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This paper discusses the general atmospheric circulation over Patagonia on the basis of the principal palaeoclimate forcings: continental drift, orography, variations in the greenhouse gases in the Earth's atmosphere, evolution of the atmosphere and the oceans, changes in the orbit of the Earth, albedo feedbacks, and the land surface. These processes affect climate on time scales of millions to hundreds of thousands of years. Additionally, orbital forcing has had a major influence on climate during the Quaternary. The palaeo-atmospheric circulation of Patagonia is analyzed for the Early to Late Jurassic, the Cretaceous, the Late Palaeocene-Eocene Thermal Maximum, the Tortonian-Oligocene cooling, the Pliocene, the Quaternary including the Last Glacial Maximum, the Holocene Optimum, and the last millennium changes. Alternative palaeo-atmospheric circulations from climatic modelling scenarios through the ages are reviewed and compared with proxy data. Detailed and updated reference information on the topics analyzed is also provided. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, , 229-249. Este trabajo discute la circulación general de la atmósfera en la Patagonia. Se han explicado los principales forzantes del palaeoclima: deriva continental, orografía, variaciones en los gases de invernadero de la atmósfera terrestre, evolución de la atmósfera y los océanos, cambios orbitales, retroalimentación debida al albedo y las condiciones generales de la superficie terrestre. Estos parámetros afectan el clima en escalas temporales de millones a cientos de miles de años, así como los forzantes orbitales dominaron los cambios climáticos durante el Cuaternario. Las palaeo-circulaciones de la atmósfera sobre Patagonia son analizadas para el Jurásico Temprano y Tardío, el Cretácico, el Máximo Termal del Palaeoceno Tardío- Eoceno, el enfriamiento del Tortoniano- Oligoceno, el Plioceno, y el Cuaternario incluyendo el Último Máximo Glacial (UMG), el Óptimo del Holoceno y los cambios del último milenio. Las palaeo-circulaciones atmosféricas alternativas a través del tiempo a partir de escenarios de modelos climáticos son revisadas y comparadas con proxy datos. Una extensiva lista de referencias provee información detallada y actualizada (Noviembre del 2010) sobre los tópicos analizados en esta publicación. [ABSTRACT FROM AUTHOR]

The Puyehue-Cordón Caulle eruption of 4 June 2011 dispersed about 100 million tonnes of pyroclastic materials resulting in ash accumulations of 30 cm depth on the Patagonian steppe, an area occupied by several lizard species. Herein we analysed, by experimental trials, the effects of ash and slope on running performance of two endemic and vulnerable species, Phymaturus excelsus and Phymaturus sinervoi, restricted to volcanic rock outcrops in Patagonia. We also determined the effect of ash fall on body condition by comparing the same populations before and after the volcanic eruption. Locomotion of P. excelsus, adapted to rocky and steep outcrops, was more affected in a negative way by ash. In contrast, P. sinervoi, which lives in mixed habitats with flat rocks and sandy substrates, ran more slowly on the inclined surface but was unaffected by ash, suggesting the two species are well adapted to the habitats they occupy. In spite of impacts of ash deposition on locomotion and potentially the feeding, reproduction and dispersal activity of P. excelsus, lizards captured 18 months after ash deposition showed improved body condition. Our study site for P. sinervoi received less ash deposition and hence body condition was similar before and after ash fall. We hypothesize that negative effects of ash on lizards were counteracted by competitive release; ash deposition caused an acute and significant increase in mortality of herbivorous competitors such as hares and sheep that feed upon the same flowers and fruits included in the Phymaturus diet. [ABSTRACT FROM AUTHOR]

Smooth-shelled blue mussels of the Mytilus edulis species complex are widely distributed bivalve molluscs whose introductions threaten native marine biodiversity (non-indigenous species - NIS). The aim of the present study was to identify the species and hybrids of Mytilus present in the Magellan Region (southern Chile). Results indicate that three mussel species of the Mytilus edulis complex are found in the region - M. edulis, M. chilensis (or the Southern Hemisphere lineage of Mytilus galloprovincialis), and M. galloprovincialis of Northern Hemisphere origin. For the first time, alleles of the introduced M. trossulus are reported from the Southern Hemisphere. In the Strait of Magellan the native Pacific blue mussel, Mytilus chilensis and the native Atlantic blue mussel, Mytilus edulis, meet and mix at a natural hybrid zone (about 125 km in length). This is the first record of a natural Mytilus hybrid zone in the Southern Hemisphere and is also the first record of the co-occurrence of genes from all four Mytilus species in any one region. These results contribute to the knowledge of the biodiversity and delimitation of mussel species in southern South America, and highlight how introduced species may threaten the genetic integrity of native species through hybridization and introgression. [ABSTRACT FROM AUTHOR]

