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The Neotropical region hosts 4225 freshwater fish species, ranking first among the world's most diverse regions for freshwater fishes. Our NEOTROPICAL FRESHWATER FISHES data set is the first to produce a large-scale Neotropical freshwater fish inventory, covering the entire Neotropical region from Mexico and the Caribbean in the north to the southern limits in Argentina, Paraguay, Chile, and Uruguay. We compiled 185,787 distribution records, with unique georeferenced coordinates, for the 4225 species, represented by occurrence and abundance data. The number of species for the most numerous orders are as follows: Characiformes (1289), Siluriformes (1384), Cichliformes (354), Cyprinodontiformes (245), and Gymnotiformes (135). The most recorded species was the characid Astyanax fasciatus (4696 records). We registered 116,802 distribution records for native species, compared to 1802 distribution records for nonnative species. The main aim of the NEOTROPICAL FRESHWATER FISHES data set was to make these occurrence and abundance data accessible for international researchers to develop ecological and macroecological studies, from local to regional scales, with focal fish species, families, or orders. We anticipate that the NEOTROPICAL FRESHWATER FISHES data set will be valuable for studies on a wide range of ecological processes, such as trophic cascades, fishery pressure, the effects of habitat loss and fragmentation, and the impacts of species invasion and climate change. There are no copyright restrictions on the data, and please cite this data paper when using the data in publications.

Biodiversity, biological traits of potential host species, and environmental conditions may mediate the emergence of new diseases. We assessed the relative influence of such factors on patterns of infection by Austrodiplostomum compactum (Digenea, Diplostomidae) in fish assemblages of the Upper Parana River floodplain, Brazil. Multiple infection parameters were modeled at the community and species levels using phylogenetic diversity (PD), abundance (total and for a main reservoir species Plagioscion squamosissimus), local environmental conditions and phylogenetic distance from P. squamosissimus (Dis_Plag). In total, 108 fish species were collected and 28 were infected. At the community level, mean parasite abundance and mean infection intensity were positively associated with PD and the interaction between PD and environmental conditions, whereas host richness was negatively associated with PD. The complementary results indicate a biodiversity sampling effect rather than dilution effect. Environmental conditions often had the strongest coefficients in community-level models and mediated associations between infection parameters and other factors. At the species level, consistent negative associations between infection parameters and Dis_Plag indicate phylogenetic niche conservatism of parasites. Integration of community and species-level analyses demonstrates that phylogenetic diversity can affect host–parasite interactions in multiple ways, but that the associations depend on phylogenetic relationships and environmental conditions.

Ecological data on marine mammal parasites represent an excellent opportunity to expand our understanding of host-parasite systems. In this study, we used a dataset of intestinal helminth parasites on 167 long-finned pilot whales Globicephala melas (Traill, 1809) from seven localities in the Faroe Islands to evaluate the extent to which the host's age and sex influence the occurrence, richness, and nested pattern of helminth parasites and the importance of individual hosts to the helminth community. We found positive effects of age on both the occurrence and richness of helminths. Older host individuals showed an ordered accumulation of parasites, as evidenced by the nested pattern in their composition. Males had a higher occurrence of parasites than females, but the richness of helminths did not differ between sexes. Our findings suggest that differences in host-parasite interactions in long-finned pilot whales result mainly from age-structured variations in biological and behavioral characteristics.

The extinction of fish species can direct and indirectly affect many groups of associated species, among which parasite communities can be the most susceptible. However, the intensity of this effect depends on the structure interaction networks. This study evaluated whether networks constituted of fish ectoparasites or endoparasites differed in their robustness to the loss of host species and to what extent these potential differences are explained by the network structures. We used path models to evaluate the direct and indirect effects of host and parasite richness, connectance, and nestedness on the robustness of ecto- and endoparasite-based networks. In most cases, nestedness was the descriptor that best explained the robustness of the fish-parasite networks, and co-extinctions are less likely when the fish species act mainly as hosts of the generalist parasites. Both the richness of the host species and connectance in the networks have an essential indirect influence on robustness. Regardless of the extinction sequence, the ectoparasite-based networks showed higher vulnerability to host species loss when compared to endoparasite-based networks. These findings highlight the importance of considering both ecto- from endoparasites to better understand the structure and vulnerability of host–parasite networks.

