Search

Copyright of Cuadernos Geograficos is the property of Cuadernos Geograficos and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The recovery of early records of maximum, minimum, and mean temperatures; pressure; and relative humidity measurements in Puerto Madryn for the period 1902–1915 is presented. A careful evaluation of the quality of the data was performed using internal coherence, tolerance, and temporal consistency tests. The monthly mean series of all the variables, constructed from daily raw data, were subject to several homogeneity tests, and only discontinuities in pressure and relative humidity were found. The homogenized monthly mean series were compared with the Twentieth Century Reanalysis series in annual and seasonal time steps. In addition, the trends of each variable were assessed using the Mann–Kendall procedure, and correlations between relative humidity and the other variables were examined. The results show a remarkably good agreement between the temperature measurements and reanalysis values with a Spearman correlation coefficient of 0.94. The raw data for minimum and maximum temperatures represent a very good upper and lower bound for the mean temperature values of both observational and reanalysis data. Agreement was found to be lower for relative humidity and pressure with the correlation coefficients being close to 0.6 in both cases. No trends were found for the variables. The correlation analysis of the humidity measurements with the other variables shows an inverse dependence of the temperatures and no relatedness with the pressure values. [ABSTRACT FROM AUTHOR]

A climate analysis of the monthly mean temperatures of Southern Patagonia during the late-XIXth and early-XXth centuries was carried out as part of the international data rescue Atmospheric Circulation Reconstructions over the Earth (ACRE) program partnership in Argentina, together with other data sources with regional and global records. The data from these diverse sources were combined to carry out a study in the coastal region of Patagonia, including Tierra del Fuego, between 42° S and 55° S for 11 locations. Furthermore, HadSST monthly/seasonal fields during the period 1880–1920 were also used. Both mean monthly and seasonal temperature values and timeseries variability were considered. Their analysis shows consistent behavior within the study region and compared to Southern Hemisphere mean results, which are characterized by a warm late-XIX century and a cooler early-XX century. This is also in agreement with SST variability along the coasts of Patagonia and hemispheric records. A comparison with present-day observations, where available, also yields consistent behavior. Low-frequency variability, i.e., in periods longer than 3 years, during the study period is consistent with present variability. Trend estimates at Trelew and Rio Gallegos for the period 1901–2020 yield significant trends, consistent with hemispheric warming at their latitudes. [ABSTRACT FROM AUTHOR]

This work's intent is to establish which was the most giant titanosaurid sauropod from Argentina. The evidence is scarce; however, we have tried to select the largest bones of the nine most giant titanosaurids. Argentinosaurus has been proposed as the largest titanosaurid, but recently a new king has been erected: the Patagotitan. In this review, we will see that there are some inconsistences and difficulties to define which is the largest. In other words, giant titanosaurids were a group of sauropods with a variable morphology and probably the overall shape was different. Among the largest titanosaurids, we have included Argyrosaurus superbus, Antarctosaurus giganteus, Argentinosaurus huinculensis, Puertasaurus reuili, Futalognkosaurus dukei, Traukutitan eocaudata, Dreadnoughtus schrani, Notocolossus gonzalezparejasi, and Patagotitan mayorum. [ABSTRACT FROM AUTHOR]

Factors affecting cetacean preservation and distribution in ancient sedimentary successions are not well understood. Actualistic studies have focused on coastal and deep marine examples, and little is known about taphonomic processes occurring within shelf environments. In this paper, we integrate sedimentological, taphonomic and palaeontological data for the cetacean-bearing lower Miocene Gaiman Formation from Patagonia, Argentina, to analyse which factors affected the distribution and preservation of cetaceans in several localities of the Southwestern Atlantic. Facies analysis shows that the formation represents a transgressive-regressive stratigraphic cycle, with palaeoenvironments including coastal, storm-dominated shoreface, inner shelf embayment and open inner shelf. Cetacean remains show preservation styles varying from isolated elements to articulated specimens, with nearly all remains restricted to both embayment and open marine inner shelf settings. Two fossil cetacean assemblages are recognized: Assemblage A comprises small-sized odontocetes dominated by Platanistoidea, preserved mostly in inner shelf embayment deposits; and Assemblage B comprises large-sized odontocetes and mysticetes, dominated by Physeteroidea and Balaenopteroidea, preserved mostly in open inner shelf deposits. Cetacean preservation style is controlled by a combination of palaeoenvironmental conditions, such as energy and sedimentation rate, and by biological factors, such as cetacean body plan and its impact on carcass buoyancy. Ecological factors may also explain the stratigraphic distribution of cetaceans between coastal and oceanic assemblages. This novel integrative and multidisciplinary analyses improves our knowledge of cetacean taphonomy in shelf environments. • Four coastal and shelf marine facies are identified for the lower Miocene Gaiman Formation of Argentina. • Cetaceans are mostly recorded in inner shelf deposits. • Cetacean preservation style is controlled by environmental and biological factors. • Cetaceans distribution is mostly controlled by palaeoecological factors. [ABSTRACT FROM AUTHOR]

