Annelida (Oligochaeta and Aphanoneura) from the Natural Reserve of Isla Martín García (upper Río de la Plata estuary, Argentina): biodiversity and response to environmental variables

The Island of Martín García – located in the Upper Río de la Plata, to the south of the Uruguay River – is an outcropping of the crystalline basement. Fourteen sampling sites were selected, five along the littoral section of the island and nine in inland ponds. Four major environmental variables were measured: water temperature, dissolved oxygen, electrical conductivity, and pH. A total of 34 species of Oligochaeta and Aphanoneura were found, 30 belonging to Naididae plus one species each of the Narapidae, Lumbricidae, Enchytraeidae, and Aeolosomatidae. The thirteen most frequent species were: A. leydigi (30%), N. bonettoi (13%), L. hoffmeisteri (11%), N. variabilis (10%), S. trivandrana (6.5%), A. pigueti (5.6%), D. sawayai (4.5%), D. digitata (3.5%), C. diastrophus (2.7%), A. costatus (2.5%), P. longiseta (2.0%), Enchytraeidae (1.5%), and A. p. paraguayensis (1.4%). UPGMA clustering of species based on their occurrence in different ecological conditions revealed two main species groups. Canonic-correspondence analysis (CCA) was conducted with the 15 most frequent and abundant species in the 9 sampling sites and the 4 environmental variables. Results from the CCA revealed that the order of fluctuation of the environmental variables during the sampling period was, from the greatest to the least: dissolved oxygen, conductivity, pH, and water temperature. Approximately 97.6% of the correlations between species and environmental variables were expressed on axis 1 of the ordination diagram. Species richness correlated with the four environmental variables in the following order, from the weakest to the strongest: water temperature, pH, electrical conductivity, and dissolved oxygen.A ilha de Martín García, que está localizada na parte alta do Rio de la Plata, ao sul da desembocadura do rio Uruguai, é um afloramento do embasamento cristalino. Quatorze pontos de coleta foram selecionados, cinco ao longo da seção litoral da ilha e nove de lagoas do interior. Quatro principais variáveis ambientais foram medidas: temperatura da água, oxigênio dissolvido, condutividade elétrica e pH. Um total de 34 espécies de Oligochaeta e Aphanoneura foram encontradas, 30 pertencentes a Naididae mais uma espécie cada de Narapidae, Lumbricidae, Enchytraeidae e Aelosomatidae. As treze espécies mais frequentes foram: A. leydigi (30%), N. bonettoi (13%), L. hoffmeisteri (11%), N. variabilis (10%), S. trivandrana (6,5%), A. pigueti (5,6%), D. sawayai (4,5%), D. digitata (3,5%), C. diastrophus (2,7%), A. costatus (2,5%), P. longiseta (2,0%), Enchytraeidae (1,5%) e A. p. paraguayensis (1,4%). A análise de agrupamento das espécies (UPGMA) com base na sua ocorrência em diferentes condições ecológicas revelou dois grupos de espécies principais. Análise canônica de correspondência análise (CCA) foi realizada com as 15 espécies mais frequentes e abundantes nos 9 pontos de amostragem e as quatro variáveis ambientais. Os resultados do CCA revelaram que a ordem de flutuação das variáveis ambientais durante o período de amostragem foi, desde o maior ao menor: oxigênio dissolvido, condutividade, pH e temperatura da água. Cerca de 97,6% das correlações entre as espécies e as variáveis ambientais foram expressos no eixo 1 do diagrama de ordenação. A riqueza de espécies foi correlacionada com as quatro variáveis ambientais na seguinte ordem, do mais fraco ao mais forte: oxigênio a temperatura da água, pH, condutividade elétrica, e oxigênio dissolvido

A new species of Hyalella (Crustacea, Amphipoda, Dogielinotidae) from the Atlantic Forest of Misiones, Argentina

