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Tapeworms (Cestoda: Proteocephalidae) are the dominant component of communities of intestinal parasites in pimelodid and other catfishes (Siluriformes) from South America. Even though these parasites have been studied intensively over more than one century, molecular taxonomy and phylogenetics have questioned their morphology-based classification, thus raising doubts about the systematic value of traits commonly used to circumscribe individual taxa. In the present study, members of three morphologically well-characterized genera of proteocephalids from pimelodid (Hemisorubim platyrhynchos and Sorubim lima) and auchenipterid (Ageneiosus inermis) catfishes from the Parana or Amazon River basins were subjected to DNA sequencing of the large subunit nuclear ribosomal RNA (lsrDNA) and complete mitochondrial cytochrome c oxidase subunit I (COI). Phylogenetic analyses revealed the sister relationship between Manaosia bracodemoca and Mariauxiella piscatorum, and among Mariauxiella pimelodi and Ageneiella brevifilis. As a result, Mar. piscatorum and A. brevifilis are transferred to Manaosia and Mariauxiella, respectively, as Manaosia piscatorum n. comb. and Mariauxiella brevifilis n. comb., and the genus Ageneiella is suppressed. Diagnoses of Manaosia and Mariauxiella are amended. In addition, the present study revealed misidentification of tapeworms whose sequences are deposited in the GenBank database.

EnglishAgeneiosus inermis is the largest species of the family Auchenipteridae (Siluriformes) and has a primarily piscivorous diet, although no comprehensive data are available on the habitat use of this species. Given this, the present study describes the diet of A. inermis, and provides inferences on its habitat use, based on the known behavior of its prey species. We analyzed the stomach contents of 14 specimens collected in the middle of Xingu River in the Brazilian state of Para, which we complemented with data on 47 other specimens obtained from two published studies. Most of the ingested items were fish associated with the bottom substrate and riverbanks. Although A. inermis is considered a pelagic species, we conclude it forages by exploring the river’s bottom and margins. Furthermore, as A. inermis is presumed to be diurnal, we assume that it does not pursue its prey actively, given that most of the prey species are nocturnal, but rather searches actively during the daytime for prey hidden in the bottom substrate. This hypothesis on the feeding strategy of A. inermis can only be confirmed by underwater observations, either in the wild or under captive conditions. portuguesAgeneiosus inermis e a maior especie da familia Auchenipteridae (Siluriformes), com um habito primariamente piscivoro. Porem, nenhum estudo focou no uso do habitat com essa especie. Em vista dessa lacuna no conhecimento, o presente estudo objetivou descrever a dieta e inferir sobre o uso do habitat do A. inermis baseado no comportamento de suas presas. Avaliamos 61 estomagos com conteudo de individuos capturados no medio Rio Xingu (Estado do Para), e outras duas literaturas publicadas. A maioria dos itens consumidos vive associado ao substrato e margens de rios. Considerando que A. inermis e um peixe pelagico, supomos que os individuos realizem um movimento lateral e vertical para forragear nas margens e fundo, respectivamente. Alem disso, A. inermis e descrito como uma especie diurna, porem se alimenta preferencialmente de presas de habitos noturnos. Isso nos leva a presumir que o A. inermis nao realiza perseguicao das presas, e sim realizaria busca ativa no substrato ou margem dos rios, pois as mesmas estariam abrigadas no periodo diurno. Para testar essa hipotese de estrategia alimentar, encorajamos estudos complementares com observacoes subaquaticas no seu habitat natural ou ate mesmo em estudos comportamentais em cativeiro.

