Resumo
ABSTRACT The aim of this study was to describe the testisac microanatomy and spermatogenesis of Helobdella simplex (Moore, 1911). The leeches were collected in the Sauce Chico River (Tornquist) during April 2012. The collection of material was carried out manually by checking rocks, logs, leaves and artificial substrates in the river bed. Helobdella simplex has six pairs of testisacs located between the gastric caeca. The testisac wall has two structurally and functionally differentiated cell types: the lining mesothelial cells and the germline cells. The lining cells are flat and form a continuous layer. In H. simplex no ciliated cells were observed into the testisacs, nor the formation of spermatogonia due to detachment of the testicular wall. Cell types were microscopically characterized, and five spermatogenesis stages are described, taking into account the maturation of germinal cells, the morphological changes in the cytophore and phagocytic activity. Testicular phagocytes actively participate during spermatogenesis. They are involved both in the removal of defective cells during the early stages of spermatogenesis and in the removal of the cytophore during the reacting reabsorption. Our study adds the knowledge of spermatogenesis in H. simplex and might be useful to differentiate the stages of development during the reproductive cycle, and to interpret aspects of its population dynamics.
Resumo
The aim of this study was to describe the testisac microanatomy and spermatogenesis of Helobdella simplex (Moore, 1911). The leeches were collected in the Sauce Chico River (Tornquist) during April 2012. The collection of material was carried out manually by checking rocks, logs, leaves and artificial substrates in the river bed. Helobdella simplex has six pairs of testisacs located between the gastric caeca. The testisac wall has two structurally and functionally differentiated cell types: the lining mesothelial cells and the germline cells. The lining cells are flat and form a continuous layer. In H. simplex no ciliated cells were observed into the testisacs, nor the formation of spermatogonia due to detachment of the testicular wall. Cell types were microscopically characterized, and five spermatogenesis stages are described, taking into account the maturation of germinal cells, the morphological changes in the cytophore and phagocytic activity. Testicular phagocytes actively participate during spermatogenesis. They are involved both in the removal of defective cells during the early stages of spermatogenesis and in the removal of the cytophore during the reacting reabsorption. Our study adds the knowledge of spermatogenesis in H. simplex and might be useful to differentiate the stages of development during the reproductive cycle, and to interpret aspects of its population dynamics.(AU)
Assuntos
Animais , Espermatogênese , Sanguessugas/anatomia & histologiaResumo
The aim of this study was to describe the testisac microanatomy and spermatogenesis of Helobdella simplex (Moore, 1911). The leeches were collected in the Sauce Chico River (Tornquist) during April 2012. The collection of material was carried out manually by checking rocks, logs, leaves and artificial substrates in the river bed. Helobdella simplex has six pairs of testisacs located between the gastric caeca. The testisac wall has two structurally and functionally differentiated cell types: the lining mesothelial cells and the germline cells. The lining cells are flat and form a continuous layer. In H. simplex no ciliated cells were observed into the testisacs, nor the formation of spermatogonia due to detachment of the testicular wall. Cell types were microscopically characterized, and five spermatogenesis stages are described, taking into account the maturation of germinal cells, the morphological changes in the cytophore and phagocytic activity. Testicular phagocytes actively participate during spermatogenesis. They are involved both in the removal of defective cells during the early stages of spermatogenesis and in the removal of the cytophore during the reacting reabsorption. Our study adds the knowledge of spermatogenesis in H. simplex and might be useful to differentiate the stages of development during the reproductive cycle, and to interpret aspects of its population dynamics.(AU)
Assuntos
Animais , Masculino , Espermatogênese , Gônadas/anatomia & histologia , SanguessugasResumo
