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Se reporta el hallazgo del acantocéfalo Profilicollis altmani, en un individuo de cigüeñuela de cuello negro (Himantopus mexicanus) en la costa norte del Perú. Profilicollis altmani no había sido reportado anteriormente en H. mexicanus, siendo este el primer reporte de este tipo. We record the presence of the acanthocephalan specie Profilicollis altmani in a black-necked stilt, Himantopus mexicanus, in the Northern coast of Peru. Profilicollis altmani had not been previously reported in H. mexicanus, this being the first report in a new host.

O objetivo deste estudo foi avaliar diferentes níveis de inclusão de sorgo com tanino condensável para controle de helmintos, parasitas de tambaqui (acantocéfalos). Made available in DSpace on 2021-12-22T14:05:39Z (GMT). No. of bitstreams: 1 Monografia-Gilberto-Batista-Viana-Filho.pdf: 374908 bytes, checksum: 1470be6bb4f74eb6675122d1c864f2c3 (MD5) Previous issue date: 2021 Monografia (Bacharelado em Zootecnia) - Universidade Federal do Amazonas, Manaus. Orientador: Dr. Jony Koji Dairiki; coorientador: Prof. Dr. Paulo César Machado de Andrade.

Máster Universitario en Biología Marina: Biodiversidad y Conservación 380 myctophid individuals of 11 different species gathered off the southwest of the islands of Tenerife and El Hierro. Through morphological, molecular and phylogenetic analysis, eight parasite species were identified in seven myctophid species. One species of copepod exoparasite: Cardiodectes bellottii (n = 4); one digenean species: Lethadena profunda (n = 16); four species of Anisakidae (n = 14): Anisakis brevispiculata (n = 1), A. simplex (sensu stricto), (n = 1), Anisakis type II (n = 8) and Pseudoterranova ceticola (n= 4); as well as two species of acantocephalus: Bolbosoma sp. (n = 1) and Neorhadynorhynchus sp. (n = 1). The study has unveiled a new species for science, Bolbosoma sp., and provided the first record at the Canary Islands for C. bellottii, L. profunda, Neorhadynorhynchus sp. and A. simplex (s.s.); the latter species might have arrived as a parasite of fin whales (Balaenoptera physalus). A. brevispiculata and P. ceticola evidenced their complex life cycle, showing that myctophids have a double role in their life cycles which includes the family Kogiidae. The general infection prevalence has been low, as expected in myctophids. In the case of L. profunda and anisakids, there were differences in the prevalence among different species of myctophids, which might be related to the diet and distribution of their definitive hosts. There were no differences in the prevalence of parasites for the same species between the islands of Tenerife and El Hierro and this might be explained by the large distribution of their final hosts. Stomach content analysis has been carried out to determine trophic relationships and parasitic transmission potential. 380 individuos de mictófidos de 11 especies diferentes pescadas en cinco lances en las aguas del suroeste de Tenerife y de El Hierro. Mediante análisis morfológicos, moleculares y filogenéticos se identificaron ocho especies de parásitos en siete especies de mictófidos. Se encontraron exoparásitos copépodos: Cardiodectes bellottii (n= 4); digeneos: Lethadena profunda (n=16); cuatro especies de Anisákidos (n=14): Anisakis brevispiculata (n=1), A. simplex (sensu stricto) (n=1), Anisakis tipo II (n= 8) y Pseudoterranova ceticola (n=4); y dos especies de acantocéfalos: Bolbosoma sp. (n=1) y Neorhadynorhynchus sp. (n=1). Destaca que el individuo de Bolbosoma sp. es una nueva especie para la ciencia, y que este trabajo constituye el primer registro para Canarias de las especies C. bellottii, L. profunda, Neorhadynorhynchus sp. y A. simplex (s.s.); esta última especie podría haber llegado a Canarias hospedada por rorcuales comunes (Balaenoptera physalus). A. brevispiculata y P. ceticola han puesto en evidencia el doble papel de los mictófidos en sus ciclos vitales que incluyen a la familia Kogiidae. En cuanto a las prevalencias de infección a nivel general han sido bajas, resultado esperable en mictófidos, y en los casos de L. profunda y en anisákidos se han visto diferencias significativas en su prevalencia entre distintas especies de mictófidos, que podrían estar vinculadas a la dieta y a la localización de los hospedadores definitivos. No se han detectado diferencias entre las islas de Tenerife y El Hierro en cuanto a los niveles de parasitación en cada especie de mictófido. Esto podría deberse a los amplios rangos de distribución de las especies hospedadoras definitivas. También se realizaron análisis de contenidos estomacales de los mictófidos para determinar relaciones tróficas y potencial de transmisión parasitaria.