The present study describes Hoferellus jutubensis n. sp., a myxozoan parasite found in the urinary bladder of the driftwood catfish Ageneiosus inermis, captured on Jutuba Island in the state of Para, northern Brazil. A total of 30 A. inermis specimens were examined, of which 26 (86.7%) had myxospores and polysporic plasmodia of varying shapes and sizes dispersed in the lumen of the urinary bladder, either floating freely or attached to the epithelium. In the apical view, the myxospores of Hoferellus jutubensis n. sp. are rounded, 6.1 ± 0.2 (5.7–6.3) μm long and 5.5 ± 0.3 (5.2–6.0) μm wide, with two sub-spherical polar capsules, equal in size and shape, 2.5 ± 0.2 (2.3–2.7) μm long and 1.7 ± 0.2 (1.4–2.2) μm wide. The phylogenetic analysis of a partial sequence of the SSU rDNA gene, indicated that the new species is the sister taxon of Hoferellus azevedoi, with these two species forming a Brazilian lineage of Hoferellus. The comparison of the morphological and molecular data with those of the existing members of the genus confirmed the species status of Hoferellus jutubensis n. sp., which adds one further Hoferellus taxon to the known myxosporean diversity of the Amazon basin.

The catfish genus Ageneiosus in the exclusively Neotropical family Auchenipteridae is revised. Species of Ageneiosus are widely distributed in all major South American continental drainages except the Sao Francisco River basin and small rivers along the Brazilian east coast. The taxonomic revision was based on examination of available type specimens, additional museum material and comparisons of original descriptions. A suite of morphometric, meristic and qualitative characters of internal and external anatomy were used to diagnose valid species and determine synonyms. Thirteen valid species are recognized in the genus Ageneiosus, some of which are widely distributed across South America. Ageneiosus pardalis is the only trans-Andean species in the genus. Ageneiosus polystictus and Ageneiosus uranophthalmus are more widely distributed than previously reported. Ageneiosus marmoratus is a junior synonym of Ageneiosus inermis. Ageneiosus dentatus is a valid species and its name is removed from the synonymy of Ageneiosus ucayalensis. Four new species are described: Ageneiosus akamai, Ageneiosus apiaka, Ageneiosus intrusus and Ageneiosus lineatus, all from the Amazon River basin. A dichotomous key for all 13 valid species of Ageneiosus species is provided.

This work describes a new species of the genus Neoechinorhynchus, a parasite found in the Siluriformes fish, Ageneiosus inermis collected in Catalão Lake. This species is most closely related to N. (N.) pterodorides and N. (N.) pimelodis than other species registered in Brazil. The size of its trunk, hooks and male reproductive system distinguish it from these 2 species. This work contributes to increase the knowledge of the biodiversity of fish parasites in the Amazon. © 2017 Universidad Nacional Autónoma de México, Instituto de Biología

Cladocaecum tomasscholzi n. gen., n. sp. infects the heart (lumen of ventricle) of driftwood catfish, Ageneiosus inermis Linnaeus, 1766 (Siluriformes: Auchenipteridae) from the Nanay River (Amazon River Basin, near Iquitos, Peru). It differs from all other aporocotylid genera by having a highly branched intestine comprising a central cecum that terminates immediately anterior to the ovary and that has numerous laterally directed diverticula. Kritsky platyrhynchi ( Guidelli, Isaac, and Pavanelli, 2002 ) n. gen., n. comb. (= Plehniella p.) is redescribed based on paratypes plus new specimens collected from the body cavity of the type host (porthole shovelnose catfish, Hemisorubim platyrhynchos Valenciennes, 1840) (Pimelodidae) from the nearby Itaya River. Kritsky differs from Sanguinicola Plehn, 1905 , Plehniella Szidat, 1951 , Nomasanguinicola Truong and Bullard, 2013 , and Cladocaecum by the combination of having a spinous anterior sucker, an intestine comprising 6 asymmetrical ceca, a lanceolate body, a straight vas deferens, an ovary with finger-like lateral projections, a small and spheroid oötype, numerous, minute, spheroid uterine eggs, and separate genital pores. An updated list of hosts, tissues infected, and geographic localities for the catfish blood flukes (9 spp.; 5 genera) is provided. This is the first report of a fish blood fluke infecting a member of Auchenipteridae and first proposal of a new genus of blood fluke (Schistosomatoidea) from South America in 64 yr. It brings the total number of Amazonian fish blood flukes to a mere 4 species.

