Variation in the parasite community of the sardine fish Triportheus nematurus (Actinopterygii: Characidae) from the Medalha lagoon in the Pantanal wetland, Brazil

Diversity of Nematoda and Digenea from different species of characiform fishes from Tocantins River, Maranhão, Brazil

During a survey of the helminth fauna of characiform fishes from the Tocantins River, Brazil, 185 fish specimens from 22 species were studied. Twelve species of Nematoda and nine species of Digenea were collected. Some of these helminth species were reported for the first time in their hosts, thus representing new host records: Procamallanus (Spirocamallanus) sp. in Bivibranchia notata, Brycon pesu, Chalceus macrolepidotus, Hemiodus microlepis and Hemiodus unimaculatus; Procamallanus (Spirocamallanus) inopinatus in Triportheus elongatus; Goezia sp. (larva) in Boulengerella cuvieri; Rhabdochona acuminata in Brycon pesu and Triportheus trifurcatus; Raphidascaris sp. (larva) in Caenotropus labyrinthicus; Cosmoxynema vianai in Cyphocharax gouldingi; Rondonia rondoni in Leporinus fasciatus and Mylesinus paucisquamatus; Klossinemella iheringi in Mylesinus paucisquamatus; Cucullanidae gen. sp. in Myloplus rubripinnis; Rhabdochona sp. in Triportheus elongatus; Alphamphistoma sp. in Myleus setiger; Chalcinotrema sp. in Cyphocharax gouldingi; Pacudistoma guianense in Hemiodus unimaculatus and Myleus torquatus; Pseudocladorchis cylindricus in Hemiodus unimaculatus; Dadaytrema oxycephala in Mylesinus paucisquamatus; Travassosinia dilatata in Myloplus asterias; and Genarchella genarchella in Raphiodon vulpinus. Studies identifying new hosts and new localities for parasites have contributed to the knowledge of local biodiversity. A list of previous records of helminths included in the present study, providing hosts, localities, and references, is presented here.

Ectoparasites community in Satanoperca jurupari (Cichlidae) from the Jari River, a tributary from Amazon River in Northern Brazil

The aim of this study was to investigate the gills parasites in Satanoperca jurupari from the Jari River, state of Amapá, in eastern Amazon (Brazil). The gills of 100% of the hosts were parasitized by Ichthyophthirius multifiliis (Protozoa), Sciadicleithrum juruparii (Monogenoidea) Genarchella genarchella, Posthodiplostomum sp. (Digenea) Ergasilus coatiarus and Argulus multicolor (Crustacea), and a total of 27,043 parasites were collected. However, the dominance was of I. multifiliis and there was aggregated dispersion of parasites with greater discrepancy for S. juruparii and A. multicolor. Low species richness of parasites (3.1 ± 1.1), low Brillouin diversity index (0.27 ± 0.23), low evenness (0.16 ± 0.13) and high dominance of Berger-Parker (0.88 ± 0.15) were found. The community of parasites in S. jurupari was characterized by low species richness, low diversity and low evenness, with high prevalence and low abundance. The size of host did not have any influence on the parasites community, but the host behavior and availability of infective stages of the parasites were factors structuring the community of ectoparasites found here.

Helmintos endoparasitos de vertebrados silvestres em Mato Grosso do Sul, Brasil

RESUMO Uma lista de espécies de vertebrados silvestres e as espécies de helmintos endoparasitos associadas foi organizada para o estado de Mato Grosso do Sul. Foram encontrados registros de 291 espécies de helmintos endoparasitos, sendo 9 de Acanthocephala, 226 de Nematoda e 65 espécies de Platyhelminthes (23 de Cestoda e 42 de Trematoda) associadas a 20 espécies de peixes, nove de anfíbios, 17 de répteis, 103 de aves e 27 espécies de mamíferos. Apenas 12% dos vertebrados do estado foram estudados quanto a sua parasitofauna, ressaltando o quanto a biodiversidade de helmintos parasitos no estado ainda é subestimada.

First study on communities of parasites in Triportheus rotundatus, a Characidae fish from the Amazon River system (Brazil)

This study was the first investigation on the parasites of Triportheus rotundatus, a Characiformes fish from the Amazon, in Brazil. All the fish collected (100%) in a tributary from the Amazon River system were infected by one or more parasite species. The mean species richness of parasites was 4.9 ± 0.9, the Brillouin index was 0.39 ± 0.16, the evenness was 0.24 ± 0.09 and the Berger-Parker dominance was 0.81 ± 0.13. A total of 1316 metazoan parasites were collected, including Anacanthorus pithophallus, Anacanthorus furculus, Ancistrohaptor sp. (Dactylogyridae), Genarchella genarchella (Derogenidae), Posthodiplostomum sp. (Diplostomidae), Procamallanus (Spirocamallanus) inopinatus (Camallanidae), Echinorhynchus paranensis (Echinorhynchidae) and Ergasilus sp. (Ergasilidae), but monogenoideans were the dominant parasites. These parasites presented an aggregate dispersion pattern, except for P. (S.) inopinatus, which showed a random dispersion pattern. The body conditions of the hosts were not affected by the parasitism levels. This first report of these parasites for T. rotundatus indicates that the presence of ectoparasites and endoparasites was due to hosts behavior and availability of infective stages in the environment, and this was discussed.

Functional morphology of the tetra fish Astyanax lacustris differs between divergent habitats in the Pantanal wetlands

This study investigated whether the body morphology of the tetra fish Astyanax lacustris (previously Astyanax asuncionensis) varied between populations inhabiting one lagoon (a lentic, shallow environment, with great habitat complexity created by aquatic macrophytes) and an adjacent river (a deeper, lotic environment where aquatic macrophytes are scarce) in a seasonally flooded wetland, despite population mixing during the wet season. Morphological differences matched a priori predictions of the theory relating functional body morphology and swimming performance in fishes between lagoon and river habitats. Observed morphological variation could have resulted from adaptive habitat choice by tetras, predation by piscivores and adaptive phenotypic plasticity during development.