Abstract Despite being an important component of the freshwater ecosystems and an important factor controlling wild fish populations, Amazonian fish parasites have been poorly studied. Here, we analyzed the fauna of metazoan parasites from 10 detritivorous and omnivorous fish species from Amapá Lake in the western Amazon. Of 159 fish specimens examined, 73.6% were parasitized by one or more species of metazoan parasites. A total of 5,260 parasites (24 Monogenea, 14 Nematoda, 10 Digenea, 2 Acanthocephala, and 6 Crustacea) were identified. Aggregated dispersion pattern of parasites was observed. There was a predominance of endohelminth species that presented a similar pattern regarding the level of component communities (i.e., a low species number, low diversity and dominance of a single species, mainly the digeneans and nematodes in their larval stages). Five species of parasites presented correlation with the body size of the hosts. In the fish community, the presence of endoparasites in the larval and adult stages suggests that these are intermediate, paratenic and definitive hosts, reflecting their detritivorous or omnivorous feeding habits. The trophic level and diet had an influence on the structuring of endohelminth communities and infracommunities. Lastly, 38% of the metazoan parasite species were new records for examined hosts. populations studied Here 1 Amazon 15 736 73 73.6 5260 5 260 5,26 24 (2 Monogenea Nematoda Digenea Acanthocephala Crustacea identified observed i.e., ie i e (i.e. number stages. . stages) hosts community intermediate habits infracommunities Lastly 38 7 73. 526 26 5,2 ( i.e. (i.e 3 52 5, i.e

Resumo Apesar de ser um importante componente dos ecossistemas de água doce e um importante fator controlador das populações naturais de peixes, os parasitos de peixes amazônicos ainda são pouco estudados. Foi analisada a fauna de parasitos metazoários em 10 espécies de peixes detritívoros e onívoros do Lago Amapá na Amazônia ocidental. Dos 159 espécimes de peixes examinados, 73,6% estavam parasitados por uma ou mais espécies de parasitos metazoários. Um total de 5.260 parasitos (24 Monogenea, 14 Nematoda, 10 Digenea, 2 Acanthocephala e 6 Crustacea) foram identificados. Houve um padrão de dispersão agregado de parasitos. Houve predominância de espécies de endohelmintos que apresentaram padrão semelhante quanto ao nível de comunidades componentes, ou seja, baixo número de espécies, baixa diversidade e dominância de uma única espécie, principalmente os digenéticos e nematoides em estágio larval. Cinco espécies de parasitos apresentaram correlação com o tamanho corporal dos hospedeiros. Na comunidade de peixes, a presença de endoparasitos em fase larval e adulta sugere que esses são hospedeiros intermediários, paratênicos e definitivos, refletindo seus hábitos alimentares detritívoros ou onívoros. O nível trófico e dieta influenciaram na estruturação das comunidades e infracomunidades de endohelmintos. Por fim, 38% das espécies de parasitos metazoários foram novos registros para os hospedeiros examinados. estudados 1 ocidental 15 examinados 736 73 73,6 5260 5 260 5.26 24 (2 Monogenea Nematoda Digenea Crustacea identificados componentes seja espécie intermediários definitivos fim 38 7 73, 526 26 5.2 ( 3 52 5.

Abstract The big-headed Amazon River turtle, Peltocephalus dumerilianus, is endemic to the Orinoco and Amazon River basins. It is a food source for local communities, often unsustainably. Knowledge about P. dumerilianus’ parasitological fauna and host-parasite relationships is limited. Thus, ecological aspects of gastrointestinal parasitism in this species were investigated. Helminths were found in the gastrointestinal tract of 21 turtles, morphologically identified, and infection descriptors calculated. All animals harbored helminths: nematodes Ancyracanthus pinnatifidus, Paratractis hystrix, Atractis trematophila, Klossinemella conciliatus indeterminate three Klossinemella species, and digeneans Nematophila grandis, Helicotrema spirale, and Telorchis hagmanni. The highest parasite load occurred in the large intestine, followed by the small intestine and stomach. Shell length directly correlated with parasite burden of heteroxenic helminths, with males having higher burden than females. This is the first record of A. trematophila, K. conciliatus, and T. hagmanni in P. dumerilianus, and new location record for A. trematophila, P. hystrix, N. grandis, H. spirale, and T. hagmanni. Three potentially new Klossinemella species are presented. bigheaded big headed turtle dumerilianus basins communities unsustainably P hostparasite host limited Thus investigated 2 turtles identified calculated helminths pinnatifidus hystrix trematophila grandis spirale stomach females A K T N H presented

