Seven new species of Urocleidoides (Monogenea: Dactylogyridae) from Brazilian fishes supported by morphological and molecular data.

Seven new species of Urocleidoides from the gills and skin of nine Neotropical fish hosts (Anostomidae, Parodontidae, and Gymnotidae) are described: Urocleidoides digitabulum n. sp. on Leporinus friderici, Leporinus octofasciatus, and Megaleporinus elongatus (Anostomidae); Urocleidoides solarivaginatus n. sp. on L. friderici, L. octofasciatus, and Leporinus striatus (Anostomidae); Urocleidoides falxus n. sp. and Urocleidoides sapucaiensis n. sp. on M. elongatus; Urocleidoides tenuis n. sp. on Apareiodon piracicabae and Apareiodon affinis (Parodontidae); Urocleidoides sinus n. sp. on L. striatus, Schizodon nasutus, and Schizodon intermedius (Anostomidae); and Urocleidoides uncinus n. sp. on Gymnotus sylvius (Gymnotidae). Urocleidoides paradoxus was also found in this study on L. friderici and included in the phylogenetic analysis. Molecular data (partial 28S rDNA and mitochondrial cytochrome oxidase subunit I) were obtained for U. digitabulum n. sp., U. tenuis n. sp., U. sinus n. sp., and U. uncinus n. sp. The identification of Urocleidoides is amended herein to include all taxonomic modifications observed in this genus over time and add new characteristics observed in the species in the present study. Phylogenetic analysis revealed Urocleidoides digitabulum n. sp. and Urocleidoides sinus n. sp. (parasites of anostomids) closely related in the tree topologies. Furthermore, the new species described herein parasitized phylogenetically distant host species (Characiformes and Gymnotiformes), suggesting the effect of the dynamic process of ecological fitting.

New data on Myxobolus imparfinis (Cnidaria, Myxosporea): host, distribution, and ultrastructural morphology.

A mass of free myxozoan spores was found in the gill filaments of specimens of Cetopsorhamdia iheringi Schubart and Gomes, 1959, popularly known as "three-barbeled catfishes" (Heptapteridae, Siluriformes) collected in streams of the Middle Paranapanema River, Upper Paraná River basin, in the state of São Paulo, Brazil. Morphological and molecular analysis identified the spores as Myxobolus imparfinis Vieira, Tagliavini, Abdallah and Azevedo, 2018. The ultrastructural morphology of this parasite is described here for the first time. Differences were observed in the number of coils of the polar filament as well as some organelles not previously described for this species. Asynchronous development was also observed, with the presence of both mature and immature spores. This is the first report of a myxozoan parasitizing C. iheringi and the first geographical record of myxozoan parasites in streams of the Middle Paranapanema River. The new data improve the original description of the species and add to the knowledge of host-parasite interactions and distribution.

Parasites of Astyanax lacustris (Pisces, Characiformes) from Brazilian streams.

Astyanax lacustris is a small characid fish widely distributed in Brazil, with fast-growing and omnivorous feeding habits. Although the species presents economic and ecological importance, little is known about its parasitological fauna in stream environments. This study aimed to characterize the parasitic fauna of A. lacustris in two streams in the state of Paraná, Brazil. Fifty-two specimens of A. lacustris were collected, 22 from the Carolina stream (Lower Iguaçu River) and 30 from the Carreira stream (Upper Paraná River), in July and September 2018. In both streams, there was a low richness of parasites, and the structure of the parasitic community was predominantly composed of monogeneans. These findings may be associated with the gregarious behavior of the host species. Moreover, the low occurrence of endohelminths, may be associated with the fact that in streams, the energy flow is low, and depends directly on the input of allochthonous matter, which favors the formation of shelters for the establishment of macroinvertebrates, which represent important sources of food for the ichthyofauna, and may act as intermediate and paratenic hosts of parasites. These environments require further studies to support conservation measures aimed at maintaining the balance of ecological relationships in these preserved ecosystems.

Morphological, ultrastructural, and molecular analysis of a new species of Myxobolus (Cnidaria, Myxosporea) parasitizing Apareiodon piracicabae (Characiformes, Parodontidae) from Brazil.