The present work documents the stratigraphic distribution of dinoflagellate cysts from the upper part (60–585 m) of the YPF.Ch. PV. es-1 borehole, Península Valdés, Argentina. The assemblages exhibit a relatively moderate to low diversity. Most samples are characterized by frequent to abundant taxa of the order Gonyaulacales, such as Spiniferites/Achomosphaera spp., Reticulatosphaera actinocoronata, Operculodinium centrocarpum, and Melitasphaeridium choanophorum. Furthermore, a continuous succession of Early Miocene–Late Miocene diagnostic dinoflagellate cyst events was recorded for the first time from the Península Valdés region. Eight diagnostic events of highest occurrences (HOs) of dinoflagellate cyst taxa are identified. These bioevents allowed a subdivision of the sedimentary succession into two well-defined stratigraphic sections: Early to Middle Miocene (Burdigalian–Langhian/probably Serravalian, 430/425–330/325 m) based on the HOs of Emmetrocysta urnaformis, Cannosphaeropsis quattrocchiae, Cousteaudinium auybriae, and Cleistosphaeridium ancyreum, and Late Miocene (Tortonian–Messinian, between 175–170 and 80/85 m) based on the HOs of Labyrinthodinium truncatum subsp. truncatum, Operculodinium piaseckii, and Reticulatosphaera actinocoronata. The ranges of these taxa are compared with well-documented information on Neogene dinoflagellate cysts recorded from different sites across the North and South Atlantic Ocean and adjacent seas. In general, the dinoflagellate cyst assemblages, as well as the selected diagnostic taxa, exhibit a clear similarity to those of the Northern Hemisphere. The only exception is Hystrichokolpoma rigaudiae, which is asynchronous, possibly indicating local paleoenvironmental conditions. [ABSTRACT FROM AUTHOR]

The settlement of Argentine Patagonia after the genocidal military campaign of 1878–1885 occurred through discursive, legal, and institutional innovations. This article focuses on the emergence and consolidating of formal property by analyzing how access mechanisms are institutionalized through the constitution of law and public authority. Contests around access to land and resources became embedded in institutional structures in a context of legacies that continue to shape land distribution and dispossession. We argue that propertization, this transition from access to property, with its racial grammar, relies on invisibilization of people, reclassification of land, and the threat of violence. [ABSTRACT FROM AUTHOR]

Here, we present the first findings of anthropogenic debris (AD) used as nest material by the Kelp Gull (Larus dominicanus) on a small semi-desert coastal ecosystem in northern Argentine Patagonia. Anthropogenic debris was found in ca. 40% of the 259 active nests, with an average of 2.80 ± 2.60 items per nest (n = 126) with >1 item recorded in >50% of surveyed nests containing debris. The average weight of AD per nest was 4.58 ± 12.74 g; the heaviest debris item weighed 82.58 g. Fragmented plastics were more abundant than unbroken items. Plastic followed by paper dominated the fraction of AD, with flexible plastic items dominating at both sites (nests: 97%, adjacent beach: 82%). Mega-sized plastics (>10 cm in length) and white/clear debris prevailed at both gull nests and the adjacent beach; fisheries and recreational activities were identified as the main sources of AD. • Anthropogenic litter was detected in nests of breeding Kelp Gulls. • Plastic and paper formed the majority of marine debris. • Flexible fragmented plastics greatly outnumbered hard fragmented plastics. • Plastics >10 cm in length and white/clear color coded debris prevailed. [ABSTRACT FROM AUTHOR]

Copyright of Revista del Museo de Antropología is the property of Museo de Antropologia - IDACOR and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Volkheimerites labyrinthus gen. et sp. nov., an angiosperm pollen type, is fully described and illustrated. The specimens were retrieved from lower Paleocene strata of the Salamanca Formation (San Jorge Basin) located in Chubut Province, Patagonia, Argentina. Medium to large size (25.5–55 μm) and a characteristic striate sculpture with labyrinthine pattern are distinguishing features of the grains in this new genus. Volkheimerites labyrinthus shares the presence of a coarse tectum supported by columellae with the fossil genera Dichastopollenites, Trisectoris and Periretisyncolpites, and some Winteraceae and Annonaceae species, but differs in having striate-labyrinthine as opposed to reticulate ornamentation. Our material is also distinguishable by the occurrence of solitary grains (monads) instead of the more frequent presence of tetrads in the Winteraceae family or grains separated into two hemispheres as in Dichastopollenites. The large thin area of the exine appears to be morphologically analogous to the proximal thinning of the exine in the monads of tetrads as occurs in some Annonaceae species. The detailed description and illustration of this new angiosperm pollen genus expands our understanding of Paleocene plant diversity in Patagonia. [ABSTRACT FROM AUTHOR]

