A pesar de la ubicuidad de Cucullanus spp. en los ecosistemas acuáticos de todo el mundo, su desa... more A pesar de la ubicuidad de Cucullanus spp. en los ecosistemas acuáticos de todo el mundo, su desarrollo embionario y post-embrionario, así como los patrones de transmisión, siguen siendo poco conocidos y, en algunos casos, controvertidos. En el presente estudio se proporcionan datos comparativos y embriológicos de Cucullanus pinnai pinnai (Travassos, Artigas & Pereira, 1928). Los nematodes adultos provenientes de Rhamdia quelen (Quoy & Gaimard, 1824) (Heptapteridae) se describen e ilustran mediante microfotografía electrónica de barrido. Se obtuvieron huevos de hembras grávidas y se siguió el desarrollo embrionario y larvario in vitro. Las etapas L y L se describen e ilustran por primera vez. El 2 3 desarrollo embrionario de C. pinnai pinnai es muy rápido a 20-22°C. En cinco días tiene lugar la eclosión y las L libres permanecen vivas menos de dos semanas. Se plantea la hipótesis de un patrón de transmisión 2 heteroxeno que involucra a R. quelen como hospedador definitivo y Bryconam...
This paper describes and illustrates a new species of digenetic trematode, parasitic in the stoma... more This paper describes and illustrates a new species of digenetic trematode, parasitic in the stomach of the sabretooth anchovy Lycengraulis grossidens (Agassiz, 1829) from the Bahía Blanca estuary and the Paraná River, Argentina, designated as Stomachicola lycengraulidis n.sp. The new taxon differs from S. bayagbonai and S. singhi congeneric species from the Gulf of Guinea and Indian Ocean respectively, mainly in the body size, the structure of the reproductive system, the development of the ecsoma and the sinus sac. It differs from the first one mainly in the presence of two frontal protuberances at the level of the preoral lobe, which are absent in the specimens studied here. Also in general terms, S. bayagbonai is comprised of slightly larger individuals, with larger pharynx, testicles and ovary. And it differs from S. singhi by their smaller duct and hermaphroditic sac and for having a well developed seminal receptacle, which is absent in the Bay of Bengal specimens. When comparing the relative size of the ecsoma, we found significant differences among both of the populations of digeneans examined, the worms collected in the Paraná River was more developed than those from the Bahia Blanca estuary. The host, L. grossidens, migrates to the Paraná river in winter and spring and then, from December to March it makes a trophic migration towards the sea and is found all along the Atlantic coast of Buenos Aires province. For this reason, it is here hypothesized that the relative development of the tail, is affected by environmental conditions, such as pH and osmolarity of the stomach, salinity and/or water temperature.
Keywords: Fish-helminthic assemblages-parasite ecology-Seriolella porosa. No previous studies wer... more Keywords: Fish-helminthic assemblages-parasite ecology-Seriolella porosa. No previous studies were carried out on aspects of the helminth assemblages of Seriolella porosa. The present study aims to analyze the metazoan parasite of S. porosa and establish the relationship between the parasitic variations and both fish size and sex. A total of 101 specimens of S. porosa from San Matías Gulf, Argentina were examined between September and October 2006. Thirteen species were reported with a total of 3366 parasites. Lecithocladium cristatum was the most prevalent, dominant and abundant species. The average species richness was 3.2 ± 1.20. The evenness showed an inverse correlation with the total number of parasites and did not reveal differences between host sexes. None of the parasite species showed interspecific associations with each other. The average richness of the infracommunity was significantly less than the component community. The helminth community of the silver warehou shows little diversity with many satellite species and only two core species (Anisakis sp. and L. cristatum). Further studies, using parasites as stock indicators, would indicate whether the San Matías population represents a reproductive aggregation that penetrates the gulf seasonally in winter or whether it is a permanent stock isolated from the continental shelf. 291
The purpose of this study was to study and redescribe Terranova galeocerdonis (Thwaite, 1927) fro... more The purpose of this study was to study and redescribe Terranova galeocerdonis (Thwaite, 1927) from Carcharias taurus off Argentina. Its fourth larval stage was described, measured and illustrated for the first time. The host and geographical range of this species is extended into the southwestern Atlantic Ocean. When the present material was compared with T. rochalimai (Pereira, 1935) and T. ginglymostomae Olsen, 1952, it was considered that both morphological and morphometrical differences between the three species did not justify differentiation at the specific level. As a result, T. rochalimai and T. ginglymostomae are considered to be junior synonyms of T. galeocerdonis.