About forty-two species of Myxobolus have been previously described to parasitize characiform fishes in South America. Here, we described a new myxozoan species, Myxobolus parodontidis n. sp., in the gills of Apareiodon piracicabae (Characiformes, Parodontidae) from the streams of the Middle Paranapanema River basin, Brazil. The proposed new species is supported by a combination of morphological, ultrastructural, and molecular characterization (small subunit ribosomal DNA). Thirteen specimens of A. piracicabae were analyzed and 30.8% was infected by Myxobolus parodontidis n. sp. The myxospores was classified as intralamellar asymmetric type. A few aberrant myxospores with three polar capsules were observed: the spore length and width were the same of normal myxospores, but the polar capsules had smaller sizes. Ultrastructural analysis showed that the plasmodial membrane of Myxobolus parodontidis n. sp. was in direct contact with the host tissue and a connective capsule surrounding the plasmodium was not observed. The phylogenetic analysis showed that the main influence in the clustering of species of myxobolids seems to be related to the phylogenetic relationships established among fish hosts, mainly at the level of family and order. This is the first record of a myxozoan species parasitizing parodontid fish, contributing to the knowledge of the biodiversity of myxozoans from Brazil.

Henneguya polarislonga n. sp. (Cnidaria: Myxosporea) parasitizing Astyanax lacustris (Lütken, 1875) with an insight on its life cycle.

Henneguya polarislonga n. sp. is described from the gills of Astyanax lacustris (Lütken, 1875) (Characiformes, Characidae) from streams of the Middle Paranapanema River, Upper Paraná River basin, in the São Paulo State, Brazil. The proposed new species is supported by a combination of morphological and molecular characterization (partial fragment of the SSU rDNA). Thirty specimens of A. lacustris were analyzed and myxospores were found in the gill lamellae of one specimen (Prevalence = 3.3%). Henneguya polarislonga n. sp. was morphometrically and genetically distinct from other Henneguya spp. previously described in Astyanax spp., mainly differing in the total length and caudal appendages length of the mature myxospores. Comparative analysis of the SSU rDNA sequences revealed that Seisactinomyxon-type actinospores previously reported parasitizing oligochaetes are developmental stages of the life cycle of Henneguya polarislonga n. sp. (similarity of 99.9%). This is the first time that an actinospore and a myxospore are correlated through molecular analysis in Brazil, contributing to the knowledge of the myxozoan ecology and biodiversity.

Three new species of Creptotrema (Trematoda, Allocreadiidae) with an amended diagnosis of the genus and reassignment of Auriculostoma (Allocreadiidae), based on morphological and molecular evidence.

Diversity of Creptotrema was investigated using morphological and molecular tools, including data for Creptotrema creptotrema (type-species). Three new species, parasites of Brazilian fishes, are described: Creptotrema conconae n. sp. (type-host, Imparfinis mirini Haseman), Creptotrema schubarti n. sp. (type-host, Characidium schubarti Travassos) and Creptotrema megacetabularis n. sp. (type-host, Auchenipterus osteomystax (Miranda Ribeiro)). The diagnosis of the genus was amended to include new features. The new species differ from each other mainly in terms of body shape, relative sucker size, and testes position. DNA sequences were obtained from Creptotrema spp. from Brazil, including 28S, ITS and COI. Genetic divergences among the new species and C. creptotrema varied from 2.1 to 5.2% (21-49 bp) for 28S, and 6.6 to 16.4% (21-45 bp) for COI. Phylogenetic analysis (28S) placed the newly generated DNA sequences of Creptotrema in a clade (Creptotrema clade sensu stricto) composed of C. creptotrema, the new species described herein, and all species previously described as Auriculostoma, revealing that Auriculostoma is best interpreted as a synonym of Creptotrema based on the principle of priority of zoological nomenclature. Creptotrema funduli, the single sequence of the genus previously available, was not grouped within the Creptotrema clade sensu stricto, suggesting the need for reevaluation of the taxonomic status of this species. Our results showed that Creptotrema represents a monophyletic genus of trematodes widely distributed across the Americas, which currently comprises 19 valid species of parasites of teleosts and anurans.

