This study provides the first investigation on acquisition of parasites in invasive O. niloticus by parasite species of native Cichlidae from the Igarapé Fortaleza basin, Northern Brazil. There were examined 576 specimens of 16 species of native cichlids and invasive O. niloticus collected in the main channel and the floodplain area of this tributary of Amazon River. The invasive O. niloticus was poorly parasitized having only Ichthyophthirius multifiliis, Trichodina centrostrigeata, Paratrichodina africana, Trichodina nobilis (Protozoa) and Cichlidogyrus tilapiae (Monogenoidea), and this host has not acquired any parasite species common to the native ichthyofauna region. In contrast, species of native cichlids showed rich fauna of parasites with predominance of Monogenoidea species, larvae and adults of Nematoda, Digenea, Cestoidea and Acanthocephala, besides four species of Protozoa and four Crustacea. However, only T. nobilis was acquired by native fish, the Aequidens tetramerus, which is a new host for this exotic Trichodinidae. In O. niloticus, well established in the region, the small number of helminth species may be associated with its rusticity, good adaptation in the new environment and also the presence of native parasites with relative specificity, but without ability to complete its life cycle in this invasive host of this ecosystem.Keywords: Colonization, biological invasion, fish parasites. ResumoEste estudo é a primeira investigação da aquisição de parasitos na invasora O. niloticus por espécies de parasitos Cichlidae nativos da bacia Igarapé Fortaleza, Norte do Brasil. Foram examinados 576 espécimes pertencentes a 16 espécies de ciclídeos nativos e à invasora O. niloticus coletados no canal principal e área da planície de inundação deste tributário do Rio Amazonas. A invasora O. niloticus foi pobremente parasitada, pois teve somente Ichthyophthirius multifiliis, Trichodina centrostrigeata, Paratrichodina africana e Trichodina nobilis (Protozoa) e Cichlidogyrus tilapiae (Monogenoidea) e não adquiriu qualquer espécie comum à ictiofauna nativa da região. Em contraste, as espécies de ciclídeos nativos apresentaram uma rica fauna de parasitos com predominância de espécies de helmintos Monogenoidea, larvas e adultos de Nematoda, Digenea, Cestoidea e Acanthocephala, além de quatro espécies de Protozoa e quatro Crustacea. Porém, somente T. nobilis foi encontrado em peixe nativo, Aequidens tetramerus, que é um novo hospedeiro para esse Trichodinidae exótico. Em O. niloticus, já bem estabelecida na região, o reduzido número de espécies de helmintos pode estar associado à sua rusticidade, boa adaptação ao novo ambiente e também à presença de parasitos nativos com relativa especificidade, mas sem habilidade em completar seu ciclo de vida nesse hospedeiro invasor desse ecossistema.Palavras-chave: Colonização, invasão biológica, parasitos de peixes.

No abstract

This study presents results from several expeditions in 1985, 1991-1995 and 2003 to the Medium Paraná River in the section that begins below the Itaipu Dam and ends at the trinational border of Brazil, Argentina and Paraguay, in the lotic and lentic zones of the reservoir of the Hydroelectric Power Station of “Itaipu Binacional” (localities Foz do Iguaçu, Santa Helena and Guaira). Ninety-eight species of freshwater fishes belonging to 22 families were examined for helminths. A host-parasite list based on Acanthocephala, Cestoda, Digenea, Monogenea and Nematoda collected from the region in question is provided. New host records are presented for Digenea and Nematoda. The Monogenea and Acanthocephala are being studied and will be published in a later paper, but are referred in the host-parasite list, in order to demonstrate the parasitism in the fishes of the reservoir. The results are compared with those presented by other authors from the Upper Paraná River.