The freshwater genus Hyalella Smith, 1874 has a distribution restricted to the Western Hemisphere with most species being found in South America. In this report we describe a new species of Hyalella from the Atlantic Forest of the Misiones province, Argentina.Fil: Colla, Maria Florencia. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División de Zoología Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: César, Inés Irma. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División de Zoología Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Annelida (Oligochaeta e Aphanoneura) da reserva natural de usos múltiplos ilha martín garcía, Río de la plata: Biodiversidade e reposta às variáveis ambientais

The Island of Martín García located in the Upper Río de la Plata, to the south of the Uruguay River-is an outcropping of the crystalline basement. Fourteen sampling sites were selected, five along the littoral section of the island and nine in inland ponds. Four major environmental variables were measured: water temperature, dissolved oxygen, electrical conductivity, and pH. A total of 34 species of Oligochaeta and Aphanoneura were found, 30 belonging to Naididae plus one species each of the Narapidae, Lumbricidae, Enchytraeidae, and Aeolosomatidae. The thirteen most frequent species were: A. leydigi (30%), N. bonettoi (13%), L. hoffmeisteri (11%), N. variabilis (10%), S. trivandrana (6.5%), A. pigueti (5.6%), D. sawayai (4.5%), D. digitata (3.5%), C. diastrophus (2.7%), A. costatus (2.5%), P. longiseta (2.0%), Enchytraeidae (1.5%), and A. p. paraguayensis (1.4%). UPGMA clustering of species based on their occurrence in different ecological conditions revealed two main species groups. Canonic-correspondence analysis (CCA) was conducted with the 15 most frequent and abundant species in the 9 sampling sites and the 4 environmental variables. Results from the CCA revealed that the order of fluctuation of the environmental variables during the sampling period was, from the greatest to the least: dissolved oxygen, conductivity, pH, and water temperature. Approximately 97.6% of the correlations between species and environmental variables were expressed on axis 1 of the ordination diagram. Species richness correlated with the four environmental variables in the following order, from the weakest to the strongest: water temperature, pH, electrical conductivity, and dissolved oxygen.Facultad de Ciencias Naturales y Muse

Annelida (Oligochaeta e Aphanoneura) da reserva natural de usos múltiplos ilha martín garcía, Río de la plata: Biodiversidade e reposta às variáveis ambientais

The Island of Martín García located in the Upper Río de la Plata, to the south of the Uruguay River-is an outcropping of the crystalline basement. Fourteen sampling sites were selected, five along the littoral section of the island and nine in inland ponds. Four major environmental variables were measured: water temperature, dissolved oxygen, electrical conductivity, and pH. A total of 34 species of Oligochaeta and Aphanoneura were found, 30 belonging to Naididae plus one species each of the Narapidae, Lumbricidae, Enchytraeidae, and Aeolosomatidae. The thirteen most frequent species were: A. leydigi (30%), N. bonettoi (13%), L. hoffmeisteri (11%), N. variabilis (10%), S. trivandrana (6.5%), A. pigueti (5.6%), D. sawayai (4.5%), D. digitata (3.5%), C. diastrophus (2.7%), A. costatus (2.5%), P. longiseta (2.0%), Enchytraeidae (1.5%), and A. p. paraguayensis (1.4%). UPGMA clustering of species based on their occurrence in different ecological conditions revealed two main species groups. Canonic-correspondence analysis (CCA) was conducted with the 15 most frequent and abundant species in the 9 sampling sites and the 4 environmental variables. Results from the CCA revealed that the order of fluctuation of the environmental variables during the sampling period was, from the greatest to the least: dissolved oxygen, conductivity, pH, and water temperature. Approximately 97.6% of the correlations between species and environmental variables were expressed on axis 1 of the ordination diagram. Species richness correlated with the four environmental variables in the following order, from the weakest to the strongest: water temperature, pH, electrical conductivity, and dissolved oxygen.Facultad de Ciencias Naturales y Muse

Secondary production of <i>Chasmagnathus granulatus</i> (Crustacea; Decapoda) in a Ramsar Site from Argentina