Se estudió la composición taxonómica de las comunidades parasitarias de dos especies marinas de peces Atherinopsidae del género Odontesthes en los golfos norpatagónicos, y se estableció el rol que estas especies cumplen como hospedadores de helmintos. Se relacionó también la diversidad de la parasitofauna con las principales características biológicas de los hospedadores (talla, sexo, dieta) y con características ambientales (estacionalidad, áreas de procedencia). Las especies elegidas fueron los pejerreyes Odontesthes smitti y O. nigricans, y las áreas de estudio los golfos Nuevo (GN) y San José (GSJ) en la provincia de Chubut. Estas dos especies superponen sus áreas de distribución y su espectro trófico, y constituyen un ítem presa de importancia variable en la dieta de peces, aves y mamíferos marinos de la región Se examinaron 182 ejemplares adultos de O. smitti de GN y 173 de GSJ. Además, se prospectaron 83 ejemplares de tallas chicas (cornalitos y cornalones) en GN y 65 en GSJ. Se examinaron 105 ejemplares adultos de Odontesthes nigricans de GN y 20 ejemplares adultos de GSJ. El bajo número de O. nigricans en GSJ se explica por la baja capturabilidad de esta especie en GSJ. En O. smitti se hallaron y describieron 17 taxa parásitos: Microsporidia, Cestoda: larvas plerocercoides Tetraphyllidea; Digenea: Prosorhynchoides sp. (Bucephalidae), Aponurus laguncula, Lecithaster sp. (Lecithasteridae), Proctotrema n. sp. (Monorchiidae), Diphterostomum sp. (Zoogonidae); Nematoda: Cucullanus marplatensis (Cucullanidae), Huffmanela moraveci (Trichosomoididae), L3 de Cosmocephalus obvelatus (Acuariidae), L3 de Anisakis sp., L3 de Pseudoterranova sp., L3 de Contracaecum sp. (Anisakidae); Acantocephala: larva cystacanta Corynosoma sp. (Polymorphidae), adulto Echinorhynchida; Crustacea: Bomolochus globiceps (Bomolochidae) y Peniculus sp. (Penelidae). En O. nigricans se hallaron las mismas especies con excepción de Microsporidea, larvas plerocercoides Tetraphyllidea, A. laguncula y Contracaecum sp. Odontesthes smitti y O. nigricans se indican como nuevos hospedadores para la mayoría de los taxa parásitos hallados. Dos especies resultaron nuevas para la ciencia, Huffmanela moraveci y Proctotrema n. sp. El análisis de la distribución de los parásitos en las poblaciones de hospedadores en base a la relación varianza‐ media, el coeficiente de agregación k y el índice de Dispersión de Morisita, mostró que la mayoría de los parásitos están distribuidos de manera agregada en la población de hospedadores. El sexo de los hospedadores no influyó en los valores de prevalencia, intensidad y abundancia de las poblaciones parásitas. Esto sugiere que no existirían diferencias tróficas y/o de comportamiento que afecten a las cargas parasitarias. La longitud de los hospedadores fue uno de los principales factores que influyó en el tamaño de las poblaciones parásitas y en la estructura de las comunidades parasitarias de O. smitti y O. nigricans. La riqueza y la abundancia de las infracomunidades correlacionaron positiva y significativamente con la longitud de los pejerreyes, mientras que la diversidad y la equitabilidad lo hicieron de manera negativa. Esto significa que los hospedadores de longitudes mayores albergaron infracomunidades más ricas, caracterizadas por la presencia de pocas especies bien representadas y varias especies raras. Se evaluó la estructura de las comunidades parasitarias a partir de la correlación de la prevalencia y la intensidad media y la distribución de frecuencias de las prevalencias. En las comunidades de O. smitti de ambos golfos se reconocieron dos especies comunes (Prosorhynchoides sp. y C. marplatensis) de acuerdo a sus altos valores de prevalencia e intensidad media. La similitud cualitativa entre infracomunidades fue alta en GN debido a la presencia de estas especies, y más baja en GSJ debido a la presencia de una mayor cantidad de especies con prevalencias e intensidades intermedias. En O. nigricans no se reconocieron especies centrales y la similitud entre infracomunidades fue baja. La riqueza promedio de las infracomunidades fue marcadamente menor que la de las comunidades componentes, característica de las comunidades insaturadas donde los hospedadores individuales albergan muchas menos especies de parásitos de las que podrían albergar y por lo tanto existen nichos vacantes. Se analizó la composición de la dieta de ambas especies hospedadoras, y se la relacionó con la fauna parasitaria hallada. Como resultado de este análisis, se propusieron las posibles vías de transmisión de los taxa parásitos en los pejerreyes a través de las tramas tróficas en los golfos norpatagónicos. Así, en la comunidad de O. smitti los taxa más prevalentes y abundantes fueron los que utilizan organismos bentónicos como hospedadores intermediarios, indicando una preferencia de O. smitti por alimentarse sobre este tipo de organismos. Por el contrario, en la comunidad parasitaria de O. nigricans predominaron aquellos taxa que emplean hospedadores intermediarios planctónicos, por lo que esta especie hospedadora tendría preferencias por una alimentación con mayores componentes del plancton. Estas diferencias se vieron reflejadas en la estructura de sus comunidades parasitarias. Odontesthes smitti se comporta como hospedador intermediario y/o paraténico para larvas plerocercoides de cestodes Tetraphyllidea y digeneos Bucephalidae constituyéndose en un ítem presa para peces cartilaginosos y teleósteos respectivamente. Además, cumplen el rol de hospedadores paraténicos para larvas de nematodes Acuariidae y Anisakidae y de acantocéfalos Polymorphidae que culminan su ciclo de vida en aves y mamíferos marinos de la región. Odontesthes nigricans cumpliría un rol similar como hospedador intermediario de helmintos en las tramas tróficas de la zona bajo estudio, ya que albergan las mismas especies en estado larval, con la única excepción de las larvas plerocercoides. La presencia de parásitos en estado larval y otros en estado adulto sugiere que las especies hospedadoras se encuentran en un nivel intermedio en las tramas tróficas de la región, además de su importante rol en las relaciones tróficas interespecíficas en el área. Además, se comprobó experimentalmente la infección de los pejerreyes con un digeneo de la familia Monorchiidae a partir de las metacercarias enquistadas en la almeja Darina solenoides. Las comunidades componentes de O. smitti y O. nigricans de los golfos norpatagónicos comparten la mayoría de sus especies parásitas, probablemente por ser especies estrechamente emparentadas filogenéticamente. Diferencias en el comportamiento trófico y en el tamaño corporal serían los factores más importantes a partir de los cuales se podrían explicar las variaciones observadas en la estructura de sus faunas parasitarias., Facultad de Ciencias Naturales y Museo

We record the presence of the acanthocephalan specie Profilicollis altmani in a black-necked stilt, Himantopus mexicanus, in the Northern coast of Peru. Profilicollis altmani had not been previously reported in H. mexicanus, this being the first report in a new host., Se reporta el hallazgo del acantocéfaloProfilicollis altmani, en un individuo de cigüeñuela de cuello negro (Himantopus mexicanus) en la costa norte del Perú.Profilicollis altmanino había sido reportado anteriormente enH. mexicanus, siendo este el primer reporte de este tipo.

The record of occurrence of acanthocephalan parasites on tambaqui farms in Northern Brazil has increased in recent years along with reports of associated economic losses, justifying further epidemiological studies of this parasite. As such, this study evaluated the occurrence of the acanthocephalan Neoechinorhynchus buttnerae and the parasite-host relationship in tambaqui (Colossoma macropomum) from three fish farms in the Amazonian town of Rio Preto da Eva, Brazil. Fish from the farms (N = 18 per farm) were collected for parasitological examination, determination of the relative condition factor and correlation tests between the parameters assessed. Of the fish examined, 37 were parasitized with N. buttnerae (68.5% prevalence), with intensity of infection variation ranging from 1 to 1,219 specimens per fish (12,279 specimens counted). In two farms was detected the high mean intensity of infection, 230.8 and 451.3 parasites per fish, with a total count of 4,155 and 8,123 parasites, respectively, whereas the third farm had a single fish infected with only one specimen. The weight-length ratio equation indicated that the fish were growing at the same rate in weight and length. It was observed significant correlation between parasite intensity and fish length, as well as significant negative correlation with parasite intensity and condition factor. The gastrointestinal tract contained ostracod invertebrates, which are intermediate N. buttnerae hosts. The high N. buttnerae intensity affect their physiological condition as suggested by the negative correlation between parasitic intensity and condition factor, emphasizing the need to implement suitable prophylactic measures to prevent infection by the parasite.