Spargana are plerocercoid larvae of cestode tapeworms of the genus Spirometra, Family Diphyllobothriidae, parasitic to frogs, reptiles, birds and mammals. This parasitic disease in humans can be transmitted through the use and consumption of amphibians and reptiles. The available knowledge about Spirometra in South America is scarce, and there are only a few reports on the occurrence of sparganum in amphibians and reptiles, many of them published in old papers not easily available to researchers. In this work we present a review on this topic, provide new records in two species of amphibians and 7 species of reptiles from Brazil and Uruguay respectively. We also summarize current knowledge of Spirometra in the continent, along with an updated of host taxonomy. We could gather from the literature a total of 15 studies about amphibian and reptile hosts, published between 1850 and 2016, corresponding to 43 case reports, mostly from Brazil (29) and Uruguay (8), Argentina (3), Peru (2), and Venezuela (1); the majority of them related to reptiles (five lizards and 26 snake species), and 14 corresponded to amphibians (9 anurans). Plerocercoid larvae were located in different organs of the hosts, such as subcutaneous tissue, coelomic cavity, peritoneum, and musculature. The importance of amphibians and reptiles in the transmission of the disease to humans in South America is discussed. Relevant issues to be studied in the near future are the taxonomic characterization of Spirometra in the region and the biological risk of reptile meat for aboriginal and other rural communities.

SUMMARYThe patterns of parasite sharing among hosts have important implications for ecosystem structure and functioning, and are influenced by several ecological and evolutionary factors associated with both hosts and parasites. Here we evaluated the influence of fish diet and phylogenetic relatedness on the pattern of infection by parasites with contrasting life history strategies in a freshwater ecosystem of key ecological importance in South America. The studied network of interactions included 52 fish species, which consumed 58 food types and were infected with 303 parasite taxa. Our results show that both diet and evolutionary history of hosts significantly explained parasite sharing; phylogenetically close fish species and/or species sharing food types tend to share more parasites. However, the effect of diet was observed only for endoparasites in contrast to ectoparasites. These results are consistent with the different life history strategies and selective pressures imposed on these groups: endoparasites are in general acquired via ingestion by their intermediate hosts, whereas ectoparasites actively seek and attach to the gills, body surface or nostrils of its sole host, thus not depending directly on its feeding habits.

Made available in DSpace on 2020-12-12T01:28:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-10-10 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Studies have demonstrated the role of acanthocephalan as environmental bioindicators. The dynamics in the parasite-host relationship that define the patterns of distribution of trace metals in parasites and, in its host, are extremely variable. In addition, the neotropical region, which is a major maintainer of the biodiversity of fish and parasites, remains little explored in this subject. Therefore, our objective was to analyze and compare the concentration of Cadmium (Cd) in the tissues of Prochilodus lineatus and Serrasalmus marginatus collected from Baía and Paraná rivers, as well as to assess the use of acanthocephalan as environmental bioindicators of pollution and their Cd bioaccumulation capacity. We collected 53 fish, 20 specimens of Prochilodus lineatus from Paraná River and 17 from Baía River, in addition to 16 specimens of Serrasalmus marginatus from Baía River, in September 2017 and March 2018. Tissues of the fish along with their parasites were subjected a Cd concentration analysis by Atomic Absorption Spectroscopy. The results revealed that the parasites had higher concentrations than all the tissues of S. marginatus, P. lineatus from Baía River and Paraná River. The high Cd concentrations in these parasites derived from their bioaccumulation capacity, because of the absorption of nutrients directly from the intestinal content of the fish through the tegument, as well as for the presence of Cd on the surface waters of Praná River floodplain. Besides that, the Coefficient of Spearman Rank Correlation showed that the infrapopulation size seems to affect Cd bioaccumulation in the parasites, smaller infrapopulations demonstrate a higher accumulation capacity compared to the larger ones. With that, we concluded that the two acanthocephalans species analyzed in this study have a good capacity for Cd accumulation, and can be used as accumulation indicators of trace-metal pollution. Accumulation indicators provide important information on the biological availability of pollutants. Graduate Program in Comparative Biology Maringá State University Graduate Program of Professional Mastering in Ecology of Continental Aquatic Environments Maringá State University São Paulo State University (UNESP) Institute of Biosciences Graduate Program of Professional Mastering in Management and Regulation of Water Resources (Profwater) Federal Technological University of Paraná (UTFPR), Campus of Campo Mourão Research Center in Limnology Ichthyology and Aquaculture (Nupélia) Maringá State University São Paulo State University (UNESP) Institute of Biosciences

