Dactylogyridae (Monogenoidea, Polyonchoinea) from the gills of Auchenipterus nuchalis (Siluriformes, Auchenipteridae) from the Tocantins River, Brazil.

Two species of Cosmetocleithrum Kritsky, Thatcher & Boeger, 1986 (both new) and two species of Demidospermus Suriano, 1983 (one new) are reported from the gills of the catfish Auchenipterus nuchalis, popularly known as "mapará", from the Tocantins River and tributaries, North Region of Brazil. Cosmetocleithrum berecae n. sp. differs from all other species presently known in the genus by the morphology of the anchors presenting an elongate shaft and short recurved point, a coiled male copulatory organ (MCO) with three rings, and an elongate slender accessory piece with a bifurcated distal end. Cosmetocleithrum nunani n. sp. differs from its congeners by the combination of the following features: (1) Ventral and dorsal anchors with moderately long curved shaft and short point; (2) Hooks with poorly developed thumb; (3) Hook pairs 5 and 6 similar to each other, but morphologically distinct from remaining hook pairs; and (4) MCO coiled, with approximately 1.5 rings. Demidospermus tocantinensis n. sp. is easily distinguished from other species of the genus by presenting an inverted-G-shaped MCO with a median knee-like expansion. Demidospermus osteomystax Tavernari, Takemoto, Lacerda & Pavanelli, 2010 is redescribed based on paratypes and specimens from the gills of A. nuchalis from the Tocantins River, a new host and locality records for this species. The monotypic Paracosmetocleithrum Acosta, Scholz, Blasco-Costa, Alves & Silva, 2017, the only other Neotropical genus reported in siluriforms besides Cosmetocleithrum with species presenting two ribbon-like projections on the posterior margin of the dorsal bar, is considered a junior subjective synonym of Cosmetocleithrum.

TITLE: Dactylogyridae (Monogenoidea, Polyonchoinea) des branchies d'Auchenipterus nuchalis (Siluriformes, Auchenipteridae) de la rivière Tocantins au Brésil. ABSTRACT: Deux espèces de Cosmetocleithrum Kritsky, Thatcher et Boeger, 1986 (toutes deux nouvelles) et deux espèces de Demidospermus Suriano, 1983 (une nouvelle) sont signalées des branchies du poisson-chat Auchenipterus nuchalis, communément appelé « mapará ¼, de la rivière Tocantins et affluents, Région Nord du Brésil. Cosmetocleithrum berecae n. sp. diffère de toutes les autres espèces actuellement connues dans le genre par la morphologie des anchors présentant un manche allongé et une pointe recourbée courte, un organe copulateur mâle (OCM) enroulé avec trois anneaux et une pièce accessoire allongée et mince avec une extrémité distale bifurquée. Cosmetocleithrum nunani n. sp. diffère de ses congénères par la combinaison des caractéristiques suivantes : (1) Anchors ventrales et dorsales avec tige incurvée modérément longue et pointe courte ; (2) Crochets avec pouce peu développé ; (3) Paires de crochets 5 et 6 similaires les unes aux autres, mais morphologiquement distinctes des paires de crochets restantes ; (4) OCM enroulé, avec environ 1,5 anneaux. Demidospermus tocantinensis n. sp. se distingue facilement des autres espèces du genre par un OCM en forme de G inversé avec une expansion médiane du genou. Demidospermus osteomystax Tavernari, Takemoto, Lacerda & Pavanelli, 2010 est redécrit sur la base de paratypes et de spécimens des branchies d'A. nuchalis de la rivière Tocantins, et représente un hôte nouveau et une localité nouvelle pour cette espèce. Le genre monotypique Paracosmetocleithrum Acosta, Scholz, Blasco-Costa, Alves & Silva, 2017, le seul autre genre néotropical signalé chez les Siluriformes en dehors de Cosmetocleithrum, avec des espèces présentant deux projections en forme de ruban sur la marge postérieure de la barre dorsale, est considéré comme synonyme subjectif junior de Cosmetocleithrum.