Dryland river systems support a diverse aquatic biota in semi-arid and arid landscapes, but they are increasingly vulnerable to natural and human impacts. This study provides the first modern diatom training set (n = 38) from three dryland rivers in northern Patagonia, Argentina. The relationship between surface-sediment diatoms and contemporary environmental variables was explored using multivariate analyses. The results showed that surface-water chemistry varies among rivers in accordance with local-scale factors such hydro-climatic variability and anthropic activities. A total of 378 diatom taxa were identified but only 45 taxa occurred with relative abundances higher than 2% in at least one sediment sample. The Colorado and Negro rivers were characterized by high abundances of small tychoplanktic fragilarioids whereas the Chubut River was dominated by epiphytic and planktic taxa. The canonical correspondence analyses (CCA) showed that conductivity, pH and HCO3− were the main environmental variables governing diatoms distributions. A transfer function was developed for water conductivity using unimodal methods because of partial CCA and λ1/λ2 ratio revealed that this variable had the largest unique effect on diatom variance. A weighted averaging (WA) model with tolerance downweighting and classic deshrinking provided a reasonably robust model (r2jack = 0.94 and RMSEP = 0.249 log10 μS cm−1). However, the diatom-inferred conductivity values should be carefully interpreted because of the uneven distribution of sampling sites and the dominance of small araphid diatoms belonging to the genera Staurosira, Pseudostaurosira and Punctastriata. By their benthic habitat, the distribution of these taxa could be influenced by other factors as light and substrate in addition to water chemistry. The autoecological information achieved through this study will provide the basis for a better insight into the hydrological responses of the dryland rivers in northern Patagonia to climate and environmental changes. [ABSTRACT FROM AUTHOR]

Abstract: A scanning and transmission electron microscopy-based ultrastructural study of Arcellites humilisVillar de Seoane and Archangelsky, 2008, from the Kachaike Formation and Piedra Clavada Formation (Albian-Cenomanian) from several localities in Patagonia (Argentina), is presented in this paper. TEM-photographs of thin-sectioned specimens show a thick spore body wall composed of three layers: a thin and dense exine, an inner granular perine sublayer with irregularly disposed small channels and lacunae, and an outer alveolate perine sublayer with channels perpendicular to the external surface. Transverse sections of the A. humilis wall are compared with fossil and extant species of Marsileaceae. We show that the wall ultrastructure is similar in A. humilis, A. santacrucensis, A. disciformis, A. stellatus and Regnellidium upatoiensis. However, the body wall and acrolamella of A. humilis are more similar to those of R. diphyllum Lindman than to those of the Marsilea L. or Pilularia L. species. Water ferns such as members of the Marsileaceae played an important role in aquatic or semi-aquatic niches in Patagonian Cretaceous floras, suggesting that high humidity and temperature prevailed during the Albian-Cenomanian in this region of Argentina. [Copyright &y& Elsevier]

This article investigates different forms of registry of the Mapuche concept in both Chile and Argentina after indigenous territories of Araucania and Patagonia were conquered, by late XIX century. A hypothesis is suggested concerning a difference in this registry, based on what was -within these contexts- the destination of Mapuche bodies on the one hand and of papers and documents created and accumulated by these populations before being included into both Sates sovereignties, on the other. We can see that in Argentina, bodies museographical inscription was privileged and, at the same time there was a document archives inscription which made Mapuche an historiographical and anthropological past element and lacking political validity at present. While in Chile, there is a population inscription of Mapuche bodies related to a kind of mestizo and state ideology through which the Mapuche concept got a kind of racial validity. This is how the idea of "reducto" arose as a category through which ambivalences from both types of inscription are analyzed so that the Mapuche concept has worked as a patrimonial capital of national sovereignty (associated to identity and autochthonousness) or, on the contrary as just the rest of a life or indigenous culture that persists and is managed in the political and historical limits of this same national sovereignty. [ABSTRACT FROM AUTHOR]

As world fisheries began to decline and massive collapses were observed, the competition between marine mammals and fisheries became an issue of growing concern. San Matías Gulf (Patagonia, Argentina) is considered to be a fishery ecosystem independent of the Argentine Continental Shelf waters, with particular oceanographic and biological properties. As a semi-enclosed ecosystem, this gulf may generate particular scenarios for interactions between the demersal trawl fishery fleet and the population of South American sea lions Otaria flavescens. In this paper, the diet of the top predator and the composition of fishery catches were characterized in order to assess the trophic overlap between these two components. This analysis and a comparison of the sizes of prey consumed revealed a low probability of competition for similar resources between the fishing fleet and the marine mammals in the San Matías Gulf ecosystem. [ABSTRACT FROM AUTHOR]

