Description of epigean arthropods in two environments Talampaya National Park, La Rioja, Argentina

Este proyecto estudia la biodiversidad y la composición de los artrópodos epigeos en dos ambientes aparentemente diferentes en cuanto a estructura y composición de la vegetación en el Parque Nacional Talampaya, La Rioja, Argentina. Los hábitat fueron designados como: "Sitio A" (pobre en materia orgánica con escaso desarrollo y estructura del suelo); y el "Sitio B" (con suelo estructurado con mayor riqueza florística). La diversidad fue considerada usando trampas de caída que proveen buena información sobre la diversidad de los artrópodos epigeos. Veinte trampas de caída fueron colocadas en cada sitio de acuerdo con el siguiente diseño: 4 trampas dispuestas en 5 filas, separadas cada trampa por 5 metros, considerando esta distancia entre las filas y las trampas. Las trampas fueron llenadas con una solución de agua y gotas de detergente, y estuvieron activas durante 2 días en cada estación a lo largo de un año, siendo revisadas tres veces al día: entre las 8:00-10:00AM; 2:00-4:00PM y 6:00-8:00PM. Los análisis estadísticos fueron realizados por medio del software InfoStat 2004. Dos mil trescientos ochenta y cinco artrópodos fueron colectados en el Parque Nacional Talampaya, correspondiente a 15 órdenes. Ambos sitios estudiados fueron diferentes en la composición de artrópodos epigeos en cuanto a la diversidad, posiblemente relacionado con la variación en la estructura de la vegetación y en la composición del suelo de cada sitio. De acuerdo con ello, ambos hábitats son importantes conservar en el Parque Nacional Talampaya, La Rioja (Argentina), debido a que ellos son complementarios en fauna.This Project studies the biodiversity composition of epigean artrhropods in two habitats of the Talampaya, National Park, La Rioja,Argentina. The two studied habitats are different in the composition and vegetational structure. The habitats were designed as follow: “Site A”: poor in organic matter with scare development and structure of the soil; “Site B”: is structured soil with more floristic richness. The diversity of the epigean arthropods was considered using pit-fall trapping that gives good information about diversity of the epigean arthropods. Twenty pit-fall traps were put on each site according with the follow design: 4 traps arranged into 5 rows, separated each trap by 5 meters considering this distance between the rows and the traps. The traps were filled with a water solution with drops of detergent. The traps were active during 2 days on each season during one year, and revised three times by day: between 8:00-10:00AM; 2:00-4:00PM and 6:00-8:00PM. The statistical analysis was carried out using the software InfoStat 2004. Two thousand three hundred and eighty five epigean arthropods of 15 orders were collected at the Talampaya National Park. Both studied sites were different in the epigean arthropod composition community in species diversity, maybe this will be relationship with the variation of the vegetation structure and the soil composition of each sites. According with them, both habitats are important to conserve in theTalampaya National Park, La Rioja (Argentina), because the have a complementary fauna.Fil: Peñaloza, O. A.. Universidad Nacional de La Rioja; ArgentinaFil: Corronca, Jose Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Salta. Facultad de Ciencias Naturales; ArgentinaFil: Balzarini, Monica Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias. Departamento de Desarrollo Rural; Argentin

Description of epigean arthropods in two environments Talampaya National Park, La Rioja, Argentina