The lack of ecological studies on parasite species is contradictory with their high diversity. In this context, the ecological network approach has drawn attention to patterns of tropical host-parasite interactions; however, it is still very restricted to a few taxonomic groups. In tropical regions, studies on host-parasite networks have encompassed specially fish, amphibian hosts, and malaria parasite communities of birds. High specificity is peculiar to parasites, either considering the host species or the site of infection. Variations in specificity indicate differentiated structural patterns between ecto- and endoparasites networks, as well as larval and adult stages of parasites, influencing the values of connectivity, nestedness, and modularity. Host characteristics also influence the structure of networks, including phylogenetic relationships and diet. Similarly to free-living species in ecosystems suffering the influences of environmental change, parasite species may also be extinct due to primary extinctions of hosts or possibly present new patterns of interaction due to the arrival of invasive species in the environment. New studies should explore network patterns between tropic and non-tropic environments, in addition to the use of molecular tools to identify especially cryptic parasites, which may provide better-supported results.

SUMMARYHosts and parasites interact with each other in a variety of ways, and this diversity of interactions is reflected in the networks they form. To test for differences in interaction patterns of ecto- and endoparasites we analysed subnetworks formed by each kind of parasites and their host fish species in fish–parasite networks for 22 localities. We assessed the proportion of parasite species per host species, the relationship between parasite fauna composition and host taxonomy, connectance, nestedness and modularity of each subnetwork (n = 44). Furthermore, we evaluated the similarity in host species composition among modules in ecto- and endoparasite subnetworks. We found several differences between subnetworks of fish ecto- and endoparasites. The association with a higher number of host species observed among endoparasites resulted in higher connectance and nestedness, and lower values of modularity in their subnetworks than in those of ectoparasites. Taxonomically related host species tended to share ecto- or endoparasites with the same interaction intensity, but the species composition of hosts tended to differ between modules formed by ecto- and endoparasites. Our results suggest that different evolutionary and ecological processes are responsible for organizing the networks formed by ecto- and endoparasites and fish.

SUMMARYProperties of ecological networks facilitate the understanding of interaction patterns in host-parasite systems as well as the importance of each species in the interaction structure of a community. The present study evaluates the network structure, functional role of all species and patterns of parasite co-occurrence in a host-parasite network to determine the organization level of a host-parasite system consisting of 170 taxa of gastrointestinal metazoans of 39 marine fish species on the coast of Brazil. The network proved to be nested and modular, with a low degree of connectance. Host-parasite interactions were influenced by host phylogeny. Randomness in parasite co-occurrence was observed in most modules and component communities, although species segregation patterns were also observed. The low degree of connectance in the network may be the cause of properties such as nestedness and modularity, which indicate the presence of a high number of peripheral species. Segregation patterns among parasite species in modules underscore the role of host specificity. Knowledge of ecological networks allows detection of keystone species for the maintenance of biodiversity and the conduction of further studies on the stability of networks in relation to frequent environmental changes.

Jainus piava n. sp. is described from the gills of Schizodon borellii (Boulenger, 1900) (Characiform), commonly named as piava from the upper Paraná River floodplain, Brazil. The new species differs from the other members of Jainus in the following features: ventral bar thin broadly V-shaped and male copulatory organ (MCO) a coil of about 1.5 rings. Jainus piava n. sp. is similar to species of Jainus by having a ventral anchor base with flattened superficial root and elongate rodlike deep root.Jainus piava n. sp. is described from the gills of Schizodon borellii (Boulenger, 1900) (Characiform), commonly named as piava from the upper Paraná River floodplain, Brazil. The new species differs from the other members of Jainus in the following features: ventral bar thin broadly V-shaped and male copulatory organ (MCO) a coil of about 1.5 rings. Jainus piava n. sp. is similar to species of Jainus by having a ventral anchor base with flattened superficial root and elongate rodlike deep root.