Abstract: Argentina is a special place to study Late Palaeozoic life and environmental change because of the excellent exposures of Late Palaeozoic sedimentary sequences. In particular, Patagonia has an almost continuous Late Palaeozoic succession containing well-preserved faunal assemblages characterized by both strong endemism and distinctive palaeobiogeographic links to Australia and northeast Asia. In this contribution an overview of the current knowledge of the invertebrate faunas of Patagonia and their biostratigraphic and palaeobiogeographic significance are presented, along with comments on the future prospects of research in the light of new findings. The Late Palaeozoic outcrops in central-western Patagonia belong to the Tepuel–Genoa Basin (Chubut province, Argentina), then located in southwestern Gondwana during the Late Palaezoic. In this basin the succession is >6000m thick, and constitutes a continuous and complete succession from the Lower Carboniferous to lower Permian. As such, it has the potential to serve as an important reference section for regional and intercontinental correlations. The marine Late Palaeozoic of Patagonia has yielded abundant and well-preserved representatives of most invertebrate groups: brachiopods, bivalves, gastropods, cephalopods, hyolithids, pelmatozoans, ostracods and cnidarians. Recently, studies of the Patagonian faunas have resulted in different opinions on the ages of the faunas. Biostratigraphic correlation is complex due to strong faunal provincialism. For this reason, there are several hypotheses concerning the biostratigraphic zonation in the basin. Since 1920, when studies of Late Palaeozoic strata in Patagonia were first carried out, numerous papers on stratigraphic, palaeogeographic and taxonomic subjects have been published, but our knowledge of Carboniferous–Permian fossils from the Tepuel–Genoa Basin is still incomplete. At present, we are attempting to integrate and calibrate the different faunal associations with a view to achieving a unified biostratigraphic biozonation scheme and hence a much improved understanding of the palaeobiogeographic relationship of Patagonian faunas with those from western Argentina and other continents. Currently, detailed stratigraphic and palaeontological research is being done in the type section of the Tepuel–Genoa Basin. The aim of our studies is to integrate all partial sequences exposed throughout the basin and to propose a biostratigraphic chart based on key invertebrate taxa. Once this goal is achieved, a global correlation can be conducted, especially with other sections in Gondwana and the Arctic. [Copyright &y& Elsevier]

Large carbonate microbialite build-ups are relatively uncommon in ancient fresh-water lacustrine basins as compared with those marine and saline environments. This paper discusses the formation of a large continental lacustrine deposit, the Oligocene-Miocene Carinao Formation in Argentina, which contains large bioherms. The lacustrine formation occurs in N-S corridor and is mostly composed by meter scale pinnacles and sheet-like carbonate beds that grade to detrital deposits towards the more subsident southern areas. The main facies are autochthonous and allochthonous limestones and detrital deposits. The autochthonous limestones include the carbonate pinnacles, which are about 4 m high and 0.5 m in diameter and coalesce laterally to form very continuous beds (several kms). The pinnacles are formed by plate-like, dome, vertically elongated and irregular horizontal bioherms, most of them with radial structure. The bioherms are boundstones of fibrous (fans and spherulites) and feather calcite crystals, micrite and inequigranular calcite mosaics. Both biogenic and abiogenic processes interfered in carbonate precipitation. Allochthonous limestones include peloidal, ostracod and intraclastic limestones, some containing coated grains. Polymictic conglomerates and cross-bedded hybrid arenites deposited in a fluvial-deltaic system located at the southwest of the basin. δ13C values vary between −0.4 and −3.2‰ VPDB and δ18O are comprised between −5.7 and −8.6‰ VPDB. The 87Sr/86Sr ratios range between 0.7061 and 0.7056. The Carinao Formation deposited in a fresh-water lake, sourced by meteoric and deep-groundwater. Tectonics was a main control determining the configuration of the lake system, the water supply and the alignment of some bioherms. The vertical succession or the different bioherms morphologies reflects well the lake level changes controlled by both tectonic and climate. [ABSTRACT FROM AUTHOR]

Summary: The pinnately lobed Aptian leaf fossil Mesodescolea plicata was originally described as a cycad, but new evidence from cuticle structure suggests that it is an angiosperm. Here we document the morphology and cuticle anatomy of Mesodescolea and explore its significance for early angiosperm evolution.We observed macrofossils and cuticles of Mesodescolea with light, scanning electron and transmission electron microscopy, and used phylogenetic methods to test its relationships among extant angiosperms.Mesodescolea has chloranthoid teeth and tertiary veins forming elongate areoles. Its cuticular morphology and ultrastructure reject cycadalean affinities, whereas its guard cell shape and stomatal ledges are angiospermous. It shares variable stomatal complexes and epidermal oil cells with angiosperm leaves from the lower Potomac Group. Phylogenetic analyses and hypothesis testing support its placement within the basal ANITA grade, most likely in Austrobaileyales, but it diverges markedly in leaf form and venation.Although many Early Cretaceous angiosperms fall within the morphological range of extant taxa, Mesodescolea reveals unexpected early morphological and ecophysiological trends. Its similarity to other Early Cretaceous lobate leaves, many identified previously as eudicots but in some cases pre‐dating the appearance of tricolpate pollen, may indicate that Mesodescolea is part of a larger extinct lineage of angiosperms. [ABSTRACT FROM AUTHOR]