TITLE: Trois nouvelles espèces de Creptotrema (Trematoda, Allocreadiidae) avec diagnostic modifié du genre et une réattribution d'Auriculostoma (Allocreadiidae) sur la base de preuves morphologiques et moléculaires. ABSTRACT: La diversité de Creptotrema a été étudiée à l'aide d'outils morphologiques et moléculaires, incluant des données pour Creptotrema creptotrema (espèce-type). Trois nouvelles espèces, parasites de poissons brésiliens, sont décrites : Creptotrema conconae n. sp. (hôte-type, Imparfinis mirini Haseman), Creptotrema schubarti n. sp. (hôte-type, Characidium schubarti Travassos) et Creptotrema megacetabularis n. sp. (hôte-type, Auchenipterus osteomystax (Miranda Ribeiro)). Le diagnostic du genre a été modifié pour inclure de nouvelles caractéristiques. Les nouvelles espèces diffèrent les unes des autres principalement en termes de forme du corps, de taille relative des ventouses et de position des testicules. Des séquences d'ADN ont été obtenues de Creptotrema spp. du Brésil, y compris 28S, ITS et COI. Les divergences génétiques entre les nouvelles espèces et C. creptotrema variaient de 2,1 à 5,2 % (21 à 49 pb) pour les séquences 28S, et de 6,6 à 16,4 % (21 à 45 pb) pour le COI. L'analyse phylogénétique (28S) a placé les séquences d'ADN nouvellement générées de Creptotrema dans un clade (Creptotrema clade sensu stricto) composé de C. creptotrema, les nouvelles espèces décrites ici et toutes les espèces précédemment décrites comme Auriculostoma, révélant qu'Auriculostoma est mieux interprété comme un synonyme de Creptotrema sur la base du principe de priorité de la nomenclature zoologique. Creptotrema funduli, la seule séquence du genre précédemment disponible, n'a pas été regroupée au sein du clade Creptotrema sensu stricto, ce qui suggère la nécessité d'une réévaluation du statut taxonomique de cette espèce. Nos résultats montrent que Creptotrema est un genre monophylétique de trématodes largement distribué à travers les Amériques, qui comprend actuellement 19 espèces valides, parasites de téléostéens et d'anoures.

Morphological and molecular data of new species of Characithecium and Diaphorocleidus (Monogenea: Dactylogyridae) from Neotropical characid fishes.

The present study describes three new species of monogenean parasites of characid fishes from the Upper Paraná River basin, Brazil: Characithecium paranapanemense n. sp. on Psalidodon paranae and Psalidodon bockmanni, Diaphorocleidus magnus n. sp. on Astyanax lacustris and Psalidodon fasciatus, and Diaphorocleidus neotropicalis n. sp. on Astyanax lacustris and P. bockmanni. An amendment for Diaphorocleidus is proposed, since additional characters observed in the new species required to extend the generic diagnostic features mainly to include: articulation process connecting the base of the MCO with accessory piece present or absent, and accessory piece with variable shapes (plate-like, pincer-shaped, wrench-shaped, sheath-shaped), divided or not into subunits. Characithecium paranapanemense n. sp. can be distinguished from other congeners by the morphology of its MCO and accessory piece. Diaphorocleidus magnus n. sp. differs from most of its congeners by the morphology of its accessory piece, the presence of articulation process connecting the base of the MCO with accessory piece, and the morphology of the sclerotized structures of the haptor. Diaphorocleidus neotropicalis n. sp. can be easily distinguished from its congeners by the morphology of the accessory piece, the sclerotized structures of the haptor and the morphology of the vagina. Molecular data of the new species (partial 28S rDNA and mitochondrial cytochrome oxidase I) were obtained and the first phylogenetic analysis based on 28S rDNA gene sequences for species of Characithecium and Diaphorocleidus are provided. Although Diaphorocleidus and Characithecium share some morphological similarities, phylogenetic analysis indicates that species of these two genera are not closely related.

Parasites of Astyanax lacustris (Pisces, Characiformes) from Brazilian streams / Parasitas de Astyanax lacustris (Pisces, Characiformes) de riachos brasileiros

Abstract Astyanax lacustris is a small characid fish widely distributed in Brazil, with fast-growing and omnivorous feeding habits. Although the species presents economic and ecological importance, little is known about its parasitological fauna in stream environments. This study aimed to characterize the parasitic fauna of A. lacustris in two streams in the state of Paraná, Brazil. Fifty-two specimens of A. lacustris were collected, 22 from the Carolina stream (Lower Iguaçu River) and 30 from the Carreira stream (Upper Paraná River), in July and September 2018. In both streams, there was a low richness of parasites, and the structure of the parasitic community was predominantly composed of monogeneans. These findings may be associated with the gregarious behavior of the host species. Moreover, the low occurrence of endohelminths, may be associated with the fact that in streams, the energy flow is low, and depends directly on the input of allochthonous matter, which favors the formation of shelters for the establishment of macroinvertebrates, which represent important sources of food for the ichthyofauna, and may act as intermediate and paratenic hosts of parasites. These environments require further studies to support conservation measures aimed at maintaining the balance of ecological relationships in these preserved ecosystems.