O rio das Mortes é um dos principais cursos d’água do estado de Mato Grosso e o maior afluente, da margem esquerda, do rio Araguaia, sendo que a seção baixa do mesmo está inserida na planície do Bananal. Este estudo objetiva caracterizar ecologicamente a comunidade de peixes considerando um período sazonal: cheia e seca. A comunidade de peixes em estudo apresenta altos valores de diversidade (4,783 bits/indivíduos do Índice de Shannon-Wiener), riqueza de espécies (66 espécies amostradas) e abundância de indivíduos (659 indivíduos) durante o período de seca, onde as espécies mais abundantes foram Pygocentrus nattereri Kner, 1858 e Boulengerella cuvieri (Agassiz, 1829). Ageneiosus inermis (Linnaeus, 1766) e Rhaphiodon vulpinus Agassiz, 1829 foram mais abundantes na época cheia. A interação entre a comunidade de peixes e a planície de inundação apresenta um padrão comparável a este observado em planícies de inundação na região Neotropical. The das Mortes River is one of the main water courses of the Mato Grosso State and the largest tributary of the Araguaia River on it’s left bank. Its low section is located in the Bananal floodplain. This study aims to characterize the fish assemblage of this river during high and low waters. Fish assemblage during low waters was characterized by high diversity (4.783 bits/individuals of the Shannon-Wiener index), species richness (69 species sampled) and abundance (659 individuals), where the most abundant species were Pygocentrus nattereri Kner, 1858 and Boulengerella cuvieri (Agassiz, 1829). Ageneiosus inermis (Linnaeus, 1766) and Rhaphiodon vulpinus Agassiz, 1829 were abundant at high waters. Interaction between the fish assemblage and the floodplain have similar pattern to that observed in other Neotropical floodplains.

Orientador: Prof. Dr. Ricardo Massato Takemoto Coorientador: Prof.ª Dr.ª Maria de los Angeles Perez Lizama Dissertação (mestrado em Biologia Comparada)--Universidade Estadual de Maringá, Centro de Ciências Biológicas, Dep. de Biologia, 2013 Resumo: Entre os vertebrados mais parasitados estão os peixes, isso provavelmente ocorra pelas peculiaridades existentes no ambiente aquático, na qual possibilita acesso e a penetração de agentes patogênicos tornam-se facilitados. O Brasil, maior país da Região Neotropical, se caracteriza por possuir inúmeros e volumosos corpos d água onde vive uma ictiofauna reconhecidamente rica e diversificada, na qual são parasitados por um grande número de espécies pertencentes a numerosos filos. Pouco se conhece sobre a diversidade dos parasitos presentes nestes peixes. A ausência de estudos relacionados à ecologia parasitária de Ageneiosusinermis, associada à hipótese de que a composição e a estrutura dos endoparasitos de A. inermis sofrem interferências intrínsecas e extrínsecas da relação parasito-hospedeiroambiente, propiciaram a realização deste trabalho, em que avaliou os efeitos e descreveu a comunidade componente de endoparasitos de 49 hospedeiros coletados na planície de inundação do alto rio Paraná, entre março de 2010 a fevereiro de 2013.Quarenta (81,63%) abrigavam pelo menos uma espécie de endoparasito, totalizando 14 espécies pertencentes a quatro taxa: Cestoda, Digenea, Nematoda e Acanthocephala, composta tanto por espécies autogênicas quanto alogênicas Abstract: Among the most infected fish are vertebrates, this probably occurs by the peculiarities existing in the aquatic environment, which enables the access and penetration of pathogens become facilitated. Brazil, the largest country of the Neotropical region, is characterized by having numerous and voluminous bodies of water where a rich and diverse fish fauna known, which are parasitized by a large number of species belonging to many phyla lives. Little is known about the diversity of parasites present in these fish. The absence of studies related to the parasite ecology of Ageneiosusinermis associated with the hypothesis that the composition and structure of endoparasites of A. inermis suffer intrinsic and extrinsic interference of parasite-host-environment, enabled the realization of this work, which evaluated effects and described the component community endoparasites of 49 hosts collected in the floodplain of the upper Paraná River, between March 2010 and February 2013 Forty (81.63%) harbored at least one species of endoparasito, totaling 14 species four rate: Cestoda, Digenea, Nematoda and Acanthocephala, composed of both autogenic as allogenic species

