Pampean Region Research Articles

Sensitivity of Daphnia spinulata Birabén, 1917 to glyphosate at different salinity levels.

Daphnia spinulata Birabén, 1917 is an endemic cladoceran species, frequent in the zooplankton communities of the shallow lakes of the Pampean region of Argentina. These lakes have varying salinity levels and, being located in agricultural areas, are frequently subject to pesticide pollution. This study aimed to determine the effects of the herbicide glyphosate (Panzer Gold®) in combination with different salinity levels on the biological parameters of D. spinulata and its recovery ability after a short exposure. Three types of assays were performed: an acute toxicity test, a chronic assessment to determine survival, growth and reproduction, and recovery assays under optimal salinity conditions (1g L-1). The LC50-48h of glyphosate was 7.5mg L-1 (CL 3.15 to 11.72). Longevity and the number of offspring and clutches were significantly reduced due to the combined exposure of glyphosate and increased salinity. The timing of the first offspring did not recover after glyphosate exposure. Our results reveal that D. spinulata is sensitive to the herbicide Panzer Gold® at concentrations well below those indicated in the safety data sheet of this commercial formulation, which causes stronger negative effects in conditions of higher salinity. Further research is needed to shed light on the sensitivity of this cladoceran to glyphosate and its variability under other interactive stress factors.

Perceptions and knowledge of local people toward an endangered armadillo from the Buenos Aires coast, Argentina

ABSTRACT In a large area used for livestock production in the north east of the Pampas region of Buenos Aires, central Argentina, there is a subpopulation of endangered armadillo species (Chaetophractus vellerosus) which is threatened by mining activities. Knowledge and perception of local communities living in the range of the endangered species were evaluated using an anonymous online questionnaire. A total of 618 questionnaires were filled out, with the majority of respondent (82%) not being aware of the existence of this species. The study documented the lack of knowledge and the need to develop strategies to increase local communities’ awareness toward this species.

Vertical distribution of edaphic oribatid mites (Acari: Oribatida) in two artificial forests planted on temperate grasslands

Context Oribatid mites are the most abundant taxon in forest soils that rely on porosity and organic matter availability. Exotic forests of Pinus radiata and Eucalyptus globulus planted over native grasslands in the Pampas region of Argentina have produced modification in soil properties, which can affect the composition and structure of native oribatids communities. Aims To compare oribatid communities in soils under artificial woodlands of pine and eucalyptus and to assess the vertical distribution of oribatids in relation to edaphic variables. Methods In each forest, oribatids were collected from three levels of the A horizon: (1) litter layer; (2) 0–5 cm; and (3) 5–10 cm. Edaphic variables measured were penetration resistance, bulk density, total porosity, pH and water content and luminosity at soil level. Density, species richness, diversity and evenness of oribatids were calculated in each level of each forest. Comparisons were made through multivariate analyses. Key results Edaphic variables showed no significant differences between plots but litters were structurally different. Richness and diversity showed no differences between plots whereas evenness was significantly higher in plot P. Density had higher values in the litter layer of both forests. Canonical Analysis of Principal Coordinates (CAP) showed that Pine plots had a more defined vertical distribution. Conclusions The structure and composition of litters promoted differences in the vertical distribution of oribatids. In Pinus, thick unaltered litter showed a marked vertical gradient of mites along levels while in Eucalyptus, thin and easily decomposing litter, showed no vertical patterns. Implications Assessment and management of soil biodiversity in artificial woodlands.

Note on the unparallel vertical distribution of nitrate and sulfate in Mollisols

AbstractSoil fertility diagnosis often omits subsoil measurements, impacting precision. Our objective was to compare the vertical distribution of nitrate and sulfate in agricultural Mollisols. Both anions were measured in 34 Mollisols of the Pampean region (Argentina) sampled to 160‐cm depth at 20 cm intervals. Nitrate exhibited a continuous downward trajectory, with maximum values at 0–20 cm (12.7 mg N kg−1) and minimum values at 140–160 cm (3.3 mg N kg−1). Sulfate displayed a sinuous pattern, with a minimum at 60–80 cm (3 mg S kg−1). The 60–160/0–160 cm concentration ratio was 42% for nitrate and 60% for sulfate, indicating greater topsoil stratification for nitrate. Predicting deep‐layer nitrate concentrations from topsoil data was more accurate than for sulfate. This poses a challenge for assessing soil S bioavailability, as subsoil sulfates go undetected in conventional sampling.