ResumenPresentamos un caso de depredación por Trachelyopterus galeatus (Teleostei, Siluriformes) sobre Leptodactylus fuscus (Amphibia, Anura). Un ejemplar adulto del pez “cangati” T. galeatus fue recolectado en una red de espera durante un trabajo de campo en la planicie de inundación del alto río Paraná. Durante el análisis del contenido estomacal observamos una presa parcialmente digerida. Este ítem fue identificado como un individuo juvenil de L. fuscus. Este es el primer registro de un anfibio anuro en la dieta de T. galeatus. Los casos de depredación de anuros por T. galeatus parecen ser poco frecuentes, por lo que el evento observado puede ser consecuencia de una estrategia oportunista de alimentación del cangati. Sin embargo, este registro es particularmente relevante, pues demuestra un posible efecto de un depredador no nativo sobre especies de anuros en la planicie de inundación del alto río Paraná. Se necesitan más estudios para entender los efectos del comportamiento depredador de peces no nativos sobre la fauna de anuros en la planicie.AbstractWe herein report a case of predation by Trachelyopterus galeatus (Teleostei, Siluriformes) on Leptodactylus fuscus (Amphibia, Anura). An adult specimen of T. galeatus was collected in a gillnets during fieldwork in the Upper Paraná River Floodplain, Brazil. During the recent analysis of stomach contents a partially digested prey was observed. We identified this item as a juvenile L. fuscus. This is the first record of an amphibian anuran in the diet of the cangati catfish, T. galeatus. We believe that cases of anuran predation by T. galeatus are rare, and that the observed event was the result to an opportunistic feeding strategy of the fish. However, this report is particularly relevant because it demonstrates a possible effect of a non-native predator species on frogs in the Upper Paraná River Floodplain. Thus, future studies are essential for understanding the effects of the predatory behavior of non-native fishes on the anuran fauna on the floodplain.

The aim of the present study was to provide a current survey of the species of parasites found in the Upper Paraná River floodplain, as well as to investigate which strategies and mechanisms used by parasites, are favored and which environmental factors influence the parasite community in the studied environments. During a seven-year period from February 2000 to September 2007, 3,768 fish belonging to 72 species were collected and analyzed for the purpose of studying the parasite fauna. A total of 337 species of parasites were reported, including 12 new descriptions: one myxosporid, Henneguya paranaensis Eiras, Pavanelli and Takemoto, 2004; eight monogeneans, Kritskyia annakohnae Boeger, Tanaka and Pavanelli, 2001; Kritskyia boegeri Takemoto, Lizama and Pavanelli, 2002; Kritskyia eirasi Guidelli, Takemoto and Pavanelli, 2003; Demidospermus labrosi França, Isaac, Pavanelli and Takemoto, 2003; Demidospermus mandi França, Isaac, Pavanelli and Takemoto, 2003; Pseudovancleaveus paranaensis França, Isaac, Pavanelli and Takemoto, 2003; Tereancistrum curimba Lizama, Takemoto and Pavanelli, 2004 and Tereancistrum toksonum Lizama, Takemoto and Pavanelli, 2004; two digeneans, Sanguinicola platyrhynchi Guidelli, Isaac and Pavanelli, 2002 and Dadayius pacupeva Lacerda, Takemoto and Pavanelli, 2003 and one cestode, Nomimoscolex pertierrae Chambrier, Takemoto and Pavanelli, 2005. In addition, several other species were reported for the first time in new hosts or in the floodplain. Monogeneans presented the highest number of species, followed by digeneans. The infection site with the highest species richness was the intestine, with 127 species.

Sciadicleithrum kritskyi n. sp. and Sciadicleithrum paranaensis n. sp. are described from the gills of the acara tinga, Geophagus proximus (Cichlidae), from the upper Parana River floodplain, Brazil. The most distinctive feature of Sciadicleithrum kritskyi n. sp. that distinguishes it from other members of Sciadicleithrum is the presence of the dorsal bar with a delicate anteromedial projection. Sciadicleithrum paranaensis n. sp. differs from other congeners by having the accessory piece composed of a variable sheath with a ring in the medial portion enclosing the distal shaft of the male copulatory organ. Sciadicleithrum paranaensis n. sp. can be differentiated easily from S. kritskyi n. sp. by having a vaginal aperture on the ventral body surface, and anchors that are similar in size.