Understanding the influence of landscape features on population differentiation is fundamental to evolutionary biology studies. We examined spatial patterns of genetic and phenotypic variability among Galaxias maculatus populations in a complex of four postglacial lakes in northwestern Patagonia differing in size and connectivity among them. A hierarchical Bayesian analysis grouped the individuals collected from eleven localities into three genetic clusters, first defining the populations of the two large lakes and separating the two small lakes in subsequent analysis. Genetic structuring was restricted within large lakes. It is known that the larval stage of Galaxias maculatus migrate to the limnetic zone of Patagonian lakes, possibly exerting an homogenizing effect on gene flow within lakes. Gene flow asymmetry and divergences among lakes can be explained by a combination of landscape characteristics and the presence of predators in the short streams that connect them. Individuals from the small lakes are the most divergent morphologically and genetically. The population in the isolated Redonda Lake, exhibits meristic differences as well, suggesting strong drift and environmental effects. This population is likely to have been isolated following the decline in water level of a paleolake that existed in this region approximately 13.2 kya BP. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ••, ••-••. [ABSTRACT FROM AUTHOR]

The Squamata, a vertebrate group that includes 'lizards', amphisbaenians and snakes, have inhabited Patagonia since the Late Cretaceous. The Mesozoic record comprises an iguanian, a scleroglossan and a great diversity of snakes that include, among others, the most primitive terrestrial forms. Snakes were also well diversified in the Palaeogene, with fossils of madtsoiids and boids (including the oldest record of the extant Boa) found as far south as 46°S, following the then dominant subtropical conditions in the region. The Palaeogene record comprises small, medium-sized and large forms. The only boids that persisted at the beginning of the Neogene are all small forms, suggesting colder temperatures than during the Palaeogene. The oldest South American 'colubrids' made their first appearance at this time, reaching latitudes south of the current Patagonian distribution (50°S). The Neogene record also includes the first occurrence of extant iguanians ( Pristidactylus and Liolaemus) and teiids ( Tupinambis). The latter reached the southernmost distribution of its evolutionary history during the Miocene. The distribution of boids, 'colubrids' and tupinambine teiids at higher latitudes than at present indicates warmer conditions during the Miocene. The uplift of the Patagonian Andes, followed by a decrease in temperature and an increase in desertification, induced a strong contraction in the distribution of tupinambine teiids to northern regions of Patagonia and even forced the complete disappearance of boids from this region. In contrast, these changes appear to have favoured the diversification of iguanian genera on both sides of the Patagonian Andes. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, , 441-457. Los Squamata ('lagartos', anfisbenas y serpientes) habitan la Patagonia desde el Cretácico tardío. El registro Mesozoico comprende un iguanio, un esclerogloso, y una gran diversidad de serpientes que incluye las formas terrestres más primitivas. Las serpientes estaban bien diversificadas durante el Paleógeno, con madtsoideos y boidos (incluyendo el registro más antiguo de la actual Boa) que alcanzaron altas latitudes (46 °S) siguiendo las condiciones subtropicales dominantes en la región. En contraste con el Paleógeno, que incluye formas pequeñas, medianas y grandes, los únicos boidos que persisten a comienzos del Neógeno son todas formas pequeñas que sugieren temperaturas más bajas que durante el Paleógeno. Los más antiguos 'colúbridos' sudamericanos son del Neógeno, cuando alcanzan latitudes (50 °S) al sur de su actual distribución. El registro del Neógeno también incluye la aparición de géneros actuales de lagartos iguanios ( Pristidactylus y Liolaemus) y teidos ( Tupinambis). Tupinambis alcanza la distribución más austral durante el Mioceno. La presencia de boidos, 'colúbridos' y teidos tupinambinos a mayores latitudes que en el presente indica condiciones más cálidas durante el Neógeno. El levantamiento de los Andes Patagónicos, seguido por la disminución de la temperatura y el incremento de la aridez, produjo una fuerte contracción en la distribución de teidos tupinambinos hacia el norte y la desaparición total de boidos de Patagonia. En contraste, estos cambios parecen haber favorecido la diversificación de los géneros de iguanios a ambos lados de los Andes. [ABSTRACT FROM AUTHOR]