Identification of long-preserved specimens reveals the historical geographic range of the Patagonian lamprey Geotria macrostoma (Burmeister, 1868) in southern South America.

The lamprey genus Geotria Gray, 1851 currently includes only two species: G. australis and G. macrostoma. However, taxonomic relationships within the genus have traditionally been ambiguous and difficult to establish due to the extreme changes in morphology, dentition, and coloration that lampreys undergo during their life cycles, particularly during upstream migration and sexual maturation. Consequently, several lamprey specimens held in museum collections have remained unidentified, especially those from Argentina. In this study, a series of morphometric characters were subjected to discriminant function analysis (DFA) to identify the lamprey species collected during 1867-2004 from the de la Plata River and Patagonia. These specimens are housed at the Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" in Buenos Aires, the Museo de Historia Natural de Montevideo, and the Naturhistoriska riksmuseet in Stockholm. Based on the proportions of the length of the oral disc, prebranchial, and pre-caudal body regions, and the depth of the trunk, DFA provided conclusive evidence that the specimens corresponded to the recently revalidated G. macrostoma (Burmeister, 1868), which was originally incorrectly named as Petromyzon macrostomus Burmeister, 1868, Exomegas macrostomus (Berg, 1899), Geotria chilensis (Berg, 1895), and Geotria macrostoma f. gallegensis Smitt, 1901, as well as other nontype museum individuals of uncertain taxonomic status. The identifications of these long-preserved museum specimens provided key information on the historical geographic range of Argentinian lampreys and suggest that the disappearance of the species reported from northern localities (the Pampean Region) can be attributed to the degradation of their critical habitats, primarily caused by anthropogenic impact and climate change.

Searching to improve connectivity in fragmented landscapes: Road verges as complementary habitats

AbstractAimsFunctional connectivity is crucial for conserving biodiversity and ecosystem services in fragmented landscapes. Linear landscape elements play an important role in providing refuge for plants and pollinators, as well as serving as biological corridors. The aim of this study was to assess the importance of road verges in maintaining the ecological connectivity of plant species assemblages in the Tandilia mountain system.LocationSouth America, Southern Pampa region of Argentina, Tandilia mountain system.MethodsUsing graph theory, landscape connectivity was quantified both at landscape scale and at the patch scale using the probability connectivity index (PCnum), taking into account the dispersal ability of observed species. The contribution of each landscape element to habitat availability and connectivity was evaluated using different fractions of the PCnum metric. Likewise, the influence of connectivity variables in explaining species assemblages grouped by functional categories was investigated using canonical ordination techniques.ResultsThe inclusion of road verges led to an 81% increase in overall connectivity at a threshold distance of 500 m. Connectivity significantly explained the assemblages of entomophilous plant species for all dispersal distances. Annual species assemblage variation was associated with intra‐patch connectivity. Variation in perennial and shrub species assemblages was explained by intra‐patch and inter‐patch connectivity.ConclusionsPreservation and restoration of these linear landscape elements play a pivotal role in transitioning toward more sustainable agroecosystems. This ecological and practical information may help prioritize plant species and the sites used to restore an essential but neglected ecosystem.

