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The Salado and Verde streams constitute the two main seasonally available freshwater courses that flow into the Atlantic coast of the Río Negro province (continental Patagonia, Argentina, 42° South). This would have favored their use in the past as corridors for human circulation between the coast and the interior. This paper presents the results of the technomorphological and geochemical analyses of the obsidian artifacts recovered in the area to constrain mobility. The results allow us to propose the existence of toolkit reconditioning or replacement activities, and the identification of different sources of provenance of the obsidians (Sacanana, Telsen, and Portada Covunco, distant up to 800 km from the study area), reinforcing the hypothesis of a coast–inland circulation, with the possible existence of circuits of exchange of this raw material. [ABSTRACT FROM AUTHOR]

Patagonian shrub and ecotonal communities were sensitive to past environmental changes and thus may also be affected by future ones. Therefore, their paleoecological study constitutes a valuable tool to understand the way in which these plant communities respond to the forcings responsible for environmental variability. The aim of this paper is to reconstruct the vegetation dynamics of the Pueyrredón Lake area (47°25′55′′ S; 72°0.7′7′′ W) for the last 3000 cal yr BP and to contextualize these changes in a regional paleoclimatic framework. The results indicate that at the beginning of the 2900 cal yr BP, the vegetation in the northwest of Santa Cruz, Argentinian Patagonia, was represented by a grass-shrub steppe associated with forest–shrub steppe ecotonal elements. This information correlates with the larger-scale environmental inferences described for the period, which indicate an increase in moisture availability due to the weakening of the westerly winds. A marked change to arid conditions is indicated in the last 1050 cal yr BP, with the establishment and development of different shrub steppe communities and the lack of ecotonal elements. Although vegetation was sensitive to changes in moisture conditions related to the variability of the westerly winds, there is evidence of differences in the composition of shrub vegetation regarding the sequences analyzed. Variations in pollen proportions of the shrub steppes in the Pueyrredón Lake area suggest that changes in vegetation are not only due to climate variability but also local factors in the areas where shrub communities grow. The integration of the information with other Patagonian sequences allowed to frame these changes in a regional context. The results obtained provide useful information to understand the way vegetation changed in the past and the manner in which it may respond to future changes. [ABSTRACT FROM AUTHOR]

The Patagonian coast has been occupied at least since the Middle Holocene but the way in which humans have interacted with spaces and resources in different areas of the coast has varied. As such, it is important to study the specifics of each occupation. In this paper, the activities that would have taken place at Cabeza de León 1 archaeological site, Monte León National Park, Santa Cruz province, Argentina, are addressed from the study of the recovered lithic assemblages. Results show the use of local raw material, the development of all manufacture stages in situ and the implementation of mainly expedient strategies. It can also be inferred that activities were mostly related to the capture and processing of resources. La costa patagónica ha sido ocupada desde mínimamente el Holoceno medio, pero el modo en que los humanos interactuaron con el espacio y los recursos a lo largo del tiempo en los distintos sectores fue diferente, lo que hace necesario estudiar las particularidades de cada ocupación. Aquí se abordan las actividades tecnológicas que se habrían desarrollado en el sitio Cabeza de León 1, sito en el Parque Nacional Monte León (Santa Cruz, Argentina), a partir del estudio de los materiales líticos allí recuperados. Estos muestran el empleo mayoritario de materias primas locales, la realización de todas las etapas de manufactura in situ, la implementación de estrategias tecnológicas principalmente expeditivas, y también permiten inferir actividades mayoritariamente vinculadas a la captura y procesamiento de recursos. [ABSTRACT FROM AUTHOR]

In order to understand the paleogeographic evolution of Viedma Lake (252 masl) sedimentary sequences with glaciolacustrine and lacustrine strata between 307 masl and 266 masl and bathymetric fluctuations between 27 ka. and 2.4 ka. were identified. The paleoenvironmental interpretation of the stratigraphic profiles was carried out based on the analysis of facies and their associations. The oldest age was recorded at 301 masl (27 ka) and the youngest corresponds to 266 masl (2.4 ka). The record of 27 ka was compared with another dated record of the Tar-San Martin Lakes basin showing that Viedma – Tar-San Martín Lakes were formed at similar ages. Taking into account that the deposits of Bahía Túnel are located at 266 masl and that the level of the lake would be above this height, it is proposed that this lake level would have restricted the movement of hunter-gatherer populations along the coast and to the west. From 2.4 ka on a new space started to be available for these populations broadening the wintering grounds (≤400 masl). The chronology of the archaeological record found in this new space fits the proposed paleogeographic evolution. This paper complements the research on the evolution of lacustrine systems in the Patagonian Mountain range and broadens the discussion of human mobility in the Viedma Lake basin during the Holocene. [ABSTRACT FROM AUTHOR]

In a seminal paper regarding the mechanisms of carbonate stromatolite formation, Ginsburg (1991, Controversies in Modern Geology, pp. 25–36) emphasized the need to question the relative role of microbes versus environment in their formation. The Maquinchao Basin is a continental lacustrine system in southern Argentina. It provides an ideal site to study carbonate buildups, the role of microbes and environmental stressors in their development and their implications in palaeoenvironmental reconstructions. Presently, the basin encompasses two lakes (Carri Laufquen Grande and Carri Laufquen Chica) joined by the ephemeral Maquinchao River. Fossil microbialites are found south and southwest of the largest lake. Preferential areas of development for fossil microbialites have been mapped using a high‐resolution differential Global Positioning System. Outcrops are located between 820 and 830 m elevation, higher than actual lake levels and the Maquinchao River where living microbialites have been observed. Field data along with microscopical observations and X‐ray diffraction analyses have revealed a heterogeneity in both distribution and macro‐morphotypes since carbonate buildups display different morphologies such as crust, columns, open flower‐like, rounded and ellipsoids. Conversely, on the meso and micro‐scale they show more homogeneous morphologies including laminations and shrubs. These microbial buildups are associated with basaltic substrates of variable size from pebbles to boulder. The homogeneity in meso and micro‐structures argue in favour of stable intrinsic parameters (i.e. microbial communities) whereas the variable macro‐morphotypes indicate changing extrinsic constraints such as steepness, energy and turbidity. The occurrence of distinctive morphotypes in buildups separated by outcrop and topography suggest that the Maquinchao microbialites are indicative of a former larger lake. Thus, the Maquinchao microbial buildups are a valuable proxy for water‐level evolution and therefore palaeoenvironmental reconstructions. They can be further used to interpret the apparently random distribution of morphological types and extension of microbialites in the geological past. [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]