Este proyecto estudia la biodiversidad y la composición de los artrópodos epigeos en dos ambientes aparentemente diferentes en cuanto a estructura y composición de la vegetación en el Parque Nacional Talampaya, La Rioja, Argentina. Los hábitat fueron designados como: "Sitio A" (pobre en materia orgánica con escaso desarrollo y estructura del suelo); y el "Sitio B" (con suelo estructurado con mayor riqueza florística). La diversidad fue considerada usando trampas de caída que proveen buena información sobre la diversidad de los artrópodos epigeos. Veinte trampas de caída fueron colocadas en cada sitio de acuerdo con el siguiente diseño: 4 trampas dispuestas en 5 filas, separadas cada trampa por 5 metros, considerando esta distancia entre las filas y las trampas. Las trampas fueron llenadas con una solución de agua y gotas de detergente, y estuvieron activas durante 2 días en cada estación a lo largo de un año, siendo revisadas tres veces al día: entre las 8:00-10:00AM; 2:00-4:00PM y 6:00-8:00PM. Los análisis estadísticos fueron realizados por medio del software InfoStat 2004. Dos mil trescientos ochenta y cinco artrópodos fueron colectados en el Parque Nacional Talampaya, correspondiente a 15 órdenes. Ambos sitios estudiados fueron diferentes en la composición de artrópodos epigeos en cuanto a la diversidad, posiblemente relacionado con la variación en la estructura de la vegetación y en la composición del suelo de cada sitio. De acuerdo con ello, ambos hábitats son importantes conservar en el Parque Nacional Talampaya, La Rioja (Argentina), debido a que ellos son complementarios en fauna.This Project studies the biodiversity composition of epigean artrhropods in two habitats of the Talampaya, National Park, La Rioja,Argentina. The two studied habitats are different in the composition and vegetational structure. The habitats were designed as follow: “Site A”: poor in organic matter with scare development and structure of the soil; “Site B”: is structured soil with more floristic richness. The diversity of the epigean arthropods was considered using pit-fall trapping that gives good information about diversity of the epigean arthropods. Twenty pit-fall traps were put on each site according with the follow design: 4 traps arranged into 5 rows, separated each trap by 5 meters considering this distance between the rows and the traps. The traps were filled with a water solution with drops of detergent. The traps were active during 2 days on each season during one year, and revised three times by day: between 8:00-10:00AM; 2:00-4:00PM and 6:00-8:00PM. The statistical analysis was carried out using the software InfoStat 2004. Two thousand three hundred and eighty five epigean arthropods of 15 orders were collected at the Talampaya National Park. Both studied sites were different in the epigean arthropod composition community in species diversity, maybe this will be relationship with the variation of the vegetation structure and the soil composition of each sites. According with them, both habitats are important to conserve in theTalampaya National Park, La Rioja (Argentina), because the have a complementary fauna.Fil: Peñaloza, O. A.. Universidad Nacional de La Rioja; ArgentinaFil: Corronca, Jose Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Salta. Facultad de Ciencias Naturales; ArgentinaFil: Balzarini, Monica Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias. Departamento de Desarrollo Rural; Argentin

Changes of arthropod diversity across an altitudinal ecoregional zonation in Northwestern Argentina

This study examined arthropod community patterns over an altitudinal ecoregional zonation that extended through three ecoregions (Yungas, Monte de Sierras y Bolsones, and Puna) and two ecotones (Yungas-Monte and Prepuna) of Northwestern Argentina (altitudinal range of 2,500 m), and evaluated the abiotic and biotic factors and the geographical distance that could influence them. Pitfall trap and suction samples were taken seasonally in 15 sampling sites (1,500–4,000 m a.s.l) during one year. In addition to climatic variables, several soil and vegetation variables were measured in the field. Values obtained for species richness between ecoregions and ecotones and by sampling sites were compared statistically and by interpolation–extrapolation analysis based on individuals at the same sample coverage level. Effects of predictor variables and the similarity of arthropods were shown using non-metric multidimensional scaling, and the resulting groups were evaluated using a multi-response permutation procedure. Polynomial regression was used to evaluate the relationship between altitude with total species richness and those of hyperdiverse/abundant higher taxa and the latter taxa with each predictor variable. The species richness pattern displayed a decrease in species diversity as the elevation increased at the bottom wet part (Yungas) of our altitudinal zonation until the Monte, and a unimodal pattern of diversity in the top dry part (Monte, Puna). Each ecoregion and ecotonal zone evidenced a particular species richness and assemblage of arthropods, but the latter ones displayed a high percentage of species shared with the adjacent ecoregions. The arthropod elevational pattern and the changes of the assemblages were explained by the environmental gradient (especially the climate) in addition to a geographic gradient (the distance of decay of similarity), demonstrating that the species turnover is important to explain the beta diversity along the elevational gradient. This suggests that patterns of diversity and distribution of arthropods are regulated by the dissimilarity of ecoregional environments that establish a wide range of geographic and environmental barriers, coupled with a limitation of species dispersal. Therefore, the arthropods of higher taxa respond differently to the altitudinal ecoregional zonation

A new marrellomorph euarthropod from the Early Ordovician of Argentina

Marrellomorphs (class Marrellomorpha) are a group of Paleozoic arthropods with a very poor fossil record. Here we describe a new marrellomorph arthropod Mimetaster florestaensis sp. nov. from the Tremadocian (earliest Ordovician) of Argentina. The new species is characterized by the shape and direction of the three pairs of principal spines, and the existence of strong secondary spines only in the proximal two-thirds of the anterolateral spines. As a result of phylogenetic analysis the new species integrates a trichotomy with Mimetaster hexagonalis and a Moroccan unnamed marrellid as sister groups. This discovery increases the known diversity of Marrellomorpha and represents the first occurrence of this group in South America, expanding the spatial distribution of the clade