Temporal (May 2005 to February 2006) and habitat distribution (pools and riffles) of Hirudinea species was analyzed at a post urban reach from Esquel stream (Chubut province, Patagonia, Argentina). Site was located 5.7 km downstream a Waste Treatment Plant. Mean values of nutrients: ammonia, nitrates and soluble reactive phosphate, as well water conductivity, turbidity and total suspended solids indicated physical and organic pollution. Leeches assemblage was composed by the glossiphonids: Helobdella scutifera Blanchard, 1900, H. michaelseni (Blanchard, 1900), H. simplex (Moore, 1911), Helobdella sp., H. hyalina Ringuelet, 1942, H. obscura Ringuelet, 1942 and the semiscolecid Patagoniobdella variabilis (Blanchard, 1900). From these H. hyalina and H. obscura are new records for Chubut province. Helobdella hyalina (810 ind.m-2) and H. simplex (465 ind. m-2) clearly dominated the assemblage at the reach. Only H. simplex displayed a spatial preference being significantly more abundant in pools than in riffle habitats (p<0.001). Species recruitment occurred mostly at September, December and March when juveniles were very abundant. Although several species of Helobdella were able to live in the disturbed section of the stream, only H. simplex and H. hyalina sustained large populations at the site and can be considered as tolerant to organic enrichment. This information is valuable to future studies on stream condition assessment in mountainous areas in Patagonia, and in other areas in which these species are present.(AU)
Se analizó la distribución temporal (mayo 2005 a febrero 2006) y espacial (pozones y rápidos) de las especies de hirudíneos en un segmento post urbano del arroyo Esquel (provincia de Chubut, Patagonia, Argentina). El sitio está localizado a 5,7 km aguas abajo de la planta de tratamiento de efluentes cloacales. Los valores promedio de nutrientes: amonio, nitratos y fósforo reactivo soluble, así como la conductividad del agua, turbidez y el total de sólidos suspendidos indican contaminación física y orgánica. Las especies de hirudíneos halladas fueron Glossiphoniidae: Helobdella scutifera Blanchard, 1900, H. michaelseni (Blanchard, 1900), H. simplex (Moore, 1911), Helobdella sp., H. hyalina Ringuelet, 1942 and H. obscura Ringuelet, 1942 y Semiscolecidae: Patagoniobdella variabilis (Blanchard, 1900). Helobdella hyalina and H. obscura representan nuevos registros para la provincia de Chubut. Helobdella hyalina (810 ind. m-2) y H. simplex (465 ind. m-2) fueron las especies claramente dominantes. Sólo H. simplex presentó una preferencia espacial siendo significativamente más abundante en los pozones que en los rápidos (p<0.001). El reclutamiento de las especies se observó principalmente en septiembre, diciembre y mayo donde los juveniles fueron muy abundantes. Aunque varias especies de Helobdella se registraron en este sector contaminado del arroyo, sólo H. simplex and H. hyalina presentaron poblaciones importantes y pueden ser consideradas como tolerantes al enriquecimiento orgánico. Esta información es de valor para futuros estudios sobre evaluación de calidad de los arroyos en áreas montañosas de la Patagonia y para otros donde estas especies están presentes.(AU)
Assuntos
Animais , Poluição Ambiental/métodos , Urbanização , Nutrientes/análise , Sanguessugas/classificaçãoResumo
Temporal (May 2005 to February 2006) and habitat distribution (pools and riffles) of Hirudinea species was analyzed at a post urban reach from Esquel stream (Chubut province, Patagonia, Argentina). Site was located 5.7 km downstream a Waste Treatment Plant. Mean values of nutrients: ammonia, nitrates and soluble reactive phosphate, as well water conductivity, turbidity and total suspended solids indicated physical and organic pollution. Leeches assemblage was composed by the glossiphonids: Helobdella scutifera Blanchard, 1900, H. michaelseni (Blanchard, 1900), H. simplex (Moore, 1911), Helobdella sp., H. hyalina Ringuelet, 1942, H. obscura Ringuelet, 1942 and the semiscolecid Patagoniobdella variabilis (Blanchard, 1900). From these H. hyalina and H. obscura are new records for Chubut province. Helobdella hyalina (810 ind.m-2) and H. simplex (465 ind. m-2) clearly dominated the assemblage at the reach. Only H. simplex displayed a spatial preference being significantly more abundant in pools than in riffle habitats (p<0.001). Species recruitment occurred mostly at September, December and March when juveniles were very abundant. Although several species of Helobdella were able to live in the disturbed section of the stream, only H. simplex and H. hyalina sustained large populations at the site and can be considered as tolerant to organic enrichment. This information is valuable to future studies on stream condition assessment in mountainous areas in Patagonia, and in other areas in which these species are present.
