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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]

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]

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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]

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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]

In this paper, we analyze the difficulties in access to social rights in Argentina by migrant groups from neighboring countries, particularly women from the Andean world (Bolivia), in the justice field. In an ethnographic approach and with contributions from the decolonial perspective, we present various situations that Quechua- -speaking women experience in the Cuenca del Golfo San Jorge (Argentina) which exemplify a set of restrictions and violence that operate in the context of social inequalities. Thus, some social practices linked to differential ways of understanding life in society and justice stand out, resignified in the migratory context that accounts for the agency of migrant groups. State institutions must initiate a process of transformation focused on legal pluralism, the intercultural approach, and the intersectionality of gender perspectives. [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]

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]

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]

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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]

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Copyright of Relaciones de la Sociedad Argentina de Antropología is the property of Sociedad Argentina de Antropologia 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 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]

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]

Analysis of 519 obsidian artifacts (pebbles, debitage, cores and small bifaces) by nondestructive X-ray fluorescence from forests and steppes of southern Lanín National Park in the northern Patagonian Andean region, from Lácar (chemical group QU/AP), Lolog (CP-LL 1), Filo Hua-Hum (FHH), Paillakura (Pk, former unknown 1 group), Meliquina (MQ, former unknown group 2) and Yuco (YC) sources. Neutron activation analysis was applied to 29 of the artifacts. We identified for the first time the presence of obsidian from distant Covunco (PC1) in the center of Neuquén. This paper is the first English language publication of our ongoing, ten-year-long research. In accordance with previous work, but using other analytical techniques, the most frequently used sources during the late Holocene remain CP/LL 1 and Pk, here we add YC, mainly by the incorporation of new sites recently surveyed in the islands and the coast of Lake Lácar, next to its source. Another result consistent with previous work is the absence of obsidian from Mendoza and Chilean sources; therefore, we suggest these obsidians circulate just to the east and northeast, allowing us to discuss issues of human territoriality during the Late Holocene. [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]

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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]

This paper presents a glacial geomorphological map of landforms produced by the Lago General Carrera–Buenos Aires and Lago Cochrane–Pueyrredón ice lobes of the former Patagonian Ice Sheet. Over 35,000 landforms were digitized into a Geographical Information System from high-resolution (<15 m) satellite imagery, supported by field mapping. The map illustrates a rich suite of ice-marginal glacigenic, subglacial, glaciofluvial and glaciolacustrine landforms, many of which have not been mapped previously (e.g. hummocky terrain, till eskers, eskers). The map reveals two principal landform assemblages in the central Patagonian landscape: (i) an assemblage of nested latero-frontal moraine arcs, outwash plains or corridors, and inset hummocky terrain, till eskers and eskers, which formed when major ice lobes occupied positions on the Argentine steppe; and (ii) a lake-terminating system, dominated by the formation of glaciolacustrine landforms (deltas, shorelines) and localized ice-contact glaciofluvial features (e.g. outwash fans), which prevailed during deglaciation. [ABSTRACT FROM AUTHOR]

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is perhaps the most iconic representative of the Abelisauridae family. It is known by a fairly complete specimen, recovered from Upper Cretaceous beds of southern Argentina. Here we present a re-study of the skull of Carnotaurus including detailed osteological descriptions, CT scans analyses and comparisons with abelisaurid taxa. Novel information concerning bones that remained undescribed (i.e., palate) is also offered. The present study allowed the recognition of several features, including some new potential autapomorphies diagnostic of Carnotaurus, such as nasolacrimal conduct with an accessory canal, ventral excavation on the quadrate and lateral fossa of the pterygoid. We identify some additional features of Carnotaurus shared with other abelisauroids, including: dorsal row of nasal foramina, lateral fossa on the squamosal, lanceolate vomeropterygoid process of palatine, apneumatic ectopterygoid and narrow and pointed angular process of surangular. CT scans revealed pneumatic recesses in the lacrimal which are similar to those present in other theropods. Furthermore, a striking feature is the presence of a small pneumatic recess on each frontal horn. Carnotaurus provides one of the most complete skulls within Abelisauridae, which allows recognising several traits of potential phylogenetic value and raises new questions regarding variability of cranial pneumaticity among ceratosaurs. [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]

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 Ameghiniana is the property of Argentine Paleontological Association / Asociacion Paleontologica Argentina 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.)

Copyright of Revista de la Sociedad Entomológica Argentina is the property of Sociedad Entomologica Argentina 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.)

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]

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]

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]

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This paper reports the pollen sources selected by Apis mellifera in the area northwest of Santa Cruz (Argentina). It evaluates the relative biomass contribution and the protein content of the collected taxa. During the apicultural period (September 2008-March 2009) pollen loads from three colonies were collected every fortnight using pollen traps. Forty-two pollen types were found in the samples, from which 15 taxa had a biomass contribution over 1% of the total pollen crop. The main pollen sources were Brassicaceae, Taraxacum officinale, Convolvulus arvensis, Rosaceae, Salix spp. and Schinus marchandii (Anacardiaceae). Of the total pollen sources identified, 15 are new records for the bee pollen flora of Argentina and 13 are native plants of South America. The contribution of native flora occurred mainly in spring. Schinus marchandii, Mulguraea-Junellia type (Verbenaceae), Adesmia spp. (Fabaceae), Sysirinchium spp. (Iridaceae), Acaena spp. (Rosaceae), Astereae and Senecio spp. (Asteraceae) were the indigenous pollen types with the highest biomass contribution. Protein content of most collected pollen types was variable (between 13.25% and 24.43%). [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]