RESUMO

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.

Assuntos

RESUMO

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.

RESUMO

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.

Assuntos

RESUMO

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.

Assuntos

RESUMO

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.

Assuntos

RESUMO

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.

Assuntos

RESUMO

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.

Assuntos

RESUMO

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.

Assuntos

RESUMO

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.

Assuntos

RESUMO

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.

Assuntos