Thesis (Ph. D.)--University of Queensland, 2003. / Includes bibliographical references.

Orientador: Vanessa Doro Abdallah Kozlowiski / Resumo: Global biodiversity has been very discussed and some authors have argued of the species of parasites as a fundamental part of this. Thus the aim of the study was to obtain a better understanding of the monogeneans biodiversity of four fish species: Cyphocharax modestus (Fernández-Yépez, 1948), Moenkhausia intermedia (Eigenmann, 1908), Serrasalmus maculatus (Kner, 1858) and Roeboides descalvadensis (Fowler, 1932) from Batalha River, São Paulo State, Brazil. During the period from November 2014 to December 2014, four collections were carried out and with 120 fish caught (30 of each species). Nine species of dactylogirids were found: Curvianchorathus singularis, Dactylogyridae gen. sp., Calpidothecium sp., Palombitrema triangulum, Jainus hexops, Jainus amazonesis, Rhinoxenus piranhus, Anacanthorus sciponophallus and Notozothecium minor. In relation to the species C. modestus, 33% of the specimens were parasitized by monogenetics, being the species: C. sigularis (Prevalence - P = 23.33%, mean intensity - I = 4.14±0.5 and mean abundance - A = 0.97±0.4), P. triangulum (P = 17%, I = 4±0.4, A = 0.67±0.3), Dactylogyridae gen. sp. (P = 3%, I = 1, A = 0.03±0.5) and Calpidothecium sp. (P = 3%, I = 2, A = 0.07±0.4). S. maculatus presented a total prevalence of parasitism by monogenetic species of 87%. The species were: A. sciponophallus (P = 73.33%, I = 22±4.47, A = 16.13±4.0), R. piranhus (P = 70%, I = 5.81±0.94, A = 4.07±0.9) and N. minor (P = 30%, I = 7±1.58, A = 2.1±1.02). M. intermed... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre

M.Sc. / Please refer to full text to view abstract / Prof. A. Avenant-Oldewage

Prior to 1989 the total number of Gyrodactylus species recorded for all British freshwater fish numbered 20. The fauna present on the British Salmonidae was poorly documented and frequently not identified to species level. The European free market, created in 1992, resulted in legislative changes allowing the movement of live fish stocks, albeit under strict disease monitoring conditions, into the UK. One stipulation maintains that the fish stock be free of the ectoparasitic monogenean Gyrodactylus salaris Malmberg, 1957, a parasite made notifiable in the UK in 1987 (Diseases of Fish Act, 1937) owing to its pathogenicity and damage to Norwegian salmon populations in 38 rivers. Although this parasite has been reported since 1957 throughout mainland Europe, its occurrence in the UK was unknown. This project set out to make a national survey of British salmon ids and investigated 250 sample sites, examined four salmonid hosts, Atlantic salmon Salmo safar, brown trout Salmo trutta, rainbow trout Oncorhynchus mykiss and Arctic charr Salvelinus alpinus. Seventy of the sites were found to be positive for Gyrodactylus. Distinctions were made between wild and farmed fish and prevalence, abundance and intensity data collected for comparison. Species determination within the genus Gyrodactylus is based upon subtle differences in hook morphology and has long posed a taxonomic problem. The discrimination of collected specimens was based on two platforms. The initial approach used classical morphometrics from the light microscope, the results being processed using multivariate analyses to separate species. The second approach analysed morphometric data collected from scanning electron micrographs. This was made possible by the development of a sclerite release technique utilising a source of ultrasound to liberate hooks from surrounding tissue and a subsequent flotation stage which permitted flat preparations. Sonication of fresh and frozen material retained the structures that would be lost by enzymatic digestion. The description of new morphometric parameters using digital image analysis allowed the subtle differences in hamuli and marginal hook shape to be discriminated when analysed using principal components analysis (PCA). Four species were identified following multivariate and morphological analyses of opisthaptoral