In this paper, the analysis of a radiocarbon database of the North Coast of Santa Cruz (central Patagonia, Argentina), is presented. Dated archaeological samples were obtained from 56 different types of archaeological sites (open-air -residential sites and burials-, and also rock shelters). The objective of this paper is assessing the continuities and discontinuities in the chronological signal of the area and identifying tendencies along the Holocene. The database currently contains 75 radiocarbon dates falling between ca. 8000 and 300 BP. The radiocarbon data base provides information on the chronological, spatial and contextual variability of the archaeological record of North Coast of Santa Cruz. By means of different analysis of sum of probabilities, we present three different chronological moments of human use of the coast and intermediate zone can be identified. A first moment is represented by early evidence of settlement during Middle Holocene. A second moment corresponds to a hiatus between ca. 5800 and ca. 3900 BP without archaeological evidence. Finally, a third moment is where an increasing of chronological signal occurred, related to greater artifactual variability and an increase in the intensity of human settlement in the Patagonian region. The causes that could have influenced in the discontinuity of the chronological signal of the study area, and the characteristics of the different moments identified are discussed. [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]

Aucasaurus garridoi is an abelisaurid theropod from the Anacleto Formation (lower Campanian, Upper Cretaceous) of Patagonia, Argentina. The holotype of Aucasaurus garridoi includes cranial material, axial elements, and almost complete fore- and hind limbs. Here we present a detailed description of the axial skeleton of this taxon, along with some paleobiological and phylogenetic inferences. The presacral elements are somewhat fragmentary, although these show features shared with other abelisaurids. The caudal series, to date the most complete among brachyrostran abelisaurids, shows several autapomorphic features including the presence of pneumatic recesses on the dorsal surface of the anterior caudal neural arches, a tubercle lateral to the prezygapophysis of mid caudal vertebrae, a marked protuberance on the lateral rim of the transverse process of the caudal vertebrae, and the presence of a small ligamentous scar near the anterior edge of the dorsal surface in the anteriormost caudal transverse process. The detailed study of the axial skeleton of Aucasaurus garridoi has also allowed us to identify characters that could be useful for future studies attempting to resolve the internal phylogenetic relationships of Abelisauridae. Computed tomography scans of some caudal vertebrae show pneumatic traits in neural arches and centra, and thus the first reported case for an abelisaurid taxon. Moreover, some osteological correlates of soft tissues present in Aucasaurus and other abelisaurids, especially derived brachyrostrans, underscore a previously proposed increase in axial rigidity within Abelisauridae. [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]

Glacial geologic studies in the Southern Hemisphere (SH) mid-latitudes (40-54°S) indicate renewed glacial activity in southern South America (Patagonia) and New Zealand's (NZ) South Island starting at ∼7 kyr, the so-called neoglaciation. Available data indicate that neoglacial advances in these regions occurred during a rising trend in atmospheric CO and CH concentrations, lower-than-present but increasing summer insolation and seasonality contrasts. In this paper we examine the climatological context in which neoglaciations occurred through analysis of the complete Paleoclimate Modelling Inter-comparison Project (PMIP2) database of simulations at 6 kyr for the SH. We observe that the amplitude of the annual insolation cycle in the SH did not change significantly at 6 kyr compared to the pre-industrial values, the largest difference occurring in autumn (MAM, negative anomalies) and spring (SON, positive anomalies). The simulated changes in temperatures over the SH respond to the insolation changes, with a 1-2 month delay over the oceans. This results in a reduced amplitude of the annual cycle of temperature and precipitation over most continental regions, except over Patagonia and NZ, that show a slight increase. In contrast, large-scale circulation features, such as the low and upper level winds and the subtropical anticyclones show an amplified annual cycle, as a direct response to the increased/decreased insolation during the transitional seasons SON/MAM. In the annual mean, there is a small but consistent equatorward shift of the latitude of maximum wind speed of 1-3° over the entire SH, which results in a small increase of wind speed over the South Pacific and Atlantic Oceans north of ∼50°S and a widespread decline south of 50°S. PMIP2 simulations for 6 kyr, indicate that in the annual mean, the SH mid-latitudes were colder, wetter and with stronger winds north of about 50°S. These conditions are consistent with the observed neoglacial advances in the region, as well as with terrestrial paleoclimate records from Patagonia that indicate cooling and a multi-millennial rising trend in Southern Westerly Wind intensity starting at ∼7.8 kyr. [ABSTRACT FROM AUTHOR]

In recent years, the colonial expansion of modern society has been studied by various disciplines and from a range of theoretical perspectives. South American historical archaeologists in particular have highlighted the homogenizing nature of this global process in order to re-evaluate the particular nature of different contexts in time and space. This paper focuses on the articulation between the scales of the global and the local and explores the role of local processes in the constitution of colonial societies. Latin-American postcolonial theory - or decolonized thinking - adds to this debate through the critical assessment of modernity in order to acknowledge colonial legacies in the social sciences. This perspective is presented here in combination with a case study from the Spanish colonization of the Patagonian coast in the late eighteenth century, in particular the settlement of Nueva Poblacion y Colonia de Floridablanca (Bahia San Julian, province of Santa Cruz, Argentina). [ABSTRACT FROM AUTHOR]

This contribution is part of a more extensive assessment of the effects of air pollution in urban environments in Patagonia (Argentina) through its effects on the lichen flora. Different methodologies were applied. This paper presents calculations of the Index of Atmospheric Purity (IAP) for urban contaminated (Bariloche city) and periurban uncontaminated environments, calculated at sites for which data were available on the elemental composition of contaminating elements. The IAP results obtained were correlated with the elemental composition of lichen thalli. Principal Component Analysis and Cluster Analysis were performed to determine data partitioning using Ward's method. The results yielded four clusters: three of them correspond to thalli and IAP values from urban areas, where the most important factors affecting the lichen flora have been identified as their proximity to medium to high traffic density or petrol stations. Thalli from periurban uncontaminated environments form an independent cluster, characterized by lower concentrations of contaminating elements and higher IAP values. The results obtained allow IAP to be related to atmospheric conditions in these human settlements and evaluation of the ecological effects of these settlements on the natural environment by comparison with unaltered surrounding environments. [ABSTRACT FROM AUTHOR]