Trinta e nove espécimes de Plagioscion squamosissimus Heckel, 1840 foram coletados com redes de espera de diferentes malhagens na planície de inundação do Alto rio Paraná. Foi registrada a ocorrência de Diplectanum piscinarius Kritsky e Thatcher, 1984, que apresentou abundância média igual a 31, intensidade média 31,8 e prevalência 97%. Realizou-se uma análise ecológica de alguns aspectos da relação parasita-hospedeiro entre D. piscinarius e P. squamosissimus. Não houve diferenças significativas entre prevalência e intensidade de parasitismo em machos e fêmeas. Não houve correlações entre abundância e prevalência com o comprimento padrão dos hospedeiros e entre o fator de condição relativo com a abundância. Através dos resultados, é possível supor que, provavelmente, existem poucas diferenças fisiológicas e comportamentais entre hospedeiros machos e fêmeas, não ocorrem mudanças fisiológicas durante o desenvolvimento dos hospedeiros e o parasita exibe baixa patogenicidadeThirty-nine specimens of Plagioscion squamosissimus Heckel, 1840 were collected through nets of different mesh sizes in the Upper Paraná River floodplain. The occurrence of Diplectanum piscinarius Kritsky and Thatcher, 1984 was registered and it presented mean abundance of 31, mean intensity of 31.8 and prevalence of 97%. This paper also brings an ecological analysis of some aspects of the host-parasite relationship between D. piscinarius and P. squamosissimus. There were not significant differences between the prevalence and intensity of parasitism of males and females. There were not correlations between abundance and prevalence and the standard length of the hosts; and between relative condition factor (Kn) and abundance. From the results it is possible to assume that there are few physiological and behavioral differences between male and female hosts. Physiological changes probably do not occur during the development of the hosts and parasites do not seem to be very pathogenic

The use of the complex network approach to study host-parasite interactions has helped to improve the understanding of the structure and dynamics of ecological communities. In this study, this network approach is applied to evaluate the patterns of organisation and structure of interactions in a fish-parasite network of a neotropical Atlantic Forest river. The network includes 20 fish species and 73 metazoan parasite species collected from the Guandu River, Rio de Janeiro State, Brazil. According to the usual measures in studies of networks, the organisation of the network was evaluated using measures of host susceptibility, parasite dependence, interaction asymmetry, species strength and complementary specialisation of each species as well as the network. The network structure was evaluated using connectance, nestedness and modularity measures. Host susceptibility typically presented low values, whereas parasite dependence was high. The asymmetry and species strength were correlated with host taxonomy but not with parasite taxonomy. Differences among parasite taxonomic groups in the complementary specialisation of each species on hosts were also observed. However, the complementary specialisation and species strength values were not correlated. The network had a high complementary specialisation, low connectance and nestedness, and high modularity, thus indicating variability in the roles of species in the network organisation and the expected presence of many specialist species.

Espécies não nativas causam danos imprevisíveis sobre os ecossistemas e são consideradas pela IUCN como a segunda maior causa mundial de perda de biodiversidade. Os ecossistemas aquáticos são particularmente vulneráveis a esse impacto e muitas pesquisas mostram que essas espécies não nativas podem alterar a composição das comunidades nativas. A proposta deste estudo é apresentar as principais causas de introduções de espécies em ecossistemas aquáticos e possíveis medidas de prevenção e controle de espécies invasoras. Em ambientes aquáticos destacam-se como causas de introduções: destruição de barreiras geográficas como construções de reservatórios e canais de transposição de rios; criação e melhoria dos estoques naturais, devido à falta de planejamento na construção e manutenção dos locais de criação; aquariofilia e ornamentação de paisagens. Além disso, o turismo através da pesca esportiva, o controle biológico na tentativa de exterminar outra espécie já introduzida, a fauna associada a qual é transportada junto com a água, substratos ou hospedeiros e água de lastro principalmente proveniente de navios mercantis, também contribuem para as introduções de espécies. Medidas de controle de espécies não nativas são escassas e a identificação de vetores, monitoramento, políticas públicas e estudos são algumas estratégias que podem ajudar a diminuir os impactos ambientais causados por espécies não nativas em ecossistemas aquáticos. A divulgação e orientação sobre os impactos ambientais causados por espécies não nativas direcionadas para a população leiga e científica faz-se necessário, sendo a Internet uma ferramenta imprescindível e prioritária no combate a espécies não nativas.

