Negleted diseases : contributions from continental malacology

Fil: Rumi, Alejandra. División Zoología Invertebrados. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Vogler, Roberto Eugenio. Departamento de Biología. Facultad de Ciencias Exactas, Químicas y Naturales. Universidad Nacional de Misiones. Posadas; Argentin

Threatened gastropods under the evolutionary genetic species concept: Redescription and new species of the genus Aylacostoma (Gastropoda: Thiaridae) from High Paraná River (Argentina-Paraguay)

The genus Aylacostoma Spix, 1827, is mainly endemic to South America, and comprises about 30 nominal species, most of which were described based solely on conchological features following the typological approaches of most of the 19th and the mid-20th century authors. Here, we redescribe Aylacostoma chloroticum Hylton Scott, 1954, and describe Aylacostoma brunneum sp. nov. from the High Paraná River (Argentina-Paraguay) by means of morphological and molecular characters. Both are threatened species currently included into an ongoing ex situ conservation programme, as their habitats have disappeared because of damming and the filling up of the Yacyretá Reservoir in the early 1990s. We used DNA sequences from cytochrome b and cytochrome oxidase subunit I (COI) genes to estimate their genetic distances, and the COI sequences were also used to assess their specific status under the evolutionary genetic species concept by means of the K/θ method. Our results clearly demonstrate that both must be recognized as evolutionary genetic species, despite only minor differences in morphological characters other than in the shells.Fil: Vogler, Roberto Eugenio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Misiones. Facultad de Ciencias Exactas, Químicas y Naturales; ArgentinaFil: Beltramino, Ariel Anibal. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología Invertebrados; Argentina. Ministerio de Ciencia, Tecnología e Innovación Productiva. Agencia Nacional de Promoción Científica y Tecnológica. Fondo para la Investigación Científica y Tecnológica; ArgentinaFil: Peso, Juana Guadalupe. Universidad Nacional de Misiones. Facultad de Ciencias Exactas, Químicas y Naturales; ArgentinaFil: Rumi Macchi Z., Alejandra. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Gasterópodos continentales de importancia sanitaria en el noreste argentino

Respecto a los moluscos, muchas especies poseen importancia biomédica, ya que actúan como vectores (hospedadores intermediarios: HI) de parásitos que se transmiten al hombre y constituyen uno de los principales agentes vectores de zoonosis. Entre las acciones necesarias de abordar, es imprescindible inicialmente desarrollar una base de datos que permita establecer programas de monitoreo locales, determinar los grupos de especies de importancia biomédica (humana y veterinaria) y que contribuya al conocimiento de la biodiversidad, del estatus de la fauna regional y permita identificar hábitats y especies amenazadas. La información generada es fundamental al momento de planificar y desarrollar estrategias de control epidemiológico de endemias establecidas a nivel local o de prevenir el asentamiento de otras, movilizadas desde diferentes regiones de Latinoamérica o desde otros continentes. Particularmente en el NEA se encuentran áreas de alta diversidad y riqueza de especies de moluscos, producto de condiciones climáticas y geográficas favorables, con gran diversidad de ambientes acuáticos y alta humedad ambiente.Trabajos presentados en el taller “Moluscos de interés sanitario en la Argentina” Instituto Nacional de Medicina Tropical (Misiones, 1 de agosto de 2012)Facultad de Ciencias Naturales y Muse

Mollusks (Gastropoda and Bivalvia) of the multiple-use reserve martín garcía Island, Río de la plata river: biodiversity and ecology

