Temporal and seasonal variation of metazoan parasites in Pimelodus ornatus (Siluriformes: Pimelodidae) from the Amazon River, Brazil.

This study investigated the influence of temporal and seasonal (i.e., rainy and dry seasons) in communities and infracommunities of metazoan parasites in Pimelodus ornatus, a Siluriformes from the Amazon River in the state of Amapá, in northern Brazil. A total of 144 fish were collected during 2020 and 2021. In 2020, five species of parasites were found (1 Monogenea, 3 Nematoda, and 1 Cestoda), and in 2021, seven species of parasites were found (1 Monogenea, 3 Nematoda, 1 Cestoda, 1 Digenea, and 1 Crustacea). In 2020, Spirocamallanus inopinatus was dominant, while in 2021, Contracaecum sp. was dominant. Brillouin diversity, species richness, and evenness were higher in 2021. There were differences for some parasite infracommunities between years and between seasonal periods. Brillouin diversity and species richness were higher in the rainy season, but there were no differences in evenness and Berger-Parker dominance between the seasonal periods. Temporal and seasonal variations were mainly influenced by rainfall levels, oxygen levels, and environmental temperature and, later, by the availability of infective stages of parasites in the environment and the size of the hosts. Lastly, the influence of the temporal and seasonal variations on the structure of communities and infracommunities of parasites was weaker than expected due to the low infection rates of the majority of parasites found.

Geographic range, distribution patterns and interactions of Monogenea Van Beneden 1858, with species of native host freshwater fishes from Brazil.

This paper investigated information on monogenean species using 312 scientific papers, to search for infection and geographic distribution patterns in native freshwater fish from Brazil. We used 1,698 samples of 296 fish species of 28 families distributed into Characiformes, Siluriformes, Cichliformes, Gymnotiformes, Perciformes, Mugiliformes, Osteoglossiformes and Clupeiformes, in addition to four hybrid fish. Among the hosts of the different orders and families, the greatest numbers of parasite-host associations were found for species of the families Serrasalmidae, Characidae, Loricariidae, Curimatidae and Anostomidae. The 578 species of monogeneans used in parasite-host interactions were distributed in 86 genera of six five families (Dactylogyridae, Gyrodactylidae, Diplectanidae, Microcotylidae, Ancylodiscoididae and Ancyrocephalidae), but with great predominance of Dactylogyridae species. There was variation in prevalence, intensity and abundance levels of monogeneans species among host fish species, as well as in infection sites that occurred predominantly in external organs. Positive correlations of prevalence, intensity and abundance with body length of hosts were observed. There was geographic distribution pattern of monogeneans limited mostly to two hydrographic basins those being the Amazon River and Paraná River. Just approximately 6% of potential monogeneans have been explored thus far, showing a clear need for further studies on this interesting group of parasites.

Ecology and diversity of metazoan parasites infecting Geophagus altifrons (Cichliformes: Cichlidae) from the Amazon River system in northern Brazil.

The aim of this study was to investigate the ecology and diversity of community and infracommunities of metazoan parasites Geophagus altifrons (Heckel, 1840) in Rio Jari, in the state of Amapá, in the eastern Amazon region. From the total of 31 fish examined, 90.3% were parasitized by one or more species, collecting a total number of 806 parasites. The parasites species identified were: Sciadicleithrum geophagi, Posthodiplostomum sp., Procamallanus (Spirocamallanus) inopinatus, Raphidascaris (Sprentacaris) sp., Genarchella genarchella, Gorytocephalus spectabilis and Ergasilus xinguensis. Most of the parasites showed an aggregate dispersion pattern. Brillouin diversity index, uniformity and species richness of parasites were low. The component community of parasites was constituted by ectoparasites and endoparasites, but with a predominance of ectoparasites. The body size of hosts had a low effect on the parasites infracommunities. This first eco-epidemiological study for G. altifrons reports these parasites in a host, for the first time, with the exception of S. geophagi and E. xinguensis.