Luciaella ivanovae n. g., n. sp. (Proteocephalidea: Peltidocotylinae) is proposed to accommodate a new cestode from a siluroid fish, the manduve Ageneiosus inermis (Linnaeus) (syn. A. brevifilis Valenciennes) (Auchenipteridae) from the Colastine River, a tributary of the Parana River, in Argentina. The new genus is placed in the Peltidocotylinae because it has a medullary ovary with projections into the dorsal cortex, cortical vitelline follicles and testes, a cortical uterine stem, and uterine branches penetrating the medulla and usually as far as the dorsal cortex. Luciaella can be distinguished from all other peltidocotyline genera by the following combination of characters: a quadrangular scolex with four biloculate suckers, each of which has a cap-peak-like structure situated on the anterior margin; the absence of a metascolex; vitelline follicles arranged in two lateral rows which are crescent-shaped in transverse section; testes distributed in two dorsal fields connected anteriorly and sometimes posteriorly; and a vagina which is always anterior to the cirrus-sac and overlaps the convoluted vas deferens. Filiform microtriches are present on all tegumental surfaces, with short filiform microtriches on the scolex and long filiform microtriches on the proliferation zone and on both immature and mature proglottides. The diagnosis of the Peltidocotylinae Woodland, 1934 given by Rego (1994) is amended. L. ivanovae is the fourth proteocephalidean described from A. inermis and the third recorded in this fish host from Argentina.

Ageneiosus is the most widely distributed genus of the family Auchenipteridae among South American river basins. Although chromosome studies in the family are scarce, this genus has the largest number of analyzed species, with 2n = 54 to 56 chromosomes, differing from the rest of the family (2n = 58). This study aimed to analyze Ageneiosus inermis from the Araguaia River basin. The diploid number found was of 56 chromosomes. Heterochromatin was allocated in terminal region of most chromosomes, plus a pericentromeric heterochromatic block in pair 1, a pair distinguished by size in relation to other chromosomes pairs. AgNORs were detected in only one submetacentric chromosome pair, which was confirmed by FISH. 5S rDNA was present in only one metacentric chromosome pair. Hybridization with [TTAGGG]n sequence marked the telomeres of all chromosomes, in addition to an ITS in the proximal region of the short arm of pair 1. The repetitive [GATA]n sequence was dispersed, with preferential location in terminal region of the chromosomes. Ageneiosus has a genomic organization somewhat different when compared to other Auchenipteridae species. Evidences indicate that a chromosomal fusion originated the first metacentric chromosome pair in A. inermis, rearrangement which may be a basal event for the genus Ageneiosus é o gênero da família Auchenipteridae mais amplamente distribuído em bacias da América do Sul. Apesar dos estudos cromossômicos nesta família serem escassos, este gênero tem o maior número de espécies analisadas, com número diploide variando de 54 a 56 cromossomos, o que difere do restante da família (2n = 58). Este estudo objetivou analisar Ageneiosus inermis da bacia do rio Araguaia. O número diploide encontrado foi de 56 cromossomos. A heterocromatina se mostrou localizada na região terminal da maioria dos cromossomos, além de um bloco heterocromático pericentromérico no par 1, um par facilmente distinguível no cariótipo pelo seu maior tamanho quando comparado aos outros pares do complemento. AgRONs foram detectadas em somente um par de cromossomos submetacêntricos, que foi confirmado pela FISH. 5S rDNA se mostrou presente em somente um par de cromossomos metacêntricos. A hibridização com a sequência [TTAGGG]n marcou os telômeros de todos os cromossomos, além de um ITS (sequência telomérica intersticial) na região proximal do braço curto do par 1. A sequência repetitiva [GATA]n se mostrou dispersa, com localização preferencial na região terminal dos cromossomos. Ageneiosus apresenta uma organização genômica um pouco diferente quando comparada a outras espécies de Auchenipteridae. As evidências indicam que uma fusão cromossômica originou o primeiro par de cromossomos metacêntricos de A. inermis, rearranjo que parece ser um evento basal para o gênero.