The Island of Martin Garcia is located in the Upper Río de la Plata, to the south of mouth the Uruguay River. The aim of the present study was to analyse the biodiversity of the island freshwater mollusks and their relationships to environmental variables. Twelve sampling sites were selected, five were along the littoral section of the island and seven were Inland ponds. Seven major environmental variables were measured: water and air temperature, percentage of oxygen saturation, dissolved oxygen, electrical conductivity, total dissolved solids and pH. Twenty-seven mollusk species were found, Antillorbis nordestensis, Biomphalaria tenagophila tenagophila, B. t. guaibensis, B. straminea, B. peregrina, Drepanotrema kermatoides, D. cimex, D. depressissimum, Chilina fluminea, C. rushii, C. megastoma, Uncancylus concentricus, Hebetancylus moricandi, Stenophysa marmorata, Heleobia piscium, H. parchappii, Potamolithus agapetus, P. buschii, P. lapidum, Pomacea canaliculata, P. megastoma Asolene platae, Corbicula fluminea, Eupera platensis, Pisidium sterkianum, P. taraguyense and Limnoperna fortunei. UPGMA clustering of species based on their occurrence in different ecological conditions revealed two main species groups. The Canonical Correspondence Analysis suggests that the species distribution is related to the physico-chemical condition of water. Axis two of the ordination diagram displayed the approximately 95.6% of the correlation between species and environmental variables. Dissolved oxygen, conductivity, water temperature and pH showed the highest fluctuations during the sampling period. The species richness (S) showed relationships mainly with water temperature and conductivity. The biodiversity of the gastropods and bivalves from Martín García Island amounts to up to 26 species. Among the Gastropoda, the Planorbidae family made the most sizeable contribution. The Lithogliphidae P. agapetus (26.28%) and P. buschii (9.50%) showed the highest relative frequencies of occurrence within the littoral environments, while the Planorbidae D. cimex (23.83%) and D. kermatoides (11.59%) likewise did so in the inland ponds

The South-American distribution and southernmost record of Biomphalaria peregrina-A potential intermediate host of schistosomiasis

Schistosomiasis remains a major parasitic disease, endemic in large parts of South America. Five neotropical species of Biomphalaria have been found to act as intermediate hosts of Schistosoma mansoni in natural populations, while others have been shown to be susceptible in experimental infections, although not found infected in the field. Among these potential intermediate hosts, Biomphalaria peregrina represents the most widespread species in South America, with confirmed occurrence records from Venezuela to northern Patagonia. In this study, we report the southernmost record for the species at the Pinturas River, in southern Patagonia, which finding implies a southward reassessment of the limit for the known species of this genus. The identities of the individuals from this population were confirmed through morphological examination, and by means of two mitochondrial genes, cytochrome oxidase subunit I (COI) and 16S-rRNA. With both markers, phylogenetic analyses were conducted in order to compare the genetic background of individuals from the Pinturas River with previously genetically characterized strains of B. peregrina from various South- American locations. In addition, we produced a potential distribution model of B. peregrina in South America and identified the environmental variables that best predict that distribution. The model was estimated through a maximum entropy algorithm and run with occurrence points obtained from several sources, including the scientific literature and international databases, along with climatic and hydrographic variables. Different phylogenetic analyses with either the COI or 16S-rRNA sequences did not conflict, but rather gave very similar topological organizations. Two major groups were identified, with sequences from the Pinturas River grouping together with haplotypes from subtropical and temperate regions. The model developed had a satisfactory performance for the study area. We observed that the areas with higher habitat suitability were found to be mainly linked to subtropical and temperate regions of South America between 15° and 45° south latitude, with different moderate- and lowsuitability areas outside this range. We also identified the coldest temperatures as the main predictors of the potential distribution of this snail. Susceptibility surveys would be required to evaluate if southern populations of B. peregrina still retain their potential as intermediate hosts of S. mansoni.Facultad de Ciencias Naturales y Muse

The South-American distribution and southernmost record of Biomphalaria peregrina-A potential intermediate host of schistosomiasis