Water footprint in rainfed summer and winter crops: The role of soil moisture

Argentina is one of the main producers and exporters of grains and oilseeds, ranking third in soybean exports and fourth in barley ones. The 90% of this production occurs within the Argentine Pampas region (APR) under rainfed conditions, but its water consumption and pollution has not been studied in depth. Likewise, the link between soil moisture (SM) and Water Footprint (WF) generation is poorly studied at the global level. And yet, SM is a critical factor for the development of rainfed crops. This study aims to evaluate, at plot scale, the role of SM in the generation of the green (WFgreen) and grey (WFgrey) (WF). Additionally, it estimates the WF for rainfed barley and soybean crops in the Southeast of APR, where there are no reference values. Yields, water consumption and nitrogen (N) pollution load were estimated for different campaigns. Field data (weather, crop and production management) recorded in the study plots were used. Results indicated an average WFgreen of 1236 m3/t for soybeans and a WFgreen of 349 m3/t and WFgrey of 547 m3/t for barley. The study highlights the critical role of SM in both WF sub-indicators. Soil water availability, based on the evaporative fraction during critical growth stages, influenced yields and final WFgreen volumes. In addition, there was an effect on N uptake by crops. In the driest barley campaign, WFgrey increased by 234%. Insufficient SM restricted nutrient uptake, reducing yields and increasing N with the potential to leach or runoff. Consequently, it is suggested to adjust the WFgrey methodology incorporating SM fluctuations and unaccounted N losses. The study contributes to understand the WF drivers and highlights the need to assess them accurately. In particular, it aims to reduce the gaps surrounding the water consumption of rainfed crops, thereby supporting resource conservation and grain provisioning efforts.

Integration of radiocarbon dating and paleomagnetic secular variation to date Las Brusquillas (LB4) archaeological site, Pampas region, Argentina

This article presents the first age model built with a combination of paleomagnetic data and radiocarbon dating for the Las Brusquillas 4 archaeological site (Pampas region, Argentina). The sedimentary sequence represents fluvio-lacustrine deposits where faunal remains and lithic artefacts were found in two archaeological layers separated by culturally sterile sediments. Our age model is fundamental to date the human occupation in the area during the Holocene and determine when paleoenvironmental changes occurred at a local scale. Paleomagnetic secular variations (PSV) recorded in 129 cm of this sedimentary sequence were compared to four global geomagnetic field models. Rock magnetic results suggest that the magnetic signal is carried by low-coercivity magnetic minerals like magnetite with an important contribution of antiferromagnetic minerals (hematite-type). The PSV of Las Brusquillas 4 compare well with other natural archives from different regions of Argentina but some differences were found in the declination data, showing the importance of further records from this region to better constrain the secular variation of the geomagnetic field.

Implications of Flat‐Slab Subduction on Hydration, Slab Seismicity, and Arc Volcanism in the Pampean Region of Chile and Argentina

AbstractThe Pampean flat slab in central Chile and Argentina is characterized by the inland migration and subsequent cessation of arc volcanism since the mid‐Miocene. Slab flattening also affects the distribution and number of intermediate‐depth earthquakes and the evolution of the overlying continental thermal structure. In this study, we combine thermal‐mechanical models with petrological models to examine temporal changes in pressure, temperature, and composition during flat‐slab subduction and estimate water carrying capacity, predicted melt distributions and predicted changes in melt composition. Model results indicate that the present‐day flattened Nazca plate carries water to ∼700 km inland from the trench and could cause flux melting if the material above the slab remains fertile. Observed slab seismicity matches areas where hydrated materials have ∼>3 wt% H2O in the oceanic crust and mantle lithosphere. Seismicity increases as slab water carrying capacity decreases (slab dehydration). As P‐T conditions and compositions of the rock trapped above the slab change during slab flattening, flux melting switches from a peridotite‐dominated early phase to a combined mid‐ocean ridge basalt/eclogite and peridotite melting at ∼8 Ma. The results provide broad consistency with known earthquake distributions, seismic velocities, and observed temporal and spatial changes in volcanic patterns above the Pampean flat slab and point toward the role of melt depletion in the decrease and ultimate cessation of arc volcanism in this region.