sclerites. G. truttae Glaser, 1975 was found to occur on S. trutta and G. derjav;ni Mikailov, 1975 was found to occur on S. trllfta, S. salar and O. mykiss. Two hitheno undescribed forms, one on S. salar and one on S. alpinus which may be a new species are desclibed. In addition, two forms of G. derjavilli from S. salar and S. alpinlls and one form of G. truttae from S. tnltta are described. Sub-populations of Gyrodactylus sp. were found to be determined by the pattern of distribution of the host; S. salar. The two sub-populations were divided into a southern celtic population (Morph 1) and a nonhern boreal population (Morph 2). Water temperature, was found to be an important environmental parameter influencing sclerite size. The principal component analyses identified key characters which could discriminate G. salaris from the native British species using novel parameters based upon both single elements and the full complement of sclerites. Of these new parameters, the hamulus angle and the size of the marginal hook sickle aperture were the most discriminating. Electronmicrographs of hamuli were traced using a digitising tablet and prepared for image processing. The hamulus angle was measured on original hook images and on enhanced (skeletonised) images using an image analyser. Skeletonisation investigated the reliability of the hook angle as a taxonomic criterion by the removal of possible age-related sclerotisation of the hamulus. Statistical analysis of the data revealed that there are significant differences in hook angle between some species. The isolation of sclerites by sonication enabled their elemental composition to be investigated. The hamuli and marginal hooks were found to have a high sulphur content, indicative of a keratin-like substance. The ventral bar composed of sulphur and calcium is weakly keratinised. The hamulus and the ventral bar were also found to contain vanadium. the significance of which is unknown. The detailed morphology and composition of the individual sclerites is discussed in relation to the functional mechanics of the entire haptoral complex. The protein profiles of G. salaris. G. truttae and G. derjvani were investigated using SDS-PAGE gel electrophoresis, with four proteins common to the three species. Two antibodies raised against G. salaris were found using Western blots. The chaetotaxy of argentophilic structures on three species of the genus Gyrodactyllis was investigated to ascertain the usefulness of this technique in distinguishing species of this genus. Chaetotaxy maps were prepared for G. salaris from Scandinavia and compared to native species of Gyrodactylus parasitizing salmonids in Britain. A formula for the arrangement of the sensilla analogues and the evolutionary position of the genus Gyrodactylus is commented upon.

This study was designed to provide the foundation for future work on the ecology and evolution of Necturus-parasite systems by providing vital parasite survey information for the aquatic salamander Necturus alabamensis. During this study 115 N. alabamensis were collected from north Florida. Hosts yielded the cestode Proteocephalus loennbergi, monogeneans from the genus Sphyranura, digeneans from the genus Gorgoderina, and what appears to be several nematode species. Nematodes, digeneans, and cestodes were abundant while monogeneans were rare. Monogenean and cestode parasites were categorized as specialists (parasites specific to one species or the species of a single genus), and digenean and nematode parasites were categorized as generalists (infecting numerous, possibly distantly related hosts). Statistical analysis did not indicate a parasite load difference between sites for digeneans and cestodes but did indicate a difference for nematodes. Helminth populations appear to be overdispersed (the majority of the parasites are found in only a few hosts). This study provides insight into some aspects of the ecological relationships of N. alabamensis and its helminths. However, parasite surveys of the other members of Necturus are necessary for the evaluation of evolutionary relationships within this system.