Ecology and diversity of metazoan parasites infecting Geophagus altifrons (Cichliformes: Cichlidae) from the Amazon River system in northern Brazil / Ecologia e diversidade de parasitos metazoários infectando Geophagus altifrons (Cichliformes: Cichlidae) do sistema do Rio Amazonas no norte do Brasil

Abstract The aim of this study was to investigate the ecology and diversity of community and infracommunities of metazoan parasites Geophagus altifrons (Heckel, 1840) in Rio Jari, in the state of Amapá, in the eastern Amazon region. From the total of 31 fish examined, 90.3% were parasitized by one or more species, collecting a total number of 806 parasites. The parasites species identified were: Sciadicleithrum geophagi, Posthodiplostomum sp., Procamallanus (Spirocamallanus) inopinatus, Raphidascaris (Sprentacaris) sp., Genarchella genarchella, Gorytocephalus spectabilis and Ergasilus xinguensis. Most of the parasites showed an aggregate dispersion pattern. Brillouin diversity index, uniformity and species richness of parasites were low. The component community of parasites was constituted by ectoparasites and endoparasites, but with a predominance of ectoparasites. The body size of hosts had a low effect on the parasites infracommunities. This first eco-epidemiological study for G. altifrons reports these parasites in a host, for the first time, with the exception of S. geophagi and E. xinguensis.

Resumo O objetivo deste estudo foi investigar a ecologia e a diversidade da comunidade e infracomunidades de parasitos metazoários em Geophagus altifrons (Heckel, 1840), do Rio Jari, estado do Amapá, na região da Amazônia oriental. De um total de 31 peixes examinados, 90,3% estavam parasitados por uma ou mais espécies e 806 parasitos foram coletados. As espécies de parasitos identificadas foram: Sciadicleithrum geophagi, Posthodiplostomum sp., Procamallanus (Spirocamallanus) inopinatus, Raphidascaris (Sprentacaris) sp., Genarchella genarchella, Gorytocephalus spectabilis e Ergasilus xinguensis. A maioria dos parasitos apresentaram dispersão agregada. Foi baixo o índice de diversidade de Brillouin, uniformidade e riqueza de espécies de parasitos. A comunidade componente de parasitos foi constituída por ectoparasitos e endoparasitos, mas com predominância de ectoparasitos. O tamanho corporal dos hospedeiros teve baixo efeito sobre as infracomunidades dos parasitos. Este primeiro estudo ecoepidemiológico para G. altifrons registra pela primeira vez estes parasitos para este hospedeiro, exceto S. geophagi e E. xinguensis.

Geographic range, distribution patterns and interactions of Monogenea Van Beneden 1858, with species of native host freshwater fishes from Brazil / Distribuição geográfica, padrões de distribuição e interações de Monogenea Van Beneden 1858, com espécies de peixes hospedeiros nativos de água doce do Brasil

Abstract This paper investigated information on monogenean species using 312 scientific papers, to search for infection and geographic distribution patterns in native freshwater fish from Brazil. We used 1,698 samples of 296 fish species of 28 families distributed into Characiformes, Siluriformes, Cichliformes, Gymnotiformes, Perciformes, Mugiliformes, Osteoglossiformes and Clupeiformes, in addition to four hybrid fish. Among the hosts of the different orders and families, the greatest numbers of parasite-host associations were found for species of the families Serrasalmidae, Characidae, Loricariidae, Curimatidae and Anostomidae. The 578 species of monogeneans used in parasite-host interactions were distributed in 86 genera of six five families (Dactylogyridae, Gyrodactylidae, Diplectanidae, Microcotylidae, Ancylodiscoididae and Ancyrocephalidae), but with great predominance of Dactylogyridae species. There was variation in prevalence, intensity and abundance levels of monogeneans species among host fish species, as well as in infection sites that occurred predominantly in external organs. Positive correlations of prevalence, intensity and abundance with body length of hosts were observed. There was geographic distribution pattern of monogeneans limited mostly to two hydrographic basins those being the Amazon River and Paraná River. Just approximately 6% of potential monogeneans have been explored thus far, showing a clear need for further studies on this interesting group of parasites.

Resumo Este estudo investigou informações sobre espécies de monogenéticos, usando 312 artigos científicos para buscar padrões de infecção e distribuição geográfica em peixes nativos de água doce do Brasil. Foram utilizadas 1.698 amostras de 296 espécies de peixes de 28 famílias, distribuídas em Characiformes, Siluriformes, Cichliformes, Gymnotiformes, Perciformes, Mugiliformes, Osteoglossiformes e Clupeiformes, além de quatro peixes híbridos. Entre os hospedeiros das diferentes ordens e famílias, os maiores números de associações parasito-hospedeiro foram encontrados para espécies das famílias Serrasalmidae, Characidae, Loricariidae, Curimatidae e Anostomidae. As 578 espécies de monogenéticos, utilizadas nas interações parasito-hospedeiro, foram distribuídas em 86 gêneros de seis famílias (Dactylogyridae, Gyrodactylidae, Diplectanidae, Microcotylidae, Ancylodiscoididae e Ancyrocephalidae), mas com grande predominância de espécie de Dactylogyridae. Houve variação nos níveis de prevalência, intensidade e abundância das espécies de monogenéticos entre as espécies de peixes hospedeiros, bem como nos locais de infecção que ocorreram predominantemente em órgãos externos. Correlações positivas de prevalência, intensidade e abundância com o comprimento corporal dos hospedeiros foram observadas. Houve padrão de distribuição geográfica dos monogenéticos limitados principalmente a duas bacias hidrográficas, sendo elas o Rio Amazonas e Rio Paraná. Apenas aproximadamente 6% dos potenciais monogenéticos são conhecidos até agora, mostrando uma clara necessidade de mais estudos sobre esse interessante grupo de parasitos.