Metazoan parasite communities of Leporinus macrocephalus (Characiformes: Anostomidae) in cultivation systems in the western Amazon, Brazil / Comunidade de metazoários parasitos de Leporinus macrocephalus (Characiformes: Anostomidae) em sistemas de cultivo no oeste da Amazônia, Brasil

ABSTRACT In the Amazon, the growing demand for fish has been boosting the expansion of fish farms. However, the intensification of cultivation can generate disequilibrium in the parasite-host environment, predisposing fish to parasitic infections. The objective of this study was to evaluate the community structure of metazoan parasites in cultivation systems of piauçu, Leporinus macrocephalus, in the state of Acre, Brazil. We examined 100 specimens from a semi-intensive cultivation system (earth tanks) and 100 from an extensive system (dams). Overall 66.5% of the hosts were parasitized. We collected 1,240 parasite specimens, classified in 15 metazoan taxa (10 monogenoidean, one digenean and four nematodes). The parasite prevalence was higher by Monogenoidea in the dams, and by Nematoda in the earth tanks. The parasitic indexes were, in general, low and varied among species. Monogeneoidea had higher values for quantitative and ecological descriptors of parasitism in the dams, while Nematoda had higher values in the earth tanks. A single species of Digenea was found in the dams, with low prevalence. No taxon was classified as central. In the dams, parasite abundance was correlated only with total fish length, while in the earth tanks, it was positively correlated with total length, weight and condition factor of fish. The endoparasite and ectoparasite infracommunities presented higher richness, dominance, diversity and evenness, respectively, in the earth tanks and in the dams. This is the first study of ecological descriptors of parasites of L. macrocephalus in the Amazon.

RESUMO Na Amazônia, a crescente demanda por pescado vem impulsionando a expansão da piscicultura. No entanto, a intensificação dos cultivos pode gerar desequilíbrio no sistema parasito-hospedeiro-ambiente, predispondo os peixes a infecções parasitárias. O objetivo deste estudo foi avaliar a estrutura das comunidades de metazoários parasitos de piauçu, Leporinus macrocephalus, em sistemas de cultivo no estado do Acre, Brasil. Foram coletados 200 peixes, sendo 100 espécimes de sistema de cultivo semi-intensivo em viveiro escavado e 100 de sistema extensivo em açude. Dos 200 hospedeiros analisados 66,5% estavam parasitados. Foram coletados 1.240 espécimes de metazoários, classificados em quinze espécies (10 de Monogenoidea, uma de Digenea e quatro de Nematoda). A prevalência de parasitismo por Monogenoidea foi maior em açude e por Nematoda em viveiro. De forma geral, os índices de parasitismo foram baixos e variaram entre as espécies, com maiores valores dos descritores quantitativos e ecológicos do parasitismo por Monogenoidea em açude e Nematoda em viveiro. A única espécie de Digenea foi encontrada em açude e com baixa prevalência. Nenhum táxon foi classificado como central. Nos açudes, a abundância parasitária foi correlacionada apenas com o comprimento total dos hospedeiros, e nos viveiros com o comprimento total, peso e fator de condição dos hospedeiros. Nos viveiros, a infracomunidade de endoparasitos apresentou os maiores índices de riqueza, dominância, diversidade e equitabilidade. Nos açudes, os ectoparasitos apresentaram os maiores índices. Este foi o primeiro registro de índices parasitários de L. macrocephalus em sistemas de cultivo na Amazônia.

Metazoan parasite communities of Leporinus macrocephalus (Characiformes: Anostomidae) in cultivation systems in the western Amazon, Brazil / Comunidade de metazoários parasitos de Leporinus macrocephalus (Characiformes: Anostomidae) em sistemas de cultivo no oeste da Amazônia, Brasil

ABSTRACT In the Amazon, the growing demand for fish has been boosting the expansion of fish farms. However, the intensification of cultivation can generate disequilibrium in the parasite-host environment, predisposing fish to parasitic infections. The objective of this study was to evaluate the community structure of metazoan parasites in cultivation systems of piauçu, Leporinus macrocephalus, in the state of Acre, Brazil. We examined 100 specimens from a semi-intensive cultivation system (earth tanks) and 100 from an extensive system (dams). Overall 66.5% of the hosts were parasitized. We collected 1,240 parasite specimens, classified in 15 metazoan taxa (10 monogenoidean, one digenean and four nematodes). The parasite prevalence was higher by Monogenoidea in the dams, and by Nematoda in the earth tanks. The parasitic indexes were, in general, low and varied among species. Monogeneoidea had higher values for quantitative and ecological descriptors of parasitism in the dams, while Nematoda had higher values in the earth tanks. A single species of Digenea was found in the dams, with low prevalence. No taxon was classified as central. In the dams, parasite abundance was correlated only with total fish length, while in the earth tanks, it was positively correlated with total length, weight and condition factor of fish. The endoparasite and ectoparasite infracommunities presented higher richness, dominance, diversity and evenness, respectively, in the earth tanks and in the dams. This is the first study of ecological descriptors of parasites of L. macrocephalus in the Amazon.