Orientador: Marlene Tiduko Ueta / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-15T11:53:43Z (GMT). No. of bitstreams: 1 Correa_LincolnLima_M.pdf: 1163732 bytes, checksum: 5fe7ecad7d270d89129854e53cdaf3b0 (MD5) Previous issue date: 2009 / Resumo: Este estudo teve como objetivo a associação entre os índices hematológicos de Hoplias malabaricus (traíra), o parasitismo por monogeneas e outras espécies de metazoários e os fatores ambientais. O estudo ocorreu nas lagoas do CEPTA/ICMBio, localizada no município de Pirassununga, SP (21º55'55"S e 47º22'37"W), no período de fevereiro de 2008 a março de 2009 em 187 traíras. Verificou-se que os parâmetros sanguíneos não sofreram alterações significativas em relação ao estágio de maturação, sexo, período de coleta e intensidade de infecção de monogeneas. Porém, os peixes apresentaram valores significativamente positivos para biometria peso/comprimento (r=0,89 e p<0,0001) e os parâmetros ambientais pH/temperatura (r=0,71 e p<0,0001). Verificou-se que os monogeneas não atuaram como indicador ambiental nas lagoas, porém os parâmetros hematológicos revelaram uma maior sensibilidade ao ambiente. Em relação à análise dos outros metazoários, verificou-se uma diferença significativa em relação ao estágio de maturação e intensidade de infecção na Lagoa I (p=0,002) e na Lagoa II não houve diferença. Houve correlação significativa entre peso do peixe e intensidade de infecção na Lagoa I (r=0,50; p<0,001) e entre comprimento e a intensidade de infecção dos metazoários (r=0,42; p<0,001). Contudo, a intensidade média de parasita diferiu significativamente entre as lagoas estudadas. Os metazoários presentes em H. malabaricus também não atuaram como indicador ambiental. / Abstract: This study aimed at the association between blood indexes of Hoplias malabaricus (betrayed), the parasitism by monogeneans and other metazoan species and environmental factors. The study took place in ponds CEPTA / ICMBio, located in the city of Pirassununga, SP (21 º 55'55 "S and 47 º 22'37" W), from February 2008 to March 2009 in 187 traíras. It was found that the blood parameters did not change significantly in relation to the stage of maturation, sex, time of collection and intensity of infection of monogeneans. But the fish had significantly positive for biometrics weight / length (r = 0.89 and p <0.0001) and the environmental parameter pH and temperature (r = 0.71 and p <0.0001). It was found that the monogeneans not acted as an environmental indicator in the lakes , but the haematological parameters showed a greater sensitivity to the environment. On the analysis of the Metazoa, there was a significant difference in the stage of ripeness and intensity of infection in the Lake I (p = 0.002) and in Lake II there was no difference. There was significant correlation between weight of fish and intensity of infection in the Lake I (r = 0.50, p <0.001) and between length and intensity of infection of metazoan (r = 0.42, p <0.001). However, the mean intensity of parasites differed significantly between the lakes studied. The metazoan present in H. malabaricus also did not act as an environmental indicator. / Mestrado / Mestre em Parasitologia

Submitted by Celso Magalhaes (celsomagalhaes@ufrrj.br) on 2017-07-06T11:45:05Z No. of bitstreams: 1 2012 - F?bio Edir Amaral Albuquerque.pdf: 3688203 bytes, checksum: deb77d79b3f829b640e9e7f0e18de1aa (MD5) / Made available in DSpace on 2017-07-06T11:45:06Z (GMT). No. of bitstreams: 1 2012 - F?bio Edir Amaral Albuquerque.pdf: 3688203 bytes, checksum: deb77d79b3f829b640e9e7f0e18de1aa (MD5) Previous issue date: 2012-03-29 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / A total of 25 specimens Caparari Pseudoplatystoma fasciatum were collected in four points of the high Xingu river sector, between April 2010 and July 2011. Two new locality records of Argulidae crustaceans are presented for Argulus pestifer and Dolops discoidalis. A new monogenetic specie was proposed, registered and studied in details. Demidospermus n. sp. differs from the other congenerics, because the anchors exhibit folds, variable forms, and deep roots