Parasites of two populations of(Characiformes): Enemy release suggesting introduction of hosts in Neotropical streams.

Abstract

is a small characiform, originally described as endemic to the Iguaçu River basin. However, a recent study recorded a population ofin the Piquiri River basin (upper Paraná), although data on its geographic distribution and parasitological aspects are still limited. The study characterized the parasitic fauna ofin two streams, one from each basin, and compared them in terms of richness, diversity, and parasite community structure. Twenty-six females were collected in a stream in the lower Iguaçu River basin, and 25 females in a stream in the Piquiri River basin (upper Paraná) in September 2018. The parasite community structure ofdiffered between areas, with a predominance of monopisthocotyls and greater richness of parasitic taxa for hosts in the lower Iguaçu River basin. In the Piquiri River basin (upper Paraná), the parasite community was characterized by a higher prevalence of larval nematodes and a lower richness of parasite taxa. The differences in the richness and structure of the parasite communities between the two areas support the hypothesis of the introduction ofinto the Piquiri River basin (upper Paraná). Therefore, we emphasize the need for further studies addressing the distribution pattern of, as well as additional parasitological studies to determine whether the parasitological taxa ofare shared in other hydrological systems. This study contributes to the knowledge of the biological aspects ofin both basins and improves our understanding of how host-parasite interactions can be informative in species introduction scenarios.