Flounders are commercially and economically important fish. A total of 120 specimens of flounders (60 Paralichthys isosceles, 30 Paralichthys patagonicus and 30 Xystreurys rasile) were collected off the coast of the state of Rio de Janeiro, Brazil. The fish were measured, necropsied and filleted, and then had their organs investigated for acanthocephalans. Taxonomic identification of the parasites was based on morphological, morphometric and genetic characters. Paralichthys isosceles and P. patagonicus were parasitized by juveniles of Serrasentis sagittifer, Bolbosoma turbinella, Corynosoma australe and C. cetaceum; Xystreurys rasile was parasitized by C. australe. Genetic characterization confirmed the identification of specimens of Bolbosoma turbinella and Corynosoma australe, as demonstrated by phylogenetic analyses using both ITS and cox1 molecular targets. Parasite indices of prevalence, intensity, mean intensity, abundance, mean abundance, and range of infection, as well as infection site, were evaluated for each parasite species. This is the first report of S. sagittifer parasitizing P. isosceles and P. patagonicus, and B. turbinella parasitizing P. patagonicus. Resumo Os linguados são peixes comercial e economicamente importantes. Um total de 120 espécimes de linguados (60 Paralichthys isosceles, 30 P. patagonicus e 30 Xystreurys rasile) foram coletados no litoral do estado do Rio de Janeiro, Brasil. Os peixes foram medidos, necropsiados, filetados e tiveram seus órgãos investigados para a presença de acantocéfalos. A identificação taxonômica foi baseada em caracteres morfológicos, morfométricos e genéticos. Paralichthys isosceles e P. patagonicus estavam parasitados por acantocéfalos juvenis de Serrasentis sagittifer, Bolbosoma turbinella, Corynosoma australe e C. cetaceum; Xystreurys rasile estava parasitado com C. australe. A caracterização genética confirmou a identificação dos espécimes de Bolbosoma turbinella e Corynosoma australe, como demonstrado por análises filogenéticas usando ambos marcadores moleculares ITS e cox1. Foram analisados os índices parasitários: prevalência, intensidade, intensidade média, abundância, abundância média, amplitude de variação da infecção e sítio de infecção de cada espécie de parasito. Este é o primeiro registro de S. sagittifer parasitando P. isosceles e P. patagonicus, e de B. turbinella parasitando P. patagonicus.

Orientador: Prof. Dr. Ricardo Massato Takemoto Coorientadora: Prof.ª Dr.ª Sybelle Bellay Tese (doutorado em Biologia Comparada) - Universidade Estadual de Maringá, 2019 As pressões antrópicas, como o uso e ocupação do solo, o processo acelerado de urbanização e industrialização têm se intensificado nas bacias hidrográficas, assim como, o uso de fertilizantes, corretivos de solo e o carreamento de substâncias alóctones para os rios e estes contribuem com o aumento da poluição e degradação da qualidade da água nos ecossistemas aquáticos. Os organismos aquáticos estão expostos à estressores ambientais, como variações de parâmetros físicos e químicos, mudanças na dieta e aumento da exposição à elementos traço (metais pesados), sendo que maiores níveis destes elementos na água podem resultar em altas taxas de bioacumulação nos organismos. Nesse sentido, o uso de parasitas de peixes (monogenéticos, cestoides e acantocéfalos) como bioindicadores, permitem avaliar o efeito dos estressores ambientais na saúde dos hospedeiros e ecossistemas aquáticos, e ainda, detectar o acúmulo de elementos traço e descrever a relação que existe, por exemplo, entre a eutrofização e o parasita de ciclo monoxênico. Dentre os grupos de parasitas, foi verificado ainda que os acantocéfalos apresentam alta capacidade de bioacumular elementos traço dos hospedeiros, exibindo assim concentrações muitas vezes superiores que nestes e no ambiente. Assim, o presente estudo foi subdividido em dois artigos que avaliaram os parasitas de peixes como bioindicadores da qualidade ambiental. O objetivo do primeiro artigo foi investigar o potencial uso dos ectoparasitas monogenéticos de Rhamdia branneri e Hypostomus sp. como bioindicadores da qualidade ambiental em seis riachos do baixo Iguaçu, caracterizados como urbanos e não urbanos; identificar os monogenéticos encontrados, bem como comparar a abundância de ectoparasitas. E por fim, determinar possível correlação entre o fator de condição relativo (Kn) dos hospedeiros e a abundância de infecção das espécies de parasitas e avaliar diferenças na abundância de parasitas de hospedeiros machos e fêmeas nos riachos urbanos e não urbanos. A abundância de parasitas em ambos hospedeiros foi significativamente distinta entre os ambientes, sendo maior nos riachos urbanos, esses resultados sugerem que estes organismos podem ser favorecidos por alterações nos fatores ambientais e serem usados como ferramentas úteis no biomonitoramento ambiental. O objetivo do segundo artigo foi analisar e comparar a concentração de Cádmio (Cd) encontrado na musculatura, fígado e intestino de Prochilodus lineatus e Serrasalmus marginatus coletados nos rios Baía e Paraná, bem como avaliar o potencial uso dos acantocéfalos como bioindicadores da poluição ambiental e a capacidade de bioacumulação de Cd por estes parasitas intestinais. Os parasitas apresentaram concentrações estatisticamente superiores que todos os tecidos de S. marginatus e P. lineatus do rio Baía e P. lineatus do rio Paraná. Os acantocéfalos representam importantes ferramentas diagnósticas para avaliar o comportamento dos elementos traço no ambiente Anthropic pressures such as land use and occupation, the accelerated process of urbanization and industrialization have intensified in the hidrographycs basins as well as the use of fertilizers, soil improvers and the transport of allochthonous substances to rivers and these contribute to increased pollution and degradation of water quality in aquatic ecosystems. Aquatic or this ganisms are exposed to environmental stressors such as variations in physical and chemical parameters, changes in diet and increased exposure to trace elements (heavy metals), and higher levels of these elements in water may result in high bioaccumulation rates in organisms. In this regard, the use of fish parasites (monogeneans, cestodes and acanthocephalans) as bioindicators allows us to evaluate the effect of environmental stressors in the health of hosts and aquatic ecosystems, and to detect the accumulation of trace elements and to describe the relationship that exists, for example, between eutrophication and the monoxenic cycle parasite. Among the parasite groups, it was also found that acanthocephalans have a high capacity to bioaccumulate trace elements of the hosts, thus exhibiting many times higher concentrations than in the hosts and in the environment. Thus, the present study was subdivided into two chapters that evaluated fish parasites as bioindicators of environmental quality. The aim of the first chapter was to investigate the potential use of the monogenetans ectoparasites of Rhamdia branneri and Hypostomus sp. as bioindicators of environmental quality in six lower Iguaçu streams, characterized as urban and non-urban; identify the monogeneans found and compare the abundance of ectoparasites. Finally, to determine a possible correlation between the relative condition factor (Kn) of hosts and the abundance of parasite species infection and to evaluate differences in parasite abundance of male and female hosts in urban and non-urban streams. The abundance of parasites in both hosts was significantly different between environments, being higher in urban streams, these results suggest that these organisms may be favored by changes in environmental factors and be used as useful tools in environmental biomonitoring. The aim of the second chapter was to analyze and compare the cadmium (Cd) concentration found in the muscles, liver and intestine of Prochilodus lineatus and Serrasalmus marginatus collected in the Baía and Paraná rivers, as well as to evaluate the potential use of acanthocephalans as bioindicators of environmental pollution and Cd bioaccumulation capacity by these intestinal parasites. The parasites presented statistically higher concentrations than all tissues of S. marginatus and P. lineatus of Baía river and P. lineatus of Paraná river. Acanthocephalans represents important diagnostic tools to evaluate the behavior of trace elements in the environment

