Abstract Geometric morphometric methods are powerful tools to discriminate between closely related ostracods taxa as well as to study the relationship between their morphological variations, taxonomy and paleoecology. In this study, valve outline analysis allows the discrimination between the non-marine ostracod C. silvestrii and R. whatleyi juveniles, pointing out differences in the posterior valve area and surface ornamentation. Modern female specimens of C. silvestrii from 23 sites located in a spatial transect (41 to 51 °S) exhibited extensive morphological variability, on the basis of which three morphotypes (acuminated, transitional, subtruncated) were determined. Multivariate analyses showed that acuminated and transitional shapes are not arranged in groups but the subtruncated morphotype, previously described as E. cecryphalium, seems to be associated with low water conductivity (372 µS cm-1), dominant cold (5 ºC) and windy (8.6 m s-1) climatic conditions. The fossil cluster which included nine cores spanning the last 15.6 kyr, only covered acuminated and transitional shapes, which may indicate that these lineages might be older than the subtruncated morphotype. In addition, morphological differences between reproduction modes suggested that parthenogenetic females exhibit de posterior margin more acuminate than sexual females. These results set the ground for more precise ecological and paleoenvironmental studies in Patagonia.

Abstract In order to characterize Patagonian (Argentina) ecoregions using non-marine ostracods, their associations in 69 environments were assessed. Twenty eight taxa were recorded, including 12 endemic of the Neotropical region. Our results indicate that Patagonian ostracods are mainly influenced by electrical conductivity (EC), altitude, pH, and temperature; and shows a correlation with Argentinian ecoregions. Assemblage I is composed of sites located at high altitude in the Andean Patagonian forest ecoregion. Host waters have low temperature, EC and pH, and support as representative species Cypris pubera, Eucypris virens, Bradleystrandesia fuscata, Tonacypris lutaria and Amphicypris nobilis. Assemblage II, related to mid-altitude environments in the Patagonian Steppe ecoregion, thrived in waters with moderate to high EC, and alkaline pH values. Dominant species includes Limnocythere rionegroensis, L. patagonica, E. virgata, Riocypris whatleyi, Riocypris sarsi, Newnhamia patagonica, Kapcypridopsis megapodus, Ilyocypris ramirezi and Penthesinelula incae. Assemblage III inhabited environments within Monte and Espinal ecoregions, situated in the eastern part of the study area at low altitude, EC moderate and temperate waters, supporting Heterocypris hyalinus, Amphicypris argentinensis, Sarscypridopsis aculeata, Cypridopsis vidua, Herpetocypris intermedia and Chlamidotheca incisa. Our results indicates that Argentinian Patagonia hosts a diverse ostracod fauna and highlights their capacity as proxies in ecological and palaeoenvironmental studies.

The results of the petrographic analysis of 69 thin sections of Belén ceramics from Valle de Hualfín are presented as a contribution to the study of pottery practices and the organization of production. The sample was obtained from six archaeological sites located chronologically between the fourteenth and sixteenth centuries. Different attributes of the paste were recorded and the inclusions in the compositional and textural levels quantified. The data expressed as percentages were analyzed using statistical methods for compositional data and the search for significant groups was carried out through cluster analysis. Most of the sample consists of sandy sediments, which might indicate non-standardized production but with a relatively structured pattern. There are few specimens with grog and with high proportions of pumiceous fragments, which enables a discussion of their production in the contexts of interactions between populations on a regional scale and the expansion of the Inka state.

Se presentan los resultados del análisis petrográfico de 69 cortes delgados de cerámica Belén del Valle de Hualfín como un aporte para el estudio de las prácticas alfareras y de la organización de su producción. La muestra se obtuvo en seis poblados arqueológicos ubicados cronológicamente entre los siglos XIV y XVI. Se registran diferentes atributos de la pasta y se cuantifican las inclusiones en los niveles composicional y textural. Los datos expresados como porcentajes se analizan utilizando métodos estadísticos para datos composicionales y la búsqueda de grupos se realiza con análisis cluster. La muestra mayoritaria está compuesta por sedimentos arenosos que llevan a considerar pautas de producción no estandarizadas pero relativamente estructuradas. Los escasos ejemplares con tiesto molido y con altas proporciones de fragmentos pumíceos permiten discutir su producción en el contexto de las interacciones entre poblaciones en la escala regional y de la expansión del Estado inkaico.

The analysis of recent benthic foraminifera from the continental shelf and San Matías Gulf is presented. Quantitative analysis was performed using methods from compositional data analysis theory. Principal Components Analysis, Cluster analysis and Geographic Information System (GIS) were used to infer a) six groups of species that respond to oceanographic conditions, four of which were related to coastal waters and the others could be influenced by the Malvinas current system; b) the relationship between 13 species and the water temperature, bottom sediments, and energetic conditions of the area c) a correlation between Cibicides dispars/Bulimina patagonica and Cibicides mckannai/Bulimina patagonica and water temperature.

Se presenta el análisis de foraminíferos bentónicos en sedimentos superficiales de un sector de la Plataforma Continental Argentina y el golfo San Matías. El estudio cuantitativo se efectuó empleando métodos de análisis estadístico de datos composicionales. Mediante el Análisis de Componentes Principales (ACP), Análisis de Agrupamiento y Sistema de Información Geográfica (SIG) se pudo inferir: a) la presencia de seis grupos de especies cuyas características responderían a las condiciones oceanográficas del lugar, cuatro de ellos indicarían el predominio del sistema de agua costera y los dos restantes, la influencia de la corriente de Malvinas; b) la vinculación entre las variaciones conjuntas que experimenta la composición de 13 especies con la temperatura del agua, las características del fondo y las condiciones energéticas en el área y c) la correlación existente entre las relaciones Cibicides dispars/Bulimina patagonica y Cibicides mckannai/Bulimina patagonica y la temperatura del agua.