Community and infracommunities of metazoan parasites in Hemiodus unimaculatus (Hemiodontidae) from Jari River basin, a tributary of Amazon River (Brazil).

Parasites are an important part of biodiversity, and knowledge of species and their relationship with their hosts helps in monitoring an ecosystem over time. The aim of this study was to investigate the fauna of metazoan parasites in Hemiodus unimaculatus from the Jari River, in the eastern Amazon region, northern Brazil. Of the fish examined, 96.7% were parasitized by one or more species, and a total of 336 parasites such as Dactylogyridae gen. sp.1, Dactylogyridae gen. sp.2, Dactylogyridae gen. sp.3, Dactylogyridae gen. sp.4, Gyrodactilydae gen. sp., Urocleidoides sp.1, Urocleidoides sp.2, Urocleidoides sp.3, metacercariae of Digenea gen. sp., Procamallanus (Spirocamallanus) inopinatus, Contracaecum sp., Neoechinorhynchus sp. and Acarina gen. sp. The parasite community showed low Brillouin diversity (0.58 ± 0.29), low evenness (0.44 ± 0.21) and low species richness (7.40 ± 3.83). There was a predominance of ectoparasites, mainly monogeneans and digeneans. The parasites showed an aggregate dispersion, except for P. (S.) inopinatus, which had a random dispersion. The size of the hosts had no effect on diversity, species richness and abundance of parasites, but other factors structured the parasite community. This is the first study on the parasite community and infracommunities in H. unimaculatus.

Diversity of metazoan parasites in fish Triportheus angulatus and Triportheus auritus living in sympatry in the Brazilian Amazon.

The aim of this study was to compare the diversity and community structure of metazoan parasites in sympatric populations of Triportheus angulatus and Triportheus auritus in the Jari River basin, in the eastern Brazilian Amazon. All the specimens of T. angulatus and T. auritus examined were infected by Anacanthorus furculus, Anacanthorus pithophallus, Digenea gen. sp., Procamallanus (Spirocamallanus) inopinatus, Rhabdochona acuminata, Contracaecum sp., Ergasilus sp. and Acarina gen. sp. These parasites displayed aggregated or random dispersion. The parasite community in T. angulatus and T. auritus presented a similarity of 78%. The diversity indice and richness of parasite species were greater in T. auritus and there were differences in levels of host parasite infection for some infracommunities. Phyllodistomum spatula occurred only in T. angulatus, while metacercariae of Clinostomum marginatum and Digenea gen. sp.2 occurred only in T. auritus. The species richness of the parasites was influenced by host size, as well as the abundance of some parasite infracommunities. This is the first report of these parasites for T. angulatus and T. auritus, except for P. (S.) inopinatus and Contracaecum sp. for T. angulatus.

Diversity and community ecology of metazoan parasites in Pimelodus ornatus (Siluriformes: Pimelodidae) from the Amazonas River in Brazil.

The present study investigated the metazoan parasite community in Pimelodus ornatus from the Amazon River, in the state of Amapá (Brazil). Of 71 fish examined, 70.4% were parasitized by Demidospermus sp. (Monogenea), Cucullanus pinnai, Procamallanus (Spirocamallanus) inopinatus and Contracaecum sp. (Nematoda) and plerocercoids from Proteocephalidae gen. sp. (Cestoda). The dominance was of nematode species such as Procamallanus (S.) inopinatus and Contracaecum sp. The parasites showed a highly aggregated dispersion and a predominance of hosts infected by one species of parasite. The parasite community was characterized by a low Shannon diversity index, low evenness and low species richness. The richness of parasite species, Shannon's diversity index, abundance of P. (S.) inopinatus and Proteocephalidae gen. sp. showed a positive correlation with the length of the hosts. Therefore, the size of the hosts had an influence on the parasite community and infracommunities, as well as their intermediate position in the food web. This is the first record of P. (S.) inopinatus and Contracaecum sp. for P. ornatus.