Se analizó la distribución temporal (mayo 2005 a febrero 2006) y espacial (pozones y rápidos) de las especies de hirudíneos en un segmento post urbano del arroyo Esquel (provincia de Chubut, Patagonia, Argentina). El sitio está localizado a 5,7 km aguas abajo de la planta de tratamiento de efluentes cloacales. Los valores promedio de nutrientes: amonio, nitratos y fósforo reactivo soluble, así como la conductividad del agua, turbidez y el total de sólidos suspendidos indican contaminación física y orgánica. Las especies de hirudíneos halladas fueron Glossiphoniidae: Helobdella scutifera Blanchard, 1900, H. michaelseni (Blanchard, 1900), H. simplex (Moore, 1911), Helobdella sp., H. hyalina Ringuelet, 1942 and H. obscura Ringuelet, 1942 y Semiscolecidae: Patagoniobdella variabilis (Blanchard, 1900). Helobdella hyalina and H. obscura representan nuevos registros para la provincia de Chubut. Helobdella hyalina (810 ind. m-2) y H. simplex (465 ind. m-2) fueron las especies claramente dominantes. Sólo H. simplex presentó una preferencia espacial siendo significativamente más abundante en los pozones que en los rápidos (p<0.001). El reclutamiento de las especies se observó principalmente en septiembre, diciembre y mayo donde los juveniles fueron muy abundantes. Aunque varias especies de Helobdella se registraron en este sector contaminado del arroyo, sólo H. simplex and H. hyalina presentaron poblaciones importantes y pueden ser consideradas como tolerantes al enriquecimiento orgánico. Esta información es de valor para futuros estudios sobre evaluación de calidad de los arroyos en áreas montañosas de la Patagonia y para otros donde estas especies están presentes.
Assuntos
Animais , Nutrientes/análise , Poluição Ambiental/métodos , Urbanização , Sanguessugas/classificaçãoResumo
The Island of Martin Garcia lies at the confluence of the Uruguay and Paraná Rivers (upper Río de la Plata). This island is an outcrop of the crystalline basement. Due to basalt exploitation the island exhibits several ponds covered by carpets of free-floating macrophytes. Seven major environmental variables were measured: water and air temperature, percentage of oxygen saturation, dissolved oxygen, electrical conductivity, total dissolved solids and pH. Eleven leech species were found, Helobdella striata, H. diploides, H. adiastola and H. hyalina were new records. UPGMA clustering of species based on their occurrence in different ecological conditions revealed three main species groups. Canonical Correspondence Analysis (CCA) explained 97.2% of the correlation between species and environmental variables. H. triserialis shows the widest range of tolerance, H. hyalina shows positive relationships to conductivity; H. diploides shows a high correlation with dissolved oxygen, H. striata, H. lineata, and S. similis are negatively correlated with water temperature, and H. simplex is positively correlated with pH. Relationships between the species richness (S) and the sampling sites were negatively correlated with water temperature and positively correlated with dissolved oxygen. Leech biodiversity from the water bodies of Martín García Island, shows a great diversity of species and a wide plasticity regarding the characteristics of the environmental factors considered.
A Ilha Martín García encontra-se na afluência dos Rios Uruguay e Paraná (no Rio de la Plata superior) e constitui um afloramento do maciço cristalino de Brasília. Por causa da exploração do basalto, formaram-se lacunas que apresentam tapetes de vegetação flutuantes e macrófitas enraizadas. Mediram-se sete variáveis físico-químicas da água: temperatura do ar e da água, porcentagem de saturação de oxigênio, oxigênio dissolvido, condutividade elétrica, sólidos totais dissolvidos e pH. Encontraram-se onze espécies de sanguessuga, como Helobdella striata, H. diploides, H. adiastola e H. hyalina que constituem novos registros para a ilha. A análise de agrupamento baseado na ocorrência das espécies em condições ecológicas diferentes revelou três grupos principais. A análise canônica da correspondência sugere que a distribuição das espécies relaciona-se às variáveis ambientais consideradas, 97,2% da correlação entre as espécies e as variáveis se distribui no eixo dois do diagrama de ordenamento. As variáveis com maior flutuação foram a condutividade e o pH. H. triserialis foi a espécie mais tolerante às variáveis ambientais; H. hyalina se relacionou positivamente com a condutividade; H. diploides teve alta correlação com o oxigênio dissolvido; H. striata, H. lineata e Semiscolex similis relacionaram-se negativamente com a temperatura da água e H. simplex, positivamente com o pH. As relações entre a riqueza de espécies (S) e os lugares de amostras foram negativas com a temperatura da água e positivas com o oxigênio dissolvido. Os corpos da água da Ilha Martín García mostram uma grande biodiversidade de espécies de sanguessuga, assim como uma ampla ductilidade com relação aos fatores ambientais considerados.