Resumo Astyanax lacustris é um caracídeo de pequeno porte, amplamente distribuído no Brasil, com hábito alimentar onívoro e rápido crescimento. Embora a espécie tenha importância econômica, pouco se sabe sobre sua fauna parasitológica em ambientes de riacho. Este estudo objetivou caracterizar a fauna parasitária de A. lacustris em dois riachos do estado do Paraná. Foram coletados 52 exemplares de A. lacustris, sendo 22 no riacho Carolina (baixo rio Iguaçu) e 30 no riacho Carreira (alto rio Paraná), nos meses de julho e setembro de 2018. Em ambos os riachos, houve baixa riqueza de parasitos e a estrutura da comunidade parasitária foi caracterizada pela predominância de monogenéticos. Esses achados podem estar associados ao comportamento gregário da espécie hospedeira. Ademais, a baixa ocorrência de endohelmintos pode estar associada ao fato de que, nos riachos, o fluxo de energia é baixo e depende diretamente do aporte de matéria alóctone, que favorece a formação de abrigos para o estabelecimento de macroinvertebrados, os quais representam uma das principais fontes de alimento da ictiofauna, e podem atuar como hospedeiros intermediários e paratênicos de parasitos. Esses ambientes necessitam de mais estudos para subsidiar medidas de conservação que visem manter o equilíbrio das relações ecológicas nesses ecossistemas preservados.

A new species of Cacatuocotyle (Monogenea, Dactylogyridae) parasitizing Astyanax spp. (Characiformes, Characidae) from Brazil, including molecular data and a key to species identification.

The present study describes Cacatuocotyle papilionis n. sp. (Monogenea, Dactylogyridae) from the skin of the characid fishes Astyanax lacustris (Lütken, 1875) (=Astyanax altiparanae Garutti & Britski, 2000) and Astyanax fasciatus (Cuvier, 1819) (Characiformes, Characidae) from the Southeast of Brazil, supported by morphological and molecular data. The new species differs from all congeners, mainly due to the morphology of the ventral bar (resembling a butterfly), accessory piece, and the number of rings of the male copulatory organ (MCO), comprising a coiled tube with 4.5-5.5 counterclockwise rings. The first molecular data for this monogenean genus is provided in this study, using the partial sequences of the ribosomal gene (28S), as well as providing an identification key to the species.

Austrodiplostomum compactum metacercariae (Digenea: Diplostomidae) in Schizodon intermedius (Characiformes: Anostomidae) from Jurumirim reservoir, Brazil.

This study reports the occurrence of Austrodiplostomum compactum metacercariae in the freshwater fish Schizodon intermedius (ximborê/piava) from a Neotropical reservoir in the Paranapanema River, state of São Paulo, Brazil. From a total of 75 fish collected, we found 38 infected with A. compactum metacercariae (prevalence = 50.67%) in the eyes. The mean intensity of infection and mean abundance were 9.05 ± 4.26 (1-155) and 4.59 ± 2.20 (0-155), respectively. Poulin's Discrepancy Index was 0.87 and four specimens presented more than 10 metacercariae in their eyes. No correlation was observed between parasite abundance and standard length, total weight and condition factor (p>0.05). These metacercariae are reported for the first time in S. intermedius.

Morphological and Molecular Characterization of Clinostomum detruncatum (Trematoda: Clinostomidae) Metacercariae Infecting Synbranchus marmoratus.

A complete morphological description, supported by molecular data, of Clinostomum detruncatum metacercariae is reported in this study. The metacercariae were found infecting Synbranchus marmoratus from the Paraná River, municipality of Guaíra, Paraná State, Brazil. The taenioidean uterus is the main morphological characteristic of this species. Both neighbor-joining (NJ) and maximum likelihood (ML) trees showed 2 clear separate clusters grouping together the species from the Palearctic region (Clinostomum complanatum, Clinostomum cutaneum, Clinostomum phalacrocoracis, Clinostomum philippinense) and those from the Nearctic/Neotropical regions (Clinostomum marginatum, Clinostomum tataxumui, C. detruncatum, Clinostomum sp. 7). The latter clade is divided into 2 subclades grouping species from North America and Mexico (C. marginatum and C. tataxumui), and those from Brazil (C. detruncatum and Clinostomum sp. 7).

Ectoparasites of Nile tilapia (Oreochromis niloticus) in cage farming in a hydroelectric reservoir in Brazil.