Resumo O cabeçudo, Peltocephalus dumerilianus, é endêmico das bacias dos rios Orinoco e Amazonas. Ele é uma fonte de alimento para as comunidades locais, frequentemente de maneira insustentável. O conhecimento sobre a fauna parasitológica de P. dumerilianus e suas relações hospedeiro-parasito são limitados. Assim, investigou-se os aspectos ecológicos do parasitismo gastrointestinal nessa espécie. Helmintos encontrados no trato gastrointestinal de 21 tartarugas, foram identificados morfologicamente e descritores de infecção calculados. Todos os animais abrigavam helmintos: nematoides Ancyracanthus pinnatifidus, Paratractis hystrix, Atractis trematophila, Klossinemella conciliatus e três espécies de Klossinemella indeterminados, além dos digenéticos Nematophila grandis, Helicotrema spirale e Telorchis hagmanni. A maior carga parasitária ocorreu no intestino grosso, seguida pelo intestino delgado e estômago. O comprimento da carapaça correlacionou-se diretamente com a carga de parasitos de helmintos heteroxênicos, e os machos apresentaram uma carga parasitária maior que as fêmeas. Este é o primeiro registro de A. trematophila, K. conciliatus e T. hagmanni em P. dumerilianus, e um novo registro de local para A. trematophila, P. hystrix, N. grandis, H. spirale e T. hagmanni. Três potenciais novas espécies de Klossinemella são apresentadas. cabeçudo Amazonas locais insustentável P hospedeiroparasito hospedeiro parasito limitados Assim investigouse investigou se espécie 2 tartarugas calculados pinnatifidus hystrix trematophila indeterminados grandis grosso estômago correlacionouse correlacionou heteroxênicos fêmeas K T N H apresentadas

Abstract Haemulidae represents one of the most diverse, widespread and conspicuous families of Perciformes, in which most species are marine, some brackish and rarely from freshwater. From April 2009 to July 2012, 120 specimens of Conodon nobilis, 60 Orthopristis rubra and 50 Anisotremus virginicus were collected off the State of Rio de Janeiro, Brazil, and analyzed for metazoan parasites. A total of 16 parasite taxa were found on/in A. virginicus, 19 on/in Co. nobilis and 21 on/in O. rubra, in which ectoparasites were most common on A. virginicus and Co. nobilis and endoparasites in O. rubra. All parasites showed aggregate pattern of distribution (discrepancy index values higher than 0.70). Mean abundance, species richness and Brillouin index (diversity) differed among the host species, i.e., O. rubra showed the highest values, followed by A. virginicus and Co. nobilis with intermediate and lowest values, respectively. At infracommunity level was possible to observe high similarity of parasite composition among the three host species. The digeneans Leurodera decora and Monorchis latus, and the acanthocephalan Koronacantha sp. represent new locality records off Brazil. Moreover, five, four and two taxa are reported, for the first time, parasitizing Co. nobilis, A. virginicus and O. rubra, respectively. diverse Perciformes marine freshwater 200 2012 12 6 5 Janeiro Brazil 1 onin Co 2 O discrepancy 0.70. 070 0.70 . 0 70 0.70) abundance diversity (diversity ie i e i.e. respectively latus sp Moreover five reported time 20 201 07 0.7 7 i.e 0.

Resumen Se estudió la comunidad de helmintos de Lithobates spectabilis (n =77) de Las Pilas (altitud baja) y Metznoxtla (altitud alta), Reserva de la Biosfera Barranca de Metztitlán, Hidalgo, México. Se comparó la diversidad de especies mediante los números de Hill a nivel de la infracomunidad y del componente de comunidad, y se calculó la diversidad beta. Se encontraron 5 especies de Digenea, 5 de Nematoda y 2 de Acanthocephala en las ranas de las 2 localidades. La riqueza de especies de parásitos en Las Pilas (9 especies) fue mayor que la de Metznoxtla (7 especies). La comunidad de helmintos en Las Pilas estuvo dominada por nemátodos y en Metznoxtla por digéneos. La especie más prevalente en Las Pilas fue Foleyellides cf. flexicauda (65% de las ranas estaban infectadas) y en Metznoxtla fue Megalodiscus americanus (76% estaban infectadas). Glypthelmins quieta fue la especie con mayor abundancia media en ambas localidades (Las Pilas = 4.5; Metznoxtla = 11.0). La diferencia en la composición de especies entre las 2 localidades fue significativa (Anosim; R = 0.54, p > 0.05). Las diferencias en la composición de especies de helmintos entre las 2 localidades sugieren que las condiciones ambientales locales son diferentes, lo que puede reflejar diferencias en la dieta de los hospederos a nivel local.