Among turtles, cases of “gigantism” occur mostly in pleurodiran Pelomedusoides and cryptodirans, but are infrequent among pleurodiran chelids, which are mostly small-medium sized turtles. Yaminuechelys spp. are extinct South American long-necked chelids (from the Late Cretaceous–early Paleocene of Patagonia, Argentina) with caparaces almost three times larger than their extant sister taxon, Hydromedusa tectifera. Since evolutionary changes in size can be analyzed based on growth dynamics, we studied growth strategies from an osteohistological point of view. We sampled both extinct (Yaminuechelys maior) and extant (H. tectifera) species, in order to test hypotheses related to the mechanisms involved in the macroevolution of size within this clade. For this purpose, thin sections of long bone (humerus and femur) shafts of specimens of different ontogenetic stages for these species were prepared. The osteohistological study reveals a similar growth dynamic in both taxa, with a poorly vascularized cortex dominated by parallel- fibered bone and interrupted by lines of arrested growth (LAGs). The huge body size of Y. maior appears to be a consequence of the prolongation of the growth phase, suggesting that it had a longer lifespan than H. tectifera, allowing to reach greater sizes. In this way, and assuming that there is no displacement at the beginning of development (e.g., a delay in the earliest stages of growth) in H. tectifera, the acquisition of a large size in Yaminuechelys would be explained by hypomorphosis of the former or hypermorphosis of the latter, depending on the reconstruction of the ancestral condition of this clade. [ABSTRACT FROM AUTHOR]

In this paper, we present an updated revision of fossil vertebrates from the Chubut Group, Golfo San Jorge Basin, while also describing some new remains. Extensive exposures of both Lower and Upper Cretaceous sedimentary sequences are present in central Patagonia. These outcrops have, over the past several decades, yielded a varied vertebrate fauna, including fishes, turtles, crocodyliforms, pterosaurs, and dinosaurs, currently herein characterized and described. Although vertebrate diversity in the Chubut Group in central Patagonia is remarkable, the most abundant vertebrates recovered are dinosaurs. The Matasiete Formation (Hauterivian?–Albian) is markedly less prolific in terms of fossils discoveries than either the Bajo Barreal Formation (Cenomanian–early Turonian) or the recently recognized Lago Colhué Huapi Formation (Coniacian–Maastrichtian). The Bajo Barreal fauna is, at a high level, typical of coeval Gondwanan faunas. However, interestingly, several taxa occupy a basal position within their respective groups. The Lago Colhué Huapi Formation has produced a more derived vertebrate fauna, again similar to those from other Gondwanan regions. Finally, in a broad context, the new materials described augment our understanding of Cretaceous terrestrial vertebrate assemblage of central Patagonia and add to the generally meager record of vertebrate in the Cretaceous of the Southern Hemisphere. • South-central Patagonia preserves a rich and important vertebrate fossil record. • New materials described augment our understanding of Cretaceous vertebrate. • The information mentioned constitutes an important source for future comparisons. [ABSTRACT FROM AUTHOR]

The genus Prochelidella is the oldest known panchelid taxon. It is widely distributed in several Cretaceous basins throughout Patagonia, Argentina. It was previously known from three named species. A fourth species presented herein, Prochelidella buitreraensis sp. nov., preserves both cranial and postcranial material from the Candeleros Formation (La Buitrera Area) of Río Negro Province, Argentina. Features observed in the nuchal bone (i.e. wide, trapezoidal cervical vertebrae, shallow nuchal notch) allow us to assign this specimen to the genus Prochelidella. Several specific traits (i.e. a large open retropterygoideum foramen, and a strongly developed muscle attachment site on the basisphenoid) suggest that the form from the Candeleros Formation is a new species of the genus Prochelidella. A phylogenetic analysis that includes the three best-preserved species of Prochelidella recovers this taxon as monophyletic. The Cenomanian age of this new taxon allows us to compare the panchelid turtles from the Patagonian (Neuquen) and Australian (Surat) basins. [ABSTRACT FROM AUTHOR]

In north‐western Patagonia, obsidian was used during the entire Holocene, and its importance increased with time. Recent fieldwork discovered a new obsidian source located in the Río Grande, which was called 'Coche Quemado' (CQ). The results indicate that the CQ source has a different geochemical signal than all other sources in the region. Its use is spatially restricted to piedmont and, to a lesser extent, the plains. Chronologically, CQ was exploited in the middle and late Holocene, and its use accounts for a range of spatial distribution between 150 and 200 km. [ABSTRACT FROM AUTHOR]

Here I describe and illustrate 19 leaf morphospecies from the Paleogene Río Turbio Formation, Santa Cruz Province, Argentina. They were referred to the extant tropical and subtropical families Lauraceae (9 morphospecies), Malpighiaceae (1 morphospecies), Vitaceae (2 morphospecies), Anacardiaceae (2 morphospecies) and Sapindaceae (5 morphospecies). These taxa were recorded throughout the unit, but they are more abundant in the lower member of the Río Turbio Formation. The observed decreasing trend in megathermal taxa throughout the unit indicates the beginning of the flora turnover that characterized Patagonian ecosystems from the Late Eocene onwards and it is in agreement with the marked global cooling trend of the terminal Paleogene. [ABSTRACT FROM AUTHOR]