For this study, we performed a parasitological analysis of cage-cultured Nile tilapia (Oreochromis niloticus) from the Água Vermelha Reservoir, Southeastern Brazil, and verified relationships with limnological data, seasonality, and fish growth phase. From March 2010 to March 2011, sixty-three specimens of O. niloticus in three growth phases (i.e., initial, intermediate, and final) were collected. All fish specimens were infested with at least one ectoparasite species (prevalence = 100%). Five species of protozoans (Trichodina compacta, Trichodina magna, Ichthyophthirius multifiliis, Piscinoodinium pillulare, and Epistylis sp.) and five species of monogenoids (Cichlidogyrus halli, Cichlidogyrus thurstonae, Cichlidogyrus sp. 1, Scutogyrus longicornis, and Gyrodactylus sp.) were observed. The abundance of Trichodina spp. and the prevalence of Epistylis sp. were higher in the dry season, and the prevalence of C. halli was higher in the rainy season. For the majority of ectoparasites found in this study, fish in the intermediate and final phases had higher parasitism rates than those in the initial phase. The data presented may help fish farmers to understand the parasite dynamics of the fish species studied in cage-farming systems.

Endohelminths in Cichla piquiti (Perciformes, Cichlidae) from the Paraná River, São Paulo State, Brazil.

Fifty specimens of Cichla piquiti were collected from the Paraná River downstream of the Ilha Solteira Hydroelectric Power Station in Brazil and surveyed for endohelminth parasites. All fish were parasitised by at least one helminth species (overall prevalence [P] = 100%). Eight parasite taxa were present: the nematode Procamallanus (Procamallanus) peraccuratus in the intestines; third-stage larvae of the anisakids Contracaecum sp. and Hysterothylacium sp. in the visceral cavity, mesentery and serosa of the stomach and intestines and on the liver and spleen; the trematodes Austrodiplostomum compactum in the eye (metacercariae) and Genarchella genarchella in the stomach; and the cestodes Proteocephalus macrophallus, Proteocephalus microscopicus, and Sciadocephalus megalodiscus in the intestines. Hysterothylacium sp. larvae (P = 86%) and P. microscopicus (P = 74%) were the most prevalent parasites. Anisakids were more prevalent and abundant in the dry season. A negative correlation between the abundances of Hysterothylacium sp. and P. microscopicus was observed, suggesting a competitive/antagonistic relationship between these parasites. Cichla piquiti represents a new host for four parasite species. These new records significantly increase the list of parasites of C. piquiti, contributing to the knowledge of the host-parasite relationship and the geographical distribution of these helminths.

New host records and a checklist of fishes infected with Austrodiplostomum compactum (Digenea: Diplostomidae) in Brazil.

This study reports the infection of fishes by Austrodiplostomum compactum metacercariae in the Chavantes reservoir, medium Paranapanema River, municipality of Ipaussu, São Paulo State, Brazil. Twenty-three fish species were analysed, and 13 were infected with A. compactum metacercariae (56.5%) in their eyes. The following six fish species are new hosts for this metacercaria: Crenicichla haroldoi (1/1), Eigenmannia trilineata (11/6), Hoplosternum littorale (11/1), Iheringichthys labrosus (17/2), Leporinus amblyrhynchus (11/1), and Piaractus mesopotamicus (3/1). These new species increase the number of Brazilian fish species infected with this parasite to 36. Based on these findings, we hypothesise that the metacercariae larval stage of the parasite has a low specificity for the second intermediate host (fish). The majority of fish species infected in Brazil belong to the Loricariidae and Cichlidae families. For the fish species with higher mean abundances in Brazil, six are non-native species, and currently, Plagioscion squamosissimus has the highest mean abundance. The majority of fish species infected with A. compactum in Brazil are concentrated in the Paraná basin, although this may be related to the distribution of researchers.

Parasitic infections of Piaractus mesopotamicus and hybrid (P. mesopotamicus x Piaractus brachypomus) cultured in Brazil.