Knowledge concerning the taxonomy and biology of species of Acanthocephala, helminth parasites of the helminth species of the phylum Acanthocephala, parasites of lizards in Brazilian Amazonia, is still insufficient, but reports of Acanthocephala in reptiles are becoming increasingly common in the literature. Cystacanth-stage Acanthocephalan larvae have been found in the visceral peritoneum during necropsy of Ameiva ameiva ameivalizards from the “Osvaldo Rodrigues da Cunha” Herpetology Collection of the Emílio Goeldi Museum, Belém, Pará, Brazil. The aim of this study was to present the morphological study of the Acanthocephala larvae found in A. ameiva ameiva lizard. Resumo O conhecimento a respeito da taxonomia e da biologia das espécies de Acanthocephala, helmintos parasitos das espécies de lagartos da Amazônia Brasileira ainda é insuficiente, mas o registro do encontro de acantocéfalos em répteis é cada vez mais comum na literatura. Foram encontradas larvas de acantocéfalos em fase cistacanto durante a necropsia, no peritônio visceral, de lagartos Ameiva ameiva ameiva provenientes da Coleção Herpetológica “Osvaldo Rodrigues da Cunha” do Museu Paraense Emílio Goeldi, Belém, Pará. O objetivo é apresentar um estudo morfológico de larvas de Acanthocephala encontradas em A. ameiva ameiva.

O presente trabalho avaliou o impacto do parasitismo sobre os parâmetros hematológicos e bioquímicos na criação de tambaqui (Colossoma macropomum) e os danos teciduais provocados pela infecção por acantocéfalo Neoechinorhynchus buttnerae. Made available in DSpace on 2019-02-04T23:37:24Z (GMT). No. of bitstreams: 1 DissertacaoMariaJulieteRocha2017.pdf: 1943478 bytes, checksum: e25ba26bc532177ce9eac82b3b3f4202 (MD5) Previous issue date: 2017-08-15 Dissertação (Mestrado em Ciências Pesqueiras nos Trópicos) - Universidade Federal do Amazonas, Manaus. Orientadora: Drª Edsandra Campos Chagas; Coorientador: Dr Oscar Tadeu Ferreira da Costa.

Fil: Núñez, Verónica. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología Invertebrados; Argentina Fil: Drago, Fabiana Beatríz. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología Invertebrados; Argentina

O objetivo do presente trabalho foi avaliar a fauna parasitária de quatro espécies de peixes ornamentais capturados no rio Chumucuí, no município de Bragança-PA. Foram coletados um total de 307 peixes pertencentes a 4 espécies, sendo elas: Moenkhausia sanctaefilomenae (olho de fogo, n = 23), Carnegiella strigata (borboleta, n = 37), Chilodus punctatus (cabeça-para-baixo, n = 7) e Astyanax bimaculatus (lambari, n = 240) coletados de junho de 2006 a dezembro de 2007. Foram observados 3 taxa parasitando os peixes: monogenéticos nas brânquias, nematóides (larvas de Capillaria sp. e Contracaecum sp.) no trato digestório e fígado e acantocéfalos (Quadrigyrus torquatus, Q. brasiliensis e Q. nickoli) no estômago e intestino. Astyanax bimaculatus apresentou maior prevalência de acantocéfalos na estação chuvosa, menor prevalência de nematóides na estação seca. Discute-se a eventual importância destes parasitas na exportação de peixes ornamentais. The objective of the present study was to evaluate the parasite fauna of four species of ornamental fish collected in the Chumucuí River, municipality of Bragança, Pará, Brazil. From June 2006 to December 2007. Fishes (n=307) belonging to four species were collected, including 23 specimens of Moenkhausia sanctaefilomenae (redeye tetra), 37 Carnegiella strigata (marbled hatchetfish), 7 Chilodus punctatus (spotted headstander), and 240 Astyanax bimaculatus (twospot astyanax). The parasites found belonged to three taxa: monogeneans in the gills, nematodes (larvae of Capillaria sp. and Contracaecum sp.) in the digestive tract and liver and acanthocephalans (Quadrigyrus torquatus, Q. brasiliensis and Q. nickoli) in the stomach and intestine. Astyanax bimaculatus presented higher prevalence of acanthocephalans in the wet season, and lower prevalence of nematodes in the dry season. The possible importance of these parasites in the exportation of ornamental fish is discussed.

