Clinostomum complanatum (Digenea, Clinostomidae) density in Rhamdia quelen (Siluriformes, Pimelodidae) from South Brazil

The density of Clinostomum complanatum metacercariae by the body regions and among the size classes of Rhamdia quelen was compared. The host size classes were defined by cluster analysis, using weight and total length as attributes. These values were related with environmental characteristics and host biological data. In all the host size classes H and PeF, CF and PF, and P and AF regions pairs, showed similar density (tested by X² test). The hosts with 30-36 cm showed largest parasite density in all the regions, except in CAV. Fishes smaller than 11 cm did not show significant differences of parasite density in all body regions. In the other classes, H was the most infected region, followed by PeF. The results suggested that the environmental conditions had little importance on the host colonization by metacercariae.A densidade de metacercárias de Clinostomum complanatum por regiões do corpo entre classes de comprimento de Rhamdia quelen foram comparadas. As classes de comprimento do hospedeiro foram definidas por analises de agrupamentos usando peso e comprimento total como atributos. Estes valores foram relacionados com características do ambiente e dados biológicos disponíveis sobre o hospedeiro. O dendrograma com sete agrupamentos foi o escolhido. O corpo do hospedeiro foi dividido em nove regiões para as necropsias: Cabeça (H); Nadadeiras, Peitoral (PeF); Dorsal (DF); Adiposa (AdF); Caudal (CF); Anal (AF) e Pélvica (PF); Pedúnculo caudal (P); Cavidade Abdominal (CAV). Em todas as classes de comprimento do hospedeiro os pares de regiões H e PeF, CF e PF e P e AF mostraram densidades similares (teste do X²). Hospedeiros com 30-36 cm mostram maior densidade de parasitas em todas as regiões exceto na CAV. Peixes com menos de 11 cm não mostram diferenças significativas na densidade de parasitas nas regiões do corpo. Nas demais classes, H é a região mais infectada, seguida por PeF. Os resultados sugerem que as variáveis ambientais têm pouca importância sobre o processo de colonização por metacercárias

<b>Observations on the Infection by <i>Kudoa</i> sp. (Myxozoa, Multivalvulida) in fishes caught off Rio Grande, Rio Grande do Sul State, Brazil

It is reported the parasitization of Kudoa sp. (Myxozoa, Multivalvulida) within the somatic muscles of the fish Odontesthes bonariensis (Valenciennes, 1835), Micropogonias furnieri (Desmarest, 1823) and Mugil liza Valenciennes, 1836, captured off Rio Grande, Rio Grande do Sul State, Brazil. Other species of fish caught at the same place were not infected. The parasites formed elongated plasmodia inside the muscle fibres. Myoliquefaction or any host tissue reaction were not observed. The morphological and morphometric features of the spores are described, the parasites are compared with other Kudoa species, and the importance of the infection is discussed

Moderate pathogenic effect of Ligophorus uruguayense (Monogenoidea, Ancyrocephalidae) in juvenile mullet Mugil liza (Actinopterygii, Mugilidae) from Brazil

ABSTRACT Monogenoidea pathogenic activity can elicit various histological responses in fish. Species of Ligophorus are specific parasites of mullets, and its relationship with host fish may result in a moderate pathogenic action. In order to ascertain this relationship, estuarine mullets (Mugil liza) were collected in an estuary, reared in laboratory, for three weeks, and forwarded for histological and parasitological analyses. Ligophorus uruguayense (Monogenoidea) infestation in the gills of the mullets was identified. The severe infestation by only one species of Monogenoidea may result from the specificity of these parasites to mullets. Mullets submitted to histological analysis exhibited respiratory epithelium detachment; mild, moderate and severe hyperplasia of the respiratory epithelium; atrophy; and telangiectasia of the gills. This is the first study reporting that mullets highly infested by Monogenoidea can show mild (100%) to severe (20%) gill changes with a distinct frequency of occurrence. Because of the high prevalence of mild alterations observed, it is possible to accept that L. uruguayense is moderately pathogenic to M. liza, even during high prevalence and intensity of infestation, as a result of its specificity

Kroyeria brasiliense sp. nov. (Copepoda, Kroyeriidae)a gill parasite of the shark, Galeorhinus vitaminicus de Buen, in Rio Grande do Sul State, Brazil