Secondary production of Chasmagnathus granulatus was calculated at the Refugio de Vida Silvestre Bahía Samborombón, Argentina (36° 16′ S and 57° 06′ W). Sampling was conducted on nine occasions between March 2001 and February 2003, crabs were collected by hand, physico-chemical variables, granulometry and organic matter contents of the sediments were registered. Crabs were classified as male, female and undifferentiated, measured (total carapace width: CW) and weighed (wet and dry weight: DW at 60 °C, during 48 hours). A correlation analysis between CW and DW was made. Morphometric growth of C. granulatus was by the application of the power function (y = a x b), where the carapace width (CW) was used as an independent variable. Males, females and undifferentiated individuals were analysed separately as well as all together as a group. The data were fitted indicating a positive allometry (constant of allometry b > 3), the males showing the greatest allometric value. The individuals (n = 957 juveniles and adults) were separated in cohorts by the polymodal width-frequency distribution converted into normal curves. Three cohorts were found during the whole study period, and two cohorts coexisting in each sampling date. Ovigerous females were caught on December 2001, 2002 and February 2003. The size-frequency method was used to estimate the annual production. The major contribution to production was carried out by the mature individuals, in particular those with size between 25 and 30 mm, but on the other hand, only few individuals measuring from 10 to 20 mm were collected. The annual production of C. granulatus was estimated in 7.76 g.m-2. The biomass (expressed as total dry weight) varied between 0.55 and 1.85 g.m-2, with the greater values being registered during autumn and spring, and the lower values during summer.Foram calculadas as primeiras estimativas da produ&ccedil;&atilde;o secund&aacute;ria de Chasmagnathus granulatus no Ref&uacute;gio da Vida Silvestre Bah&iacute;a Samboromb&oacute;n, Argentina (36&deg; 16&rsquo; S e 57&deg; 06&rsquo; W). As amostragens foram realizadas em nove ocasi- &otilde;es, entre o per&iacute;odo de mar&ccedil;o de 2001 a fevereiro de 2003. Os caranguejos foram coletados manualmente. Vari&aacute;veis f&iacute;sico-qu&iacute;micas, granulometria e teor de mat&eacute;ria org&acirc;nica dos sedimentos foram analisados. O caranguejos (n = 957, jovens e adultos) foram classificados em: machos, f&ecirc;meas e indiferenciados; foram mensurados (Largura da Carapa&ccedil;a, LC) e pesados (peso &uacute;mido e seco, PS a 60 &deg;C, 48 horas). Uma an&aacute;lise de correla&ccedil;&atilde;o entre LC vs. PS foi efetuada. O crescimento morfom&eacute;trico de C. granulatus foi analisado pela aplica&ccedil;&atilde;o da fun&ccedil;&atilde;o potencial (PS = a LC b ), sendo que machos, f&ecirc;meas e indiv&iacute;duos com sexo n&atilde;o diferenciado foram analisados separadamente e em conjunto. O ajuste dos dados indicou uma alometria positiva, com os machos apresentando o maior valor. Os indiv&iacute;duos foram separados em coortes por meio da convers&atilde;o de curvas de normalidade de uma distribui&ccedil;&atilde;o de freq&uuml;&ecirc;ncia polimodal. Tr&ecirc;s coortes foram encontradas durante todo o per&iacute;odo de estudo, e duas coexistindo em cada data de amostragem. F&ecirc;meas ov&iacute;- geras foram coletadas em dezembro de 2001 e 2002 e em fevereiro de 2003. Utilizou-se o m&eacute;todo da distribui&ccedil;&atilde;o de freq&uuml;&ecirc;ncia de tamanho para estimar a produ&ccedil;&atilde;o anual. A maior contribui&ccedil;&atilde;o para a produ&ccedil;&atilde;o &eacute; dada pelos indiv&iacute;duos sexualmente maduros, particularmente por aqueles com tamanhos entre 25 e 30 mm. A produ&ccedil;&atilde;o anual foi estimada em 7,76 g.m-2. A biomassa, expressa em peso seco, variou entre 0,55 e 1,85 g.m-2, com maiores valores registrados no outono e na primavera, e menores valores registrados no ver&atilde;o

Catálogo de los ejemplares de Trichodactylidae (Crustacea, Brachyura) depositados en el Museo de La Plata, Argentina