Abstract The helminth community of Lithobates spectabilis (n =77) was studied from Las Pilas (low altitude) and Metznoxtla (high altitude), Biosphere Reserve Barranca de Metztitlán, Hidalgo, Mexico. Species diversity was compared at the infracommunity and the component community level using Hill numbers, and the beta diversity was calculated. Five species of Digenea, 5 of Nematoda, and 2 of Acanthocephala were found in the frogs from the 2 localities. The species richness of parasites in Las Pilas (9 species) was higher than that of Metznoxtla (7 species). The helminth community in Las Pilas was dominated by nematodes and, in Metznoxtla, it was dominated by digeneans. The most prevalent species in Las Pilas was Foleyellides cf. flexicauda (65% of frogs were infected) and, in Metznoxtla, it was Megalodiscus americanus (76% were infected). Glypthelmins quieta was the species with the highest mean abundance in both localities (Las Pilas = 4.5; Metznoxtla = 11.0). The difference in species composition between the 2 localities was significant (Anosim; R = 0.54, p < 0.05). The differences in the composition of species of helminths between the 2 localities suggest that local environmental conditions are different, which may reflect differences in local host diet.

Abstract Digeneans are common parasites of small mammals. Dicrocoeliidae is a family with a cosmopolitan distribution, with 18 genera previously recorded from mammals in the Americas, six of them parasitizing rodents in Argentina. In this study, an updated compilation is provided of Dicrocoeliidae from rodents in the Americas. Also, a new Platynosomoides species is described parasitizing the cricetid rodent Akodon montensis of the Atlantic Forest in Argentina. Digital repositories were used to search for Dicrocoeliidae from rodents in the Americas. Rodents were collected in four localities of the Atlantic Forest, Argentina. Digeneans were removed from the rodent’s bile duct, and conventional studies were used for the morphological description. A total of 15 Dicrocoeliidae species were found parasitizing 18 rodent species from eight countries in the Americas. The new species of Platynosomoides from Akodon montensis differs from the other two species of genus by the size of body, testes, ovary, cecum length and position and length of the vitelline bands. Dicrocoeliidae show growing diversity, and the compilation of species in a rodent host base allows a clearer comparison and identification of new taxa in the future.

RESUMEN Se efectuó un examen helmintológico a 14 especímenes de Eucinostomus melanopterus (mojarra bandera) y 19 Eugerres plumieri (mojarra rayada), de los cuales se recolectaron un total de 461 helmintos. Se identificaron 12 taxones (cinco a nivel de especie, cinco a género y dos a familia) como sigue: cuatro monogéneos, cinco digéneos (cuatro adultos, una metacercaria), un céstodo (plerocercoide) y dos nemátodos (larvas). La prevalencia más alta fue para Neodiplectanum mexicanum (29 %) en E. melanopterus y Aristocleidus hastatus (37 %) en E. plumieri. Ambos hospederos comparten el 50 % de los taxones de parásitos. Ninguno de los helmintos representa un riesgo zoonótico.

ABSTRACT A helminthological examination was carried out on 14 specimens of Eucinostomus melanopterus (flagfin mojarra) and 19 Eugerres plumieri (striped mojarra), of which a total of 461 helminths were collected. As a result, and 12 taxa were registered (five species, five genus and tow family), as follows: four monogeneans, five digeneans (four adults, one metacercaria), one cestode (larva) and tow nematodes (larvae). The highest prevalence was for Neodiplectanum mexicanum (29 %) infecting E. melanopterus and Aristocleidus hastatus (37 %) infecting E. plumieri. Both hosts shared 50 % of recorded species, and none of the identified helminthes represents a zoonotic risk.