RESUMO Na Amazônia, a crescente demanda por pescado vem impulsionando a expansão da piscicultura. No entanto, a intensificação dos cultivos pode gerar desequilíbrio no sistema parasito-hospedeiro-ambiente, predispondo os peixes a infecções parasitárias. O objetivo deste estudo foi avaliar a estrutura das comunidades de metazoários parasitos de piauçu, Leporinus macrocephalus, em sistemas de cultivo no estado do Acre, Brasil. Foram coletados 200 peixes, sendo 100 espécimes de sistema de cultivo semi-intensivo em viveiro escavado e 100 de sistema extensivo em açude. Dos 200 hospedeiros analisados 66,5% estavam parasitados. Foram coletados 1.240 espécimes de metazoários, classificados em quinze espécies (10 de Monogenoidea, uma de Digenea e quatro de Nematoda). A prevalência de parasitismo por Monogenoidea foi maior em açude e por Nematoda em viveiro. De forma geral, os índices de parasitismo foram baixos e variaram entre as espécies, com maiores valores dos descritores quantitativos e ecológicos do parasitismo por Monogenoidea em açude e Nematoda em viveiro. A única espécie de Digenea foi encontrada em açude e com baixa prevalência. Nenhum táxon foi classificado como central. Nos açudes, a abundância parasitária foi correlacionada apenas com o comprimento total dos hospedeiros, e nos viveiros com o comprimento total, peso e fator de condição dos hospedeiros. Nos viveiros, a infracomunidade de endoparasitos apresentou os maiores índices de riqueza, dominância, diversidade e equitabilidade. Nos açudes, os ectoparasitos apresentaram os maiores índices. Este foi o primeiro registro de índices parasitários de L. macrocephalus em sistemas de cultivo na Amazônia.

Description of free-living marine nematodes found in the intestine of fishes from the Brazilian coast.

The marine nematodes usually comprise free-living species, although a few are parasitic. However, several cases of free-living nematodes found accidentally in the digestive tract of certain vertebrates, especially fishes, have sometimes been recorded and categorized as pseudoparasites. In the present work, two species of marine fishes, the rhomboid crappie, Diapterus rhombeus, and the silvered crappie, Eucinostomus argenteus (Perciformes: Gerreidae), from Angra dos Reis on the coast of Rio de Janeiro (Brazil) were examined. Seven species of free-living marine nematodes were found in the digestive tract of these fish. Several of these species remain unknown as free-living forms in Brazil. The combination of the fish feeding strategies and the poor preservation of the body of the nematode specimens found could indicate that these nematodes are pseudoparasites, appearing in the fishes' digestive tracts through accidental ingestion and thereafter surviving for brief periods of time. Descriptions, illustrations and tables of measurements are provided for all species. Six of these species (Croconema torquens, Dorylaimopsis pellucida, Oncholaimellus labiatus, Parodontophora breviamphida, Prooncholaimus ornatus, Trissonchulus latus) have been reported for the first time from the Brazilian coast.

New data on some species of Monogenea and Digenea parasites of marine fish from the coast of the State of Rio de Janeiro, Brazil.

Fifty four specimens of marine fish belonging to seven species collected from the coast of the State of Rio de Janeiro, Brazil were examined for helminths, and results relating to Monogenea and Digenea are presented. The monogeneans Metamicrocotyla macracantha, Microcotyle pomatomi and Gotocotyla acanthura are reported in new hosts. The digeneans Parahemiurus merus, Lecithochirium microstomum, Gonocercella pacifica, Aponurus laguncula, Gonocerca trematomi and Lampritrema miescheri are reported in new hosts, and the latter two species are also reported for the first time in Brazil.

New data on some species of Monogenea and Digenea parasites of marine fish from the coast of the State of Rio de Janeiro, Brazil / Novos dados sobre algumas especies de Monogenea e Digenea parasitas de peixes marinhos da costa do estado do Rio de Janeiro, Brasil

Fifty four specimens of marine fish belonging to seven species collected from the coast of the State of Rio de Janeiro, Brazil were examined for helminths, and results relating to Monogenea and Digenea are presented. The monogeneans Metamicrocotyla macracantha, Microcotyle pomatomi and Gotocotyla acanthura are reported in new hosts. The digeneans Parahemiurus merus, Lecithochirium microstomum, Gonocercella pacifica, Aponurus laguncula, Gonocerca trematomi and Lampritrema miescheri are reported in new hosts, and the latter two species are also reported for the first time in Brazil.