Schistosomiasis remains a major parasitic disease, endemic in large parts of South America. Five neotropical species of Biomphalaria have been found to act as intermediate hosts of Schistosoma mansoni in natural populations, while others have been shown to be susceptible in experimental infections, although not found infected in the field. Among these potential intermediate hosts, Biomphalaria peregrina represents the most widespread species in South America, with confirmed occurrence records from Venezuela to northern Patagonia. In this study, we report the southernmost record for the species at the Pinturas River, in southern Patagonia, which finding implies a southward reassessment of the limit for the known species of this genus. The identities of the individuals from this population were confirmed through morphological examination, and by means of two mitochondrial genes, cytochrome oxidase subunit I (COI) and 16S-rRNA. With both markers, phylogenetic analyses were conducted in order to compare the genetic background of individuals from the Pinturas River with previously genetically characterized strains of B. peregrina from various South- American locations. In addition, we produced a potential distribution model of B. peregrina in South America and identified the environmental variables that best predict that distribution. The model was estimated through a maximum entropy algorithm and run with occurrence points obtained from several sources, including the scientific literature and international databases, along with climatic and hydrographic variables. Different phylogenetic analyses with either the COI or 16S-rRNA sequences did not conflict, but rather gave very similar topological organizations. Two major groups were identified, with sequences from the Pinturas River grouping together with haplotypes from subtropical and temperate regions. The model developed had a satisfactory performance for the study area. We observed that the areas with higher habitat suitability were found to be mainly linked to subtropical and temperate regions of South America between 15° and 45° south latitude, with different moderate- and lowsuitability areas outside this range. We also identified the coldest temperatures as the main predictors of the potential distribution of this snail. Susceptibility surveys would be required to evaluate if southern populations of B. peregrina still retain their potential as intermediate hosts of S. mansoni.Facultad de Ciencias Naturales y Muse

Ecology of the non-native snail Sinotaia cf quadrata (Caenogastropoda: Viviparidae). A study in a lowland stream of South America with different water qualities

Sinotaia quadrata is a snail native from Asia recorded for the first time in South America in 2009 in central Argentina. In 2015, this species was also found in a lowland stream with different water qualities. Our aims were to contribute to the knowledge of its population ecology and to compare the individuals from the two locations anatomically. Snails were searched at 6 sites, where physicochemical and hydraulic parameters were measured. Biological samples were also taken at two sites (S3 and S4) to study the population traits of S. cf quadrata (density, size structure, fecundity and sex ratio) and to assess the water quality through macroinvertebrates' biological indices (richness, diversity and IBPamp). Physicochemical and biological parameters allowed us classifying sites as "moderately polluted" (S3) and "heavily polluted" (S4). At S4, the population showed a lower density, larger individuals, higher fecundity and a scarce representation of young snails. The differences observed in the radula and mantle border of snails from the two geographical regions might be attributed to environmental differences. We conclude that this species is tolerant to a wide range of environmental variables which, along with its high fecundity and morphological plasticity, could allow this species to colonize neighbor streams.Fil: Ferreira, Ana Clara. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; ArgentinaFil: Paz, Laura Estefania. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; ArgentinaFil: Rumi Macchi Z., Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; ArgentinaFil: Ocon, Carolina Silvia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; ArgentinaFil: Altieri, Paula Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; ArgentinaFil: Rodrigues Capitulo, Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; Argentin

Populational studies of an endemic gastropod from waterfalls environments

Chilinidae is a family endemic to South America, ranging from the Tropic of Capricorn to Cape Horn and the Falkland Islands, and includes 32 species. However, there are few population studies on the Chilinidae. We study aspects of the ecology of an endemic species, Chilina megastoma Hylton Scott, 1958, from the Arrechea Falls in the Iguazú National Park, Argentina, such as density and individual annual growth trends. Nine samplings were carried out between December 2003 and December 2005, using two transects that crossed the waterfall. Individual annual growth rate was analyzed according to length, following von Bertalanffy's model. Six cohorts were identified, some in the same climatic season but successive years (two in winter and two in summer). The winter and autumn cohorts reached 85% of their last whorl length in the first year. Compared to other families of gastropods from subtropical climates, these populations have several recruitment events per year, but never in winter.Fil: Gutierrez Gregoric, Diego Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología Invertebrados; ArgentinaFil: Nuñez, Maria Veronica. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Rumi Macchi Z., Alejandra. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentin

Larval survival strategy during winter of Chordodes nobilii Camerano, 1901 (Gordiida, Nematomorpha)

There are numerous open questions concerning the life cycle of Gordiida (Nematomorpha), especially about egg development and viability of larvae during winter, when the temperature of freshwater environments where they inhabit is low. On the basis of experimental studies we demonstrate that egg development of Chordodes nobilii takes 20-25 days at 22°C and 45-55 days at 5°C. We also observed that larvae of C. nobilii obtained from egg strings at 5°C and maintained at that temperature during six months remained inside their egg shells as a survival strategy.Facultad de Ciencias Naturales y Muse