Made available in DSpace on 2016-09-23T15:58:51Z (GMT). No. of bitstreams: 1 PIBIC_FINAL.pdf: 779701 bytes, checksum: ad5fab4c79861a0e865fa37bb800ed95 (MD5) Previous issue date: 2015-07-31 FAPEAM Ocorrência de doenças particularmente devido a parasitas tem-se tornado um grande constrangimento na aquicultura. Os peixes estão continuamente expostos aos parasitos principalmente em condições de cultivo. Dentre os parasitas identificados em tambaquis cultivados, estão os acantocéfalos intestinais. Estes são vermes cilíndricos, considerados patogênicos por serem dotados de probóscide retrátil, portadora de ganchos, que os adultos utilizam para fixar-se na parede do intestino do hospedeiro. A patogenicidade de acantocéfalos é principalmente causada por dois fatores: a densidade dos vermes e a profundidade de penetração do parasita nos tecidos do hospedeiro. Assim, estudos morfológicos em nível macroscópico podem evidenciar quanto e como os parasitos se distribuem ao longo do tubo intestinal; já em nível histológico podem revelar de que forma em que intensidade o parasita afeta a estrutura dos tecidos que compõem o òrgão e que diminui a eficiência de absorção dos nutrientes pelo organismo. Neste projeto, essas informações serão levantadas para tambaqui obtido de cultivo intensivo com evidente ocorrência de infecção por acantocéfalos intestinais. Portanto, neste projeto os objetivos são: determinar a densidade de acantocéfalos Neoechynorrnynchus sp. nos diferentes segmentos do tubo intestinal de tambaquis obtidos do cultivo intensivo; descrever as alterações observadas nos tecidos do hospedeiro afetados pelo parasito e verificar possível relação entre a densidade parasitária e o grau de danos teciduais ao longo do tubo intestinal do hospedeiro. Exemplares de tambaquis serão coletados de uma piscicultura intensiva com sistema de viveiro escavado, na cidade de Manaus (Amazonas). Uma amostragem preliminar de exemplares de tambaquis coletados no local, mostrou ocorrência de infecção intestinal maciça por acantocéfalo Neoechynorrhyncus sp. Para determinação da densidade de parasitos, em dez exemplares, os intestinos serão cuidadosamente removidos, abertos longitudinalmente e os parasitos serão contados em cada um dos sete segmentos morfologicamente distintos do tubo intestinal. Para as análises histológicas, intestinos infectados de seis espécimes de tambaqui serão cuidadosamente removidos, após amarrar ambas extremidades, da cavidade celomática e uma amostra padronizada de cada um dos sete segmentos do intestino serão fixadas em líquido de Bouin, desidratadas em séries crescentes de alcool, diafazinados em xilol e impregnados com parafina histológica liquida. Após emblocadas, as amostras serão seccionadas em micrótomo e os cortes histológicos corados com Hematoxilina e Eosina. Dois cortes histológicos de cada segmento do tubo intestinal serão observados em microscópio Leica. As alterações teciduais serão descritas e qualitativamente classificadas quanto ao grau do dano tecidual, conforme metodologia adaptada de Kang, et al. (1983). Os resultados desta análise serão comparados entre os segmentos intestinais e relacionados com a densidade parasitária.

Cuatro especies de acantocéfalos pertenecientes a la familia Oligacanthorhynchidae son estudiados. Dos de ellas corresponden a nuevos hallazgos geográficos. Adicionalmente se registra por primera vez en el Perú a Oligacanthorhynchus carinii y Oligacanthorhynchus major.Four species of acanthocephalan (Oligacanthorhynchidae) were studied. Two species are new geographical records. Additionally, Oligacanthorhynchus carinii and Oligacanthorhynchus major are registered for the first time in Peru.

ResumenLa riqueza actual de acantocéfalos asociados a vertebrados silvestres de México asciende a 60 especies nominales, lo que representa el 5% de la diversidad conocida para este grupo en el mundo. Este valor fue obtenido a partir del análisis de 227 especies de hospederos distribuidos en 28 estados de la República, entre los que destacan los actinopterigios como el grupo más intensamente estudiado, con 151 especies registradas como hospederos de por lo menos 1 especie de acantocéfalo. Consideramos que el conocimiento de la diversidad de este grupo de helmintos es limitado, especialmente si tomamos en cuenta que de los 5 488 vertebrados registrados para el país el 94.5% no se han registrado como hospederos de especies de este grupo. Sólo a través de estudios sistemáticos que integren los caracteres morfológicos con los ecológicos y moleculares se podrá lograr un conocimiento más preciso de la diversidad de este grupo en México.AbstractRichness of acanthocephalans associated to wild vertebrates of Mexico is currently composed of 60 nominal species, representing 5% of the known diversity for this group worldwide. This value was derived from the analysis of 227 host species in 28 states of the country, among which the actinopterygians were the most intensively studied vertebrate group, with 151 species being reported as hosts of at least 1 species of acanthocephalan. We believe that knowledge of the diversity of this group of helminths is still limited, especially if we consider that 94.5% of 5 488 recorded vertebrates in the country have not been reported as hosts for species of this group. Only through a systematic study that integrates ecological, morphological, and molecular data, a more comprehensive view of this group of parasites will be obtained

O objetivo desse trabalho foi registrar a primeira ocorrência sazonal do acantocefala Quadrigyrus nickoliSchmidt & Hugghins, 1973(Quadrigyridae) no peixe “Mato Grosso”,Hyphessobrycon eques Steindachner, 1882 (Characidae), capturados no Rio Chumucuí, região Bragantina, Pará, Brasil. Os peixes foram coletados no período de julho∕2006 a junho∕2007 e examinados com técnica padrão para detecção de parasitas. Um total de 75 parasitas foram encontrados no estômago e intestino. Dos 83 peixes capturados (50 na estação seca e 33 na chuvosa), 22 estavam parasitados por cistacantos de Quadrigyrus nickoli. No presente trabalho discute-se a importância do H. eques como hospedeiro paratênico para Quadrigyrus nickoli. Os presentes dados constituem o primeiro estudo sobre a biologia e a infecção de Q. nickoli na Amazônia oriental. The objective of this work was to report the first seasonal occurrence of the acanthocephalan Quadrigyrus nickoliSchmidt & Hugghins, 1973(Quadrigyridae), in the “Mato Grosso”Hyphessobrycon eques (Characidae) (Steindachner, 1882), collected from the Chumucuí River, state of Pará, Brazil. The fish were collected between July 2006 (rainy season) and June 2007 (dry season) and were examined for parasites using pattern techniques. A total of 75 parasites were found in the stomach and intestine. Among 83 fish examined (50 in the dry season and 33 in the rainy season), 22 were parasitized by cystacanths of Q. nickoli. The importance of H. eques as a paratenic host for Q. nickoli is discussed. This is the first study on the biology of and infection by Q. nickoli occurring in the eastern Amazon region. ALMEIDA, E. S.; DINIZ, D. G. UFPA - Universidade Federal do Pará