Abstract: The Mexican free-tailed bat (Tadarida brasiliensis) is an abundant, widely distributed species in Mexico, except for most of the Yucatán peninsula. We studied the helminth fauna of T. b. mexicana at seven localities in the State of Zacatecas in order to advance the knowledge of helminth parasites of wild vertebrates in northern-central Mexico. Eighty-four bat specimens were examined for the presence of helminth parasites following standard procedures; helminths found were identified and infections were characterized. Of the specimens examined, 65.47 % were parasitized. The helminth fauna comprises five taxa: three digeneans (Dicrocoelium rileyi, Ochoterenatrema labda, and Urotrema scabridum); one cestode (Vampirolepis sp.); and one nematode (Tadaridanema delicatus). We present a brief morphological description of Urotrema scabridum. D. rileyi was the most prevalent and abundant helminth species. The intestine was the habitat most parasitized, with four species. Indirect life cycles predominate, and are related to the insectivorous habits of this host. Further studies on this host-parasite system are necessary to contribute to population monitoring and conservation; biogeographic patterns of helminth parasites of bats should also be studied to explore their origins and evolution in the region. U. scabridum is reported for the first time from Zacatecas. All species are new locality records.

Resumen: El murciélago de cola libre mexicano (Tadarida brasiliensis), es una especie abundante y ampliamente distribuida en México, excepto en la mayor parte de la península de Yucatán. Para contribuir al conocimiento de los helmintos parásitos de vertebrados de vida silvestre en el centro-norte de México, la fauna helmíntica de T. b. mexicana se estudió en siete localidades del estado de Zacatecas. Se analizaron ochenta y cuatro especímenes de murciélagos de siete localidades dentro de Zacatecas. Los huéspedes fueron examinados para detectar helmintos parásitos siguiendo los procedimientos estándar de revisión, identificación taxonómica y se carcaterizaron las infecciones. El 65.47 % de los huéspedes examinados fueron parasitados. La fauna de helmintos consistió en cinco taxones: tres digéneos (Dicrocoelium rileyi, Ochoterenatrema labda, y Urotrema scabridum); un céstodo (Vampirolepis sp.) y un nemátodo (Tadaridanema delicatus). Se presenta una breve descripción morfológica de Urotrema scabridum. D. rileyi es la especie de helminto más prevalente y abundante. El intestino es el hábitat más parasitado con cuatro especies. El ciclo de vida indirecto es predominante y está relacionado con los hábitos alimentarios insectívoros de este huésped. Es necesario aumentar el número de estudios sobre este sistema huésped-parásito para contribuir al monitoreo de las poblaciones y la conservación, así como realizar estudios sobre patrones biogeográficos de helmintos parásitos de murciélagos que permitan explorar su origen y evolución en la región. U. scabridum se reporta por primera vez de Zacatecas, México. Todas las especies son registros nuevos de localidad.

ABSTRACT During a survey of helminth parasites of the brown ground snake, Atractus major Boulenger, 1894 (Serpentes: Dipsadidae) from Moyobamba, region of San Martin (northeastern Peru), a new species of Glossidiella Travassos, 1927 (Plagiorchiida: Plagiorchiidae) was found and is described herein based on morphological and ultrastructural data. The digeneans found in the lung were measured and drawings were made with a drawing tube. The ultrastructure was studied using scanning electron microscope. Glossidiella peruensis sp. nov. is easily distinguished from the type- and only species of the genus, Glossidiella ornata Travassos, 1927, by having an oblong cirrus sac (claviform in G. ornata), distinctly ovate testes (rounded testes in G. ornata) and button-like papillae on the dorsal edge of the oral sucker region (absent in G. ornata). In addition, G. peruensis sp. nov. differs from G. ornata by possessing a longer distance between testes and substantially wider oral and ventral suckers. This is the first time that a species of digenean is described and reported parasitizing snakes in Peru.

