species is most similar to M. britskii Azevedo-Santos & Benine, M. grandisquamis (Müller & Troschel) and M. xinguensis Steindachner by presenting a deep body, a large, round humeral blotch and fins without discrete patches of dark pigmentation (i.e., without well-defined blotches or stripes). With the description of M. goya, the number of species endemic to the upper rio Tocantins basin (considered upstream from the mouth of the rio Paranã) is raised to 51. Of these, some are widespread in the upper rio Tocantins basin, while others seem to be restricted to one of its sub-basins.