Sixty-one specimens of the piranha Serrasalmus marginatus Valenciennes, 1837 were analyzed, aiming at assessing the community structure of their gill parasites. The samples were collected in lagoons of the Paraná, Ivinheima and Baia Subsystems within the Upper Paraná River Floodplain (Brazil). Host size and sex had little or no influence on the abundance and prevalence of parasites. The organization of the gill parasite infracommunities of S. marginatus was significantly non-random according to null models and ordination analyses. In general, parasite infrapopulations were not affected by interspecific associations or host characteristics (e.g. size, sex), what highlights the importance of local habitat characteristics to community organization of gill parasites of S. marginatus in the Upper Paraná River Floodplain.

Jainus piava n. sp. is described from the gills of Schizodon borellii (Boulenger, 1900) (Characiform), commonly named as piava from the upper Parana River floodplain, Brazil. The new species differs from the other members of Jainus in the following features: ventral bar thin broadly V-shaped and male copulatory organ (MCO) a coil of about 1.5 rings. Jainus piava n. sp. is similar to species of Jainus by having a ventral anchor base with flattened superficial root and elongate rodlike deep root.

Demidospermus paranaensis sp. nov. is described from the gills of Loricariichthys platymetopon Isbrücker et Nijssen (Loricariidae, Siluriformes) from the Upper Paraná River floodplain, Brazil. This new species differs from other members of Demidospermus in the following features: tegument with annulations throughout trunk and peduncle, eyes absent, longer male copulatory organ (MCO) with ovate base. Demidospermus paranaensis sp. nov. is similar to its congenerics by having tandem gonads, a counterclockwise-coiled MCO, non-articulated groove-like accessory piece serving as a MCO guide, sinistral vaginal aperture, and V-shaped haptoral bars.

Two new species of Sciadicleithrum are described from the gills of Neotropical cichlid fishes collected from Paraná River, Brazil. Sciadicleithrum satanopercae sp. nov. is described from the gills of Satanoperca pappaterra and differs from congeners by having a dorsal anchor with the distal portion complex and the inner margin with a “denticulum” between shaft and point. Sciadicleithrum joanae sp. nov. is described from the gills of Crenicichla niederleinii and C. britskii collected from Paraná River. Sciadicleithrum joanae sp. nov. differs from congeners by having a male copulatory organ comprising about half a clockwise loop and a vaginal pore “bulb-shaped”.

Specialized interactions tend to be more common in systems that require strong reciprocal adaptation between species, such as those observed between parasites and hosts. Parasites exhibit a high diversity of species and life history strategies, presenting host specificity which increases the complexity of these antagonistic systems. However, most studies are limited to the description of interactions between a few parasite and host species, which restricts our understanding of these systems as a whole. We investigated the effect of the developmental stage of the parasite on the structure of 30 metazoan fish-parasite networks, with an emphasis on the specificity of the interactions, connectance and modularity. We assessed the functional role of each species in modular networks and its interactions within and among the modules according to the developmental stage (larval and adult) and taxonomic group of the parasites. We observed that most parasite and host species perform a few interactions but that parasites at the larval stage tended to be generalists, increasing the network connectivity within and among modules. The parasite groups did not differ among each other in the number of interactions within and among the modules when considering only species at the larval stage. However, the same groups of adult individuals differed from each other in their interaction patterns, which were related to variations in the degree of host specificity at this stage. Our results show that the interaction pattern of fishes with parasites, such as acanthocephalans, cestodes, digeneans and nematodes, is more closely associated with their developmental stage than their phylogenetic history. This finding corroborates the hypothesis that the life history of parasites results in adaptations that cross phylogenetic boundaries.