not defined. Demidospermus sp. n. also exhibits a thickened ventral bar, straight or slightly curved anteriorly, with the extended Extremities, and with the Presence or Absence of an above-median keel. The dorsal bar is variable in form, straight and slender, with Presence or Absence of an above-median depression and tapered Extremities. The hooks are different in size and form, the first and second pairs have the tip and the shaft lightly curved, protuberant and truncated thumb, and the rod is dilated and tapered in proximal region. Hooks different in size and shape, 1-2 pairs: blade point and slightly curved or curved, thumb protruding, truncate, dilated or slender rod, tapered proximally, showing or not bulbs at the proximal end; the pairs 3-4-6-7: point slightly bent, curved or straight blade almost straight or moderately curved, thumb truncated or depressed, moderately dilated or slender rod, presented a bulb at the proximal end; The male copulatory organ (MCO) is variable in shape, with a convolute tube in the counterclockwise, and flaps that connect themselves on a sclerotized edge. Male copulatory organ (MCO), with variable shape, like a coiled tube, varying the number of rings in a counterclockwise direction, with tabs that connect to a margin esclerotizada or G-shaped, with a ring in order counterclockwise, showing a dilated base margin esclerotizada developed, from which protrudes a flap. The accessory piece, with variable shape, slightly concave or concave, the distal tapered, curved or slightly curved, serving as a guide to the MCO, the presence or absence of spines on the proximal end. The vagina has a bag-shaped vestibule connected or not to the vaginal channel through an annulated narrow. The study will can contribute to future research, in order to improve our knowledge about the parasite fauna of aquatic organisms in the Amazon region. / Um total de 25 esp?cimes de Caparari P. fasciatum foram coletados no alto rio Xingu, entre Abril de 2010 ? Julho de 2011. Foram apresentados dois novos registros de localidade de crust?ceos parasitos da fam?lia Argulidae, foram registrados, Argulus pestifer e Dolops discoidalis, e uma esp?cie de monogen?tico foi proposta como nova, examinada, registrada e comentada em detalhes. Demidospermus sp. n. difere dos seus cong?neres por apresentar ?ncoras em formas vari?veis, ra?zes profundas n?o definidas, apresentando uma dobra. Barra ventral em forma vari?vel, grossa, levemente curvada para a regi?o anterior, extremidades alargadas, com presen?a ou n?o de uma quilha na parte antero-medial. Barra dorsal, em forma vari?vel, reta e delgada, apresentando ou n?o uma depress?o antero-medial com extremidades afiladas. Ganchos diferentes em tamanho e forma, pares 1-2: ponta e l?mina levemente curva ou curvada, polegar protuberante, truncado, haste dilatada ou delgada, afilada proximalmente, apresentando ou n?o bulbos na extremidade proximal; pares 3-4-6-7: ponta levemente curvada, curva ou reta, l?mina quase retas ou moderadamente curvadas, polegar truncado ou deprimido, haste moderadamente dilatada ou delgada, apresentado um bulbo na extremidade proximal; par 5: ponta e l?mina retas, polegar achatado, haste alongada e fina, apresentando um bulbo na regi?o proximal. ?rg?o copulat?rio masculino (OCM), apresentando forma vari?vel, como um tubo enrolado, variando no n?mero de an?is no sentido anti-hor?rio, apresentando abas que se conectam a uma margem esclerotizada ou em forma de G ao contr?rio, com um anel em sentido anti-hor?rio, base dilatada apresentando uma margem esclerotizada desenvolvida, de onde se projeta um flap. Pe?a acess?ria, apresentando forma vari?vel, ligeiramente c?ncava ou c?ncava, parte distal afilada, curvada ou pouco curva, servindo de guia para o OCM, presen?a ou n?o de espinhos na extremidade proximal. Vagina apresentando um vest?bulo saculiforme, ligado ao canal vaginal atrav?s de um estreitamento anelado presente ou n?o. O presente estudo poder? colaborar com futuras pesquisas, com o prop?sito de melhorar o nosso conhecimento sobre a fauna dos organismos aqu?ticos da regi?o Amaz?nica

