A new species of Raphidascaris (Nematoda: Raphidascarididae) infecting the fish Gymnogeophagus balzanii (Cichlidae) from the Pantanal wetlands, Brazil and a taxonomic update of the subgenera of Raphidascaris based on molecular phylogeny and morphology.

Raphidascaris (Sprentascaris) andersoni n. sp. (Nematoda: Raphidascarididae) collected in the intestine of the humphead cichlid Gymnogeophagus balzanii (Perugia) from the Pantanal wetlands, State of Mato Grosso do Sul (Brazil) is described and genetically characterized. The new species differs from its congeners mainly by having a conspicuous papilla-like formation slightly anterior to the cloacal aperture. Furthermore, males of R. (S.) lanfrediae and R. (S.) mahnerti have caudal alae, and R. (S.) hypostomi and R. (S.) pimelodi lack lateral alae, whereas in the new species caudal alae are absent and lateral alae present. The remaining congeners, namely, R. (S.) marano and R. (S.) saltaensis differ from Raphidascaris (Sprentascaris) andersoni n. sp. mainly because males have three pairs of postcloacal papillae (vs five pairs). In the phylogenetic reconstructions, using three nuclear genetic markers (18S, ITS1-5.8S-ITS2 and 28S rDNA) and one mitochondrial (cox1 mtDNA), the new species was separated from other representatives of Raphidascarididae, and the absence of monophyly in Hysterothylacium and Raphidascaroides was confirmed. Moreover, the subgenera Sprentascaris and Ichthyascaris appeared to be monophyletic. Therefore, even though Raphidascaris (Raphidascaris) was apparently not monophyletic, the subgenera of Raphidascaris should be re-erected as valid genera. The updated diagnoses of Ichthyascaris, Raphidascaris and Sprentascaris are given. The present study represents the first parasitological survey in G. balzanii.

Genetic Diversity of the Endangered Neotropical Cichlid Fish (Gymnogeophagus setequedas) in Brazil.

Gymnogeophagus setequedas is a rare and rheophilic species of tribe Geophagini, considered endangered in Brazilian red lists. Its previously known geographical distribution range was the Paraná River basin, in Paraguay, and a tributary of the Itaipu Reservoir in Brazil. Since its description no specimens have been collected in the original known distribution area. However, recent records of G. setequedas in the lower Iguaçu River, in a region considered highly endemic for the ichthyofauna, extended the known geographical distribution and may represent one of the last remnants of the species. The aim of this study was to estimate the genetic diversity and population structure of G. setequedas, using microsatellite markers and mitochondrial haplotypes, in order to test the hypothesis of low genetic diversity in this restricted population. Muscular tissue samples of 86 specimens were obtained from nine locations in the Lower Iguaçu River basin, between upstream of the Iguaçu Falls and downstream of the Salto Caxias Reservoir. Seven microsatellites loci were examined and a total of 120 different alleles were obtained. The number of alleles per locus (NA) was 17.429, effective alleles (NE) 6.644, expected heterozygosity (HE) 0.675, observed (HO) heterozygosity 0.592, and inbreeding coefficient (FIS) 0.128. Twelve haplotypes in the D-Loop region were revealed, with values of h (0.7642) and π (0.00729), suggesting a large and stable population with a long evolutionary history. Thus, both molecular markers revealed high levels of genetic diversity and indicated the occurrence of a single G. setequedas population distributed along a stretch of approximately 200 km. The pattern of mismatch distribution was multimodal, which is usually ascribed to populations in demographic equilibrium. Nevertheless, the construction of a new hydroelectric power plant, already underway between the Salto Caxias Reservoir and Iguaçu Falls, could fragment this population, causing loss of genetic diversity and population decline, and for this reason it is necessary to maintain the Iguaçu River tributaries and downstream area from the Lower Iguaçu Reservoir free of additional dams, to guarantee the survival of this species.

A new mouth brooder species of Gymnogeophagus with hypertrophied lips (Cichliformes: Cichlidae)

A new mouth breeder species of Gymnogeophagus is described from a tributary of the río Uruguay. It is distinguished from most species of the genus by the presence of hypertrophied lips, and from G. labiatus and G. pseudolabiatus by the color pattern. The presence of successive allopatric species of the Gymnogeophagus gymnogenys clade inhabiting the tributaries of the río Uruguay is discussed.(AU)

Una nueva especie incubadora bucal de Gymnogeophagus es descripta de un tributario del Río Uruguay. Se distingue de la mayoría de las especies del género por la presencia de labios hipertrofiados, y de G. labiatus y G. pseudolabiatus por su patrón de coloración. Se discute la presencia de sucesivas especies alopátricas del clado Gymnogeophagus gymnogenys habitando los tributarios del Río Uruguay.(AU)

A new mouth brooder species of Gymnogeophagus with hypertrophied lips (Cichliformes: Cichlidae)

A new mouth breeder species of Gymnogeophagus is described from a tributary of the río Uruguay. It is distinguished from most species of the genus by the presence of hypertrophied lips, and from G. labiatus and G. pseudolabiatus by the color pattern. The presence of successive allopatric species of the Gymnogeophagus gymnogenys clade inhabiting the tributaries of the río Uruguay is discussed.(AU)