Phenogenetic profile and agronomic contribution of Azospirillum argentinense Az39T, a reference strain for the South American inoculant industry

Azospirillum sp. is a plant growth-promoting rhizobacteria largely recognized for its potential to increase the yield of different important crops. In this work, we present a thorough genomic and phenotypic analysis of A. argentinense Az39T to provide new insights into the beneficial mechanisms of this microorganism. Phenotypic analyses revealed the following in vitro abilities: growth at 20–38 °C (optimum, 28 °C), pH 6.0–8.0 (optimum, pH 6.8), and in the presence of 1% (w/v) NaCl; production of variable amounts of PHB as intracellular granules; nitrogen fixation under microaerophilic conditions; IAA synthesis in the presence of L-tryptophan. Through biochemical (API 20NE) and carbon utilization profiling (Biolog) assays, we proved that A. argentinense Az39T is able to use 15 substrates and metabolize 19 different carbon substrates. Lipid composition indicated a predominance of medium and long-chain saturated fatty acids. A total of 6 replicons classified as one main chromosome, three chromids, and two plasmids, according to their tRNA and core essential genes contents, were identified. Az39T genome includes genes associated with multiple plant growth-promoting (PGP) traits such as nitrogen fixation and production of auxins, cytokinin, abscisic acid, ethylene, and polyamines. In addition, Az39T genome harbor genetic elements associated with physiological features that facilitate its survival in the soil and competence for rhizospheric colonization; this includes motility, secretion system, and quorum sensing genetic determinants. A metadata analysis of Az39T agronomic performance in the pampas region, Argentina, demonstrated significant grain yield increases in wheat and maize, proving its potential to provide better growth conditions for dryland cereals. In conclusion, our data provide a detailed insight into the metabolic profile of A. argentinense Az39T, the strain most widely used to formulate non-legume inoculants in Argentina, and allow a better understanding of the mechanisms behind its field performance.

Drainage network dynamics in an agricultural headwater sub-basin

Headwaters provide many ecosystems services. Currently, these vulnerable systems are subject to threats related to human activities. This work aims to analyse the spatial pattern changes (expansion/contraction) in the drainage network (DN) of a headwater sub-basin under agriculture between 1966 and 2019 in the Argentine Pampas Region. We study and discuss the hydrometeorological and land use context to understand the spatial and temporal dynamics of the DN, and propose a conceptual model that synthesizes the complex interactions between the factors involved in that dynamics. A broad (1950–2019, at the Del Azul Creek basin) and a short (1996–2019, at the sub-basin of the Videla Creek -SVC-) temporal and spatial scale analysis of data were carried out. We studied rainfall, evapotranspiration, water table depth, streamflow and land use. Temporal and spatial changes in the DN of the SVC were analysed by aerial photos and historical satellite images. Four wet and three dry periods were identified, and close surface-subsurface water interactions typical of plains, were found. The area under agriculture showed a first gradual increase (1975–2012), which turned sharp from 2012 (30,908 ha year−1), with a leading role of soybeans' sown area. The area of the DN increased 1.4699*105 m2 between 1966 and 2010, both under dry conditions, which evidenced its expansion. The study of the flatlands' particular hydrology within the current land use and management trends provided key elements to understand DN area's changes. Complex interactions between processes associated with climatic forcing and the system's sensitivity (its state to receive and process the inputs), are involved in the spatial and temporal dynamics of the DN. Our work improves the understanding of the functioning of these vulnerable systems within agricultural areas, nowadays under productive pressures associated with increasing global food demand, and threats to changes in the hydrological dynamics by global change.

Beyond extinction: Uncovering morphological aspects of the last typotherid population (Mesotherium cristatum) and the unexpected body mass decrease