A pesar de la ubicuidad de Cucullanus spp. en los ecosistemas acuáticos de todo el mundo, su desa... more A pesar de la ubicuidad de Cucullanus spp. en los ecosistemas acuáticos de todo el mundo, su desarrollo embionario y post-embrionario, así como los patrones de transmisión, siguen siendo poco conocidos y, en algunos casos, controvertidos. En el presente estudio se proporcionan datos comparativos y embriológicos de Cucullanus pinnai pinnai (Travassos, Artigas & Pereira, 1928). Los nematodes adultos provenientes de Rhamdia quelen (Quoy & Gaimard, 1824) (Heptapteridae) se describen e ilustran mediante microfotografía electrónica de barrido. Se obtuvieron huevos de hembras grávidas y se siguió el desarrollo embrionario y larvario in vitro. Las etapas L y L se describen e ilustran por primera vez. El 2 3 desarrollo embrionario de C. pinnai pinnai es muy rápido a 20-22°C. En cinco días tiene lugar la eclosión y las L libres permanecen vivas menos de dos semanas. Se plantea la hipótesis de un patrón de transmisión 2 heteroxeno que involucra a R. quelen como hospedador definitivo y Bryconam...
This paper describes and illustrates a new species of digenetic trematode, parasitic in the stoma... more This paper describes and illustrates a new species of digenetic trematode, parasitic in the stomach of the sabretooth anchovy Lycengraulis grossidens (Agassiz, 1829) from the Bahía Blanca estuary and the Paraná River, Argentina, designated as Stomachicola lycengraulidis n.sp. The new taxon differs from S. bayagbonai and S. singhi congeneric species from the Gulf of Guinea and Indian Ocean respectively, mainly in the body size, the structure of the reproductive system, the development of the ecsoma and the sinus sac. It differs from the first one mainly in the presence of two frontal protuberances at the level of the preoral lobe, which are absent in the specimens studied here. Also in general terms, S. bayagbonai is comprised of slightly larger individuals, with larger pharynx, testicles and ovary. And it differs from S. singhi by their smaller duct and hermaphroditic sac and for having a well developed seminal receptacle, which is absent in the Bay of Bengal specimens. When comparing the relative size of the ecsoma, we found significant differences among both of the populations of digeneans examined, the worms collected in the Paraná River was more developed than those from the Bahia Blanca estuary. The host, L. grossidens, migrates to the Paraná river in winter and spring and then, from December to March it makes a trophic migration towards the sea and is found all along the Atlantic coast of Buenos Aires province. For this reason, it is here hypothesized that the relative development of the tail, is affected by environmental conditions, such as pH and osmolarity of the stomach, salinity and/or water temperature.
Keywords: Fish-helminthic assemblages-parasite ecology-Seriolella porosa. No previous studies wer... more Keywords: Fish-helminthic assemblages-parasite ecology-Seriolella porosa. No previous studies were carried out on aspects of the helminth assemblages of Seriolella porosa. The present study aims to analyze the metazoan parasite of S. porosa and establish the relationship between the parasitic variations and both fish size and sex. A total of 101 specimens of S. porosa from San Matías Gulf, Argentina were examined between September and October 2006. Thirteen species were reported with a total of 3366 parasites. Lecithocladium cristatum was the most prevalent, dominant and abundant species. The average species richness was 3.2 ± 1.20. The evenness showed an inverse correlation with the total number of parasites and did not reveal differences between host sexes. None of the parasite species showed interspecific associations with each other. The average richness of the infracommunity was significantly less than the component community. The helminth community of the silver warehou shows little diversity with many satellite species and only two core species (Anisakis sp. and L. cristatum). Further studies, using parasites as stock indicators, would indicate whether the San Matías population represents a reproductive aggregation that penetrates the gulf seasonally in winter or whether it is a permanent stock isolated from the continental shelf. 291
The purpose of this study was to study and redescribe Terranova galeocerdonis (Thwaite, 1927) fro... more The purpose of this study was to study and redescribe Terranova galeocerdonis (Thwaite, 1927) from Carcharias taurus off Argentina. Its fourth larval stage was described, measured and illustrated for the first time. The host and geographical range of this species is extended into the southwestern Atlantic Ocean. When the present material was compared with T. rochalimai (Pereira, 1935) and T. ginglymostomae Olsen, 1952, it was considered that both morphological and morphometrical differences between the three species did not justify differentiation at the specific level. As a result, T. rochalimai and T. ginglymostomae are considered to be junior synonyms of T. galeocerdonis.
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