High prevalence and intensity of fish nematodes with zoonotic potential in the Brazilian Amazon, including a brief reflection on the absence of human infections

This study aimed to characterize the prevalence, mean abundance, and mean intensity of potential fish-borne zoonotic nematode larvae infecting the predator fish Hoplias aff. malabaricus from the Tapajós River, in the municipality of Santarém, in the Brazilian Amazon. After capture, the specimens of H. aff. malabaricus were analyzed for infection by Contracaecum sp. and Eustrongylides sp. third-stage larvae, and the prevalence, mean abundance, and mean intensity were calculated. A literature search was carried out to clarify the relationship between these indicators and eventual human cases of infection in the Amazon region. Third-stage larvae of nematodes of the Contracaecum and Eustrongylides genera were found in the specimens of H. aff. malabaricus sampled from the Tapajós River. The prevalence of Contracaecum larvae was 100%, while its mean abundance and mean intensity were both 54.8 larvae/fish. The prevalence of Eustrongylides larvae was 62.9%, and its mean abundance and mean intensity were 1.8 and 2.8 larvae/fish, respectively. Despite the high prevalence and intensity values, there are no cases of human infection by these nematode larvae in the Brazilian Amazon reported. The absence of human infections by these nematode larvae in the Brazilian Amazon despite the high prevalence/intensity of Contracaecum and Eustrongylides larvae and the high consumption of fish in the region, is most probably due to the fact that the local populations do not eat raw or undercooked fish. However, it is noteworthy that the absence of zoonotic cases in the region is based only on the examination of the available published papers. A better knowledge of the situation would require surveying hospitals and clinics, and data from the region's medical treatment facilities. However, the authors consider that cases of human infection, if any, are extremely rare, mainly due to the eating habits of the local population.

Community and infracommunities of metazoan parasites in Hemiodus unimaculatus (Hemiodontidae) from Jari River basin, a tributary of Amazon River (Brazil) / Comunidade e infracomunidades de parasitos metazoários em Hemiodus unimaculatus (Hemiodontidae) da bacia do Rio Jari, um tributário do Rio Amazonas (Brasil)

Abstract Parasites are an important part of biodiversity, and knowledge of species and their relationship with their hosts helps in monitoring an ecosystem over time. The aim of this study was to investigate the fauna of metazoan parasites in Hemiodus unimaculatus from the Jari River, in the eastern Amazon region, northern Brazil. Of the fish examined, 96.7% were parasitized by one or more species, and a total of 336 parasites such as Dactylogyridae gen. sp.1, Dactylogyridae gen. sp.2, Dactylogyridae gen. sp.3, Dactylogyridae gen. sp.4, Gyrodactilydae gen. sp., Urocleidoides sp.1, Urocleidoides sp.2, Urocleidoides sp.3, metacercariae of Digenea gen. sp., Procamallanus (Spirocamallanus) inopinatus, Contracaecum sp., Neoechinorhynchus sp. and Acarina gen. sp. The parasite community showed low Brillouin diversity (0.58 ± 0.29), low evenness (0.44 ± 0.21) and low species richness (7.40 ± 3.83). There was a predominance of ectoparasites, mainly monogeneans and digeneans. The parasites showed an aggregate dispersion, except for P. (S.) inopinatus, which had a random dispersion. The size of the hosts had no effect on diversity, species richness and abundance of parasites, but other factors structured the parasite community. This is the first study on the parasite community and infracommunities in H. unimaculatus.

Resumo O objetivo deste estudo foi investigar a fauna de parasitos metazoários em Hemiodus unimaculatus do Rio Jari, na Amazônia oriental brasileira. Dos peixes examinados, 96,7% estavam parasitados por uma ou mais espécies, e um total de 336 parasitos, como Dactylogyridae gen. sp.1, Dactylogyridae gen. sp.2, Dactylogyridae gen. sp.3, Dactylogyridae gen. sp.4, Gyrodactilydae gen. sp., Urocleidoides sp.1, Urocleidoides sp.2, Urocleidoides sp.3, metacercárias de Digenea gen. sp., Procamallanus (Spirocamallanus) inopinatus, Contracaecum sp., Neoechinorhyncus sp. e Acarina gen. sp. A comunidade de parasitos apresentou baixa diversidade de Brillouin (0,58 ± 0,29), baixa equitabilidade (0,44 ± 0,21) e baixa riqueza de espécies (7,40 ± 3,83). Houve predominância de ectoparasitos, principalmente monogeneas e digeneas. Os parasitos apresentaram dispersão agregada, exceto P. (S.) inopinatus, que teve uma dispersão aleatória. O tamanho dos hospedeiros não teve efeito sobre a diversidade, riqueza de espécies e abundância de parasitos, mas outros fatores estruturaram a comunidade de parasitos. Este é o primeiro estudo sobre a comunidade e infracomunidades de parasitos em H. unimaculatus.