We present a detailed analysis of the craniomandibular and dental remains of Mesotherium cristatum, the quaternary mesotheriid typotherid notoungulate, from Corralito, Santa María Department, Cordoba Province. This population represents the final lineage of Typotheria during middle Pleistocene, Post-Ensenadan Age (>220 ± 13 ka). We compared these new craniomandibular and postcranial samples from Corralito with those from Toscas del Río de La Plata, as well as other localities in the province of Buenos Aires dating to the Ensenadan Age 1.98–0.4 Ma). Our investigation reveals a substantial decline in the size and body mass of the last known population of M. cristatum during the Bonaeran Age period, before its extinction. This occurrence, hitherto unrecorded in any prior South American Land Mammal Age leading up to extinction, might be attributed to the climatic and abiotic changes of the Pleistocene. These changes notably caused a marked reduction in the paleobiogeographical distribution area ofM. cristatum during the Middle Pleistocene. This size and body mass reduction, possibly an outcome of compelled reproductive isolation, is situated against the context of global cooling and heightened predatory pressures. Moreover, our analysis unveiled distinctive taxonomic attributes specific to this taxon, we compare dental size and find a preliminary evidence of an accelerated tooth replacement pattern. Furthermore, we have effectively updated the faunal composition information of the Corralito deposit, elucidating previous biostratigraphic inferences that had led to the belief of Corralito being an Ensenadan Age site. This adjustment impacts the first appearance datum (FAD) of the Neolicaphrium recens proterotheriid litoptern, younger than previously estimated and revised Bonaerian-Lujanian. Finally, this study provides insights into the biological analysis of the iconic species M. cristatum, prevalent in the South American quaternary of the Pampean region. It unreveils new faunal features specific to the Pampean region, shedding light particularly on the lesser-explored western area. These findinngs provide crucial insight into the ever-evolving ecosystem dynamics during the Middle Pleistocene.

Factors affecting exit intentions from dairy farming in the Pampas region of Argentina.

TThis article examines the factors which explain exit from dairy farming in the Pampas region of Argentina. A representative sample of dairy farms was used, of which 12 % indicated their intention to exit in the next five years. High technical efficiency and the existence of a successor reduce the likelihood of exit dairy farming; while age of farmer, hired labor, and climate risk exposure are positively associated with exit intentions. The small dairy farms are more prone to exit than large ones, albeit with a smaller marginal effect.

Size spectra of the edaphic fauna of typical Argiudol soils of the Rolling Pampa Region, Argentina.

Soil-dwelling organisms populate the spaces-referred to as interstices-between the litter on the soil surface and the pores in the soil's organo-mineral matrix. These organisms have pivotal roles in soil ecosystem functions, such as the breakdown and decomposition of organic matter, the dispersal of bacterial and fungal spores and biological habitat transformation. These functions, in turn, contribute to broader ecosystem services like carbon and nutrient cycling, soil organic matter regulation and both chemical and physical soil fertility.This study provides morphological data pertaining to a range of soil organism sizes, specifically in Argiudol soils subjected to varying levels of agricultural activity in the Rolling Pampas Region, one of the world's most extensive and fertile plains.The primary focus is on soil microarthropods-namely, Acari (mites) and Collembola (springtails)-with a body width of less than 2 mm. These organisms constitute the majority of life in the intricate soil pore network. Additionally, the study documents species of earthworms (Oligochaeta, Crassiclitelata), recognised as ecosystem engineers for their ability to create physical channels in the soil matrix and to distribute organic matter. Moreover, the study includes measurements of morphological traits of soil-dwelling "macrofauna" (organisms with a body width greater than 2 mm), which are also implicated in various soil ecosystem functions. These include population regulation by apex predators, organic matter decomposition, biogenic structure formation, nutrient mobilisation and herbivory. In this paper, we report both the geographical locations and individual measurements of key morphological traits for over 7,000 specimens, covering a range of soil-dwelling organisms. These include springtails (Entognatha, Collembola), mites (Arachnida, Acari), earthworms (Oligochaeta, Crassiclitellata) and additional soil macrofauna. All specimens were collected from typical Argiudol soils located in three distinct agricultural systems characterised by varying levels of land-use intensity. To our knowledge, no other dataset exists providing this information for the Argentinian Pampas.