This paper describes the diversity, taphonomy and palaeoecology of angiosperm leaves that dominate a palaeoflora of Cretaceous (Cenomanian–Coniacian) age from the Mata Amarilla Formation in the Austral Basin, south-west Patagonia, Argentina. Twelve morphotypes of angiosperm leaves are recognized based on foliar morphotype analysis of more than 500 specimens. These were divided into six morphological groups based on major architectural patterns. The relative dominance of these morphotypes, mode of preservation and relationship with sedimentary facies were evaluated from two levels within the formation. This analysis identified two different plant palaeocommunities. The lower, María Elena, level (MEL) was deposited in a marine coastal area on a subaerial delta plain; the dominant angiosperm morphotypes preserved in it are group 1 (MA100) and group 2 (MA101, 102); morphotypes MA109 and 110 are scarce but exclusive to this level. The upper, Mata Amarilla, level (MAL), accumulated inland in flood-plain environments; the most abundant angiosperm morphotypes are groups 3 (MA103–105), 4 (MA106) and 1 (MA100); morphotypes MA103–105 and 108 are exclusive to this level. Comparisons with other floras of similar age from Antarctica, Australia and New Zealand indicate that the Mata Amarilla flora has a slightly higher morphological diversity of angiosperm leaves, providing the first evidence for an angiosperm-dominated early Late Cretaceous macroflora in south-west Gondwana. [ABSTRACT FROM AUTHOR]

We often wonder how many of the pristine places left on Earth we can protect from deterioration before it is too late. The assumption that remote regions remain pristine plays a key role in directing policies for regional environmental management and conservation, and affects the local and global financial impetus to do so. In this paper, we use Argentinean Patagonia and the SW Atlantic as examples to argue that the assumption 'remote region = pristine region' is unjustified and based on a lack of information rather than on scientific evidence. We also discuss the major existing environmental threats to this supposedly 'pristine' region, and use emblematic examples to provide a more realistic picture of the regional environmental integrity and to set recommendations directed to improve environmental management and conservation within this context. [ABSTRACT FROM AUTHOR]

A new gigantic titanosaur Bustingorrytitan shiva gen. et sp. nov. is described. The four specimens upon which this species is erected come from Neuquén Province, Argentina, from levels of the Huincul Formation (Cenomanian). Bustingorrytitan shiva gen. et sp. nov. exhibits some autapomorphic characters such as posterior dorsal vertebrae with spinodiapophyseal laminae bifurcated in two, very well developed anterior and posterior spinodiapophyseal lamina rami, which limit a deep, vertical, socket-like fossa; posterior dorsal neural arches with forked centropostzygapophyseal laminae; hyposphene in anterior caudal vertebrae; humerus with deltopectoral crest strongly expanded distally; and femur with a low longitudinal crest on the lateromedial half of the anterior face, bifurcated in two minor crests, which are directed to their respective condyles. The phylogenetic analysis performed recovers B. shiva gen. et sp. nov. as a lithostrotian, the sister taxon of Saltasauridae. The estimated body mass is 67.297 metric tons (with a standard error of ±17.228), which makes B. shiva gen. et sp. nov. one of the largest sauropods ever recorded. The record of this new sauropod corroborates the idea that gigantism (evolution of forms over the 50 metric tons) would have evolved many times within Eutitanosauria. [ABSTRACT FROM AUTHOR]

Question: Livestock grazing affects plant communities in drylands worldwide. However, our current understanding of the Patagonian drylands has primarily been derived from comparing exclosures with grazing conditions or from single‐site grazing gradients. The pending question is: do impacts of grazing intensification on Patagonian plant communities change along aridity gradients? Location: Patagonia, Argentina. Methods: We surveyed vegetation cover of perennial species in paddocks with different sheep‐grazing pressure (ungrazed, lightly, moderately, and intensively grazed, based on long‐term stocking rates), in three plant communities located along a regional aridity gradient: a semi‐desert (arid), a shrub–grass steppe (semi‐arid), and a grass steppe (dry sub‐humid). In these communities, we analyzed the effects of grazing pressure on the total cover of vegetation, the cover of dominant plant life‐forms (grasses and shrubs), the plant species diversity, and the traits of dominant plant species. Results: Intensification of sheep grazing significantly decreased total vegetation cover in the semi‐desert, but not in the steppes. Although grazing decreased the cover of grasses (particularly of the highly preferred ones) in all communities, in the shrub–grass and grass steppes this reduction was offset by an increase in the cover and size of shrubs. Plant diversity was not consistently affected by grazing pressure in these communities. Traits of dominant plant species partially explained community responses to grazing intensification. Conclusions: Livestock grazing intensification reduces the forage quantity and quality of Patagonian plant communities, but the severity depends on plant community types. In semi‐deserts (the most arid), grasses were drastically affected, while in the steppes, the grazing effects on grasses were low and partially compensated by an increase in the cover and size of shrubs, which fulfill critical roles other than forage provision. It is fundamental that grazing pressure be adapted to forage resource availability for each community type to achieve sustainable management in the context of climate change. [ABSTRACT FROM AUTHOR]

Polychaetes, echinoids and gastropods have been proposed as tracemakers for Bolonia Meunier, an elongate positive epirelief trace fossil characterized by two lobes composed of biserial, subtriangular pads and a mostly heart‐shaped cross‐section. Here, the internal structure and micromorphology of Bolonia are described for the first time using serial thin sections from shallow‐marine Lower Cretaceous intervals of the Agrio Formation (Neuquén Basin, Argentina). In vertical thin sections, a conical structure of variable width extends centrally from the base to the top of the trace. In horizontal thin sections, grains are reoriented and reworked, forming a central zigzag structure. The organic matter and clays form grain aggregates representing the internal structure of individual pads of the trace fossil. The sediment has mostly been reoriented, with grains making up subcircular pods. We interpret the central conical structure as the collapse of the medial zone of the trace fossil, which could have destroyed drain tubes, especially in the absence of early cementation. Studying horizontal thin sections, we reconstruct the diagnostic biserial pads as biserial concave structures. These are interpreted as backfilling structures produced by the aboral and lateral spines of irregular echinoids, which worked together to compact the sediment anteroposteriorly and moved alternatively, explaining the zigzag pattern in the menisci. We propose Spatangoidea or Cassiduloidea (or a closely related group) with a similar burrowing ability and spine movement as tracemakers of these Bolonia specimens. [ABSTRACT FROM AUTHOR]