Una nueva especie incubadora bucal de Gymnogeophagus es descripta de un tributario del Río Uruguay. Se distingue de la mayoría de las especies del género por la presencia de labios hipertrofiados, y de G. labiatus y G. pseudolabiatus por su patrón de coloración. Se discute la presencia de sucesivas especies alopátricas del clado Gymnogeophagus gymnogenys habitando los tributarios del Río Uruguay.(AU)

A new species of Gymnogeophagus Miranda Ribeiro from Uruguay (Teleostei: Cichliformes)

Describimos una nueva especie de Gymnogeophagus con incubación de sustrato, en base a caracteres cromáticos. La nueva especie puede ser diferenciada de las restantes especies del género por la exclusiva pigmentación de la aleta dorsal, la que consiste de bandas oblicuas de color celeste sobre fondo rojo en la porción espinosa y una combinación de manchas redondas, elípticas, o alargadas azul brillantes sobre fondo rojo en la porción blanda. Además puede ser distinguida de las otras especies de Gymnogeophagus por la siguiente combinación de caracteres: banda horizontal azul iridiscente situada por encima de la línea lateral superior discontinua en la región humeral, manchas azules brillantes redondeadas sobre fondo rojo anaranjado en la aleta anal, bandas horizontales azul brillante en el cuerpo conspicuas. La nueva especie habita una amplia gama de hábitats de agua dulce en el sector inferior de la cuenca del río Uruguay, los drenajes costeros del Río de la Plata y drenajes costeros del Océano Atlántico en Uruguay.(AU)

We describe a new species of a substrate-brooding Gymnogeophagus , based on coloration characters. The new species can be distinguished from the remaining substrate-brooding species in the genus by the unique pigmentation of the dorsal fin which consists of light blue, diagonal stripes over a red background in the spiny section and a combination of round, elliptic, and elongated bright blue spots over a red background in the soft section. It can be further distinguished from all other species of Gymnogeophagus by the following combination of characters: a discontinuous bright blue band above the upper lateral line in the humeral area, light blue roundish spots over a red to orange background on the anal fin, and conspicuous bright blue horizontal bands on body. The new species inhabits a wide range of freshwater habitats in the lower rio Uruguay basin, Rio de la Plata coastal drainages and Atlantic Ocean coastal drainages in Uruguay.(AU)

A new species of Gymnogeophagus Miranda Ribeiro from Uruguay (Teleostei: Cichliformes)

Describimos una nueva especie de Gymnogeophagus con incubación de sustrato, en base a caracteres cromáticos. La nueva especie puede ser diferenciada de las restantes especies del género por la exclusiva pigmentación de la aleta dorsal, la que consiste de bandas oblicuas de color celeste sobre fondo rojo en la porción espinosa y una combinación de manchas redondas, elípticas, o alargadas azul brillantes sobre fondo rojo en la porción blanda. Además puede ser distinguida de las otras especies de Gymnogeophagus por la siguiente combinación de caracteres: banda horizontal azul iridiscente situada por encima de la línea lateral superior discontinua en la región humeral, manchas azules brillantes redondeadas sobre fondo rojo anaranjado en la aleta anal, bandas horizontales azul brillante en el cuerpo conspicuas. La nueva especie habita una amplia gama de hábitats de agua dulce en el sector inferior de la cuenca del río Uruguay, los drenajes costeros del Río de la Plata y drenajes costeros del Océano Atlántico en Uruguay.

We describe a new species of a substrate-brooding Gymnogeophagus , based on coloration characters. The new species can be distinguished from the remaining substrate-brooding species in the genus by the unique pigmentation of the dorsal fin which consists of light blue, diagonal stripes over a red background in the spiny section and a combination of round, elliptic, and elongated bright blue spots over a red background in the soft section. It can be further distinguished from all other species of Gymnogeophagus by the following combination of characters: a discontinuous bright blue band above the upper lateral line in the humeral area, light blue roundish spots over a red to orange background on the anal fin, and conspicuous bright blue horizontal bands on body. The new species inhabits a wide range of freshwater habitats in the lower rio Uruguay basin, Rio de la Plata coastal drainages and Atlantic Ocean coastal drainages in Uruguay.

Descriptions of five new species of the Neotropical cichlid genus Gymnogeophagus Miranda Ribeiro, 1918 (Teleostei: Cichliformes) from the rio Uruguay drainage

Gymnogeophagus is a Neotropical cichlid genus distributed in the río Paraguay, rio Paraná and rio Uruguay drainages and also in the coastal rivers of Uruguay and southern Brazil. Its monophyly is supported by two derived features: the absence of supraneurals and the presence of a forward spine in the first dorsal-fin pterygiophore. Herein, five new species of Gymnogeophagus are described from middle to upper tributaries of the rio Uruguay drainage and from the rio Negro. All these new species belong to a clade, which includes G. gymnogenys , easily recognized by sharing two synapomorphies: the absence of an oblique bar between the dorsal border of the eye and the nape, and the possession of a black bar originating in the dorsal contour near the dorsal-fin origin and directed downward and backward on the dorsum. A key to all species of Gymnogeophagus is provided.(AU)