Abstract: Notothens are abundant fish in the Austral Ocean, therefore they stablish many interactions with other species, and thus they have become important components in the ecosystem. However, the relationships between these fish and their parasites are poorly understood. The parasite community of the intertidal notothen Patagonotothen cornucola has been analyzed in this study considering two sampling sites at the Strait of Magellan and the sex of the fish. The fish samples were collected in January 2017 at Rinconada Bulnes (RB), and San Isidro (SI). A total of 98 fish individuals, with total body length between 4.2 and 13.4 cm, were obtained. Of these fish, 15 parasite species were recorded. Four species were the most prevalent or abundant, three digeneans (Caudotestis kerguelensis, Whitegonimus ozoufae and Genolinea cf. bowersi) and one acantocephalan (Corynosoma beaglense). The similarity of parasite composition based on the abundance of parasites showed significant differences among sites because the fish from SI had only five parasite species and two of them with higher abundances than RB. There were no differences in parasite composition between male and female fish. Therefore, the sampling site was important for composition and abundance of parasites, indicating ecological and environmental differences between sites that affect parasite transmission. This is the first study on the parasite community of a species of Patagonotothen in the Patagonia area, showing a wide diversity of parasite species in this little fish.

Resumen: Nototénidos son peces abundantes del océano Austral, que tienen múltiples interacciones con otras especies, siendo importantes componentes de su ecosistema. Sin embargo, la relación de estos peces y sus parásitos es poco conocida. En este estudio se analiza las comunidades de parásitos de Patagonotothen cornucola considerando dos sitios de muestreo en el estrecho de Magallanes, y el sexo de este hospedero. Las muestras de peces fueron recolectadas en enero de 2017 en Rinconada Bulnes (RB) y San Isidro (SI), obteniendo 98 peces, cuyas longitudes corporales fueron de 4,2 a 13,4 cm. Del total de peces, 15 especies de parásitos fueron reconocidas, cuatro de ellas fueron prevalentes o abundantes, 3 digeneos (Caudotestis kerguelensis, Whitegonimus ozoufae and Genolinea cf. bowersi) y un acantocéfalo (Corynosoma beaglense). La similitud de la composición de parásitos, basada en la abundancia de éstos, mostró diferencias significativas entre sitios, debido a que solo cinco especies de parásitos fueron encontrados en los peces de SI, y dos de ellas tenían mayor abundancia en comparación a RB. No hubo diferencias entre peces machos y hembras en su composición parasitaria. Por lo tanto, el sitio de muestreo fue un factor importante para la composición parasitaria lo que significa que existen diferencias ecológicas y ambientales en los sitios que afectarían la transmisión de parásitos. Este es el primer estudio que entrega antecedentes de las comunidades parasitarias en una especie de Patagonotothen en el área Patagónica, en el cual se demostró una amplia diversidad a pesar del pequeño tamaño del pez.

Abstract Specimens of Xiphophorus birchmanni (Teleostei: Poeciliidae) (55 individuals) (Sheepshead swordtail) were collected from 2 localities in the Pánuco River drainage from Hidalgo and Veracruz [at Atlatipa (n = 26) and Benito Juárez (n = 29), respectively], México. The structure of the parasite communities of fish from the 2 localities was examined and compared. Helminths from 10 taxa were recovered: 6 species of larval digeneans (Posthodiplostomum sp., Uvulifer sp., Centrocestus formosanus, Ascocotyle sp., Haplorchis pumilio, and Echinostomatidae gen. sp.); 2 adult monogeneans (Urocleidoides vaginoclastrum and Gyrodactylus sp.); 1 larval cestode (metacestode stage; Glossocercus auritus); and 1 larval nematode, Eustrongylides sp. Urocleidoides vaginoclastrum and C. formosanus were the most frequent and abundant species. The remaining taxa were rare and found at low mean abundance. Component community and infracommunity differences observed in this study could be attributed to abiotic and biotic environmental factors resulting from the geographic separation of these localities during the orogeny of the Sierra Madre Oriental that restricted fish to isolated localities.