Goeppertella has been postulated as a monophyletic group, whose precise position within the Gleichenoid families Dipteriaceae and Matoniaceae, remains poorly understood. Previously described Goeppertella specimens are based on frond fragments and its fertile morphology is represented by a few, poorly preserved specimens. We describe a new species based on the largest collection of fertile specimens known to date and discuss the evolutionary history of the genus based on the additional reproductive characters provided by the fossils described. Plant impressions were collected in Early Jurassic sediments of Patagonia, Argentina. The specimens were described, and silicone rubber casts were developed to examine in detail vegetative and reproductive features. The new species was compared with other Goeppertella species. Finally, a backbone analysis was performed in the context of a previously published combined matrix of Dipteridaceae, using the maximum parsimony criterion. The new species is described based on a combination of features that have not been previously reported. The vegetative morphology shows affinities with most fossil and extant Dipteriaceae, contrasting with the reproductive morphology which is more comparable with the scarce number of fossil dipteridaceous forms and it is more spread in the sister family, Matoniaceae. The backbone analysis indicates that the position of the new species vary among different positions among Dipteridaceae and Matoniaceae. Additional analyses, discriminating the signal of reproductive and vegetative character, are provided to discuss the base of this uncertainty. We consider Goeppertella as a member of the family Dipteridaceae since we interpret most shared features with Matoniaceae as plesiomorphic conditions for the family. In contrast, most shared features with Dipteridaceae represent apomorphies for the group. Thus, Goeppertella would represent an early diverging genus in Dipteridaceae, considering the venation characters as the most important in order to define the family. [ABSTRACT FROM AUTHOR]

Ruddy-headed goose Chloephaga rubidiceps has a migratory population that overwinters mainly in the Pampas region, Argentina, and breeds in Southern Patagonia. This population has decreased considerably, with less than 800 individuals remaining to date. We conducted the first assessment on the influence of environmental and anthropogenic-impact (wind farms and high-voltage networks) variables on ruddy-headed goose migration pathways across the Patagonian coast by applying kernel density analyses and statistical procedures. We used satellite tracking data obtained from six ruddy-headed geese during their migration pathways between 2015 and 2018. Five core distribution areas were identified during migration. During autumn migration, core areas were associated with high primary productivity and low elevation areas, while during spring migration they were located in the proximity of watercourses and waterbodies. We found that more than 30% of the grid cells included in the influence area of high-voltage networks overlapped with high-density areas for ruddy-headed geese during both migrations. Around 30% of the grid cells included in the influence zone of wind farms overlapped with high-density areas for ruddy-headed goose during autumn migration; while this applied to only 13% during spring migration. We highlight areas of high-risk along the distributional range of the species where large-scale patterns of collision mortality are likely to occur and mitigation measures should be prioritized. We suggest proactive measures that could mitigate future collisions with energy infrastructure because, given their threatened status, a few deaths may have a large effect on the small remnant population. [ABSTRACT FROM AUTHOR]

This study presents the first detailed description of the upper sedimentary succession of the late Pleistocene and Holocene deposits in the Gulf of San Jorge (Patagonia) based on several hundred kilometers of high‐resolution seismic (sparker) profiles and numerous sediment cores. High‐resolution seismic stratigraphy confirms the existence of a paleo‐fluvial network formed during sea‐level lowstands and buried by central basin estuarine deposits during the last marine transgression. Analyses of lithostratigraphy and radiocarbon ages indicate the onset of subtidal sedimentation at ~14 cal ka bp. Before the onset of subtidal conditions, the first steps of marine incursion seem to have led to the development of lagoonal/wind–tidal flat environments, advocating for a sea‐level stillstand. An abrupt increase in the log(Ti/Ca) ratio in a distinct multi‐centimeter‐thick layer and the identification of a wave‐ravinement surface suggest rapid sea‐level rise in the gulf prior to ~14 cal ka bp, consistent with Meltwater Pulse 1A. Overall, this study highlights the significant impact of sea‐level rise on sedimentation in the gulf from the onset of marine incursions to the mid‐Holocene, as well as the reduced contribution, as currently observed, of riverine inputs due to the progressive diminution and withdrawal of glacial drainage starting before the Holocene. [ABSTRACT FROM AUTHOR]

Patagonia features the most extensive glaciers of the Southern Hemisphere, excluding Antarctica, and a vast inventory of glacial landforms, so it is thought to have played a key role in (paleo)glacier studies since the late 19th century. However, no systematic attempts to characterize the specific research trends and the scientific community focused on Patagonian cryosphere have been conducted so far. To fill this gap, we analyzed the metadata associated to 305 articles compiled from the Web of Science database following a bibliometric approach covering the period between 1976 and 2020. Our results point to an irregular but net increase on the number of contributions on Patagonian (paleo)glaciers. Mass balance analyses based on satellite data of present-day glaciers and the reconstruction of past glacier activity by dating glacial landforms formed during the Last Glacial Termination, were the most addressed topics during the analyzed period. Patagonian (paleo)glacier studies are mostly published in generic Earth Sciences publications, followed by Quaternary and glaciological journals. Most of the studies were led by scientists from the United Kingdom, followed by Chile, Argentina and United States. In terms of collaborations, these studies can be divided into two main clusters, one composed by researchers from United States, Chile and Argentina institutions, and another mostly composed by British researchers. So far, the most prolific authors are nearly equally distributed in nationality, yet gender inclusion and international collaborations are still caveats that must be solved. Even though our query on the Web of Science missed highly influential (so-called) grey literature, such as local scientific journals and technical reports, the reviewed scientific literature unambiguously indicates that Patagonia is a privileged location for (paleo)glaciers studies worldwide and that it will continue offering vast opportunities to tackle critical questions related to global cryosphere and past-to-present climate changes. • Patagonia is a privilege site for studying present and past glacier dynamics and the evolution of climate changes at hemispheric and global scale. • Glacier dynamics during the 20th century and and the Last Glacial Termination are the most common topics addressed in past decades in the WOS. • Patagonian (paleo)glacier studies has contributed to the development or improvement of diverse analytical techniques. • United Kingdom, United States, Chile and Argentina produced the largest number of WOS-listed papers on (paleo)glaciers in past decades. • The related scientific community is fairly heterogeneous. Although, inclusion and international collaboration issues still need to improve. [ABSTRACT FROM AUTHOR]

