Trace metal accumulation is infrapopulation-dependent in acanthocephalans parasites of the white mullet (Mugil curema) from an estuarine environment of southeastern Brazil coast.

Here, in an estuarine canal in southeast Brazil, we evaluated the potential for trace metal accumulation of the acanthocephalan parasite Floridosentis mugilis, which infects the fish host Mugil curema. The quantities of the trace metals were quantified using Inductively Coupled Plasma Mass Spectrometry (ICP-MS), which was used to analyze samples of the fish's muscle, intestine, and liver as well as the parasites. The parasites and the host's tissues had significantly different trace metal concentrations, according to our data. Furthermore, some metals have quite high bioconcentration factors, including Al, Cr, Ni, and Cd. We also found that the trace metal concentrations in the parasites were impacted by the sizes of the parasitic infrapopulations, with smaller infrapopulations tending to accumulate more metals. This study shows this acanthocephalan species' effective ability to store metals and is the first to investigate metal accumulation using it as a model.

Taxonomy and Systematics of Two New Species of Myxobolus (Cnidaria: Myxobolidae) Parasitizing the Gills of Mugil curema (Mugilidae) from the Brazilian Coast.

PURPOSE: We describe two new species of Myxobolus (Myxobolidae) found parasitizing Mugil curema from two locations in Brazil: Myxobolus curemae n. sp. from gill arch and rays and Myxobolus maceioensis n. sp. from gill lamellae. METHODS: We based the descriptions on myxospore morphology, histology, and small-subunit ribosomal DNA sequences. RESULTS: Myxospores of the two new species had similar morphology and morphometry but differed in spore body width and length, and ssrDNA sequences differed by 10.5%. These data supported the diagnosis of the parasites as distinct and novel species. The phylogenetic analysis showed a subclade formed by species that parasitize Mugiliformes, with M. maceioensis n. sp. as a sister species of Myxobolus episquamalis and Myxobolus bizerti, while there is a group of six species that are sister related to M. curemae n. sp. Our analysis was consistent with previous studies suggesting that orders of the hosts are strongly correlated with phylogenetic signals in the Myxobolidae. CONCLUSIONS: Myxobolus curemae n. sp. and M. maceioensis n. sp. are new species identified parasitizing M. curema.

First record of Hysterothylacium fabri (Rudolphi 1819) Deardorff and Overstreet 1980 from Scomber Colias of the South Atlantic waters.

Among several marine pelagic species of the Brazilian coast, Scomber colias Gmelin, 1789 (Perciformes: Scombridae) stands out for having great economic importance, since it is widely used as a food resource and presents moderate vulnerability. Twenty specimens of S. colias were purchased from October 2015 to October 2016 from the coast of Santa Catarina, Brazil. In the present study, we recorded Hysterothylacium fabri (Rudolphi, 1819) (Deardorff and Overstreet, Proc Biol Soc Wash 93(4):1035-1079 1980) from the S. colias intestine using an integrative taxonomy approach, where morphological data are used in combination with partial sequences of the ITS gene, to validate the taxonomic status of the species and establish their relationships with other members of the genus. This species is being recorded for the first time in the South Atlantic and S. colias. The specimens of H. fabri collected in this study parasitizing S. colias presented morphology similar to the other specimens already registered parasitizing other hosts. The distance matrix generated showed that the partial sequences obtained in this study were more similar to sequences of Hysterothylacium sp. collected in China. In phylogenetic analysis, the two detected haplotypes of this study were grouped with H. fabri haplotypes deposited in GenBank in a monophyletic subclade.

Biodiversity of the metazoan parasites of Prochilodus lineatus (Valenciennes, 1837) (Characiformes: Prochilodontidae) in anthropized environments from the Batalha River, São Paulo State, Brazil / Biodiversidade dos metazoários parasitos de Prochilodus lineatus (Valenciennes, 1837) (Characiformes: Prochilodontidae) em ambientes antropizados no rio Batalha, Estado de São Paulo, Brasil

Abstract: Biodiversity of fish parasites is a field of significant growth worldwide, whether due to the advancement of fish farms or the important role of these organisms as indicators of environment quality and ecosystem health, making them useful tools in the conservation and maintenance of the biodiversity as a whole. The objectives of this study were to evaluate the structure and composition of the parasitic fauna of Prochilodus lineatus collected from two structurally distinct stretches of the Batalha River. Fifty specimens of P. lineatus were collected between June 2015 and June 2016. Of these 50 hosts, 875 parasite specimens were collected, divided into 30 species, belonging to seven groups: Myxozoa, Monogenea, Digenea, Acanthocephala, Nematoda, Copepoda and Hirudinea. In addition to new records of known parasites of P. lineatus for this locality, 13 species were newly recorded parasitizing this fish, including a new monogenean species (Tereancistrum sp. n.), with Monogenea being the most representative class in the study. The findings of this study expands the known geographic distribution of these parasite species and helps to increase the knowledge of the biodiversity of these organisms in different hosts and environments. In general, the structure and composition of the P. lineatus parasitic fauna did not seem to be influenced by the structural characteristics of the two stretches studied, due to the migratory habits of the host.

Resumo: A biodiversidade de parasitos de peixes é um campo de pesquisa com significativo crescimento mundial, seja pelo aumento das pisciculturas ou pelo importante papel desses organismos como indicadores da qualidade do ambiente e da saúde do ecossistema, tornando-os importantes ferramentas na conservação e manutenção da biodiversidade como um todo. O objetivo desse estudo foi de avaliar a estrutura e composição da fauna parasitária de Prochilodus lineatus coletados em dois trechos estruturalmente distintos do rio Batalha. Cinquenta espécimes de P. lineatus foram coletados entre junho de 2015 e junho de 2016. Desses 50 hospedeiros, foram coletados 875 espécimes de parasitos, divididos em 30 espécies, pertencentes a sete grupos: Myxozoa, Monogenea, Digenea, Acanthocephala, Nematoda, Copepoda e Hirudinea. Além dos novos registros para a localidade com parasitos já observados parasitando P. lineatus anteriormente, obteve-se o novo registro de 13 espécies parasitando este peixe, além do registro de uma nova espécie de monogenético (Tereancistrum sp. n.). Os achados desse estudo expandem a distribuição geográfica dessas espécies de parasitos e ajudam a aumentar o conhecimento da biodiversidade desses organismos em diferentes hospedeiros e ambientes. De modo geral, a estrutura e composição da fauna parasitária de P. lineatus não pareceu ser influenciada por características estruturais dos dois trechos estudados, devido aos hábitos migratórios do hospedeiro.