Diversity and community ecology of metazoan parasites in Tetragonopterus argenteus Cuvier, 1816 (Characiformes, Characidae) from Jaguaribe River basin in Brazil.

The present study aims to inventory the metazoan parasites of Tetragonopterus argenteus from the Lima Campos weir, municipality of Icó, Ceará, Brazil and to analyze the influence of the host size and sex on the prevalence and parasitic abundance. A total of 359 metazoan parasites specimens were collected from 54 specimens of T. argenteus, presenting a mean intensity of 7.04 parasites/fish and prevalence of 94%. A richness of 10 parasite taxa were recorded, taxonomically classified into the following groups: Monogenea (n=1), Digenea (n=2) and Nematoda (n=7). The parasite community of T. argenteus was composed of helminth species with low prevalence, low mean intensity, low mean abundance, low dominance and low diversity, predominance of endoparasites of the phylum Nematoda. As for the importance value, six species were considered secondary and showed an aggregated dispersion pattern. The host size influenced significantly the abundance of Creptrotrema sp. and the prevalence of Procamallanus (Spirocamallanus) hilarii. The results present new reports of parasites have been recorded for this host, thus expanding the ecological interactions between parasites and Characiformes fish and contributing to the knowledge of the freshwater biodiversity from Brazilian Caatinga domain.