Resumen Se revisaron 55 ejemplares de Xiphophorus birchmanni (Teleostei: Poeciliidae) (espada del tempoal), recolectados de 2 localidades [Atlatipa (n = 26) y Benito Juárez (n = 29)] de la cuenca del río Pánuco pertenecientes a los estados de Hidalgo y Veracruz, México, respectivamente. La estructura de las comunidades de parásitos fue examinada y comparada. Se reportaron 10 especies de helmintos, 6 metacercarias Posthodiplostomum sp., Uvulifer sp., Centrocestus formosanus, Ascocotyle sp., Haplorchis pumilio y Echinostomatidae gen. sp.; 2 monogéneos, Urocleidoides vaginoclastrum y Gyrodactylus sp.; 1 larva de céstodo (estadio metacéstodo), Glossocercus auritus, y una larva del nemátodo Eustrongylides sp. Urocleidoides vaginoclaustrum y C. formosanus fueron las más frecuentes y abundantes, mientras que el resto de las especies fueron raras y poco frecuentes. Las diferencias observadas a nivel de comunidad componente e infracomunidad entre las localidades estudiadas, pueden ser atribuidas a factores bióticos y abióticos resultado de la separación geográfica de las localidades durante la orogenia de la sierra Madre Oriental, que restringe y aísla a los peces.

RESUMO Este estudo investigou a diversidade de parasitos metazoários em Colossoma macropomum do Rio Jari, na Amazônia oriental, norte do Brasil. Foram coletados um total de 4.966 parasitos, incluindo monogeneas (Anacanthorus spathulatus, Mymarothecium boegeri, Notozothecium janauachensis e Linguadactyloides brinkmanni), nematoides (larvas de Spectatus spectatus, larvas de Contracaecum sp. eProcamallanus (Spirocamallanus) inopinatus), digeneas (metacercárias de Cladorchiidae), acantocéfalos (Neoechinorhynchus buttnerae), crustáceos (Ergasilus turucuyus, Argulus multicolor, Perulernaea gamitanae e Braga patagonica), ácaros e sanguessugas. A dominância foi de espécies de monogeneas, encontradas nas brânquias dos hospedeiros, e houve elevada dispersão agregada dos parasitos, exceto Contracaecum sp., que teve dispersão uniforme e P. (S.) inopinatus, que mostrou dispersão randômica. A riqueza de espécies de parasitos variou de 1 a 9, o índice de diversidade de Brillouin de 0 a 1,52, a uniformidade de 0 a 0,63 e o índice de dominância de Berger-Parker de 0,39 a 1,00. A abundância de parasitos não foi influenciada pelo comprimento dos hospedeiros, mas houve significativa correlação com o peso corporal em alguns casos. A comunidade parasitária foi caracterizada por baixa riqueza de espécies e moderada diversidade, com predominância de ectoparasitos com elevada prevalência e abundância, bem como pela presença de endoparasitos em estágio larval.

ABSTRACT This study investigated the diversity of metazoan parasites in Colossoma macropomum from the Jari River, in the eastern Amazon, northern Brazil. We collected a total of 4966 parasites from 34 fishes, including monogeneans (Anacanthorus spathulatus, Mymarothecium boegeri, Notozothecium janauachensis and Linguadactyloides brinkmanni), nematodes (Spectatus spectatus larvae, Contracaecum sp. larvae andProcamallanus (Spirocamallanus) inopinatus), digeneans (Cladorchiidae metacercariae), acanthocephalans (Neoechinorhynchus buttnerae), crustaceans (Ergasilus turucuyus, Argulus multicolor, Perulernaea gamitanae and Braga patagonica), mites and leeches. The dominance was of monogenean species, found in the gills of the hosts. The parasites exhibited high aggregate dispersion, except Contracaecum sp. and P. (S.) inopinatus, that showed uniform and random dispersion, respectively. The species richness of parasites varied from 1 to 9, the Brillouin diversity index from 0 to 1.52, evenness from 0 to 0.63 and the Berger-Parker dominance index from 0.39 to 1.00. Abundance of parasites was not influenced by host length, but there was significant correlation with host body weight in some cases. The parasite community was characterized by low species richness and moderate diversity, with a predominance of ectoparasites with high prevalence and abundance, as well as the presence of endoparasites in the larval stage.

Abstract Tilapia is the second most important cultured species in the world fish culture but it can be affected by parasites. We conducted a cross-sectional parasitic study in tilapia larvae during sexual reversion for two seasons in Costa Rica. A total of 320 larvae from a concrete pond were necropsied and we found ten parasite species: Ichtyobodo sp., Apiosoma sp., Chillodonella sp., Heteropollaria sp., Trichodina sp.,Dactylogyrus sp., Girodactylus sp., Centrocestus sp., lasidies and glochidies (two larval forms). These were classified in five taxonomic groups (two subtypes of protozoa, two metazoan classes and a type of mollusk). Protozoans and monogeneans (except Trichodina sp.) had a higher prevalence in the rainy season, when water had more solid waste, while digeneans and molluscs were more prevalent in the dry season, with different infection dynamics over gills, skin, fins and head.