Kroyeria brasiliense sp. nov. from the shark, Galeorhinus vitaminicus de Buen, 1950, from Rio Grande do Sul, State, Brazil, is described on the basis of 14 adult females. The new species is superficially similar to Kroyeria deetsi Dippenaar, Benz & Olivier, 2000, but differs from it in the following characters. The maxillipeds of the new species are large and project well beyond the lateral margins of the cephalothorax. Those of K. deetsi are much smaller. The third endopodal segments of K. deetsi are twice as long as the second endopodal segments and are provided with prominent marginal denticles. The second and third endopodal segments of the new species are rounded, of similar length and lack teeth.Kroyeria brasiliense sp. nov. proveniente de guelras de G. vitaminicus de Buen, 1950 do Rio Grande do Sul, é descrita baseada em 14 fêmeas adultas. A nova espécie aproxima-se de Kroyeria deetsi Dippenaar, Benz & Oliver, 2000, mas a nova espécie se distingue por apresentar os maxilípedes grandes e estendendo-se bem além das margens do cefalotorax. Os terceiros segmentos dos endopoditos de K. deetsi são duas vezes mais cumpridos que os segundos e têm dentículos marginais proeminentes. Os segundos e terceiros segmentos dos endopoditos da nova espécie são arredondados, de tamanhos parecidos e carecem de dentículos

Brasilochondria riograndensis gen. nov., sp. nov. (Copepoda, Chondracanthidae) a parasite of flounders of Rio Grande do Sul State, Brazil

Brasilochondria riograndensis gen. nov., sp. nov. (Copepoda, Chondracanthidae) a parasite of the flounder, Paralichthys orbignyanus (Valenciennes, 1839), is described. The new genus has a spherical head a post-mandibular "neck" and two pairs of modified biramous legs. In these respects, it resembles Argentinochondria patagonensis Etchegoin, Timi & Sardella, 2003. In the Argentine genus, however, the bulbous head has a medial constriction and the posterior of the female lacks the lateral extensions that are present in the new genus. Pseudolernentoma brasiliensis Luque & Alves, 2003, also resembles the new genus but it lacks the lateral extensions of the trunk and the latter is cylindrical rather than flat. The second leg of the new genus is small and the endopod is shorter than the exopod. The other two genera have large second legs with subequal rami.<br>Brasilochondria riograndensis gen. nov., sp. nov. (Copepoda, Chondracanthidae), um parasito do linguado, Paralichthys orbignyanus (Valenciennes, 1839), é descrito. O novo gênero tem uma cabeça esférica, um "pescoço" pós-mandíbular e dois pares de pernas que são birremes e modificados na fêmea. Nestes aspectos, ela parece com Argentinochondria patagonensis Etchegoin, Timi & Sardella, 2003. Nesta, no entanto, a cabeça é esférica com uma constrição medial e na parte posterior do tronco faltam as extensões póstero-laterais que o novo gênero possui. Pseudolernentoma brasiliensis Luque & Alves, 2003, é também parecido com o novo gênero, mas carece das extensões póstero-laterais e o mesmo tronco é cilíndrico em vez de achatado. A segunda perna no novo gênero é pequena e o endopodito é mais curto que o exopodito. Nos outros dois gêneros, as segundas pernas são grandes e os ramos são sub-iguais

Metazoan parasites of Geophagus brasiliensis (Perciformes: Cichlidae) in Patos lagoon, extreme south of Brazil

Abstract This study has evaluated the parasitic fauna of 79 pearl cichlids (Geophagus brasiliensis) from the estuary of Patos Lagoon (31° 57' S and 52° 06' W), Rio Grande do Sul, Brazil, during the months of May and June in 2011 and 2012. All the hosts analyzed were infected with at least one species of parasite. A total of eleven metazoa were identified in 459 specimens collected. The trematode Austrodiplostomum compactum (34.2%) and ergasilids Ergasilus lizae (32.9%) and Gauchergasilus lizae (32.9%) were the most prevalent species. The trematodes Thometrema overstreeti and Posthodiplostomum sp. had significantly higher prevalence in fish longer than 20 cm. The sex of the host had no effect on parasite prevalence and abundance. Pearl cichlids are registered as a new host for the trematodes Lobatostoma sp., Homalometron pseudopallidum and Thometrema overstreeti, for the ergasilids Ergasilus lizae and Gauchergasilus euripedesi and for the argulid Argulus spinolosus. The crustacean E. lizae is recorded in Rio Grande do Sul for the first time