Sciadicleithrum frequens n. sp. is described from the gills of the acara, Geophagus brasiliensis (Cichlidae), from nine reservoirs in the State of Parana, Brazil. The new species differs from the others members of Sciadicleithrum in the following features: dorsal anchors more than twice as long as the ventral anchors and hook pair 5 reduced in size. Sciadicleithrum frequens n. sp. is similar to species of this parasite genus from South America by having the male copulatory organ comprising less than 2 rings, and to species of Sciadicleithrum from Central America and southeast Mexico by the presence of longitudinal lateral grooves on the shafts and points of the ventral and dorsal anchors. This new species is the first species of Sciadicleithrum in South America with longitudinal lateral grooves on shafts and point of the ventral and dorsal anchors. It is the first dactylogyrid described from G. brasiliensis, and it is the first species of Sciadicleithrum described from Southern Brazil.

One of the most fascinating challenges in ecology and conservation biology is understanding the factors that determine patterns on species distribution and coocorrence. Generally, this understanding occurs through taxonomic studies of species assemblage. However, functional attributes of species provide informations about resources use and requirement of species habitat, and so it has potential to elucidate processes that govern these patterns in local, regional and continental scales. Furthermore, with functional atribbutes it is also possible to assess changes in species traits along time and space using metrics of functional dissimilarity, i.e., functional β-diversity. So, this thesis aimed to explore: (i) assembly rules and (ii) partitioning components of β-diversity of fish assemblage in a Neotropical floodplain. Initialilly, nine environments were sampled quarterly over 12 years (2000-2011),and posteriorlytwenty environments were sampled quarterly in years 2000, 2001, 2010 and 2011. This thesis demonstrated that there are distincts assembly processes of fish assemblage acting in the upper Paraná river floodplain. Moreover, when it is assessed that a specific assembly process occurs in the environment, it is need to be cautious, because scale can mask the actual process that the assemblage is going to settle down. Additionally, describing spatial patterns of functional and taxonomic β-diversity and analysing their determinants is fundamental to assess their temporal tendencies in the context of environmental changes induced naturally or not. In this sense, turnover component was the main responsible by changes in β-diversity of fish in floodplain, and functional and taxonomic β-diversity varied in space and time, mainly due to environmental alterations. That would be an indicative of environmental filters are importants as assembly rules on structuring of functional characteristics of fishes in floodplain. Finally, both approaches, functional and taxonomic, capture different aspects of biodiversity and provide complementary mechanisms to understand human impacts over world ecosystems. Thus, future studies of fish assemblages, in floodplain and other aquatic ecosystems, need to test if changes in patterns of taxonomic diversity follow changes in functional diversity and to evaluate how two components of β-diversity respond to biotic and abiotic changes. Um dos mais fascinantes desafios em ecologia e biologia da conservação é entender os fatores que determinam padrões na distribuição e coocorrência das espécies. Em geral, tal entendimento é realizado por meio de estudos taxonômicos e funcionais de assembleias de espécies. Os atributos funcionais das espécies, ao fornecer informações sobre o uso de recursos e requerimentos de habitat de espécies, tem o potencial de esclarecer os processos que governam esses padrões em escala local, regional e continental. Com os atributos funcionais pode-se também avaliar as mudanças no traços das espécies ao longo do tempo e espaço através de métricas de dissimilaridade funcional, ou seja, diversidade beta funcional. Diante disso, esta tese de doutorado visou explorar: (i) regras de montagem e (ii) partição dos componentes da diversidade da assembleia de peixes uma planície de inundação neotropical. Inicialmente, foram amostrados 9 locais ao longo de 12 anos, e posteriormente foram amostrados 20 locais trimestralmente em 2000, 2001, 2010 e 2011. Os principais padrões demonstrados foram que há diferentes processos de estabelecimento de assembleias de peixes atuando na planície de inundação do alto Rio Paraná. Além disso, quando se avalia que um determinado processo ocorre num ambiente, é necessário ter cautela, pois a escala pode mascarar o real processo que a assembleia está passando para se estabelecer. Adicionalmente, descrever os padrões espaciais da diversidade beta taxonômica e funcional e analisar seus determinantes é fundamental para avaliar suas tendências temporais no contexto de mudanças ambientais naturais ou antropogênicas. Nesse sentido, o componente turnover foi o principal responsável pela mudança na diversidade beta de peixes de planícies de inundação; e a diversidade beta taxonômica e funcional mudou no espaço e no tempo, principalmente devido as alterações ambientais. Isto seria um indicativo de que os filtros ambientais são importantes, como regras de estabelecimento, na estruturação das características funcionais de peixes na planície de inundação. Enfim, as duas abordagens, funcional e taxonômica, capturam diferentes aspectos da biodiversidade, e proveem mecanismos complementares para entender os impactos humanos sobre os ecossistemas do mundo. Assim, estudos futuros de peixes, em planícies de inundação e em outros ecossistemas aquáticos, necessitam testar se as mudanças nos padrões de diversidade taxonômica seguem mudanças na diversidade funcional e avaliar como os componentes da diversidade beta respondem as mudanças bióticas e abióticas. 66 f