At present, the metazoan parasite fauna of most species of otariids is generally poorly known, in part because these marine mammals are mostly protected and, therefore, sampling is limited to specimens stranded on the coast or captured as by-catch in fisheries. Similar problems also occur for the larval stages of gastrointestinal helminths of otariids. For most of these parasite species, the specific identity of the intermediate/paratenic of hosts is unknown and, therefore, many stages of their life cycles remain to be described. Similarly, little is known about the routes of transmission of these parasites between intermediate/paratenic hosts to their otariids definitive hosts. The present thesis is committed to improving the knowledge on these aspects, characterizing for the first time, the intestinal helminth fauna of 56 South American sea lions Otaria flavescens (Shaw, 1800), and 5 South American fur seals Arctocephalus australis (Zimmerman, 1783), from the Patagonian coast of Argentina. Additionally, a total of 542 specimens of 20 marine fish species collected in the same locality, were analysed for helminths, identifying and quantifying the larval forms of parasite infecting otariids. The large dataset obtained provided the opportunity to describe the larval forms and to assess pathways of transmission of these parasites between intermediate/paratenic fish hosts and their definitive otariid hosts. Finally, the large number of larval specimens from several fish species collected in the course of this study allowed us to know essential aspects to understand the population dynamics of these parasites, as the effects of the different host species on some life history traits of the larvae, such as growth patterns or sex ratio, or the potential role of the host in the transmission of the parasite. This study targeted the following objectives: 1) To quantify and describe the intestinal metazoan parasite communities of O. flavescens and A. australis off northern Patagonia, Argentina, based on a detailed morphological and taxonomical study. This information is used to ascertain the role of parasite host specificity in shaping helminth community diversity in otariids. 2) To characterize the component populations of cystacanths of Corynosoma australe (Acanthocephala: Polymorphidae) in paratenic fish hosts off the Patagonian coast of Argentina. The main goal is to elucidate the pathways of transmission of this species between paratenic hosts and definitive otariid hosts, and to assess the effect of different fish hosts on growth, body size, fitness and sex ratio of the cystacanths of C. australe. 3) To describe, for the first time, the temporal allocation of investment on holdfast structures (trunk spines) between cystacanths and adults of two congeneric species of acanthocephalans (Corynosoma cetaceum and C. australe), and investigating the factors that may account for the patterns of trunk spine growth. 4) To carry out a taxonomic identification and description of third-stage larvae of species of Pseudoterranova (Nematoda: Ascaridoidea) from various fish species of Patagonia using sequence data for the mitochondrial cytochrome c oxidase subunit 1 (cox 1) gene and a detailed morphological study. This evidence is then used to describe the component populations of third-stage larvae of species of Pseudoterranova in fishes, assessing the role of different fish hosts on the microhabitat selection, transmission strategies and infection parameters of the third-stage larvae. A total of 97,325 helminth specimens were collected from O. flavescens from the Patagonian coast in Argentina. The intestinal helminth fauna of sea lions in this locality comprised 11 taxa (1 trematode, 1 cestode, 5 nematodes and 4 acanthocephalans). Gravid individuals were represented by 6 species: Ascocotyle (Ascocotyle) patagoniensis, Contracaecum ogmorhini (s.s.), Corynosoma australe, Diphyllobothrium spp., Pseudoterranova cattani and Uncinaria hamiltoni. Third-stage larvae of Anisakis sp. type I and Contracaecum sp., and juvenile specimens of Andracantha sp., Corynosoma cetaceum and Profilicollis chasmagnathi were also collected. Four of these parasites species, Andracantha sp., A. (A.) patagoniensis, C. ogmorhini (s.s.) and P. chasmagnathi represent new host records. A total of 1,516 helminth specimens were collected from the intestine of A. australis. The intestinal helminth fauna of fur seals comprises 7 parasite taxa (2 cestodes, 3 nematodes and 2 acanthocephalans). Gravid individuals were represented by 4 species of parasites: C. ogmorhini (s.s.), C. australe, Diphyllobothrium spp., and P. cattani. Third-stage larvae of Contracaecum sp. and juvenile specimens of C. cetaceum were also collected. Corynosoma australe was the most prevalent and abundant parasite in both hosts, accounting for > 90% of all specimens. In northern Patagonia, sea lions and fur seals harbour the intestinal helminth communities that could be predicted for otariids worldwide, i.e. the combination of species of the genera Corynosoma, Diphyllobothrium, Pseudoterranova, Contracaecum and, in pups, Uncinaria. The estimation of helminth community parameters in sea lions and fur seals, especially species richness at component community level, was affected by the inclusion or exclusion of parasites for which both species of otariids are putative non-hosts (i.e. hosts in which the parasite is unable to reproduce). This study demonstrates that the inclusion of these taxa can exert a significant influence on some community parameters. Information about the reproductive status of helminth species is often lacking in parasitological surveys on otariids and other marine vertebrates, but it is of significance to improve precision in parascript studies or ecological meta-analyses. A new species of a heterophyid trematode was described from the intestine of South American sea lions. A detailed morphological and morphometrical analysis of specimens of Ascocotyle (Ascocotyle) patagoniensis Hernández-Orts, Montero, Crespo, García, Raga and Aznar, 2012 suggests that this trematode can be distinguished from the other species of the subgenus by the number of circumoral spines, which are arranged in 2 rows of 18 to 23, by having a gonotyl without papillae, and by their widest seminal receptacle. Species of the subgenus Ascocotyle usually infect fish-eating birds or mammals in freshwater or brackish habitats. Ascocotyle (A.) patagoniensis is the first species of the subgenus described from a marine mammal. However, no metacercariae of Ascocotyle spp. were found in 542 marine teleosts from 20 species collected along the Patagonian Shelf. The absence of metacercariae in marine fish inhabiting this area could be related to the fact that the life cycle of this trematode is restricted to littoral waters. Nevertheless, more fishes should be analysed to confirm this hypothesis as the small metacercariae could have been overlooked, mainly in host species with small sample sizes. A total of 1,367 cystacanths of C. australe was collected in 18 species of marine fish from the Patagonian coast. The most infected fish species with n ≥ 15 were as follows: Acanthistius patachonicus, Paralichthys