Cystic echinococcosis caused by Echinococcus granulosus is a major zoonosis of public health significance in the Patagonian region of Argentina. This investigation sought to test the hypothesis that the persistence and dispersion of the parasite eggs can be explained by physical and meteorological parameters along with final host infection and behaviour. This observational study was carried out over a five-year period within an enclosure where two dogs harbouring a worm burden ranging from 100 to 1000 mature adult E. granulosus , as well as two uninfected dogs, had previously been kept for six months. Environmental canine faeces, topsoil, pond water, and sediment samples were examined to control for the presence of eggs and coproantigens of the parasite using microscope-based techniques and copro-ELISA plus copro-Western Blot tests. The parasite eggs were detected up to 41 months later in faeces from infected dogs, soil and sediment, and coproantigen tests remained positive for up to 70 months in faeces. Overall, parasite eggs were found within a maximum distance of 115 m from the contaminated dog faeces deposition site. Our findings indicate that under Patagonian environmental conditions, egg persistence and dispersion seem to be related to the worm burden and habits of the infected dog, to prevailing wind direction and to the existence of low bushes as well as natural bodies of water. The present study is the first to provide direct evidence of interaction between bioclimatic conditions and E. granulosus egg dispersion under Patagonian field conditions. [ABSTRACT FROM AUTHOR]

Centrorynchus nahuelhuapensis n. sp. is described from the intestine of Strix rufipes , the rufous-legged owl, in Patagonia, Argentina. This species is characterized by the presence of 31–33 hook rows with 16–17 hooks per row, distributed as follows: 5 true hooks, 4 transitional hooks with 4 alate processes, more evident in the first three, 7–8 spiniform hooks, and three cement glands. It differs from most members of the genus by having a filiform body, the arrangement and size of the hooks, the number of cement glands, and egg size. Part of the SSU and LSU genes were sequenced and compared to those in GenBank. Sequences are most similar to other species of Centrorhynchus , supporting their placement within this genus. We present the first molecular study for a species of Centrorhynchus from South America. Additionally, it is the second species of the genus described in Argentina, and the first species of a terrestrial acanthocephalan from a bird in Patagonia. [ABSTRACT FROM AUTHOR]

Copyright of Tourism Geographies is the property of Routledge and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Jurassic siliceous hot-spring (sinter) deposits from Argentine Patagonia were evaluated to determine the distribution and preservation quality of their entombed microbial fabrics. Detailed study showed that the Claudia palaeo-geothermal field hosts the best-preserved sinter apron in the Deseado Massif geological province, where we also found hot-spring silica–biotic interactions extending into hydrothermally influenced fluvial and lacustrine settings. Carbonaceous material was identified by petrography and Raman spectroscopy mapping; it is inter-laminated with silica across proximal vent to distal marsh facies. The ubiquitous presence of microbial biosignatures has application to studies of hydrothermal settings of early life on Earth and potentially Mars. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Raptor Research is the property of Raptor Research Foundation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Exotic species introductions are a global phenomenon and protected areas are susceptible to them. Understanding the drivers of exotic species richness is vital for prioritizing natural resource management, particularly in developing countries with limited resources. We analyzed the influence of coarse resolution factors on exotic species richness (plants, mammals, and birds) in Argentina's National Parks System. We collected data on native species richness, year of park formation, park area, region, elevation range, number of rivers crossing area boundaries, roads entering area, mean annual rainfall, mean annual temperature, mean annual number of visitors, and Human Influence Index within and surrounding each park. We compiled 1,688 exotic records in 36 protected areas: 83% plants and 17% animals (9.5% mammals, 5.5% birds, 1.5% fishes, 0% amphibians, 0% reptiles). The five parks with the most exotic species (all taxa combined) were in north Patagonia. Exotic grasses were the most common exotic plants, and within animals, lagomorphs and feral ungulates were remarkably widespread. Exotic plant richness was mostly influenced by temperature and native plant richness, while exotic mammal and bird richness was driven mostly by anthropogenic variables, with models explaining 36-45% of data deviance. Most variables that positively influenced exotic taxa were indirectly related to an increase in spatial heterogeneity (natural or anthropogenic), suggesting greater niche space variability as facilitators of exotic richness increase. Additional data are needed to further investigate the patterns and mechanisms of exotic species richness in protected areas, which will help to prioritize the greatest needs of monitoring and management. [ABSTRACT FROM AUTHOR]

We present for the first time the vulnerability to disturbance of a bivalve assemblage situated in the middle intertidal zone of the Atlantic coast of the Southern South America (53°36′S, 67°58′W). This intertidal zone is characterized by a high level of sand movement preventing any establishment of sessile organisms on the vertical sides of rock outcrops. The coast is prone to potential spills from nearby hydrocarbon marine platforms, but this benthic assemblage has been poorly studied. In February 2001, we exposed the assemblage to two different experimental conditions: a complete removal of bivalves and a physical disturbance and tracked its recovery during the following 4 years. The disturbance lowered the diversity of associated fauna and made the sediment layer trapped among bivalves disappear, which was not restored. Mytilus chilensis was recruited into crevices or between byssi in the following settlement season, i.e. summer 2002. The recuperation of mussel coverage to predisturbance levels took 3 years after the total removal. In April 2004 the size frequency distributions, density and biomass/number ratio of M. chilensis were similar to those at the start of the experiment. Perumytilus purpuratus recovered more slowly than M. chilensis, probably due to its slower growth rate compared to M. chilensis and dependence on an adequate byssus matrix for settlement. The main apparent stressor was the irruption of sand, covering the bivalve assemblage for variable periods of time. This bivalve assemblage is characterized by low predatory pressure and therefore we hypothesize that it is predominantly controlled by competition for space. [ABSTRACT FROM AUTHOR]