Se presenta un catálogo de la colección de cangrejos dulceacuícolas de la familia Trichodactylidae (Crustacea, Brachyura), depositada en la Colección Carcinológica del Museo de La Plata, Argentina. Se estudiaron ochenta lotes integrados por ocho especies. Entre estos lotes, varios de ellos fueron determinados por R. Ringuelet y C. Magalhães. Se identificaron varios lotes de diferentes regiones de Argentina. Para cada lote se proporciona la siguiente información: localidad de colección georeferenciada, colector y fecha de recolección, número de colección, los datos de la etiqueta (transcriptos con exactitud de la redacción original), observaciones y el mapa de las localidades geográficas.We present here a catalog of the Trichodactylidae (Crustacea, Brachyura) deposited in the Crustacean Collection of Museo de La Plata, Argentina. Eighty lots were studied, comprising eight species. Among these lots, many had been characterized by R. Ringuelet and by C. Magalhães; several lots from different regions of Argentina were identified. For each lot the following information is provided: georeferenced locality of collection, collector and collecting date, collection number, labelling data (a precise transcription of the original wording), remarks, and map of the locations.Facultad de Ciencias Naturales y Muse

Type and non-type specimens of Aegla (Decapoda: Anomura: Aeglidae) housed in the Museo de La Plata, Argentina

The present contribution deals with the type and non-type material of the species of Aegla (Decapoda: Anomura: Aeglidae) deposited in the Invertebrate Collection of Museo de La Plata, Argentina. One hundred and thirty-four lots are included, of which 10 lots are type specimens. The material examined includes 11 of the 13 species known from Argentina. Among the studied lots, those examined by Ringuelet (1948, 1960) and by Bond-Buckup & Buckup (1994) stand out. Also, several lots from different regions of Argentina were identified. Type specimens examined were compared with the original descriptions; photographs of the specimens are given in the present report. For each lot the following information is provided: georeferenced locality of collection, collector and collecting date, bibliographical references, category, number of collection according to the rules of the Museo de La Plata, label data (precise transcription), remarks and map of the locations.Fil: César, Inés Irma. 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 de Zoología Invertebrados; ArgentinaFil: Damborenea, Maria Cristina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División de Zoología Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentin

Annelida (Oligochaeta e Aphanoneura) da reserva natural de usos múltiplos ilha martín garcía, Río de la plata: Biodiversidade e reposta às variáveis ambientais

The Island of Martín García located in the Upper Río de la Plata, to the south of the Uruguay River-is an outcropping of the crystalline basement. Fourteen sampling sites were selected, five along the littoral section of the island and nine in inland ponds. Four major environmental variables were measured: water temperature, dissolved oxygen, electrical conductivity, and pH. A total of 34 species of Oligochaeta and Aphanoneura were found, 30 belonging to Naididae plus one species each of the Narapidae, Lumbricidae, Enchytraeidae, and Aeolosomatidae. The thirteen most frequent species were: A. leydigi (30%), N. bonettoi (13%), L. hoffmeisteri (11%), N. variabilis (10%), S. trivandrana (6.5%), A. pigueti (5.6%), D. sawayai (4.5%), D. digitata (3.5%), C. diastrophus (2.7%), A. costatus (2.5%), P. longiseta (2.0%), Enchytraeidae (1.5%), and A. p. paraguayensis (1.4%). UPGMA clustering of species based on their occurrence in different ecological conditions revealed two main species groups. Canonic-correspondence analysis (CCA) was conducted with the 15 most frequent and abundant species in the 9 sampling sites and the 4 environmental variables. Results from the CCA revealed that the order of fluctuation of the environmental variables during the sampling period was, from the greatest to the least: dissolved oxygen, conductivity, pH, and water temperature. Approximately 97.6% of the correlations between species and environmental variables were expressed on axis 1 of the ordination diagram. Species richness correlated with the four environmental variables in the following order, from the weakest to the strongest: water temperature, pH, electrical conductivity, and dissolved oxygen.Facultad de Ciencias Naturales y Muse