Resumen La tilapia es la segunda especie de cultivo más importante en el mundo de la pesca, pero puede verse afectada por parásitos. Realizamos un estudio transversal de parásitos en larvas de tilapia durante la reversión sexual en dos temporadas en Costa Rica. Un total de 320 larvas de un estanque de concreto fueron necropsiados y encontramos diez especies de parásitos: Ichtyobodo sp., Apiosoma sp., Chillodonella sp., Heteropollaria sp., Trichodina sp., Dactylogyrus sp., Girodactylus sp., Centrocestus sp., lasidios y gloquidios (dos formas larvarias). Estos se clasifican en cinco grupos taxonómicos (dos subtipos de protozoarios, dos clases de metazoarios y un tipo de molusco). Los protozoarios y monogeneos (excepto Trichodina sp.) tuvieron una mayor prevalencia en la época lluviosa, cuando el agua tenía más residuos sólidos, mientras que los digeneos y moluscos eran más frecuentes en la estación seca, con diferentes dinámicas de infección sobre las branquias, la piel, las aletas y la cabeza.

Abstract: Between May and November 2015, 8 specimens of Didelphis marsupialis Linnaeus, 1758 (Didelphimorphia: Didelphidae) collected in San Martín, Peru were examined for the presence of helminths. A total of 582 helminths representing 11 taxa were identified (2 digeneans and 9 nematodes). Five new host records and 4 species of nematodes [Gongylonemoides marsupialis (Vaz & Pereira, 1934) Freitas & Lent, 1937, Trichuris didelphis Babero, 1960, Viannaia hamata Travassos, 1914 and Viannaia viannaia Travassos, 1914] are added to the composition of the helminth fauna of the marsupials in this country. Further, a checklist of all available published accounts of helminth parasites reported from Peru is provided. To date, a total of 38 helminth parasites have been recorded. Digeneans have the highest species richness in number and percentage (n = 19, 50%), followed by nematodes (n = 17, 45%) and acanthocephalans (n = 2, 5%). The parasites with the highest number of records were the digeneans Plagiorchis didelphidis (Parona, 1896) Stossich, 1904 (n = 4) and Rhopalias coronatus Kifune & Uyema, 1982 (n = 4) and the nematode Aspidodera sp. (n = 4). Additional sampling in this country will probably increase the richness of the helminthological inventory of this group of mammals.

Resumen: Entre mayo y noviembre del 2015, 8 ejemplares de Didelphis marsupialis Linnaeus, 1758 (Didelphimorphia: Didelphidae) recolectados en San Martín, Perú, fueron examinados en busca de helmintos. Un total de 582 helmintos representando 11 taxones fueron identificados (2 digéneos y 9 nemátodos). Cinco registros nuevos y 4 especies de nemátodos [Gongylonemoides marsupialis (Vaz y Pereira, 1934) Freitas y Lent, 1937, Trichuris didelphis Babero, 1960, Viannaia hamata Travassos, 1914 y Viannaia viannaia Travassos, 1914] se agregan a la composición de la fauna de helmintos de marsupiales de Perú. Además, se proporciona una lista de todos los registros publicados de este grupo de parásitos para marsupiales en dicho país. Hasta la fecha, se ha registrado un total de 38 helmintos; los digéneos tienen la mayor riqueza de especies en número y porcentaje (n = 19, 50%), seguido por los nemátodos (n = 17, 45%) y acantocéfalos (n = 2, 5%). Los parásitos con mayor número de registros fueron los digéneos Plagiorchis didelphidis (Parona, 1896) Stossich, 1904 (n = 4) y Rhopalias coronatus Kifune y Uyema, 1982 (n = 4) y el nemátodo Aspidodera sp. (n = 4). Nuevos muestreos en este país probablemente aumentarán la riqueza del inventario helmintológico de este grupo de mamíferos.