Península Valdés, Patagonia, Argentina, is recognized as a calving ground for the southern right whale (SRW, Eubalaena australis) population from the southwestern Atlantic Ocean. Previous studies have reported that SRWs feed during their calving season, but little is known about their foraging ecology in this area. Here, we collected photo data of SRWs at Península Valdés from 2007 to 2019 to monitor and investigate the SRW feeding frequency and to know whether calves also feed on zooplankton (i.e., the diet composed of both milk and solid food). In addition, we systematically reviewed studies on the composition and abundance of zooplankton to assess the available prey for SRWs in the area. Finally, we examined satellite-derived chlorophyll-a (chl-a) to study if the chl-a variability shows any relationship with SRW feeding. Observations show that at Península Valdés, SRWs feed at and below the surface, primarily on calanoid copepods. We also found evidence that SRWs feed near-bottom. In addition, we report calves feeding at surface including the first-ever photographs documentation. Whales feed mainly during austral spring, with a higher mean frequency in November. A time lag of 1 month was found between highest chl-a levels and the highest number of feeding events observed. Over the 12-year study period, we observed that whales were foraging yearly, which indicates that feeding in this calving area is more frequent than prior studies suggested. These data reveal the importance of the waters off Península Valdés as a multi-use habitat for SRW. [ABSTRACT FROM AUTHOR]

Noting the minimal research in South America related to cultural remains which could have become submerged due to sea-level rise at different stages in the past since the Pleistocene–Holocene transition, we take a systematic approach in this article towards making a positive contribution regarding inundated sites and landscapes in Eastern Patagonia and Tierra del Fuego, Argentina. This is a region with a vast continental shelf and high potential for addressing significant archaeological topics such as human migration routes, characteristics of peopling processes, and the use of space and natural resources in the Southernmost part of the American continent. In the context of the latter, the study of submerged landscapes can shed light on past use of the marine environment and its resources. We begin by presenting a regional overview of the archaeological record which can be chronologically and geographically relevant for the topics considered. The characteristics of such record, combined with a general evaluation of coastal and underwater geomorphology as well as other environmental variables, is used to infer some possible targets or "hotspots" with higher potential for past human use as well as preservation of cultural remains. This article provides a basis for further model-developing and ground-truthing surveys. [ABSTRACT FROM AUTHOR]

The most representative ankylosaurian remains from Argentina have been found in sediments of the Allen Formation (Campanian–Maastrichtian) in Salitral Moreno, Río Negro Province. Several authors have discussed the identity and history of these remains. In this study, we review all published material along with some new remains in order to summarize all the knowledge about these ankylosaurs. Previously published material includes a tooth, dorsal and anterior caudal vertebrae, a femur and several osteoderms. The new remains include synsacral and caudal elements, a partial femur and osteoderms. The anatomy of the tooth, the synsacrum, the mid-caudal vertebra, the femur and the osteoderms, and the histology of the post-cervical osteoderms, support a nodosaurid identification, as proposed in previous descriptions of the Salitral Moreno material. Patagopelta cristata gen. et sp. nov. is a new nodosaurid ankylosaur characterized by the presence of unique cervical half-ring and femoral anatomies, including high-crested lateral osteoderms in the half rings and a strongly developed muscular crest in the anterior surface of the femur. The ∼2 m body length estimated for Patagopelta is very small for an ankylosaur, comparable with the dwarf nodosaurid Struthiosaurus. We recovered Patagopelta within Nodosaurinae, related to nodosaurids from the 'mid'-Cretaceous of North America, contrasting the previous topologies that related this material with Panoplosaurini (Late Cretaceous North American nodosaurids). These results support a palaeobiogeographical context in which the nodosaurids from Salitral Moreno, Argentina, are part of the allochthonous fauna that migrated into South America during the late Campanian as part of the First American Biotic Interchange. [ABSTRACT FROM AUTHOR]

Permo-Triassic magmatism is widespread in the eastern North Patagonian Massif and has been related to the Gondwanide orogeny. Although a magmatic arc setting is widely accepted for the Permian plutonic rocks, the origin and geotectonic setting for the Triassic plutonic and volcanic rocks are still unknown. A NW-SE Triassic dyke swarm composed of andesites and latites with minor rhyolites was previously described in the Sierra Grande – Rincon de Paileman area. The dyke swarm was associated with extensional tectonics which was linked to a postorogenic process. In this paper we present new geochemical data of the rocks that form the swarm. Trachyandesites and rhyolites were separated based on their geochemical characteristics. Both groups may be considered originated from different sources. On the other hand, the content of incompatible elements (LILE and HFSE) indicates a strong relation between the swarm and an active continental margin. The samples also show a transitional signature between continental-arc and postcollisional or anorogenic settings. The new geochemical data on the dyke swarm support the idea of a magmatism that was linked to a postorogenic extensional tectonic regime related to a continental magmatic arc. Such an extension started in the Paleopacific margin of Pangea during the Anisian and might indicate the beginning of the Pangea break-up. [ABSTRACT FROM AUTHOR]

The aim of this paper is to evaluate the usefulness of TanDEM-X DEM (digital elevation model) for remote geomorphological analysis in Argentinian Patagonia. The use of a DEM with appropriate resolution and coverage might be very helpful and advantageous in vast and hardly accessible areas. TanDEM-X DEM could represent an unprecedented opportunity to identify geomorphological features because of its global coverage, ~12 m spatial resolution and low cost. In this regard, we assessed the vertical accuracy of TanDEM-X DEM through comparison with Differential Global Positioning System (DGPS) datasets collected in two areas of the Patagonia Region during a field survey; we then investigated different types of landforms by creating the elevation profiles. The comparison indicates a high agreement between TanDEM-X DEM and reference values, with a mean absolute vertical error (MAE) of 0.53 m, and a root mean squared error (RMSE) of 0.73 m. The results of landform analysis show an appropriate spatial resolution to detect different features such as beach ridges, which are impossible to delineate with other lower resolution DEMs. For these reasons, TanDEM-X DEM constitutes a useful tool for detailed geomorphological analyses in Argentinian Patagonia. [ABSTRACT FROM AUTHOR]