Macroinvertebrados bentónicos litorales de la reserva de usos múltiples Isla Martín García: diversidad y respuesta a las variables ambientales

El objetivo de este trabajo está centrado en la diversidad y respuesta a las variables ambientales de los macroinvertebrados bentónicos litorales de la Isla. Se realizaron campañas estacionales (Marzo 1995- Marzo 1996), en ocho sitios. Variables del agua: temperatura, oxígeno disuelto, % saturación del oxígeno, conductividad eléctrica, sólidos disueltos totales y pH. Se recolectaron: Oligochaeta, 22 especies, Naididae, Narapidae, Tubificidae, Aelosomatidae y Enchytraeidae; de Mollusca, Bivalvia (4), Gastropoda (15); Ostracoda (5); Isopoda, Cumacea, Tanaidacea y Amphipoda (1c/u). Insecta, Chironomidae, Ceratopogonidae, Psephaenidae, Elmidae, Baetidae, Leptophlebidae, Pleidae, Coenagrionidae y Protoneuridae. También, Nematoda, Cladocera, Copepoda Cyclopoida, Calanoida y Harpacticoida. Abundancia relativa/taxa/sitio/estación del año, en conjunto, los taxa mejor representados fueron: Heleobia parchappii (78%), Nematoda,(58%), Limnodrilus hoffmeisteri (51%), Stenophysa marmorata (53%), Potamolithus bushii (44%), Sinelobus stanfordi (41%), P. lapidum y P. agapetus (40%), Heleobia piscium (38%), Biomphalaria straminea (24%), Coleoptera Psephaenidae (25%) y Limnoperna fortunei (21%). La diversidad H varió entre 2,16 (Playa Basural, Agosto 1995) y 0,35 (Playa de Arena río, Noviembre 1995).Análisis Canónico de Correspondencia: realizado entre 8 sitios/4 variables ambientales/15 especies. Variables ambientales más fluctuantes: OD, pH, TºC y conductividadn. El 95% de las correlaciones especies/variables se expresan en el Eje 1 del diagrama de ordenamiento. Gomphocythere argentinensis y Chironomidae ubicadas casi en el centroide del diagrama; Stephensoniana trivandrana, Aulodrilus pigueti, Limnodrilus hoffmeisteri, Sinelobus stanfordi, Chaetogaster diastrophus y Nais variabilis cercanas a valores promedio del pH, OD y TºC y Narapa bonettoi más relacionada a valores promedio del pH. Corbicula fluminea, Potamolithus bushii y P. agapetus relacionadas a valores medios de conductividadResúmenes del VII Congreso Argentino de Limnología. 21 al 25 de agosto de 2016 Tucumán, Argentin

Ecological aspects of natural populations of Hyalella pampeana (Crustacea, Amphipoda, Hyalellidae) from the Natural Reserve Island of Martín García (Río de La Plata, Argentina)

Freshwater amphipods of the genus Hyalella have a great importance in aquatic ecosystems due to their role in matter and energy cycling and its utilization as bioindicators of environmental health. The aim of this work was to analyze relevant population parameters of Hyalella pampeana, such as population density and structure, individual body size, sex ratio, fecundity and recruitment, and to study the possible relation of these parameters to variations in environmental variables. Samples were taken monthly during a one-year period (2006) at three small ponds in the Natural Reserve Island of Martín García, Argentina. The inland aquatic environments showed distinctive physicochemical characteristics, mainly related to pH and conductivity values. Amphipod population density varied among sites and throughout the year, with population peaks during spring, positively correlating with pH values. The operational sex ratio of the total population was almost equal to 1 male: 1 female, displaying seasonal variation. Mean fecundity and mean size of ovigerous females were higher during winter and early spring months than in summer months. The presence of ovigerous females and juveniles in all months indicated that reproduction is continuous during the year for Hyalella, in its natural environmentFil: Colla, Maria Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Catamarca. Universidad Nacional de Catamarca. Centro de Investigaciones y Transferencia de Catamarca; ArgentinaFil: César, Inés Irma. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología; Argentina. Comisión de Investigaciones Científicas de la Provincia de Buenos Aires; Argentin