Orientador: Marlene Tiduko Ueta / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-20T22:39:13Z (GMT). No. of bitstreams: 1 Muller_MariaIsabel_D.pdf: 17246609 bytes, checksum: 3a8aafad3f2f9c39e25664a81ae6e807 (MD5) Previous issue date: 2012 / Resumo: O pacu Piaractus mesopotamicus (Holmberg, 1887) é uma das principais espécies de importância econômica no Brasil. Peixe nativo da Bacia dos rios Paraná e Paraguai é uma das espécies mais comuns em pisciculturas. Mixosporídeos e monogêneas são parasitos de alta prevalência e causam danos em cultivos comerciais, tornando importante seu estudo detalhado. Neste estudo foram examinados 278 especimens de P. mesopotamicus de vários tamanhos, no período de Fevereiro de 2008 a Julho de 2010, coletados nos tanques do Centro de Pesquisa e Conservação de Peixes Continentais - CEPTA/ Instituto Chico Mendes de Conservação da Biodiversidade - ICMBio, Pirassununga, SP e em pisciculturas particulares da mesma região. Os parasitos identificados foram os mixosporídeos Henneguya piaractus (Martins & Souza, 1997) e Myxobolus colossomatis (Molnár & Békési, 2007) e os monogêneas Anacanthorus penilabiatus (Boeger, Husak & Martins, 1995), Mymarothecium viatorum (Boeger, Piasecki & Sobecka, 2002) e Dactylogyridae sp1 (não identificada). Análises ultraestruturais mostraram em Henneguya piaractus uma fina camada granular entre o plasmódio e as células do hospedeiro, uma única parede no plasmódio com numerosos canais de pinocitose. Myxobolus colossomatis apresentou uma camada plasmodial com numerosa atividade fagocítica em comunicação com as células do hospedeiro. A histopatologia apresentou hiperplasia nas lamelas branquiais em peixes altamente infectados e deformação das lamelas em relação a cistos de H. piaractus. A microscopia eletrônica de varredura mostrou para A. penilabiatus tegumento relativamente liso e microvilosidades nas regiões adesivas. Mymarothecium viatorum apresentou na superfície de seu tegumento, projeções similares a escamas com variações tipo microvilosidades. Análises moleculares utilizando marcadores ribossomais para mixosporídeos e monogeneas (porção18S) posicionaram as espécies em árvores filogenéticas. A descrição do genoma mitocondrial parcial de A. penilabiatus é apresentada / Abstract: The freshwater fish Piaractus mesopotamicus (Holmberg, 1887), popularly known as "pacu", is one of the most economically important species of fish in Brazil. The fish is endemic to the Paraná-Paraguay river basin, and is one of the species that is most cultivated in fish farms. A detailed study of Myxosporea and Monogenea is important, due to their high prevalence and the damage they cause in commercial fish farms. A total of 278 specimens of P. mesopotamicus were examined from February 2008 to July 2010, collected in fish ponds at the Centro de Pesquisa e Conservação de Peixes Continentais (CEPTA), Instituto Chico Mendes de Conservação da Biodiversidade (ICMBio), in the city of Pirassununga, in the state of Sao Paulo, and in other commercial fish farms nearby. The main parasites found were the myxosporeans Henneguya piaractus (Martins & Souza, 1997) and Myxobolus colossomatis (Molnár & Békési, 2007) and the monogeneans Anacanthorus penilabiatus (Boeger, Husak & Martins, 1995), Mymarothecium viatorum (Boeger, Piasecki & Sobecka, 2002) and Dactylogyridae sp1 (not identified). Ultrastructural analysis of H. piaractus showed a thin layer of granular material between the plasmodial wall and the host cells. The single plasmodial wall was connected to a plasmodial ectoplasm zone through numerous and extensive pinocytotic canals. Myxobolus colossomatis showed a plasmodial ectoplasm zone with numerous and extensive phagocytic activity, and numerous projections in the direction of the host cells. Histopathological data showed hyperplasia in the lamellae in highly infected fish and deformation of the lamellae regarding cysts of H. piaractus. Scanning electron microscopy found that A. penilabiatus had a relatively smooth tegument and microvilli in the adhesive regions. However, the M. viatorum tegument showed that the top surface had variations similar to scales. Molecular analysis, using ribosomal markers for myxosporeans and monogeneans (18S rDNA) positioned the species in phylogenetic trees. The partial mitochondrial genome of A. penilabiatus is also recorded / Doutorado / Parasitologia / Doutor em Parasitologia