Diversity of metazoan parasites in fish Triportheus angulatus and Triportheus auritus living in sympatry in the Brazilian Amazon / Diversidade de parasitos metazoários em peixes Triportheus angulatus e Triportheus auritus vivendo em simpatria na Amazônia brasileira

Abstract The aim of this study was to compare the diversity and community structure of metazoan parasites in sympatric populations of Triportheus angulatus and Triportheus auritus in the Jari River basin, in the eastern Brazilian Amazon. All the specimens of T. angulatus and T. auritus examined were infected by Anacanthorus furculus, Anacanthorus pithophallus, Digenea gen. sp., Procamallanus (Spirocamallanus) inopinatus, Rhabdochona acuminata, Contracaecum sp., Ergasilus sp. and Acarina gen. sp. These parasites displayed aggregated or random dispersion. The parasite community in T. angulatus and T. auritus presented a similarity of 78%. The diversity indice and richness of parasite species were greater in T. auritus and there were differences in levels of host parasite infection for some infracommunities. Phyllodistomum spatula occurred only in T. angulatus, while metacercariae of Clinostomum marginatum and Digenea gen. sp.2 occurred only in T. auritus. The species richness of the parasites was influenced by host size, as well as the abundance of some parasite infracommunities. This is the first report of these parasites for T. angulatus and T. auritus, except for P. (S.) inopinatus and Contracaecum sp. for T. angulatus.

Resumo O objetivo deste estudo foi comparar a diversidade e comunidade de parasitos metazoários em populações simpátricas de Triportheus angulatus e Triportheus auritus da bacia do Rio Jari, na Amazônia oriental brasileira. Todos os espécimes de T. angulatus e T. auritus examinados estavam infectados por Anacanthorus furculus, Anacanthorus pithophallus, Digenea gen. sp., Procamallanus (Spirocamallanus) inopinatus, Rhabdochona acuminata, Contracaecum sp., Ergasilus sp. e Acarina gen. sp. Esses parasitos apresentaram dispersão agregada ou randômica. A comunidade de parasitos em T. angulatus e T. auritus apresentou uma similaridade de 78%. A diversidade e riqueza de espécies de parasitos foram maiores em T. auritus e houve diferenças nos níveis de infecção parasitária entre os hospedeiros para algumas infracomunidades. Phyllodistomum spatula ocorreu somente em T. angulatus, enquanto metacercárias de Clinostomum marginatum e Digenea gen. sp.2 ocorreram somente em T. auritus. A riqueza de espécies de parasitos foi influenciada pelo tamanho dos hospedeiros, bem como pela abundância de algumas infracomunidades de parasitos. Este é o primeiro relato desses parasitos para T. angulatus e T. auritus, exceto P. (S.) inopinatus e Contracaecum sp. para T. angulatus.

Diversity and community ecology of metazoan parasites in Pimelodus ornatus (Siluriformes: Pimelodidae) from the Amazonas River in Brazil / Diversidade e ecologia da comunidade de parasitos metazoários em Pimelodus ornatus (Siluriformes: Pimelodidae) do Rio Amazonas no Brasil

Abstract The present study investigated the metazoan parasite community in Pimelodus ornatus from the Amazon River, in the state of Amapá (Brazil). Of 71 fish examined, 70.4% were parasitized by Demidospermus sp. (Monogenea), Cucullanus pinnai, Procamallanus (Spirocamallanus) inopinatus and Contracaecum sp. (Nematoda) and plerocercoids from Proteocephalidae gen. sp. (Cestoda). The dominance was of nematode species such as Procamallanus (S.) inopinatus and Contracaecum sp. The parasites showed a highly aggregated dispersion and a predominance of hosts infected by one species of parasite. The parasite community was characterized by a low Shannon diversity index, low evenness and low species richness. The richness of parasite species, Shannon's diversity index, abundance of P. (S.) inopinatus and Proteocephalidae gen. sp. showed a positive correlation with the length of the hosts. Therefore, the size of the hosts had an influence on the parasite community and infracommunities, as well as their intermediate position in the food web. This is the first record of P. (S.) inopinatus and Contracaecum sp. for P. ornatus.