Resumo
Sixty specimens of Pimelodus maculatus from the Guandu River in Rio de Janeiro State were examined to describe their parasitofauna, in the period from August 1999 to February 2001. Specimens of twelve metazoan parasite species were collected, allocated into seven taxonomic groups - Monogenoidea: Demidospermus uncusvalidus Gutiérez and Suriano, 1992, D. paravalenciennesi Gutiérez and Suriano, 1992, D. majusculus Kritsky and Gutiérez, 1998 and Scleroductus sp.; Digenea: Austrodiplostomum compactum (Lutz, 1928); Eucestoda: Nomimoscolex sp.; Nematoda: Cucullanus pinnai Travassos, Artigas and Pereira, 1928 and Procamallanus sp. (young specimen); Hirudinea: Helobdella sp.; Myxozoa: Henneguya sp. and Myxobolus absonus Cellere, Cordeiro and Adriano, 2002, along with one unidentified species of Acanthocephala (cystacanth). There was a correlation between the host sex and the prevalence and abundance of D. paravalenciennesi. The most dominant species in the parasite community of P. maculatus from the Guandu River was D. uncusvalidus (50%), followed by C. pinnai (18,3%). This study is the first report of D. majusculus and Henneguya sp. in P. maculatus, while it expands the known geographic distribution of D. uncusvalidus, D. paravalenciennesi, D. majusculus, Scleroductus sp., Nomimoscolex sp., C. pinnai, Procamallanus sp., Helobdella sp., Henneguya sp. and M. absonus.
Sessenta espéimes de Pimelodus maculatus provenientes do rio Guandu, Estado do Rio de janeiro, foram examinados para estudo de sua parasitofauna, no perído de agosto de 1999 a fevereiro de 2001. Foram coletados espéimes de doze espécies de parasitos metazoários alocados em sete grupos taxonômicos - Monogenoidea: Demidospermus uncusvalidus Gutiérez and Suriano, 1992, D. paravalenciennesi Gutiérez and Suriano, 1992, D. majusculus Kritsky and Gutiérez, 1998 e Scleroductus sp.; Digenea: Austrodiplostomum compactum (Lutz, 1928); Eucestoda: Nomimoscolex sp.; Nematoda: Cucullanus pinnai Travassos, Artigas and Pereira, 1928 e Procamallanus sp. (jovem); Hirudinea: Helobdella sp.; Myxozoa: Henneguya sp. e Myxobolus absonus Cellere, Cordeiro e Adriano, 2002, al de uma espie de Acanthocephala (cistacanto) não identificada. Houve correlação entre o sexo do hospedeiro com a prevalcia e com a abundâcia de D. paravalenciennesi. A espéie mais dominante na comunidade parasitáia de P. maculatus do rio Guandu foi D. uncusvalidus (50%), seguida de C. pinnai (18,3%). Demidospermus majusculus e Henneguya sp. constituem primeiro registro em P. maculatus. Demidospermus uncusvalidus, D. paravalenciennesi, D. majusculus, Scleroductus sp., Nomimoscolex sp., C. pinnai, Procamallanus sp., Helobdella sp., Henneguya sp. e M. absonus apresentam ampliada sua distribuio geogrica conhecida.
Resumo
A detailed preliminary histological analysis of Helobdella hyalina Ringuelet, 1942 male system from Los Talas, Buenos Aires, Argentina is described. Six pairs of testisacs, located between the crop caeca, form the male reproductive system. Each testisac is clothed by the mesotelium. Inside it, the germinal cells are connected to the citophore and develop functional unit called poliplast. The spermatozoa are released into testisacs after the reabsortion of the citophore. Five stages of spermatogenesis are described taking into account the successive maturation stages of germinal cells and the changes in the citophore size. Lining cells and gland cells were found in the seminal vesicle. Five different types of gland cells are placed inside the ejaculatory ducts, as well as two kinds of cells are found in its distal portion: type 1, which produces eosinophilic granular secretion, type 2, with amorphous and slightly eosinophilic. Three distinct gland cells are located in the proximal portion of the duct: type 3, which produces a strongly eosinophilic granular secretion; type 4, with a negative eosinophilic amorphous secretion and type 5, with a basophilic granular secretion. Type 5 gland cells are described for the ducts of this species only.
Resumo
A detailed preliminary histological analysis of Helobdella hyalina Ringuelet, 1942 male system from Los Talas, Buenos Aires, Argentina is described. Six pairs of testisacs, located between the crop caeca, form the male reproductive system. Each testisac is clothed by the mesotelium. Inside it, the germinal cells are connected to the citophore and develop functional unit called poliplast. The spermatozoa are released into testisacs after the reabsortion of the citophore. Five stages of spermatogenesis are described taking into account the successive maturation stages of germinal cells and the changes in the citophore size. Lining cells and gland cells were found in the seminal vesicle. Five different types of gland cells are placed inside the ejaculatory ducts, as well as two kinds of cells are found in its distal portion: type 1, which produces eosinophilic granular secretion, type 2, with amorphous and slightly eosinophilic. Three distinct gland cells are located in the proximal portion of the duct: type 3, which produces a strongly eosinophilic granular secretion; type 4, with a negative eosinophilic amorphous secretion and type 5, with a basophilic granular secretion. Type 5 gland cells are described for the ducts of this species only.