This paper summarizes and discusses the main results achieved over three decades of research on paleodemographic aspects of Late Holocene hunter-gatherers in Northwestern Santa Cruz (Argentina). Research has been guided by a model of regional settlement that proposes that, as a result of the progressive aridization process recorded in Patagonia during the Late Holocene, human groups would have reduced their residential mobility and concentrated their settlements in low altitude basins with water availability, such as Lake Cardiel and Lake Salitroso. Paleodemographic questions derived from the model relate to population regional continuity and dynamics and were tested using several lines of research at regional and local scales. The assessment of the chronological information and temporal trends of the archaeological record at the regional level allowed for a coarse grain paleodemographic approach, and acted as a mean to support hypotheses related to changes in mobility and land use strategies. Building on this, several lines of bioarchaeological evidence were used to address paleodemographic aspects of the model, including temporal, distributional, and compositional studies of the mortuary record, isotopic, morphometric and DNA analyses and the sex and age structure of the skeletal samples recovered in Lake Salitroso basin. Results point to a biological and cultural population continuity in the region during the Late Holocene. Also, a reduction in residential mobility would have favored a slight population growth of Lake Salitroso populations during the last millennium. [ABSTRACT FROM AUTHOR]

Premise: Two distinct types of fossil infructescences from the early Eocene Laguna del Hunco flora, Chubut Province, Patagonia, Argentina, preserve features of the family Cunoniaceae. The goal of the study was to assess their affinities within Cunoniaceae and to interpret their evolutionary and biogeographical significance. Methods: Specimens were collected from the Tufolitas Laguna del Hunco, Huitrera Formation. They were prepared, photographed, and compared morphologically with similar extant and fossil fruits and infructescences using published literature and herbarium material. Results: The fruit and infructescence morphology place the fossil taxa within Cunoniaceae. They do not conform to any extant genus, supporting the erection of two new fossil genera. Racemofructus gen. nov. shares diagnostic features of the tribe Cunonieae, especially Weinmannia s.l., and exhibits two tribal morphological synapomorphies: a racemose inflorescence and a replum composed of a single column. Cunoniocarpa gen. nov. specimens are paniculate inflorescences with basipetally dehiscent, bicarpellate capsules that have persistent styles and calyces. Its replum morphology suggests an affinity to the tribe Caldcluvieae, particularly to the genus Ackama. Conclusions: The new Patagonian fossils described herein constitute the oldest record of cunoniaceous capsules globally, supplementing a significant body of fossil evidence from pollen, wood, and reproductive structures from southern South America and Antarctica that suggests that the Cunoniaceae were diversified and widely distributed in the southern hemisphere by the early Eocene. Racemofructus and Cunoniocarpa are, respectively, the first fossil records from South America of reproductive structures with affinity to tribes Cunonieae and Caldcluvieae. [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]

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]

Abstract: The average age at sexual maturity (ASM) is an important parameter for evaluating the reproductive potential or status of a population. South American sea lions, Otaria flavescens in Patagonia (Argentina) were exploited and reduced to less than 10% of pre-exploitation numbers. At present, the population is recovering at a rate of 6%. In this paper, we studied growth and age at sexual maturity of South American sea lions in the south-western south Atlantic by examining 219 individuals (females and males) collected between 1989-2008. Individuals were aged by counting growth layer groups in tooth sections, standard body length was measured and male and female reproductive organs were examined macroscopically and histologically to establish individual sexual maturity. Maximum recorded length for males and females was 264cm and 200cm, respectively, and maximum ages 19 and 21 yrs. ASM defined as the age where 50% of females are mature, was estimated at 4.8±0.5 years old, corresponding to a mean SL of 147cm, about 81% of their asymptotic length. First observed ovulation occurred during the 4th year, first birth may occur between 4 and 5 years old. Males physiologically mature between 4-6 years, but the size of the testes shows that all males became sexually mature by the age of 9 years when they reach a mean SL of 212cm, about 86% of their asymptotic body length. The present information on ASM and growth of O. flavescens will improve the development of population dynamics models, to investigate the impact of recovering sea lions populations on its marine environment, as well as its trophic interactions with commercial fisheries. [ABSTRACT FROM AUTHOR]

The western slope of Cerro Domuyo in northern Patagonia is characterized by thermal springs with boiling waters, Quaternary silicic domes, and pyroclastic deposits that suggest the existence of a geothermal reservoir. According to geochemical studies, the reservoir may have a temperature of 220 °C and one of the largest advective heat fluxes reported for a continental volcanic center. In this paper, we propose a more refined conceptual model for the Domuyo geothermal area, based on a geological survey supported by U Pb, U Th, and Ar Ar geochronology and by magnetotelluric and gravity surveys. Our study indicates that the Domuyo Volcanic Complex (DVC) is a Middle Pleistocene dome complex overlying middle Miocene to Pliocene volcanic sequences, which in turn cover: 1) the Jurassic-Early Cretaceous Neuquén marine sedimentary succession, 2) silicic ignimbrites dated at ~186.7 Ma, and 3) the Paleozoic metamorphic basement intruded by ~288 Ma granite bodies. The volcanic cycle in the DVC is distinctly bimodal, characterized by the emplacement of massive silicic domes and less voluminous olivine basalts on its southern slope. A major collapse of the central dome at ~600 ka produced a voluminous (19.4 km3 and 133 km2) block-and-ash flow, and associated pyroclastic flows, that filled a valley to the southwest at distances up to ~30 km from Cerro Domuyo summit. This was followed by a period of intense effusive activity that formed the Cerro Guitarra, Cerro Las Pampas, Cerro Domo, and Cerro Covunco silicic domes. The last two domes are the youngest and largest edifices, dated at 0.50 Ma (Ar Ar age) and 0.25 Ma (U Th age). Pre-Cenozoic successions were affected by N-S reverse and thrust faults that were later displaced by an ENE-WSW-trending transtensional belt. The basement rocks at the northern termination of the Cordillera del Viento anticlinorium were also displaced towards the east-northeast by this belt, which is observed NNW of Cerro Domuyo. The DVC was emplaced within this zone of crustal weakness. The integration of geologic observations with magnetotelluric and gravity data, allowed us to develop an updated conceptual model of the geothermal system. The geothermal reservoir is inferred at a depth of less than 2 km within pre-Pliocene fractured rocks, bounded by ~WSW-ENE trending faults and sealed by the pyroclastic deposits and rhyolitic lavas of the DVC. The location of most thermal springs is not directly controlled by faults. Instead, flows emerge at the contact between the fractured and faulted basement and the caprock. • The Domuyo Volcanic Complex (DVC) is a silicic dome complex formed in the Pleistocene. • The central dome collapsed at ~600 ka producing a voluminous (19.4 km3) pyroclastic deposit. • The youngest domes were emplaced at ~500 ka and 250 ka. • The DVC was emplaced within a ENE-WSW trending transtensional zone of crustal weakness. • The geothermal reservoir is hosted in pre-Pliocene rocks sealed by the DVC pyroclastics and lavas. [ABSTRACT FROM AUTHOR]