The Capsalidae is a diverse family of ectoparasites of marine fish (Platyhelminthes: Monogenea). It is a large family with approximately 180 described species and many more yet to be discovered. Capsalids have a global distribution and parasitise a diversity of hosts from the Chondrichthyes to bony fishes. A morphological classification exists for the family based on a few key characters such as testes number, their arrangement and morphology of the posterior attachment organ (haptor). Phylogenetic relationships within the family and its position within the Monogenea are largely unexplored. I have used various molecular phylogenetic techniques to resolve relationships and explore the evolution and radiation of this family. Specimens from the Capsalidae and other monogenean families (outgroups) were obtained through fresh collections and generous donations by other parasitologists. Specimens were stored in 95% undenatured ethanol. Three unlinked nuclear genes (28S ribosomal RNA, Histone 3 and Elongation Factor 1 α) and two mitochondrial genes (Cytochrome Oxidase 3 and Cytochrome B) were amplified for 78 capsalid taxa in 28 genera representing all nine subfamilies and 30 outgroup taxa (eight Polyopisthocotylea and 22 Monopisthocotylea). Analyses showed the Capsalidae is monophyletic, with the sister group remaining unresolved. Some analyses supported Gyrodactylidae and Udonellidae as the sister group but in other analyses, it was unresolved with the Monocotylidae and Microbothriidae also possible sister groups. The Capsalinae, Encotyllabinae and Nitzschiinae are monophyletic, but analyses did not support monophyly for the Benedeniinae, Entobdellinae and Trochopodinae. Monophyly was supported for Capsala, Capsaloides, Encotyllabe, Entobdella, Listrocephalos, Neobenedenia, Nitzschia and Tristoma, but Metabenedeniella is paraphyletic and Benedenia and Neoentobdella are polyphyletic. Comparisons of the distribution of character states for the small number of morphological characters on a molecular phylogeny show a high frequency of apparent homoplasy. Consequently the current morphological classification for the Capsalidae shows little correspondence with the phylogenetic hypotheses I present. I also sequenced the first complete mitochondrial (mt) genome for a capsalid species, Benedenia seriolae. The mt genome of B. seriolae shows some tRNA rearrangements in comparison to three Gyrodactylus spp. (Gyrodactylidae), the only other complete monopisthocotylean mt genomes sequenced. It also lacks the duplicated, conserved non-coding regions present in Gyrodactylus spp. making the genome smaller in size. I combined this genome with other available platyhelminth mt genomes to investigate the monophyly of Monogenea and the evolution of diet across the Neodermata. Results confirm paraphyly for the Monogenea and also suggest paraphyly for the epidermal feeding Monopisthocotylea. I hypothesise that the Monopisthocotylea represent the first shift to parasitism in the Neodermata from a free living ancestor and following this, there was a dietary shift to blood feeding (Polyopisthocotylea). The Digenea and Cestoda independently evolved dietary specialisations to suit their diverse microhabitats and broad range of vertebrate final hosts. Using Elongation Factor 1 α I have estimated molecular divergence dates for the Neodermata, Monogenea and Capsalidae. Molecular clock analyses estimate the Neodermata diverged from the free living platyhelminths 513 million years ago (mya) (95% HPD [highest posterior density]: 473–605) before the appearance of vertebrates in the fossil record. The Monogenea diverged from the other neodermatan classes 441 mya (95% HPD: 420–547) coinciding with the appearance of fish in the fossil record. The most recent common ancestor of the Capsalidae arose approximately 235 million years ago (95% HPD: 200–274) following the Permian/Triassic