isosceles, Prionotus nudigula, Raneya brasiliensis and Xystreurys rasile. Eight fish species, i.e. A. patachonicus, Brama brama, Congiopodus peruvianus, Cottoperca gobio, Genypterus blacodes, Patagonotothen ramsayi, Seriolella porosa and Stromateus brasiliensis represent new host records for C. australe. Results of this study demonstrate that cystacanths of C. australe are able to infect and colonize a wide array of fish species, which would act as paratenic hosts. The ubiquity of this acanthocephalan through the trophic web would guarantee infections to their definitive hosts through alternative pathways. Nevertheless, this study suggest that R. brasiliensis, is one of the prey that most likely contributes to the transmission of cystacanths of C. australe in this area, due to both the high prevalence in this fish species, and its high relative importance in the diet of sea lions and fur seals. There were significant differences in the levels of infection of cystacanths of C. australe between fish inhabiting different zones of the water column, being the ones associated with benthic zone those with highest cystacanth infections. This study suggests that at least 2 main factors could be directly promoting differences in the infection levels of C. australe between fish from different zones: 1) distribution of the invertebrate intermediate hosts; and 2) patterns of transmission of cystacanths between paratenic fish hosts through food webs. The overall sex ratio of cystacanths of C. australe infecting fish hosts was slightly, but significantly, female-biased and no significant differences were found among fish species. This suggests that the sex ratio would begin to be biased before individuals of C. australe infect the definitive host, in which the sex ratio is known to become strongly female-biased because females have a longer life span. In other words, part of the biased sex ratio that we observe in the definitive hosts would be already transferred from paratenic hosts. In theory, 3 factors could be involved in generating the sex ratio biases in our sample, namely, sampling error, differential sampling of female and male larvae, and/or differential mortality between the sexes. This study analyses, for the first time, the potential costs that trophically-transmitted helminths may face in paratenic-to-paratenic transmission. The results suggest that some fish species, in particular Acanthistius patachonicus, might actually be unsuitable paratenic hosts for C. australe since most cystacanths found in this species were not viable. Also, a slight, but statistically significant, tendency to decrease body size of cystacanths was observed as the trophic level of fish species increased. This tendency, which was not related to crowding effects, appears to suggest that C. australe may incur in non-negligible energetic costs when experiencing putative paratenic-to-paratenic transmission. The implications of this finding cannot be underestimated, since this negative consequence may have an important role on the population dynamics of trophically-transmitted helminths. Acanthocephalans have evolved a hooked proboscis and some taxa have trunk spines to attach to their definitive hosts. These structures are generated before being used, thus a key question is how investment in attachment could optimally be allocated through the ontogeny. The number and arrangement of hooks and spines are never modified in the definitive host, but it is unclear whether these structures grow during adult development. The present study compared, for the first time using inferential statistics, the size of holdfast structures between cystacanths and adults of acanthocephalans. The results suggest that the size of trunk spines grows between cystacanths and adults of C. australe and an allied species infecting cetaceans, C. cetaceum, but only in females, which also had significantly larger spines than males. However, this sexual dimorphism did not result from pure allometry since the body of females was smaller, and did not grow more than that of males. Nevertheless, females have longer lifespan, and therefore this factor would induce different investment and development schedules for spines, in order to withstand the extreme flow conditions prevailing in marine mammals for longer time. Unexpectedly, the patterns of spine growth appear also to differ between both species of Corynosoma. In C. cetaceum fore-trunk spines and hind-trunk spines grew, whereas in C. australe only fore-trunk spines differed between cystacanths and adults. An explanation of these differences is that females of C. cetaceum fine-tune the size of spines during the development in the definitive hosts because they achieve a larger adult size, a trait that correlates with stronger dislodging forces and, possibly, with a longer lifespan. This study sheds light on the question of whether or not the holdfast of acanthocephalans is fully developed prior to entering the definitive host. It suggests that temporal allocation of investment in attachment structures may differ, not only between congeneric species, but also between sexes of the same species, possibly due to the different selective pressures that each population subset faces. A total of 635 encapsulated third-stage larvae of Pseudoterranova (sealworm larvae) were collected from 12 species of marine fish from the Patagonian coast. The most infected fish species with sealworm larvae was P. nudigula, followed by A. patachonicus, P. isosceles, Percophis brasiliensis and Pseudopercis semifasciata. Five species of fish, i.e. C. gobio, Nemadactylus bergi, M. argentinae, P. brasiliensis and P. nudigula represent new host records for larval sealworms. Sequences obtained for the mitochondrial cytochrome c oxidase subunit 1 gene (cox 1) of sealworms from the red searobin, P. nudigula, formed a reciprocally monophyletic lineage with published sequences of P. cattani from definitive hosts. A detailed morphological and morphometrical description of larvae of P. cattani from the red searobin is provided. On the other hand, sealworm larvae from other fish species did not differ morphologically from L3 of P. cattani from the red searobin. However, the results of the comparative morphometric analyses carried out on larvae from different fish hosts indicated significant differences in some distances. However, we provisionally identified all larvae as P. cf. cattani, awaiting further identification based on molecular genetic markers. The results of this study suggest that the main microhabitat for sealworm larvae infecting fish hosts from Patagonia is the muscle (principally the epaxial musculature, followed by the hypaxial muscles), and to a lesser degree, in the mesenteries and liver. The lines of evidence obtained in this study suggest that most important fish prey of otariids inhabiting the Patagonian coast presented low infection levels of sealworm larvae. Given that P. cattani is specific to otariids, transmission of this nematode appears to rely on the catholic diet of both sea lions and fur seals, which include a number of specimens of many fish species from the benthic realm, where transmission most likely occurs.