This study evaluated the occurrence of parasitic infections in the "pacu" fish Piaractus mesopotamicus and the "patinga" hybrid (P. mesopotamicus x Piaractus brachypomus) in the northwest of São Paulo State, Brazil. Fish from the following three fish farms were evaluated every two months: A, a hatchery and larviculture farm (n = 16 pacu / n = 19 patinga), B, a growout farm (n = 35 patinga) and C, a fee-fishing property (n = 28 pacu / n = 7 patinga). Thirty-five fish from each property were collected from February 2010 to February 2011 and subjected to parasitological analysis. The parasites found were the following: Mymarothecium viatorum, Anacanthorus penilabiatus, Notozothecium janauachensis (Dactylogyridae, Monogenea), Trichodina spp., Ichthyophthirius multifiliis, Chilodonella sp. (Protozoa), Myxobolus spp., Henneguya spp. (Myxozoa), Rondonia rondoni, Contracaecum sp. (Nematoda), and Dolops carvalhoi (Crustacea). Of the fish examined, 62.9% from "A" and 100% from "B" and "C" were infested with at least one parasite species. Pacu fish (n = 44) showed a higher susceptibility to Anacanthorus penilabiatus infestations, whereas patinga (n = 61) were more susceptible to Mymarothecium viatorum (p < 0.05). Appropriate fish handling (nutrition, transport and storage), in conjunction with monitoring of water quality, can reduce the stress to which the farmed fish are exposed and is essential for pathogen control.

Sphincterodiplostomum musculosum (Digenea, Diplostomidae) infecting Steindachnerina insculpta (Characiformes, Curimatidae) in the Chavantes Reservoir, Southeastern Brazil.

This study aimed to report the infection by Sphincterodiplostomum musculosum metacercariae in Steindachnerina insculpta from the Chavantes Reservoir, medium Paranapanema River, municipality of Ipaussu, State of São Paulo, Brazil. Thirty specimens of S. insculpta were collected and 29 were infected with S. musculosum metacercariae (prevalence = 96.67%) in the eyes and visceral cavity. The mean intensity of infection and abundance were 96.6 ± 29.41 (7-846) and 93.3 ± 28.6 (0-846), respectively. Positive correlation was observed between parasite abundance in the eyes and standard length (rs = 0.5, p = 0.005), total weight (rs = 0.649, p = 0.0001), and condition factor (rs = 0.439, p = 0.0154). The high parasitism rates by S. musculosum metacercariae in S. insculpta can be an indicative that this fish species is highly susceptible to infection by this diplostomid, and even reflect the presence of a large abundance of the intermediate host. Moreover, S. musculosum metacercariae are reported for the first time in S. insculpta.

Austrodiplostomum compactum metacercariae (Digenea: Diplostomidae) in Schizodon intermedius (Characiformes: Anostomidae) from Jurumirim reservoir, Brazil / Metacercárias de Austrodiplostomum compactum (Digenea: Diplostomidae) em Schizodon intermedius (Characiformes: Anostomidade) do reservatório de Jurumirim, Brasil

Abstract This study reports the occurrence of Austrodiplostomum compactum metacercariae in the freshwater fish Schizodon intermedius (ximborê/piava) from a Neotropical reservoir in the Paranapanema River, state of São Paulo, Brazil. From a total of 75 fish collected, we found 38 infected with A. compactum metacercariae (prevalence = 50.67%) in the eyes. The mean intensity of infection and mean abundance were 9.05 ± 4.26 (1-155) and 4.59 ± 2.20 (0-155), respectively. Poulin's Discrepancy Index was 0.87 and four specimens presented more than 10 metacercariae in their eyes. No correlation was observed between parasite abundance and standard length, total weight and condition factor (p>0.05). These metacercariae are reported for the first time in S. intermedius.

Resumo Este estudo reporta a ocorrência de metacercárias de Austrodiplostomum compactum na espécie de peixe de água doce Schizodon intermedius (ximborê/piava), oriunda de um reservatório Neotropical no rio Paranapanema, Estado de São Paulo, Brasil. Um total de 75 peixes foram coletados, sendo que 38 estavam infectados com metacercárias de A. compactum (prevalência = 50,67%) nos olhos. A intensidade média de infecção e abundância média foram 9,05 ± 4,26 (1-155) e 4,59 ± 2,20 (0-155), respectivamente. O Índice de Discrepância de Poulin foi de 0,87, e quatro exemplares apresentaram mais do que 10 metacercárias em seus olhos. Não foram observadas correlação entre abundância média e comprimento padrão, peso total e fator de condição (p>0,05). Esse é o primeiro registro dessa espécie de metacercária para S. intermedius.