Twelve species of parasitic helminths, seven trematodes, four nematodes and one acanthocephalan are reported from various hosts. Creptotrema lynchi, a parasite from Bufo marinus in Colombia, is described for the first time in fish and from Brazil, parasitizing two different species. A list of the host species, measurements and figures of most parasites are included with particular reference to the tegument of Bellumcorpus major recovered from a new host. The genus Zonocotyloides Padilha, 1978 is considered a synonym of Zonocotyle and the new combination: Zonocotyle haroltravassosi is proposed to the species Zonocotyloides haroltravassosi Padilha, 1978. The nematodes Cucullanus pinnai and Procamallanus (Spirocamallanus) inopinatus and the trematode Pararhipidocotyle jeffersoni are reported in new hosts. The description of the acanthocephalan Neoechinorhynchus curemais (new locality record) is supplemented. Other parasites recovered include the nematodes Travnema travnema (new locality record), Rondonia rondoni and the digenetic trematodes Cladocystis intestinalis, Pseudosellacotyla lutzi (new locality record), Teratotrema sp. and Zonocotyle bicaecata.
No presente trabalho são apresentados sete trematódeos, quatro nematóides e um acantocéfalo parasitas de diferentes espécies de peixes do rio Mogi-Guassu. Creptotrema lynchi, tramatódeo descrito originalmente de anfíblio (Bufo marinus) na Colômbia, é referido pela primeira vez em peixes e no Brasil. Bellumcorpus major é assinalado em um novo hospedeiro e são apresentados novos dados morfológicos referentes ao tegumento. O gênero Zonocotyloides Padilha, 1978 é considerado sinônimo de Zonocotyle Travassos, 1948 e é proposta uma nova combinação para a espécieZonocotyloides haroltravassosi Padilha, 1978. Os nematóides Cucullanus pinnai e Procamallanus (Spirocamallanus) inopinatus e o trematódeo Pararhipidocotyle jeffersoni são assinalados em novos hospedeiros. O acantocéfalo Neoechinorhynchus curemai é redescrito de nova localidade. São também registrados nematóides Travnema travnema (referido em nova localidade) e Rondonia rondoni; e os trematódeos Cladocystis intestinalis, Pseudosellacotyla lutzi (em nova localidade), Teratotrema sp. e Zonocotyle bicaecata

This paper concerns the parasitism of Nematoda, Trematoda, Acanthocephala and Cestoda from 1027 fishes of 45 species from Mogi Guassu river, examined in the years 1927, 1946, 1947, 1962, 1983 and 1985 as a contribution to the knowledge of the parasitological fauna in 58 years. Thirty two species of nematodes, 21 of trematodes, 3 of acanthocephalans and 2 of cestodes are reported. New hosts are presented for the nematodes Cucullanus pinnai, Spirocamallanus inopinatus and Travnema travnema, for the trematode Pararhipidocotyle jeffersoni and for the acanthocephalan Gorytocephalus spectabilis. New measurements for the trematode Creptotrema lynchy, tables, graphics and a list of the examined hosts with their parasites are presented.

Rhipidocotyle pentagonum (Ozaki, 1924) is reported for the first time in South America parasitizing Auxis thazard and in a new host Katsuwonus pelamis. Tergestia laticollis (Rudolphi, 1819) is reported for the first time in South America and in Thunnus albacares, representing a new host record. Copiatestes filiferus (Leuckart, in Sars, 1885) is recorded for the first time in Brazil and in Thunnus albacares, another new host record. Tetrochetus coryphaenae (Yamaguti, 1934) is presented for the first time in Brazil parasitizing Thunnus albacares.

Fifty four specimens of marine fish belonging to seven species collected from the coast of the State of Rio de Janeiro, Brazil were examined for helminths, and results relating to Monogenea and Digenea are presented. The monogeneans Metamicrocotyla macracantha, Microcotyle pomatomi and Gotocotyla acanthura are reported in new hosts. The digeneans Parahemiurus merus, Lecithochirium microstomum, Gonocercella pacifica, Aponurus laguncula, Gonocerca trematomi and Lampritrema miescheri are reported in new hosts, and the latter two species are also reported for the first time in Brazil.Keywords: Monogenea, Digenea, Brazil, marine fish. ResumoCinquenta e quatro espécimens de peixes marinhos pertencentes a sete espécies coletados do litoral do estado do Rio de Janeiro, Brasil foram examinados para helmintos, os resultados referentes a Monogenea e Digenea são apresentados. Os monogenéticos Metamicrocotyla macracantha, Microcotyle pomatomi e Gotocotyla acanthura são apresentados em novos hospedeiros. Os digenéticos Parahemiurus merus, Lecithochirium microstomum, Gonocercella pacifica, Aponurus laguncula, Gonocerca trematomi e Lampritrema miescheri são registrados em novos hospedeiros, as duas últimas espécies são também registradas pela primeira vez no Brasil.

ABSTRACT. Digcnca (Trcmaloda)