Resumo
A detailed preliminary histological analysis of Helobdella hyalina Ringuelet, 1942 male system from Los Talas, Buenos Aires, Argentina is described. Six pairs of testisacs, located between the crop caeca, form the male reproductive system. Each testisac is clothed by the mesotelium. Inside it, the germinal cells are connected to the citophore and develop functional unit called poliplast. The spermatozoa are released into testisacs after the reabsortion of the citophore. Five stages of spermatogenesis are described taking into account the successive maturation stages of germinal cells and the changes in the citophore size. Lining cells and gland cells were found in the seminal vesicle. Five different types of gland cells are placed inside the ejaculatory ducts, as well as two kinds of cells are found in its distal portion: type 1, which produces eosinophilic granular secretion, type 2, with amorphous and slightly eosinophilic. Three distinct gland cells are located in the proximal portion of the duct: type 3, which produces a strongly eosinophilic granular secretion; type 4, with a negative eosinophilic amorphous secretion and type 5, with a basophilic granular secretion. Type 5 gland cells are described for the ducts of this species only.
Resumo
Sixty specimens of Pimelodus maculatus from the Guandu River in Rio de Janeiro State were examined to describe their parasitofauna, in the period from August 1999 to February 2001. Specimens of twelve metazoan parasite species were collected, allocated into seven taxonomic groups - Monogenoidea: Demidospermus uncusvalidus Gutiérez and Suriano, 1992, D. paravalenciennesi Gutiérez and Suriano, 1992, D. majusculus Kritsky and Gutiérez, 1998 and Scleroductus sp.; Digenea: Austrodiplostomum compactum (Lutz, 1928); Eucestoda: Nomimoscolex sp.; Nematoda: Cucullanus pinnai Travassos, Artigas and Pereira, 1928 and Procamallanus sp. (young specimen); Hirudinea: Helobdella sp.; Myxozoa: Henneguya sp. and Myxobolus absonus Cellere, Cordeiro and Adriano, 2002, along with one unidentified species of Acanthocephala (cystacanth). There was a correlation between the host sex and the prevalence and abundance of D. paravalenciennesi. The most dominant species in the parasite community of P. maculatus from the Guandu River was D. uncusvalidus (50%), followed by C. pinnai (18,3%). This study is the first report of D. majusculus and Henneguya sp. in P. maculatus, while it expands the known geographic distribution of D. uncusvalidus, D. paravalenciennesi, D. majusculus, Scleroductus sp., Nomimoscolex sp., C. pinnai, Procamallanus sp., Helobdella sp., Henneguya sp. and M. absonus.
Sessenta espéimes de Pimelodus maculatus provenientes do rio Guandu, Estado do Rio de janeiro, foram examinados para estudo de sua parasitofauna, no perído de agosto de 1999 a fevereiro de 2001. Foram coletados espéimes de doze espécies de parasitos metazoários alocados em sete grupos taxonômicos - Monogenoidea: Demidospermus uncusvalidus Gutiérez and Suriano, 1992, D. paravalenciennesi Gutiérez and Suriano, 1992, D. majusculus Kritsky and Gutiérez, 1998 e Scleroductus sp.; Digenea: Austrodiplostomum compactum (Lutz, 1928); Eucestoda: Nomimoscolex sp.; Nematoda: Cucullanus pinnai Travassos, Artigas and Pereira, 1928 e Procamallanus sp. (jovem); Hirudinea: Helobdella sp.; Myxozoa: Henneguya sp. e Myxobolus absonus Cellere, Cordeiro e Adriano, 2002, al de uma espie de Acanthocephala (cistacanto) não identificada. Houve correlação entre o sexo do hospedeiro com a prevalcia e com a abundâcia de D. paravalenciennesi. A espéie mais dominante na comunidade parasitáia de P. maculatus do rio Guandu foi D. uncusvalidus (50%), seguida de C. pinnai (18,3%). Demidospermus majusculus e Henneguya sp. constituem primeiro registro em P. maculatus. Demidospermus uncusvalidus, D. paravalenciennesi, D. majusculus, Scleroductus sp., Nomimoscolex sp., C. pinnai, Procamallanus sp., Helobdella sp., Henneguya sp. e M. absonus apresentam ampliada sua distribuio geogrica conhecida.