Ectoparasites of Nile tilapia (Oreochromis niloticus) in cage farming in a hydroelectric reservoir in Brazil / Ectoparasitas de tilápias-do-Nilo (Oreochromis niloticus) criadas em tanques-rede em um reservatório de usina hidrelétrica no Brasil

For this study, we performed a parasitological analysis of cage-cultured Nile tilapia (Oreochromis niloticus) from the Água Vermelha Reservoir, Southeastern Brazil, and verified relationships with limnological data, seasonality, and fish growth phase. From March 2010 to March 2011, sixty-three specimens of O. niloticus in three growth phases (i.e., initial, intermediate, and final) were collected. All fish specimens were infested with at least one ectoparasite species (prevalence = 100%). Five species of protozoans (Trichodina compacta, Trichodina magna, Ichthyophthirius multifiliis, Piscinoodinium pillulare, and Epistylis sp.) and five species of monogenoids (Cichlidogyrus halli, Cichlidogyrus thurstonae, Cichlidogyrus sp. 1, Scutogyrus longicornis, and Gyrodactylus sp.) were observed. The abundance of Trichodina spp. and the prevalence of Epistylis sp. were higher in the dry season, and the prevalence of C. halli was higher in the rainy season. For the majority of ectoparasites found in this study, fish in the intermediate and final phases had higher parasitism rates than those in the initial phase. The data presented may help fish farmers to understand the parasite dynamics of the fish species studied in cage-farming systems.

O presente estudo teve como objetivo realizar análise parasitológica de tilápias-do-Nilo, (Oreochromis niloticus) criadas em tanques-rede no Reservatório de Água Vermelha, Sudeste do Brasil, bem como verificar suas inter-relações com as características limnológicas, sazonalidade e fase de criação. Durante o período de março de 2010 a março de 2011, espécimes de O. niloticus, pertencentes a três fases de criação (inicial, intermediária e final), foram colhidos, totalizando 63 indivíduos. Todos os peixes estavam infestados por pelo menos uma espécie de ectoparasita (prevalência = 100%). Foi observada a ocorrência de cinco espécies de protozoários (Trichodina compacta, Trichodina magna, Ichthyophthirius multifiliis, Piscinoodinium pillulare e Epistylis sp.), assim como cinco espécies de monogenóides (Cichlidogyrus halli, Cichlidogyrus thurstonae, Cichlidogyrus sp. 1, Scutogyrus longicornis e Gyrodactylus sp.). A abundância de Trichodina spp. e prevalência de Epistylis sp. foram maiores no período seco, e a prevalência de C. halli foi maior no período chuvoso. Para a maioria dos ectoparasitas encontrados neste estudo, os peixes pertencentes às fases intermediária e final apresentaram maiores taxas de parasitismo do que aqueles pertencentes à fase inicial. Os dados apresentados neste estudo podem ser de grande importância para piscicultores, de forma a auxiliá-los no conhecimento da dinâmica dos parasitas da espécie de peixe estudada em sistemas de tanques-rede.

Parasitic infections of Piaractus mesopotamicus and hybrid (P. mesopotamicus x Piaractus brachypomus) cultured in Brazil / Infecções parasitárias de Piaractus mesopotamicus e do híbrido (P. mesopotamicus x Piaractus brachypomus) cultivados no Brasil

This study evaluated the occurrence of parasitic infections in the "pacu" fish Piaractus mesopotamicus and the "patinga" hybrid (P. mesopotamicus x Piaractus brachypomus) in the northwest of São Paulo State, Brazil. Fish from the following three fish farms were evaluated every two months: A, a hatchery and larviculture farm (n = 16 pacu / n = 19 patinga), B, a growout farm (n = 35 patinga) and C, a fee-fishing property (n = 28 pacu / n = 7 patinga). Thirty-five fish from each property were collected from February 2010 to February 2011 and subjected to parasitological analysis. The parasites found were the following: Mymarothecium viatorum, Anacanthorus penilabiatus, Notozothecium janauachensis (Dactylogyridae, Monogenea),Trichodina spp., Ichthyophthirius multifiliis, Chilodonella sp. (Protozoa), Myxobolus spp.,Henneguya spp. (Myxozoa), Rondonia rondoni, Contracaecum sp. (Nematoda), and Dolops carvalhoi(Crustacea). Of the fish examined, 62.9% from "A" and 100% from "B" and "C" were infested with at least one parasite species. Pacu fish (n = 44) showed a higher susceptibility to Anacanthorus penilabiatus infestations, whereas patinga (n = 61) were more susceptible to Mymarothecium viatorum (p < 0.05). Appropriate fish handling (nutrition, transport and storage), in conjunction with monitoring of water quality, can reduce the stress to which the farmed fish are exposed and is essential for pathogen control.