Resumo Este estudo investigou a comunidade de parasitos metazoários em Pimelodus ornatus do Rio Amazonas, no estado do Amapá (Brasil). De 71 peixes examinados, 70,4% estavam parasitados. Um total de 147 parasitos foi coletado, entre Demidospermus sp. (Monogenea), Cucullanus pinnai (Nematoda), Procamallanus (Spirocamallanus) inopinatus e Contracaecum sp. (Nematoda) e plerocercoides de Proteocephalidae gen. sp. (Cestoda). A dominância foi de nematoides como Procamallanus (S.) inopinatus e Contracaecum sp. Os parasitos apresentaram dispersão altamente agregada e predomínio de hospedeiros infectados por uma espécie de parasito. A comunidade de parasitos foi caracterizada por baixo índice de diversidade de Shannon, baixa equitabilidade e baixa riqueza de espécies. A riqueza de espécies de parasitos, índice de diversidade de Shannon, abundância de P. (S.) inopinatus e Proteocephalidae gen. sp. apresentaram correlação positiva com o comprimento dos hospedeiros. Portanto, o tamanho dos hospedeiros teve influência sobre a comunidade e infracomunidades de parasitos, bem como sua posição intermediária na cadeia alimentar. Este é o primeiro registro de P. (S.) inopinatus e Contracaecum sp. para P. ornatus.

Isopods Cymothoidae ectoparasites of fish from the Amazon.

Most freshwater species of Cymothoidae are distributed in South America. They have mainly been recorded in the eastern and western regions of the Amazon River basin. However, in this ecosystem, the biodiversity of this group may be greater if the entire Amazon basin is considered. In this regard, the aim of the present study was to provide an updated list of isopod species of the family Cymothoidae that are found in fish in the Brazilian Amazon region and to report on new fish host occurrences and expanded geographical distributions for cymothoid isopods that parasitize fish in the southwestern Brazilian Amazon region. The parasites found in fish specimens were collected, fixed and identified later. We found eight species of Cymothoidae parasitizing different host fish species in the southwestern Amazon region. However, we found 14 species of Cymothoidae throughout the Brazilian Amazon region. Three additional species are thus reported here, which increases the number of species of Cymothoidae in this region to 17. These additional species are also new records for Brazil. Therefore, this study has contribute to expand the knowledge about the distribution and diversity of Cymothoidae in the Amazon basin.

First report of Livoneca guianensis (Isopoda: Cymothoidae) in Leporinus fasciatus (Pisces: Anostomidae) in Brazil.

This study aimed to report the first record of the occurrence of the parasite Livoneca guianensis in Leporinus fasciatus in Brazil. In September 2019, during surveys of the parasites in 12 specimens of L. fasciatus from the lower Jari River basin, in Amapá State, Brazil, one specimen of L. guianensis was found in the tongue of one host. The prevalence of L. guianensis was 8.3%, and it was observed that this parasite has a geographic distribution restricted to South America, parasitizing fish species from Guyana and Brazil. This study contributed to the first report on the occurrence of L. guianensis for L. fasciatus in Brazil. In addition, increased the knowledge on the geographic distribution of this parasite with morphometric data, which are scarce for this Cymothoidae.

New species of Urocleidoides (Monogenoidea: Dactylogyridae) from the gills of two species of Anostomidae from the Brazilian Amazon.

Three species (2 new) of Urocleidoides are described and/or reported from the gills of Schizodon fasciatus and Laemolyta proxima (Anostomidae) from the Jari River in the eastern Brazilian Amazon. Urocleidoides jariensis n. sp. presents a sclerotized, tubular, spiral male copulatory organ (MCO) with one counterclockwise coil, a circular sclerotized tandem brim associated with the base of the MCO; a heavily sclerotized, funnel-shaped vaginal vestibule; and a broadly V-shaped ventral bar with anteromedial constriction and enlarged ends. Urocleidoides ramentacuminatus n. sp. has a sclerotized, tubular, spiral MCO with one counterclockwise coil; an accessory piece with a hook-shaped distal portion; and a dorsal anchor with a short, straight shaft; anchor point with ornamentation as sclerotized shredded filaments. Urocleidoides paradoxus is reported for the first time parasitizing S. fasciatus.