Gymnogeophagus é um gênero Neotropical de ciclídeos que ocorre nas drenagens dos rios Paraguay, Paraná e Uruguay e também em rios costeiros do Uruguay e do sul do Brasil. A monofilia do gênero é baseada em duas sinapomorfias: a ausência de supraneurais e a presença de um espinho dirigido para frente no primeiro pterigióforo da nadadeira dorsal. Neste trabalho são descritas cinco espécies novas de Gymnogeophagus de afluentes do médio ao alto rio Uruguai e rio Negro. Todas as espécies pertencem a um clado que inclui G. gymnogenys , facilmente reconhecido pelo compartilhamento de duas sinapomorfias: a ausência da barra cinza escura oblíqua entre a margem dorsal da órbita e a margem dorsal da cabeça, e a presença de uma barra cinza escura originando-se no dorso, anteriormente à nadadeira dorsal e direcionada para trás e para baixo na lateral do corpo. É fornecida uma chave de identificação para todas as espécies de Gymnogeophagus .(AU)

Descriptions of five new species of the neotropical cichlid genus Gymnogeophagus Miranda Ribeiro, 1918 (Teleostei: Cichliformes) from the rio Uruguay drainage

Gymnogeophagus is a Neotropical cichlid genus distributed in the río Paraguay, rio Paraná and rio Uruguay drainages and also in the coastal rivers of Uruguay and southern Brazil. Its monophyly is supported by two derived features: the absence of supraneurals and the presence of a forward spine in the first dorsal-fin pterygiophore. Herein, five new species of Gymnogeophagus are described from middle to upper tributaries of the rio Uruguay drainage and from the rio Negro. All these new species belong to a clade, which includes G. gymnogenys , easily recognized by sharing two synapomorphies: the absence of an oblique bar between the dorsal border of the eye and the nape, and the possession of a black bar originating in the dorsal contour near the dorsal-fin origin and directed downward and backward on the dorsum. A key to all species of Gymnogeophagus is provided.

Gymnogeophagus é um gênero Neotropical de ciclídeos que ocorre nas drenagens dos rios Paraguay, Paraná e Uruguay e também em rios costeiros do Uruguay e do sul do Brasil. A monofilia do gênero é baseada em duas sinapomorfias: a ausência de supraneurais e a presença de um espinho dirigido para frente no primeiro pterigióforo da nadadeira dorsal. Neste trabalho são descritas cinco espécies novas de Gymnogeophagus de afluentes do médio ao alto rio Uruguai e rio Negro. Todas as espécies pertencem a um clado que inclui G. gymnogenys , facilmente reconhecido pelo compartilhamento de duas sinapomorfias: a ausência da barra cinza escura oblíqua entre a margem dorsal da órbita e a margem dorsal da cabeça, e a presença de uma barra cinza escura originando-se no dorso, anteriormente à nadadeira dorsal e direcionada para trás e para baixo na lateral do corpo. É fornecida uma chave de identificação para todas as espécies de Gymnogeophagus.

Feeding of two Cichlidae species (Perciformes) in an hypertrophic urban lake

Diet of two cichlid species, Cichlasoma facetum (Jenyns, 1842), and Gymnogeophagus rhabdotus Hensel, 1870, was studied in Rodó Lake, an urban hypertrophic lake in Uruguay. The stomach contents from 192 individuals of C. facetum and 202 of G. rhabdotus, obtained through seasonal sampling in the year 2000, were analyzed. The occurrence frequency and the alimentary importance index of each food item were calculated for each season and size class in both species. Cichlasoma facetum fed upon insects (mainly chironomid larvae and pupae), fish (Cnesterodon decemmaculatus Jenyns, 1842), and vegetals (algae, periphyton and macrophytes debris); large individuals also fed upon the freshwater shrimp Palaemonetes argentinus Nobili, 1901. Gymnogeophagus rhabdotus consumed zooplankton (mainly copepods), vegetals (algae and detritus) and Chironomidae larvae in a lesser extent.

Feeding of two Cichlidae species (Perciformes) in an hypertrophic urban lake

Diet of two cichlid species, Cichlasoma facetum (Jenyns, 1842), and Gymnogeophagus rhabdotus Hensel, 1870, was studied in Rodó Lake, an urban hypertrophic lake in Uruguay. The stomach contents from 192 individuals of C. facetum and 202 of G. rhabdotus, obtained through seasonal sampling in the year 2000, were analyzed. The occurrence frequency and the alimentary importance index of each food item were calculated for each season and size class in both species. Cichlasoma facetum fed upon insects (mainly chironomid larvae and pupae), fish (Cnesterodon decemmaculatus Jenyns, 1842), and vegetals (algae, periphyton and macrophytes debris); large individuals also fed upon the freshwater shrimp Palaemonetes argentinus Nobili, 1901. Gymnogeophagus rhabdotus consumed zooplankton (mainly copepods), vegetals (algae and detritus) and Chironomidae larvae in a lesser extent.