extinction event and coinciding with the diversification of bony fishes in the marine environment. I compared the capsalid phylogeny to a phylogeny of fishes that I generated using eight nuclear and three mt genes to explore the evolution and the radiation of the Capsalidae across fishes. There is no significant global signal of coevolution with only five parasite-host associations that may be a result of coevolution. Estimated molecular divergence dates are also compared and do not reveal temporal congruence. Radiation of the family may have been driven by host switching constrained by shared host ecology, biology, behaviour and plasticity in morphological adaptations by the parasites. This study advances our understanding of the evolution of this monogenean family and provides insights into the evolution of the Neodermata and the complicated realities of reconstructing the evolutionary history of parasitic groups. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1522353 / Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2010

Orientador: Reinaldo José da Silva / Resumo: Nos últimos anos, os parasitas foram reconhecidos como importantes componentes dabiodiversidade global, dado os importantes papéis desempenhados por esses organismosem ecossistemas naturais. Embora o conhecimento sobre a diversidade de parasitas tenhaaumentado nas últimas décadas, o número de espécies de parasitas de peixes no Brasil érelativamente baixo quando comparado com a biodiversidade das espécies hospedeiras.Desta forma, o presente trabalho teve como objetivo realizar um levantamento dabiodiversidade dos parasitas de peixes procedentes de quatro locais em uma área sob ainfluência de Pequenas Centrais Hidrelétricas (PCHs) no rio Sapucaí-Mirim, Estado de SãoPaulo, Brasil, bem como avaliar a estrutura das comunidades de metazoários parasitas depeixes Characiformes e de quatro espécies do gênero Leporinus. Durante o período demarço de 2012 a julho de 2013, foram coletados 462 espécimes pertencentes a 16 espéciesde peixes das ordens Characiformes, Siluriformes, Gymnotiformes e Perciformes.Observou-se que 86,58% dos espécimes estavam parasitados por pelo menos um taxon demetazoário parasita. Os parasitas encontrados pertenciam a oito diferentes grupos(Myxozoa, Monogenea, Digenea, Cestoda, Nematoda, Acantocephala, Arthopoda eAnnelida), sendo coletado um total de 6.830 parasitas. Noventa e sete taxa de parasitasforam encontrados, sendo que a classe Monogenea foi o grupo que apresentou o maiornúmero de espécies, seguido do filo Nematoda e da s... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Recently, parasites have been recognized as important components of global biodiversitybecause the important roles played by these organisms in natural ecosystems. Althoughknowledge about the diversity of parasites has increased in recent decades, the number ofparasite species of fishes in Brazil is relatively low compared to the biodiversity of hostspecies. Thus, this study aimed to survey the biodiversity of fish parasites from foursampling sites in an area under the influence of Small Hydroelectric Power Plants in theSapucaí-Mirim River, São Paulo State, Brazil, as well as to evaluate the structure ofmetazoan parasite communities of Characiformes and four species of Leporinus sp. FromMarch 2012 to July 2013, 462 fish specimens of 16 species of Characiformes,Siluriformes, Perciformes, and Gymnotiformes were collected. It was observed that86.58% of fish specimens were parasitized by at least one metazoan parasite taxon. Theparasites found belonged to eight different groups (Myxozoa, Monogenea, Digenea,Cestoda, Nematoda, Acantocephala, Arthopoda and Annelida) and a total of 6,830parasites were collected and analyzed. Ninety-seven parasite taxa were found, andMonogenea was the group that had the highest number of species, followed by Nematodaand Digenea. The parasite communities of Characiformes showed mainly differencesamong the host species, although belonging to the same order or family. The sampling site,condition factor and the host body ... (Complete abstract click electronic access below) / Doutor