Cinquenta e quatro espécimens de peixes marinhos pertencentes a sete espécies coletados do litoral do estado do Rio de Janeiro, Brasil foram examinados para helmintos, os resultados referentes a Monogenea e Digenea são apresentados. Os monogenéticos Metamicrocotyla macracantha, Microcotyle pomatomi e Gotocotyla acanthura são apresentados em novos hospedeiros. Os digenéticos Parahemiurus merus, Lecithochirium microstomum, Gonocercella pacifica, Aponurus laguncula, Gonocerca trematomi e Lampritrema miescheri são registrados em novos hospedeiros, as duas últimas espécies são também registradas pela primeira vez no Brasil.

New data on species of Demidospermus (Dactylogyridae: Monogenea) parasitizing fishes from the reservoir of the Itaipu Hydroelectric Power Station, Parana State, Brazil, with new synonymies / Novos dados sobre Demidospermus (Dactylogyridae: Monogenea) parasitas de peixes do reservatório da Usina Hidrelétrica de Itaipú, Estado do Paraná, Brasil, com novas sinonimias

Eight known species of Demidospermus (Dactylogyridae, Monogenea) were collected from siluriform fishes from reservoir of the Itaipu Hydroelectric Power Station, Paraná, Brazil. Four of them are recorded for the first time in Brazil, enlarging their geographical distribution: Demidospermus armostus, Demidospermus anus, Demidospermus bidiverticulatum and Demidospermus valenciennesi. Demidospermus labrosi is synonymized with Demidospermus cornicinus and Demidospermus mandi with Demidospermus leptosynophallus and reported from two new hosts. Demidospermus paravalenciennesi and Demidospermus uncusvalidus were also collected.

Oito espécies de Demidospermus (Dactylogyridae, Monogenea) foram coletadas de peixes Siluriformes do reservatório da Usina Hidrelétrica de Itaipú, Paraná, Brasil. Quatro dessas são registradas pela primeira vez no Brasil, aumentando sua distribuição geográfica: Demidospermus armostus, Demidospermus anus, Demidospermus bidiverticulatum e Demidospermus valenciennesi. Demidospermus labrosi é considerada sinônima de Demidospermus cornicinus e Demidospermus mandi sinônima de Demidospermus leptosynophallus e registradas em dois novos hospedeiros. Foram também coletados exemplates de Demidospermus paravalenciennesi e Demidospermus uncusvalidus.

New data on species of Demidospermus (Dactylogyridae: Monogenea) parasitizing fishes from the reservoir of the Itaipu Hydroelectric Power Station, Paraná State, Brazil, with new synonymies.

Eight known species of Demidospermus (Dactylogyridae, Monogenea) were collected from siluriform fishes from reservoir of the Itaipu Hydroelectric Power Station, Paraná, Brazil. Four of them are recorded for the first time in Brazil, enlarging their geographical distribution: Demidospermus armostus, Demidospermus anus, Demidospermus bidiverticulatum and Demidospermus valenciennesi. Demidospermus labrosi is synonymized with Demidospermus cornicinus and Demidospermus mandi with Demidospermus leptosynophallus and reported from two new hosts. Demidospermus paravalenciennesi and Demidospermus uncusvalidus were also collected.

Ultrastructure of the tegument of Prosorhynchoides arcuatus (Linton, 1900) Bray, 1984 (Trematoda, Bucephalidae)

The tegument of the adult form of Prosorhynchoides arcuatus (Linton, 1900) (Trematoda, Bucephalidae) from the intestine of Pomatomus saltator (L.) from the Atlantic coast of the State of Rio de Janeiro, Brazil was studied by transmission electron microscopy. The tegument consists of two layers: an external, constituted by a syncytium, containing spines, unicilliated papilae, inclusion bodies and mitochondria and an internal, consisting of a muscular layer and mononucleated tegumental cells.

Scanning electron microscopic study of Prosorhynchoides arcuatus (Linton, 1990) (Bucephalidae: Digenea)

Prosorhynchoides arcuatus (Linton, 1900) from the intestine of Pomatomus saltator (L.) from the Atlantic coast of the State of Rio de Janeiro is studied by scanning electron microscopy, with detailed description of tegumental spines. Comments on the synonymy of this species with Bucephalopsis callicotyle Kohn, 1962 are made. The tegument of adult P. arcuatus presents scale like and serrated spines and uniciliated sensory papillae, distributed over the body surface and is compared with other digenetic trematodes.