Anisotropy of soil hydraulic properties induced by repeated machinery traffic in a Typic Argiudoll of the Argentinean Pampas Region

The increase in heavy machinery traffic due to crop sequence intensification under no-tillage (NT) management can lead to soil compaction, modifying the soil pore configuration, with negative effects on water dynamics. The objective of this work is to evaluate the residual effects of repeated machinery traffic under different soil water contents on the anisotropy of soil hydraulic properties. The residual effect of repeated machinery traffic under different soil moisture conditions (partially dry, PD, and wet, W) on soil compaction was evaluated and compared with the control treatment (no traffic, T0). Field infiltration using tension disc infiltrometer was carried out, and in laboratory, in order to analyse the anisotropy of soil hydraulic properties infiltration experiments were carried out on vertical and horizontal undisturbed soil samples. No significant differences in field soil hydraulic conductivity K(h) were observed between treatments. The W treatment showed a decrease on the transmission and storage pores in the vertical direction, as compared to T0. Anisotropic behavior of soil hydraulic properties was observed for the compacted treatments. The W treatment showed an increment in the transmission porosity in the horizontal direction. In addition, the W treatment presented higher values of transmission and storage pores in the horizontal direction as compared with the vertical direction. From laboratory infiltration experiments, it was observed a strong reduction on the hydraulic conductivity measured at 0, − 3 and − 6 cm water pressure heads (K0, K3 and K6) in the vertical direction under W treatment. An anisotropic behavior for both compacted treatments was observed, with higher values of K0 in the vertical direction under the PD treatment and higher values of K0 and K3 in the horizontal direction under the W treatment. These results show that machinery traffic under wet conditions causes a disruption in soil porosity, not only with a reduction of the pore space, but also with a change in its configuration.

Quaternary Mammals from Central-Western Argentina in the Stratigraphic Context of Southern South America

This is an updated contribution to the Quaternary geology and paleontology from central-western Argentina, focused on San Luis Province. It is mostly based on unpublished data; only some fossils had previously been briefly mentioned in broader faunal contexts. The fossil-bearing sediments correspond to eolian and alluvial environments of moderate energy, dominated by sands and sandy silts. They overlie high-energy fluvial cycles and underlie edaphic horizons. They have a wide distribution, and several radiocarbon dates allow their regional correlation. Stratigraphic sequences with the precise origin of fossils allow for the improvement of lithostratigraphic and faunal correlations with the Pampean Region (central and east Argentina; La Pampa and Buenos Aires provinces), where Pleistocene assemblages are better known, but also with central-western (Cuyo Region), northwestern, and northeastern Argentina. Faunal remains correspond to large mammals, represented by xenarthrans (Cingulata and Tardigrada), macraucheniids (Litopterna), gomphotheres (Proboscidea), and equids (Perissodactyla), a typical Pleistocene mixture of native (xenarthrans and litopterns) and immigrant mammals.

La presencia de monticulos tipo Mima en la Argentina en relación con roedores del género Ctenomys

The discovery of Mima mounds pocking the Pampean region in the south-east of San Luis, south of Córdoba and north of La Pampa, as well as in some Monte regions in Mendoza, confirms the hypothesis that fossorial rodents are the origin of this type of phenomenon and that such mounds are present in different regions of the world coinciding with the presence of families of fossorial rodents showing similar morphology and behavior.
 This similarity with geomyds of the United States and other families from West and South Africa, becomes evident in Argentine Ctenomydae, which activity is responsible for the formation of this type of relief, Which has nowadays disappeared in most of the central part of the country due to agricultural practices.
 The discovery of Mima mounds in Argentina unquestionably confirms the discussed origin of this type of topographic accident, which has been subject to the most varied interpretations.