In Northern Patagonia, the long-term vegetation–climate relationships that gave shape to southern South American forests have been the subject of extensive investigations in the Andean regions of Argentina and Chile for about a century. The Río Manso Superior originates in one of the tongues of the Cerro Tronador Glacier, near the international border, discharging into the Pacific Ocean after feeding present Lago Mascardi and flowing east to west on a mountain landscape. Ongoing pollen studies in this watershed provide us with a modern analogue to better understand the vegetation history of the region. A pollen record from a 15 m long sediment core retrieved from Lago Mascardi (41°08°S, 71°34°W) contains continuous evidence of vegetation changes in the Río Manso watershed extending back to the last deglaciation. High Andean steppe vegetation with forest patches, and extended waterlogged areas gave place to a forest, probably deciduous, during the Lateglacial–Holocene transition. A forest diversification took place during the climate amelioration that encompassed the deglaciation whilst the vegetation became more open before the onset of the Huelmo-Mascardi cold reversal. A mixed Nothofagus-Austrocedrus forest expanded during the middle Holocene. This forest became denser under the higher climate variability registered in the region during the late Holocene as shown by independent published data. Statistical analyses of modern pollen samples along an altitudinal transect from low Nothofagus forest and shrubland to high Andean semi-desert support this interpretation. Pollen results are discussed in the context of paleoenvironmental reconstructions at a regional scale. [ABSTRACT FROM AUTHOR]

Herein we describe a new rhynchocephalian taxon from the Middle Jurassic of Patagonia, Argentina, representing the first Jurassic record of the group in South America. The new taxon, consisting of a complete dentary, is ascribed to Sphenodontia based on the presence of a deep and wide Meckelian groove, long posterior process, well-developed coronoid process, and acrodont teeth showing dental regionalization including successional, alternate hatchling, and additional series. This allocation is reinforced by a phylogenetic analysis that places the new taxon in a basal position within a clade of sphenodontians that excludes Diphydontosaurus and Planocephalosaurus. Additionally, the new taxon clusters within a Gondwanan clade with the Indian Godavarisaurus from the Jurassic Kota Formation, sharing the presence of recurved and relatively large posterior successional teeth that are ribbed and bear a peculiar anterolingual groove. This sister-group relationship is intriguing from a palaeobiogeographical viewpoint, as it suggests some degree of endemism during the initial stages of the breakup of Pangaea. We also discuss the ontogenetic stage of the new taxon and provide insights on the evolution of successional dentition in rhynchocephalians. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 166, 342-360. [ABSTRACT FROM AUTHOR]

We describe fossil fruits collected from outcrops of the Salamanca Fm. (Paleocene, Danian, 63.3-61.9 Ma) at the Estancia Las Violetas locality, Chubut, Argentina that show affinities with members of the Subtribe Attaleinae, Tribe Cocoseae, Subfamily Arecoideae within the Arecaceae. The fossils are preserved as permineralizations, and were examined by longitudinal, tangential and cross-sections, as well as by the application of Computed Tomography Scanning technology (CT Scan). The fruits are ovoid drupes with 3 longitudinal grooves delimiting three valves; displaying apical stigmatic remains and a single apical germination pore. The exocarp and mesocarp are fused and anatomically indistinguishable one from another; they contain longitudinal fibrous bands with brachysclereids. A centrally placed seed occupies the single locule entirely; the seeds are deltoid with a basal hilum and acuminate tip while the endosperm is ruminate. The taxonomic position of the fossils was explored using phylogenetic analyses of molecular sequences combined with morphological data. Along with the suite of morphological characters that points to an affinity with the Subtribe Attaleinae, Tribe Cocoseae, subfamily Arecoideae, the results of the combined phylogenetic analyses confirm the taxonomic placement. This report constitutes the first confirmed record for the Subtribe Attaleinae worldwide and the first record of fossil palm fruits from Argentina. [ABSTRACT FROM AUTHOR]

The article presents a study which evaluates the use of mixed-breed guarding dogs for the reduction of predation and retaliatory killing of carnivores in Patagonia. It says that 64 herders in an approximately 57,000 kilometer square (km2) were interviews about predation on their livestock by different carnivore species from 2005-2011. Results show that mixed-breed dogs were effective in the reduction of both herder perceptions predation losses and retaliatory killing of carnivores.