The article offers information on the heterogeneity of Rhodotorula mucilaginosa, a carotenogenic yeast from Patagonia, Argentina. Rhodotorula mucilaginosa is a yeast species with world-wide distribution in terrestrial, freshwater, and marine habitat. It also has an ability to colonize a large variety of substrate. A study was conducted to assess the phenotypic and genetic variability of Rhodotorula mucilaginosa, collected from natural and artificial environments in Argentina. The study allowed the detection of a genetically distinct group of the yeast species.

Riverine and wind-borne materials transferred from Patagonia to the SW Atlantic exhibit a homogeneous rare earth element (REE) signature. They match well with the REE composition of Recent tephra from the Hudson volcano, and hence this implies a dominance of material supplied by this source and other similar Andean volcanoes. Due to the trapping effect of proglacial and reservoir lakes, the larger Patagonian rivers deliver to the ocean a suspended load with a slightly modified Andean signature, that shows a REE composition depleted in heavy REEs. In this paper we redefine Patagonia as a source of sediments, which is in contrast with other sources located in southern South America. Quaternary sediments deposited in the northern and, to a lesser extent, in the southern Scotia Sea, and most of the dust in ice cores of east Antarctica have REE compositions very similar to the loess from Buenos Aires Province and to Patagonian eolian dust. However, we rule out Buenos Aires province as a Holocene major source of sediments. Similarly to Buenos Aires loess (a proximal facies), it is likely that the REE compositions of most sediment cores of the Scotia Sea and Antarctica reflect a distal transport of dust with an admixed composition from two main sources: a major contribution from Patagonia, and a minor proportion from source areas containing sediments with a clear upper crustal signature (e.g., western Argentina) or from Bolivia’s Altiplano. Evidence indicates that only during the Last Glacial Maximum, Patagonian materials were the predominant sediment source to the southern latitudes. [Copyright &y& Elsevier]

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]

In this study we explored how picoplankton community structure and diversity varied along three cascade oligo-mesotrophic reservoirs of the Limay River (Patagonia, Argentina): Alicura, Piedra del Águila and Ramos Mexía. We analyzed the spatial changes, covering lotic and lentic stretches along a gradient of 262 km from Andes to steppe, and we also sampled the main affluent of the Limay River (Collon Cura). In all sampling sites the main limnological variables were measured, and the picoplankton abundance (autotrophic and heterotrophic) was analyzed by flow cytometry. The bacterial biodiversity was assessed using high throughput sequencing Illumina MiSeq. We expected an increase in the trophic state along this series of cascade reservoirs, which would determine spatial differences in the structure of the picoplankton communities. We also hypothesized that the lotic and lentic conditions along the system would influence the bacterial composition. The results showed a slight increase in trophic state together with an increase in overall picoplankton abundance downstream, towards Ramos Mexía Reservoir. Picocyanobacteria were represented by phycoerythrin-rich cells all along the system, in accordance to the pattern described for oligotrophic aquatic ecosystems. Multivariate analyses based on bacterial OTU composition and environmental variables showed a spatial ordination of sites following the trend of increasing trophic state downstream. Molecular analyses of bacterial OTU diversity also showed an increase in richness and a decrease in evenness at the lotic stretches, and the opposite pattern in the reservoirs, suggesting that water retention time may play a role in structuring the community composition. [ABSTRACT FROM AUTHOR]

The short-term effects of coastal untreated effluents from Ushuaia Bay, Beagle Channel, on the biochemical and physiological biomarkers of Mytilus chilensis were assessed. An integrated biomarker response (IBR) index was calculated as a helpful tool to represent the general stress of the experimental organisms. Cultured mussels were exposed during 96 h to three coastal sites impacted by sewage effluents. At the beginning (T0) and every 24 h, mussels were subsampled from each site and different biochemical and physiological biomarkers were determined. There was no mortality registered in the experiments during the 96 h. However, biochemical and physiological biomarkers presented significant variations. Lipid peroxidation mean levels in mussels decreased in mantle and increased in digestive gland with respect to T0 in almost all cases. Acetylcholinesterase activity was inhibited in all sites, reaching a maximal decrease of 35% with respect to T0. Catalase remained stable and glutathione-S-transferase was activated. Oxygen consumption and ammonia excretion rates increased in organisms from two sites and, consequently, O:N ratio decreased, denoting a symptom of stress. IBR values showed the existence of different stress levels between exposed and unexposed mussels. These results exhibited an alteration of the general metabolism of mussels exposed for a short period of time to untreated coastal wastewater, suggesting the use of these organisms as early indicators of changes in the environmental quality of coastal waters of Ushuaia Bay. [ABSTRACT FROM AUTHOR]

The North Patagonian gulfs, Argentina, support an important population of small pelagic fish (SPF) that play a key role in the marine ecosystem. Here, we assessed the seasonal SPF distribution in Nuevo gulf and San Matías Gulf concerning several environmental variables and the nautical area scattering coefficient (NASC) of Munida gregaria using generalized additive models (GAMs). We collected biological data by a 38/200 kHz echosounder along zigzag transects in all four seasons. The echoes of fish were separated from other targets using a dB difference algorithm. Then, we calculated the mean NASC of pelagic fishes every 0.5 nm. Satellite‐derived data were used to characterize the environment at study sites. GAMs were built in two stages for each gulf considering all season in a single model in one hand, and each season separately in the other one. In the first stage, we modeled the probability of presence as a function of predictors. In the second stage, we used the NASC of fish as the response for presence data only. In general terms, the probability of fish presence increases with bottom depth, and the fish density was higher in cold waters and zones with higher chlorophyll‐a concentration. The relative importance of the variables was different according to the season. The formation and rupture of the thermocline and its subsequent spatial heterogeneity observed in spring and autumn could be important drivers of SPF distribution. Squat lobsters' distributions related positively with SPF in San Matías Gulf summer and negatively in Nuevo Gulf summer. [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.)