Impact of complementary irrigation on soil properties in the Argentine Pampas

The growing application of complementary irrigation in extensive agricultural systems in the Pampas region (Argentina) has increased the frequency of disturbed soil cases. Irrigation management requires appropriate indicators for decision-making in order to avoid disturbance in soil quality. Among these indicators, the use of the sodium adsorption ratio adjusted by the dilution factor (SARdf), which considers the contributions of irrigation water and rainfall during the period projected, could be a sensitive tool. Based on studies conducted under extensive conditions of agricultural production, the objectives of this work were to (i) quantify the changes in the soil chemical and physical properties caused by the use of complementary irrigation with sodium bicarbonate water; (ii) establish relationships between the changes in the chemical and physical properties of the soil; (iii) validate the use of SARdf as a tool to help manage complementary irrigation; and (iv) identify the threshold values to be considered when monitoring and analyzing the evolution of soil properties in areas under complementary irrigation. Twenty-three sites under dryland and irrigated conditions were evaluated. With increasing SARdf, an increase was also recorded in surface bulk density (r = 0.59), subsurface bulk density (r = 0.50), electrical conductivity (r = 0.30; 0.41), pH (r = 0.56; 0.70) and exchangeable sodium ratio (ESR) (r = 0.45; 0.77), measured in the layers up to 0.10 m and up to 0.20 m in depth. The ESR was evaluated as a sensitive indicator of the effects of irrigation on the physical and chemical properties of soils. In the predominant Typic Argiudoll conditions of the Pampas region, it is advisable to avoid the complementary application of water with a SAR dilution factor greater than 3.0. This threshold value was associated with a > 60% reduction in basic infiltration. In climate change scenarios, the use of SARdf can help plan the proper management of complementary irrigation.

Pleistocene South American native ungulates (Notoungulata and Litopterna) of the historical Roth collections in Switzerland, from the Pampean Region of Argentina

The fossil collections made by early explorers in South America have been fundamental to reveal the past diversity of extinct mammals and unravel their evolutionary history. One important early explorer in South America was the Swiss-Argentine palaeontologist Kaspar Jacob Roth, known as Santiago Roth (1850, Herisau, Switzerland-1924, Buenos Aires, Argentina), who made significant collections of fossil mammals that are housed in museums in Europe and Argentina. The important collections of Roth in Switzerland include iconic Pleistocene megafauna from the Pampean Region (Argentina). The palaeontological significance of the Pampean Region relies on its abundant record of fossil vertebrates that documents diversity dynamics and paleoenvironmental change in southern South America, serving as the basis for the South American biostratigraphical scale of the late Neogene and Quaternary. The South American native ungulates (SANUs) were hoofed placental mammals that radiated in South America. The clades Notoungulata and Litopterna include, among others, the last representatives of SANUs megafauna in the continent. We revise and describe for the first time the SANUs specimens from the Pampean Region of the Roth collections in Switzerland. The collections include two species of notoungulates (Toxodon cf. T. platensis and Mesotherium cristatum) and one litoptern species (Macrauchenia patachonica). The occurrences are restricted to the early and middle Pleistocene (pre-Lujanian Stages/Ages). Although the SANUs diversity in the Roth collections is low in comparison with other groups (e.g., xenarthrans), some of the specimens are very complete, including skulls and postcranial remains. The completeness of the Ma. patachonica material allows an update and reinterpretation of some of the details of the dentition and the postcranial skeleton of this iconic species. In addition to its historical importance, the SANU specimens from the Roth collections provide important information to study the paleobiology and evolution of South American megafauna and evaluate hypotheses about their extinction in the continent.

Scientific evidence does not support the translocation of guanacos in Argentina

AbstractThe Argentinian Ministry of Environment has approved the translocation of 45 guanacos from Southern Patagonia to the Pampas region, a distance of 1500 km, as the initial phase toward future translocations into a National Park located in the Chaco region, another 1600 km further North. This decision raises concerns about the technical and ethical aspects of the translocation. Firstly, there is a lack of proper evaluation and scientific evidence to support the need, opportunity, and feasibility of this translocation. The guanaco population is currently over one million and is increasing, and genetic differences exist among local populations. The translocation could produce anthropogenic‐driven admixed populations, leading to genetic swamping and disrupting evolutionary processes. Second, there are ethical conflicts around managing wild species populations that prioritize private objectives and disregard local, publicly funded science. Rewilding projects require a deep understanding of interacting ecosystem processes, and of the socio‐economic context. This management decision violates guiding principles for rewilding and should have followed proper scientific evaluation and transparent local consultation.