We constructed a model to predict the potential distribution of Oligoryzomys longicaudatus, the reservoir of Andes virus (Genus: Hantavirus), in Argentina. We developed an extensive database of occurrence records from published studies and our own surveys and compared two methods to model the probability of O. longicaudatus presence; logistic regression and MaxEnt algorithm. The environmental variables used were tree, grass and bare soil cover from MODIS imagery and, altitude and 19 bioclimatic variables from WorldClim database. The models performances were evaluated and compared both by threshold dependent and independent measures. The best models included tree and grass cover, mean diurnal temperature range, and precipitation of the warmest and coldest seasons. The potential distribution maps for O. longicaudatus predicted the highest occurrence probabilities along the Andes range, from 32°S and narrowing southwards. They also predicted high probabilities for the south-central area of Argentina, reaching the Atlantic coast. The Hantavirus Pulmonary Syndrome cases coincided with mean occurrence probabilities of 95 and 77% for logistic and MaxEnt models, respectively. HPS transmission zones in Argentine Patagonia matched the areas with the highest probability of presence. Therefore, colilargos presence probability may provide an approximate risk of transmission and act as an early tool to guide control and prevention plans. [ABSTRACT FROM AUTHOR]

The Argentine Anchovy (Engraulis anchoita) is one of the most important pelagic fishery resources of the Patagonian Shelf and is known to be an important prey item for several seabirds of the northern Argentine coast. The South American Tern (Sterna hirundinacea) is endemic to the Atlantic and Pacific coasts of South America and, on the Atlantic coast, breeds from central Brazil to southern Argentina. Large non-breeding flocks form during the austral winter and spring from southern Brazil to northern Patagonia. The diet of the South American Tern was studied over three consecutive non-breeding seasons through the analysis of regurgitated pellets. The Argentine Anchovy comprised >80% (index of relative importance) of fish prey in the diet, and remained important throughout the study period. Other important fish prey were Cornalito Silverside (Odonthestes incisa), Pejerrey Silverside (O. argentinensis) and Stripped Weakfish (Cynoscion guatucupa). The growing interest in commercially fishing Argentine Anchovies makes it important that studies are conducted to determine the potential effect of the harvest of Anchovies on South American Terns and other top predators. [ABSTRACT FROM AUTHOR]

Copyright of Studies on Neotropical Fauna & Environment is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The ichnospecies Phagophytichnus pseudocircus isp. nov. is described to include trace fossils characterized by leaf-margin excisions showing eccentricity values of 0.35–0.65 and more than 270 degrees of an arc, a non cuspate margin and vein stringers or necrotic flaps of tissue along the margin. A method for determining ellipse eccentricity was performed on leaf discs obtained from the nests of the modern leafcutter bee Megachile rotundata (Hymenoptera: Megachilidae), which provided objectively obtained values comparable to the trace fossil from the middle Eocene of Argentina and other world-wide ichnological records, historically and subjectively considered to be ‘circular’ trace fossils and attributed to leafcutter bees. The material described herein represents the first evidence for fossil Megachilidae from the Southern Hemisphere. [ABSTRACT FROM AUTHOR]

Research Highlights: Lodge abandonment by beavers is apparently a common phenomenon in Patagonia, but it is still poorly understood and we ignore what drives it. In relatively slow growth Nothofagus forests, resource depletion can impact abandonment while water availability may be a major driver in the semiarid steppe. Background and Objectives: North American beaver (Castor canadensis) was introduced in 1946 on the island of Tierra del Fuego (TDF) in southern Argentina. Since then, beavers have become a major disturbance affecting not only forest but also treeless steppe landscapes. Our goal was to determine the factors affecting lodge abandonment by beavers in two habitats of TDF: forest and steppe. Materials and Methods: A total of 47 lodges were surveyed between February and March from 2012 to 2014 in both habitat types, 22 in the forest and 25 in the steppe. To explain factors involved in lodge abandonment by beavers, we measured the following variables: water level variation, stream gradient, vegetation cover adjacent to shore and forest structure. Results: We recorded 24 abandonments events, with a similar proportion of lodges abandoned in both habitats. Our results revealed that lodge abandonment was mostly linked to water level fluctuations irrespective of habitat type. The water level at the entrances of the lodge generally decreased in abandoned lodges. Variables that characterize understory cover had some influence on lodge abandonment in the forest, and no effect in the steppe. Conclusions: Water level variation was associated with lodge abandonment in both habitats, and we found some evidence of resource depletion in the forest. However, we caution that changes in water level may be not only due to extrinsic factors but rather to beaver's own activities or to a decay in pond maintenance following abandonment. [ABSTRACT FROM AUTHOR]

Over 80 samples of fossil woods were collected from numerous outcrops of the Río Turbio Formation, southwestern Patagonia. Preservation of the woods is variable and only about half of these samples could be identified to genus level. The assemblage consists of six types of conifers and four types of dicotyledons, one of them a new species of Caldcluvioxylon (Cunoniaceae). We provide an emended diagnosis of Caldcluvioxylon. A previously described fossil wood from this stratigraphic unit, thought to have affinity with Proteaceae, was re-examined and is described herein as Scalarixylon romeroi sp.nov. Other families recognized in the Río Turbio Formation wood assemblage are Araucariaceae, Podocarpaceae, and Nothofagaceae. Differences in the taxonomic composition of the upper and lower members of the Río Turbio Formation are consistent with the age difference between them according to recent isotopic dating. The diversity of fossil wood is also consistent with the fossil leaves and pollen from each stratigraphic level and most of the taxa are shared with coeval Antarctic fossil wood floras. [ABSTRACT FROM AUTHOR]