Este estudo avaliou a ocorrência de infecções parasitárias em pacus Piaractus mesopotamicus e do híbrido patinga (P. mesopotamicus x P. brachypomus) procedentes da região Noroeste do Estado de São Paulo, Brasil. Peixes de três pisciculturas foram avaliados bimestralmente: A - Reprodução e Larvicultura (n = 16 pacus / n = 19 patingas), B-Engorda n = 35 patingas), e C- Pesque-pague (n = 28 pacus / n = 7 patingas). Trinta e cinco peixes de cada propriedade foram coletados de fevereiro de 2010 a fevereiro de 2011, para análises parasitológicas. Os parasitas encontrados foram: Mymarothecium viatorum, Anacanthorus penilabiatus, Notozothecium janauachensis (Dactylogyridae, Monogenea), Trichodina spp., Ichthyophthirius multifiliis, Chilodonella sp. (Protozoa), Myxobolus spp., Henneguya spp. (Myxozoa), Rondonia rondoni, Contracaecum sp. (Nematoda), and Dolops carvalhoi (Crustacea). Dentre os peixes analisados, 62,9% de "A" e 100% de "B" e "C" estavam infectados/infestados por pelo menos uma espécie de parasita. Pacus (n = 44) apresentaram maior suscetibilidade a infestações por Anacanthorus penilabiatus, e patingas (n = 61), por Mymarothecium viatorum (p < 0.05). A profilaxia e cuidados durante o manejo (alimentação, transporte e estocagem), associados ao monitoramento da qualidade de água reduzem o estresse o qual os peixes cultivados estão submetidos, sendo medidas imprescindíveis para o controle de patógenos.

Endohelminths in Cichla piquiti (Perciformes, Cichlidae) from the Paraná river, São Paulo state, Brazil / Endohelmintos de Cichla piquiti (Perciformes, Cichlidae) procedentes do rio Paraná, estado de São Paulo, Brasil

Fifty specimens of Cichla piquiti were collected from the Paraná River downstream of the Ilha Solteira Hydroelectric Power Station in Brazil and surveyed for endohelminth parasites. All fish were parasitised by at least one helminth species (overall prevalence [P] = 100%). Eight parasite taxa were present: the nematode Procamallanus (Procamallanus) peraccuratus in the intestines; third-stage larvae of the anisakids Contracaecum sp. and Hysterothylacium sp. in the visceral cavity, mesentery and serosa of the stomach and intestines and on the liver and spleen; the trematodes Austrodiplostomum compactum in the eye (metacercariae) and Genarchella genarchella in the stomach; and the cestodes Proteocephalus macrophallus, Proteocephalus microscopicus, and Sciadocephalus megalodiscus in the intestines. Hysterothylacium sp. larvae (P = 86%) and P. microscopicus (P = 74%) were the most prevalent parasites. Anisakids were more prevalent and abundant in the dry season. A negative correlation between the abundances of Hysterothylacium sp. and P. microscopicus was observed, suggesting a competitive/antagonistic relationship between these parasites. Cichla piquiti represents a new host for four parasite species. These new records significantly increase the list of parasites of C. piquiti, contributing to the knowledge of the host-parasite relationship and the geographical distribution of these helminths.

Cinquenta espécimes de Cichla piquiti foram colhidos do Rio Paraná, a jusante da Usina Hidrelétrica de Ilha Solteira, Brasil, na pesquisa de endohelmintos. Todos os peixes estavam parasitados por, pelo menos, uma espécie de helminto (prevalência total [P] = 100%). Foram encontrados oito taxa de parasitas: os nematóides Procamallanus (Procamallanus) peraccuratus no intestino; larvas de terceiro estádio dos anisaquídeos Contracaecum sp. e Hysterothylacium sp. na cavidade abdominal, mesentério e serosa do estômago e do intestino, e sobre o fígado e baço; metacercárias do trematódeo Austrodiplostomum compactum no olho e um indivíduo adulto de Genarchella genarchella no estômago; os cestóides Proteocephalus macrophallus, Proteocephalus microscopicus e Sciadocephalus megalodiscus no intestino. Larvas de Hysterothylacium sp. (P = 86%) e P. microscopicus (P = 74%) foram os parasitas mais prevalentes. Anisaquídeos apresentaram maior prevalência e abundância no período seco. Foi observada uma correlação negativa entre as abundâncias de Hysterothylacium sp. e P. microscopicus, sugerindo uma relação de antagonismo/competição entre esses parasitas. Cichla piquiti é descrito como novo hospedeiro para quatro espécies de parasitas. Estes novos registros aumentam significativamente a lista de parasitas de C. piquiti, contribuindo para o conhecimento da relação parasito-hospedeiro e distribuição geográfica desses helmintos.