New records of hosts for Excorallana longicornis and Nerocila acuminata (Crustacea: Isopoda) in brackish fish from the coast of the State of Amapá (Brazil), with an update on the geographic distribution of Nerocila acuminata.

Fish are parasitized by several species of crustaceans, including Cymothoidae and Corallanidae. The aim of this study was to investigate the crustacean parasite fauna in Anableps anableps, Amphiarius rugispinis, Bagre bagre, Cathorops spixii, Cynoscion acoupa, Centropomus undecimalis, Macrodon ancylodon, Mugil curema, Megalops atlanticus, Pseudachenipterus nodosus, Plagioscion squamosissimus, Platystacus cotylephorus, Sciades passany, Sciades herzbergii, and Hypostomus ventrimaculata from the coast of the State of Amapá, eastern Amazon. In addition, an update on the geographic distribution of Nerocila acuminata in Brazilian Amazon is present. A total of 204 fish were examined and prevalence was 16.17%. A total of 185 Excorallana longicornis and Nerocila acuminata were collected and E. longicornis was the most frequent parasite species. The community of parasitic crustaceans in fish species from the coast of the State of Amapá consisted of two species of isopods, E. longicornis and N. acuminata, which are new records for nine host species here studied. Lastly, this is the first record of Nerocila acuminata for Brazil, besides the first report of E. longicornis for M. curema, C. acoupa, H. vetrimaculata, A. anableps, A. rugispinis, C. spixii and S. herzbergii; as well as N. acuminata for A. anableps, P. nodosus, A. rugispinis, C. spixii and M. atlanticus.

Length-weight relationship and condition factor for twelve fish species from the Igarapé Fortaleza basin, a small tributary of the Amazonas River estuary

Length and weight data are useful in fisheries management and standard results of fish monitoring programs. Length-weight relationship (LWR) is used for estimating the weight corresponding to a given length, and the condition factor is used to compare the body condition, fatness or health of fish populations. This study aimed to estimate the LWR and the condition factor for 12 freshwater fish species from the Igarapé Fortaleza basin, a tributary of the Amazonas River system in the State of Amapá, eastern Amazon (Brazil). The coefficient of determination, the allometric condition factor and the allometric coefficient varied among species, and were compared with populations elsewhere. In 83.3% of the species, the allometric coefficient remained within the expected range. This was the first record of LWR parameters for Acestrorhynchus falcirostris. (AU)

First report of Livoneca guianensis (Isopoda: Cymothoidae) in Leporinus fasciatus (Pisces: Anostomidae) in Brazil / Primeiro registro de Livoneca guianensis (Isopoda: Cymothoidae) em Leporinus fasciatus (Pisces: Anostomidae) no Brasil

Abstract This study aimed to report the first record of the occurrence of the parasite Livoneca guianensis in Leporinus fasciatus in Brazil. In September 2019, during surveys of the parasites in 12 specimens of L. fasciatus from the lower Jari River basin, in Amapá State, Brazil, one specimen of L. guianensis was found in the tongue of one host. The prevalence of L. guianensis was 8.3%, and it was observed that this parasite has a geographic distribution restricted to South America, parasitizing fish species from Guyana and Brazil. This study contributed to the first report on the occurrence of L. guianensis for L. fasciatus in Brazil. In addition, increased the knowledge on the geographic distribution of this parasite with morphometric data, which are scarce for this Cymothoidae.

Resumo Este estudo objetivou registrar a primeira ocorrência de Livoneca guianensis em Leporinus fasciatus no Brasil. Em setembro de 2019, durante uma pesquisa sobre parasitos em 12 espécimes de L. fasciatus do baixo Rio Jari, Estado do Amapá, norte do Brasil, um espécime de L. guianensis foi encontrado na língua de um hospedeiro. A prevalência de L. guianensis foi de 8,3% e foi observado que esse parasito tem distribuição geográfica restrita à América do Sul, parasitando espécies de peixes da Guiana e do Brasil. Este estudo contribuiu com o primeiro relato da ocorrência de L. guianensis para L. fasciatus no Brasil. Além disso, aumentou o conhecimento sobre a distribuição geográfica desse parasito, contribuindo com dados morfométricos que são escassos para esse Cymothoidae.

