Parasite biodiversity of Leporinus piau Fowler, 1941 (Characiformes, Anostomidae) in a lentic ecosystem from the Salgado River basin, Caatinga Domain, Brazil.

Leporinus piau is a freshwater fish belonging to the family Anostomidae, popularly known as "piau" in Brazil. This species has wide distribution in Brazilian northeast basins and presents an economic and sporting fishing importance. The present study aims to inventory the parasitofauna of L. piau of a freshwater ecosystem of Caatinga domain (Brazil). A total of 598 parasite specimens were recovered from nine parasitized hosts, belonging to four taxonomic groups: one Myxozoa (Henneguya sp.); four Monogenea (Dactylogyridae gen. sp., Jainus sp., Urocleidoides sp. 1 and Urocleidoides sp. 2); one Nematoda (Procamallanus (Spirocamallanus) inopinatus) and two Copepoda (Ergasilus sp. and Gamispatulus schizodontis). Previous studies reported five parasitic associations in L. piau: two nematodes (P. (S.) inopinatus and Procamallanus (Spirocamallanus) saofrancicencis) and three crustaceans (Argulus sp., Brasergasilus sp. and Ergasilus sp.). For the first time, this study records myxozoan and monogeneans parasitizing the host L. piau. The present study stands out the importance of the knowledge of the parasite biodiversity of freshwater fish in neotropics, reporting new occurrences and parasitic association for ichthyofauna of the Caatinga domain.

Metazoan parasite community of Hoplias malabaricus (Characiformes, Erythrinidae) in a stream of Caatinga domain, Brazil.

We purpose to describe and characterize the structure of the parasitic community of H. malabaricus in a stream from Caatinga domain, Ceará state, Brazil. A total of 42 specimens of H. malabaricus have been collected between December 2018 and August 2019, in which, 34 specimens were parasitized by at least one parasite. A total of 1,872 parasites were recovered, of which, 157 were Urocleidoides cuiabai (prevalence = 50%), 268 Urocleidodes brasiliensis (prevalence = 71.43%), 98 Dactylogyridae gen. sp. (prevalence = 14.29%), 401 Diplostomidae gen. sp. (prevalence = 4.76%), 183 Spiroxys sp. (prevalence = 42.86%) and 765 Pindapixara tarira (prevalence = 9.52%). The respective parasite species of H. malabaricus showed a pattern of overdispersion (or aggregation) typical of the parasitehost systems, corroborating with previous studies of parasitic communities of freshwater fish in Brazil. A positive and significant correlation between the host size and abundance of U. brasiliensis was verified. The ontogeny of fish can influence the parasitic load, some larger hosts tend to host larger quantities of parasites. The parasitic levels can vary with the host sex due to the differences in the ecological and physiological interactions between male and female. However, the host sex did not show influences in the prevalence and parasitic burden. All parasite taxa in this study have not yet been reported in the Carás stream, Caatinga domain. This finding extends the geographical distribution of this parasite species, furthermore, contributing to the knowledge of the biodiversity of fish parasites in the Neotropical region.

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.