Seventy six specimens of Cyphocharax platanus were collected downstream Salto Grande dam, lower Uruguay River, Uruguay, between August 2012 and June 2013 and examined for digenean parasites. Three digenean taxa were identified: Saccocoelioides spp. (Haploporidae), Zonocotyle bicaecata (Zonocotylidae) (both adult in intestine) and Sphincterodiplostomum musculosum (Diplostomidae) metacercariae inside eyes. We found that 69.7% of examined fish were parasitized by at least one digenean taxon. Saccocoelioides spp. showed highest values of prevalence, mean intensity and mean abundance (43.4%, 5.45, and 2.37, respectively) of infection throughout the study than Z. bicaecata (28.9%, 1.32 and 0.38, respectively) and S. musculosum (13.2%, 2.80 and 0.37, respectively). Saccocoelioides spp. and S. musculosum showed an aggregated distribution pattern, while Z. bicaecata presented a random distribution in the host population. No significant differences in infection indexes of any digenean taxa in relation to host sex were found, and only Saccocoelioides spp. showed a significant association with host size, being more frequent in small fish. The infection indexes of the two intestinal digeneans (Saccocoelioides spp. and Z. bicaecata) were not significantly associated. These are the first records of Saccocoelioides spp. and Z. bicaecata from C. platanus in the Uruguay River, and the finding of S. musculosum metacercariae is a new host-parasite relationship.

Entre agosto de 2012 y junio de 2013 estudios parasitológicos fueron llevados a cabo en 76 ejemplares de Cyphocharax platanus procedentes del tramo inferior del río Uruguay en la zona de influencia de la represa de Salto Grande. Tres taxones de digeneos fueron identificados: Saccocoelioides spp. (Haploporidae) y Zonocotyle bicaecata (Zonocotylidae) en intestino, y metacercarias de Sphincterodiplostomum musculosum (Diplostomidae) en el interior de los ojos. El 69,7% de los peces analizados resultaron parasitados por al menos un taxón de digeneo. Saccocoelioides spp. mostro los mayores valores de prevalencia, intensidad media y abundancia media (43,4%, 5,45, 2,37 respectivamente) de infección, en relación a Z. bicaecata (28,9%, 1,32 y 0,38 respectivamente) y S. musculosum (13,2%, 2,82 y 0,37 respectivamente). Saccocoelioides spp. y S. musculosum mostraron un patrón de distribución agregado, en tanto que Z. bicaecata presentó una distribución aleatoria en la población de hospedadores. No se hallaron diferencias significativas en los índices de infección de ninguno de los taxones de digeneos en relación al sexo de los hospedadores, y sólo Saccocoelioides spp. presentó una asociación significativa con el tamaño, siendo más frecuente en peces pequeños. Los dos parásitos intestinales (Saccocoelioides spp. y Z. bicaecata) no presentaron una asociación significativa entre sus índices de infección. Los registros de Saccocoelioides spp. y Z. bicaecata corresponden a los primeros para este hospedador en el río Uruguay, y el hallazgo de las metacercarias de S. musculosum constituye una nueva relación parásito-hospedador.

The work was aimed to increase knowledge on the diversity of parasitic digeneans in freshwater turtles from southern Brazil. Phrynops hilarii and Acanthochelys spixii are common turtle species of the Rio Grande do Sul fauna; however, little is known about the helminths parasitizing these hosts. In this context, 14 A. spixii and 5 P. hilarii were necropsied and helminthologically examined. The digenean species Cheloniodiplostomum sp. (Proterodiplostomidae), and Telorchis platensis (Telorchiidae) were reported for the first time in A. spixii. This is the first report of Cheloniodiplostomum testudinis, and Telorchis birabeni in P. hilarii from Brazil.

El propósito de este trabajo es incrementar el conocimiento sobre la diversidad de digéneos parásitos de tortugas de agua dulce en el sur de Brasil. Phrynops hilarii y Acanthochelys spixii son especies comunes de la fauna del Rio Grande do Sul; sin embargo, poco se sabe acerca de los helmintos que parasitan a estos hospedadores. En este contexto, se examinaron 14 A. spixii y 5 P. hilarii en busca de helmintos. El presente estudio registra A. spixii como un nuevo hospedador para los digéneos Cheloniodiplostomum sp. (Proterodiplostomidae) y Telorchis platensis (Telorchiidae). Además, los digéneos Cheloniodiplostomum testudinis y Telorchis birabeni son registrados por primera vez en P. hilarii en Brasil.