The discovery of theropod shed teeth associated with sauropod remains is relatively common in Cretaceous deposits of Patagonia. However, only a handful of studies have thoroughly explored the phylogenetic affinities of the theropod dental material. Here, we describe and identify twelve theropod shed teeth associated with a partially complete skeleton of a titanosaur sauropod from the Allen Formation (middle Campanian-lower Maastrichtian; Upper Cretaceous) of Paso Córdoba, Río Negro, Argentina. Using three methods, namely a cladistic analysis performed on a dentition-based data matrix, and a discriminant and cluster analyses conducted on a large dataset of theropod teeth measurements, we identify three dental morphotypes which are confidently referred to abelisaurid theropods. Whether the morphotypes represent different abelisaurid subclades or different positional entities within the jaw of the same abelisaurid species, is unknown. Such an identification, nevertheless, provides additional evidence of abelisaurids feeding on sauropod carcasses. This study highlights the importance of using combined qualitative and quantitative methodologies to identify isolated theropod teeth, especially those that can provide direct information on feeding ecology. [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.)

Species in the genus Notocotylus (Trematoda, Notocotylidae) are cosmopolitan parasites of mainly aquatic birds and, to a lesser extent, mammals. In this paper we describe Notocotylus primulus n. sp. parasitizing the Crested Duck, Lophonetta specularioides , from the Patagonian coast, southwestern Atlantic Ocean, based on morphological and molecular data. The new species could be distinguished from its congeners by the combination of several features; among them, the position of the genital pore that is prebifurcal and located close to the posterior margin of the oral sucker, a greater number of both ventral papillae and uterine loops, and a large cirrus sac. Molecular results of the ITS2 sequence support the location of this new species in the genus Notocotylus due to a close relationship with Notocotylus malhamensis (the lower genetic distance of the ITS2 sequences). Unlabelled Image • Notocotylus primulus n. sp. is described from Lophonetta specularioides from Argentina. • The new species is morphologically and genetically characterized • It is the first record of a trematode parasite in the endemic Crested Duck. [ABSTRACT FROM AUTHOR]

Cephalomys is the best-known cephalomyid, recorded in five localities in Argentina and known from well-preserved mandibles, fragments of skull, and a large number of isolated teeth, from both juveniles and adults. Despite this, a modern description is lacking and the validity of some species of Cephalomys has been questioned in the last few years. New material from the Deseadan locality of Cabeza Blanca (Chubut, Argentina), including skull fragments unknown for the species thus far, and well-preserved juvenile teeth, along with a large number of specimens from collections in Argentina, allow us to propose a more complete description of the genus and a new taxonomic arrangement for the Cephalomys species. We also analysed some dubious records of Cephalomys from Quebrada Honda and Pico Truncado and confirm that they are not part of this genus. We consider C. plexus to be a synonym of C. arcidens, we consider the combination previously proposed for C. bolivianus (as a species of Asteromys) to be valid, and we consider C. ceciae also to be a valid species. We performed a phylogenetic analysis including for the first time all cephalomyids (Cephalomys, Litodontomys, Cephalomyopsis, Soriamys and Banderomys) and possibly related genera (Perimys, Scotamys, Asteromys) to test the position of the family Cephalomyidae among the other caviomorph rodents, as well as its validity and internal relationships. The results recovered Cephalomyidae as a clade, including Cephalomys, Cephalomyopsis and Litodontomys. The monophyly of Cephalomys could not be confirmed. Soriamys and Banderomys were recovered within Cavioidea. Perimys, Scotamys and Asteromys were recovered within Chinchilloidea, and we analysed the implications of their positions within the group. The implications in terms of the biochron, distribution and evolutionary history of the Cephalomyidae, considering the new definition for the family proposed herein (including only Cephalomys, Cephalomyopsis and Litodontomys), are discussed, as well as inferences regarding caviomorph evolution at the scale of the entire group. [ABSTRACT FROM AUTHOR]

This study presents the first detailed glacial geomorphological map of the sediment-landform assemblages formed by three eastern outlet glaciers of the former Patagonian Ice Sheet. These glaciers occupied the Río Corcovado, Río Huemul and Lago Palena/General Vintter valleys, Chubut province, Argentina (43°S, 71°W). By combining remote sensing and field-mapping, we build on previous ice-sheet scale mapping and geological surveys to provide high-resolution spatial information on local ice-contact glaciogenic, glaciofluvial, glaciolacustrine, and subglacial landforms. Twenty-five landform types, many of which are newly mapped in the region, were digitized as georeferenced shapefiles over a 5300 km2 area. This map enables the identification of former ice-flow directions, relative ice-margin positions and glaciofluvial drainage pathways for each preserved Quaternary glaciation. It also elucidates the former areal extent, geolocation and spillways of glaciolacustrine bodies formed during the last deglaciation. The map delivers an essential framework on which to build robust glacier-scale geomorphological and geochronological reconstructions. [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]

Aims: Photodegradation of senescent plant material has been identified as an important vector of aboveground carbon (C) loss in aridland ecosystems, but the consequences for biotic activity and soil C in the field are not well understood. Methods: We established an experiment in a semiarid woodland in Patagonia, Argentina with attenuation of solar radiation and additions of leaf litter to evaluate impacts of photodegradation on changes in labile C and biotic activity in aboveground litter and surface soils. Results: Litter decomposition was significantly accelerated by exposure to solar radiation. Moreover, labile sugars (hexoses and pentoses), microbial enzymatic activity (β-glucosidase activity) and available carbohydrates for cellulase degradation (saccharification) all significantly increased in sunlight-exposed litter. None of these stimulatory effects were observed in the surface soils exposed to sunlight. On the contrary, soil microbial biomass and β-glucosidase activity in surface soils were significantly greater only with litter addition and attenuated sunlight. Conclusions: Our results suggest that photodegradation of plant litter (production of volatile compounds through photochemical mineralization) and photofacilitation (stimulation of biotic activity due to change in litter chemistry with exposure to sunlight) generate rapid turnover of C in aboveground litter. The consequences of this accelerated C turnover may be that a fraction of leaf litter decomposes and is directly released back to the atmosphere as CO2 and never enters soil organic matter pool. Taken together, these results highlight the functional importance of solar radiation in determining the C balance in semiarid ecosystems. [ABSTRACT FROM AUTHOR]

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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]