Isopods Cymothoidae ectoparasites of fish from the Amazon / Isópodes Cymothoidae ectoparasitos de peixes da Amazônia

Abstract Most freshwater species of Cymothoidae are distributed in South America. They have mainly been recorded in the eastern and western regions of the Amazon River basin. However, in this ecosystem, the biodiversity of this group may be greater if the entire Amazon basin is considered. In this regard, the aim of the present study was to provide an updated list of isopod species of the family Cymothoidae that are found in fish in the Brazilian Amazon region and to report on new fish host occurrences and expanded geographical distributions for cymothoid isopods that parasitize fish in the southwestern Brazilian Amazon region. The parasites found in fish specimens were collected, fixed and identified later. We found eight species of Cymothoidae parasitizing different host fish species in the southwestern Amazon region. However, we found 14 species of Cymothoidae throughout the Brazilian Amazon region. Three additional species are thus reported here, which increases the number of species of Cymothoidae in this region to 17. These additional species are also new records for Brazil. Therefore, this study has contribute to expand the knowledge about the distribution and diversity of Cymothoidae in the Amazon basin.

Resumo A maioria das espécies de água doce de Cymothoidae está distribuída na Sul e foi registrada principalmente nas regiões Leste e Oeste da bacia do Rio Amazonas. Entretanto, nesse ecossistema, a biodiversidade desse grupo pode ser maior se toda a bacia amazônica for considerada. Nesse sentido, o objetivo do presente estudo foi fornecer uma lista atualizada de espécies de isópodes da família Cymothoidae que são encontrados em peixes na Região Amazônica brasileira e relatar novas ocorrências de peixes hospedeiros, ampliando as distribuições geográficas para isópodes cimotoides que parasitam peixes na região Sudoeste da Amazônia brasileira. Os parasitos encontrados em espécimes de peixes coletados foram analisados e posteriormente identificados. Foram encontradas oito espécies de Cymothoidae parasitando diferentes espécies de peixes hospedeiros na região Sudoeste da Amazônia. No entanto, foram encontradas 14 espécies de Cymothoidae em toda a Região Amazônica brasileira. Três novos relatos de espécies foram observados, o que aumenta o número de espécies de Cymothoidae nessa região para 17. Essas espécies relatadas, também são novos registros para o Brasil. Portanto, este estudo ajudou a expandir o conhecimento sobre a distribuição e diversidade de Cymothoidae na bacia amazônica.

New species of Urocleidoides (Monogenoidea: Dactylogyridae) from the gills of two species of Anostomidae from the Brazilian Amazon / Novas espécies de Urocleidoides (Dactylogyridae) das brânquias de duas espécies de Anostomidae da Amazônia brasileira

Abstract Three species (2 new) of Urocleidoides are described and/or reported from the gills of Schizodon fasciatus and Laemolyta proxima (Anostomidae) from the Jari River in the eastern Brazilian Amazon. Urocleidoides jariensis n. sp. presents a sclerotized, tubular, spiral male copulatory organ (MCO) with one counterclockwise coil, a circular sclerotized tandem brim associated with the base of the MCO; a heavily sclerotized, funnel-shaped vaginal vestibule; and a broadly V-shaped ventral bar with anteromedial constriction and enlarged ends. Urocleidoides ramentacuminatus n. sp. has a sclerotized, tubular, spiral MCO with one counterclockwise coil; an accessory piece with a hook-shaped distal portion; and a dorsal anchor with a short, straight shaft; anchor point with ornamentation as sclerotized shredded filaments. Urocleidoides paradoxus is reported for the first time parasitizing S. fasciatus.

Resumo Três espécies (2 novas) de Urocleidoides são descritas e/ou reportadas das brânquias de Schizodon fasciatus e Laemolyta proxima (Anostomidae) da bacia do Rio Jari, na Amazônia oriental brasileira. Urocleidoides jariensis n. sp. apresenta um órgão copulatório masculino (OCM) convoluto, com uma volta no sentido anti-horário, uma borda em tandem esclerotizada circular, associada à base do OCM; um vestíbulo vaginal fortemente esclerotizado e em forma de funil; um canal vaginal esclerotizado na porção proximal; e uma barra ventral em forma de V com constrição anteromedial e ampliações terminais. Urocleidoides ramentacuminatus n. sp. tem um OCM convoluto com, aproximadamente, uma volta no sentido anti-horário; uma peça acessória com uma porção distal em forma de gancho; uma âncora dorsal com haste curta e reta; e ponta da âncora com ornamentação como filamentos desfiados esclerotizados. Urocleidoides paradoxus é relatada pela primeira vez parasitando S. fasciatus.