Four species of acanthocephalan (Oligacanthorhynchidae) were studied. Two species are new geographical records. Additionally, Oligacanthorhynchus carinii and Oligacanthorhynchus major are registered for the first time in Peru. Cuatro especies de acantocéfalos pertenecientes a la familia Oligacanthorhynchidae son estudiados. Dos de ellas corresponden a nuevos hallazgos geográficos. Adicionalmente se registra por primera vez en el Perú a Oligacanthorhynchus carinii y Oligacanthorhynchus major.

La deforestación de bosques tropicales está amenazando la biodiversidad de las especies de primates y su estado de salud, dependiente de un lugar ecológicamente equilibrado. Con el fin de evaluar esta relación, se analizó la presencia de parásitos en los intestinos de esta especie. El estudio se realizó en la Estación Biológica La Suerte (EBLS), Limón, Costa Rica. El grupo de monos capuchinos cariblancos (Cebus capucinus) fue observado entre marzo y diciembre de 2006. Se recolectaron 75 muestras de heces a las que se les identificó las plantas ingeridas, y se procesaron en el laboratorio para evaluar la prevalencia de parásitos. Moraceae fue la familia de plantas más reportada. Strongyloides spp. y acantocéfalos fueron los más comunes. La distribución positiva de las mismas fue similar independientemente del sexo y la edad. Microsporidios se reportaron mayoritariamente en heces asociadas con la familia Piperaceae. Fue encontrada una baja existencia de éstos parásitos en muestras asociadas con Myrtaceae en cuyo género Psidium, se han reportado compuestos activos antiparasitarios. La aparición de parásitos fue relativamente mayor en la EBLS, comparado con muestras de otras regiones más secas de Costa Rica. Por lo tanto, esa expresión parasitaria puede deberse al hecho de ser la EBLS una selva lluviosa, además de estar rodeada por zonas con actividades antrópicas. Se sugiere incrementar las investigaciones de parasitología de campo en primates neotropicales con el fin de entender plenamente las relaciones parásitos-hospederos, para en un largo plazo poder comprender los ecosistemas donde conviven, y en consecuencia, preservar la diversidad biológica.Intestinal parasites in white-faced capuchin monkeys Cebus capucinus Primates: Cebidae) inhabiting a protected area in the Limón province of Northeastern Costa Rica. Deforestation of tropical forests is threatening monkey biodiversity and their health status, dependent of an ecologically undisturbed area. To asses this relationship, we analyzed parasite occurrence in their intestines. The study was conducted at the Estación Biológica La Suerte (EBLS), Limón, Costa Rica. The group of white-faced capuchin monkeys (Cebus capucinus) was observed between March and December of 2006. A total of 75 feces samples were obtained. Once a sample was collected, the eaten plant type was identified to family and species level, and feces were processed in the laboratory to determine parasite incidence. Results showed that Moraceae was the most represented family in the samples. Among parasites, Strongyloides spp. and Acanthocephala were the most common. Positive prevalence of parasites was found similar and independent of sex and age of capuchin individuals. Microsporids were mainly reported in feces associated with Piperaceae. A low presence of these parasites was found in samples associated with Myrtaceae, with possible anti-parasite active components. The occurrence of parasites was relatively high in EBLS, when compared to other regions in Costa Rica. The higher occurrence of parasites observed in capuchins at EBLS may be due to the fact that this rain forest is surrounded by areas affected by human activities. We suggest the promotion of research in neotropical primates parasitology, for a better comprehension of the parasite-host relationship, and in a long term, being able to understand the ecosystems where they coexist, and consequently, preserve the biodiversity of the whole region. Rev. Biol. Trop. 58 (4): 1335-1346. Epub 2010 December 01.

Se describe y se compara la morfología y fecundidad de individuos adultos del acantocéfalo Profilicollis bullocki Mateo, Córdova & Guzmán 1982 (Acanthocephala: Polymorphidae) extraídos del intestino de cuatro especies de aves costeras Larus dominicanus Lichtenstein 1823, Larus pipixcan Wagler 1831, Podiceps occipitalis Garnot 1826 y Numenius phaeopus Linné 1758, capturadas en Caleta Lenga (36º45' S, 73º10' O), Chile. Los resultados señalan que la identidad de la especie hospedadora es un factor relevante para entender las variaciones de la morfología y de la fecundidad del parásito. Los acantocéfalos recolectados desde L. dominicanus y L. pipixcan eran los de mayor tamaño corporal. Además, la fecundidad de los parásitos aumentaba con su tamaño corporal. Sin embargo, el análisis de los residuos de la regresión entre la fecundidad y la longitud total del cuerpo de P. bullocki mostró que la fecundidad del parásito en L. dominicanus es similar a la encontrada en L. pipixcan y que en estas especies es significativamente mayor que la encontrada en los parásitos recolectados de P. occipitalis. Se discute que para establecer qué hospedadores son de mejor calidad para este parásito, aparte de su desempeño reproductivo del parásito en cada especie hospedadora, es necesario también considerar la abundancia de los hospedadores y la magnitud que alcanzan las poblaciones del parásito en cada una de ellas

Se describe y se compara la morfología y fecundidad de individuos adultos del acantocéfalo Profilicollis bullocki Mateo, Córdova & Guzmán 1982 (Acanthocephala: Polymorphidae) extraídos del intestino de cuatro especies de aves costeras Larus dominicanus Lichtenstein 1823, Larus pipixcan Wagler 1831, Podiceps occipitalis Garnot 1826 y Numenius phaeopus Linné 1758, capturadas en Caleta Lenga (36º45' S, 73º10' O), Chile. Los resultados señalan que la identidad de la especie hospedadora es un factor relevante para entender las variaciones de la morfología y de la fecundidad del parásito. Los acantocéfalos recolectados desde L. dominicanus y L. pipixcan eran los de mayor tamaño corporal. Además, la fecundidad de los parásitos aumentaba con su tamaño corporal. Sin embargo, el análisis de los residuos de la regresión entre la fecundidad y la longitud total del cuerpo de P. bullocki mostró que la fecundidad del parásito en L. dominicanus es similar a la encontrada en L. pipixcan y que en estas especies es significativamente mayor que la encontrada en los parásitos recolectados de P. occipitalis. Se discute que para establecer qué hospedadores son de mejor calidad para este parásito, aparte de su desempeño reproductivo del parásito en cada especie hospedadora, es necesario también considerar la abundancia de los hospedadores y la magnitud que alcanzan las poblaciones del parásito en cada una de ellas We describe and compare the variations in morphology and fecundity of Profilicollis bullocki Mateo, Córdova & Guzmán 1982 (Acanthocephala: Polymorphidae) adults collected from 4 alternative sympatric and definitive marine coastal bird host species (Larus dominicanus Lichtenstein 1823, Larus pipixcan Wagler 1831, Podiceps occipitalis Garnot 1826 and Numenius phaeopus Linné 1758), sampled at Caleta Lenga, Chile (36º45' S, 73º10' W). Results show that the specific identity of the host species is a relevant factor to explain morphometric and reproductive variations of P. bullocki. Parasites in Larus spp. attain larger body size than in the two other host species. In addition, fecundity increases with parasite body size. However, analysis on the residuals of the linear regression between fecundity and body size show that fecundity in L. dominicanus and in L. pipixcan are similar and both higher than in P. occipitalis. We suggest that estimates of host abundance along with abundance of parasites within each host species are needed to determine which is the best host for a parasite, as well as the reproductive performance of the parasite in each host species