Orientador: Prof. Dr. Ricardo Massato Takemoto Tese (doutorado em Biologia Comparada)--Universidade Estadual de Maringá, Centro de Ciências Biológicas, Dep. de Biologia, 2015 Resumo: A construção de reservatórios transforma o ambiente lótico em lêntico, alterando desta forma as condições físicas, químicas e biológicas deste rio. Diversos grupos de organismos são estudados com a finalidade de avaliar e minimizar os impactos causados por estas grandes construções. Quanto ao grupo dos parasitos de peixes, são encontrados na literatura trabalhos que analisam os parasitos em reservatórios isolados, no entanto pouco se sabe sobre o impacto destes empreendimentos sobre a fauna parasitária. O objetivo desta tese foi o de conhecer e verificar como se comportam os parasitos metazoários de Metynnis cf. lippincottianus coletados no rio Tietê e verificar como estes parasitos se organizam em cada um dos ambientes de coleta, considerando que cada reservatório possui características limnológicas e biológicas diferentes. Entre os parasitos coletados foram encontradas quatro espécies de monogenéticos novas para a ciência, descritas como Anacanthorus n. sp.1, Anacanthorus n. sp.2, Notozothecium n. sp.1 e Notozothecium n. sp.2. Também foram coletados Nematoda Spinoxyuris oxydoras e Procamallanus (Spirocamallanus) inopinatus e Digenea Ascocotyle sp. Pode-se verificar que a abundância e a riqueza de parasitos aumentou em função da distância do reservatório de Barra Bonita, o ponto de maior poluição do rio Tietê, refletindo desta forma as condições ambientais dos locais de coleta. Quanto a organização da comunidade de parasitos, observou-se que eles seguem o padrão de organização segregado entre os reservatórios. Por ser um peixe de hábito sedentário, M. cf. lippincottianus se apresentou como uma espécie de hospedeiro com potencial para estudos de parasitos bioindicadores. Considerando a existência de reservatórios como componentes indissociáveis da paisagem brasileira, este estudo contribuiu com importantes dados disponibilizados para a ciência a respeito da fauna parasitária de peixes de reservatórios em cascata de região neotropical Abstract: The construction of reservoirs turns the lotic environment in still water, thereby altering the physical, chemical and biological conditions of the river. Several groups of organisms are studied in order to assess and minimize the impacts caused by these great buildings. As for the group of parasites of fish are found in the literature that analyze the parasites in isolated reservoirs, however little is known about the impact of these developments on the parasitic fauna. The objective of this thesis was to know how to behave parasites Metynnis cf. lippincottianus collected in the Tiete River and see how these parasites are organized in each of the collection environments, considering that each tank has different limnological and biological characteristics. Among the parasites collected were found four species new to science monogeneans described as Anacanthorus n. sp.1, Anacanthorus n. sp.2, Notozothecium n. sp.1 and Notozothecium n. sp.2. They were also collected Nematoda Spinoxyuris oxydoras and Procamallanus (Spirocamallanus) inopinatus and Digenea Ascocotyle sp. It can be seen that the abundance and richness of parasites increased depending on the distance from the point of greater pollution of the river Tiete, reflecting this way the environmental conditions of the collection sites. As the organization of the parasite community, it was observed that they follow a pattern of segregated organization. For being a fish sedentary, M. cf. lippincottianus performed as a host species with potential for parasites biomarkers studies. Considering the existence of reservoirs as inseparable components of the Brazilian landscape, this study contributed important data available to science about the parasitic fauna reservoirs of fish cascading Neotropics