Reptile responses to fire across the western Mediterranean Basin.

Effects of anthropogenic activities, including climate change, are modifying fire regimes, and the dynamic nature of these modifications requires identification of general patterns of organisms' responses to fire. This is a challenging task because of the high complexity of factors involved (including climate, geography, land use, and species-specific ecology). We aimed to describe the responses of the reptile community to fire across a range of environmental and fire-history conditions in the western Mediterranean Basin. We sampled 8 sites that spanned 4 Mediterranean countries. We recorded 6064 reptile sightings of 36 species in 1620 transects and modeled 3 community metrics (total number of individuals, species richness, and Shannon diversity) as responses to environmental and fire-history variables. Reptile community composition was also analyzed. Habitat type (natural vs. afforestation), fire age class (time since the last fire), rainfall, and temperature were important factors in explaining these metrics. The total number of individuals varied according to fire age class, reaching a peak at 15-40 years after the last fire. Species richness and Shannon diversity were more stable during postfire years. The 3 community metrics were higher under postfire conditions than in unburned forest plots. This pattern was particularly prevalent in afforested plots, indicating that the negative effect of fire on reptiles was lower than the negative effect of afforestation. Community composition varied by fire age class, indicating the existence of early- and late-successional species (xeric and saxicolous vs. mesic reptiles, respectively). Species richness was 46% higher in areas with a single fire age class relative to those with a mixture of fire age classes, which indicates pyrodiverse landscapes promoted reptile diversity. An expected shift to more frequent fires will bias fire age distribution toward a predominance of early stages, and this will be harmful to reptile communities.

Respuestas de reptiles al fuego en la Cuenca Mediterránea occidental Resumen Los efectos de actividades antropogénicas, incluyendo el cambio climático, están modificando los regímenes de fuego, y la naturaleza dinámica de estas modificaciones requiere la identificación de patrones generales de las respuestas de los organismos al fuego. Esta es una tarea desafiante debido a la gran complejidad de los factores involucrados (incluyendo clima, geografía, uso de suelo y la ecología de cada especie). Nuestro objetivo fue describir las respuestas de la comunidad de reptiles al fuego bajo diversas condiciones ambientales e historias de fuego en la Cuenca Mediterránea occidental. Muestreamos ocho sitios en cuatro países mediterráneos. Registramos 6064 avistamientos de reptiles de 36 especies en 1620 transectos y modelamos tres métricas comunitarias (número total de individuos, riqueza de especies y diversidad de Shannon) como respuestas a las variables ambientales y de historia de fuego. También analizamos la composición de la comunidad de reptiles. El tipo de hábitat (natural versus forestación), la clase de edad del fuego (tiempo transcurrido desde el último incendio), la precipitación pluvial y la temperatura fueron factores importantes en la explicación de estas métricas. El número total de individuos varió de acuerdo con la clase de edad del fuego, alcanzando un pico a los 15­40 años después del último incendio. La riqueza de especies y la diversidad de Shannon fueron más estables durante los años posteriores a incendios. Las tres métricas de la comunidad fueron más altas bajo condiciones post incendio que en las parcelas sin historial de fuego. Este patrón fue particularmente prevalente en parcelas forestadas, lo cual indica que el efecto negativo del fuego sobre los reptiles fue menor que el efecto negativo de la forestación. La composición de la comunidad varió por clase de edad del fuego, indicando la existencia de especies sucesionales tempranas y tardías (reptiles xéricos y saxícolas, respectivamente). La riqueza de especie fue 46% mas alta en áreas con una sola clase de edad del fuego que en aquellas con una mezcla de clases de edad del fuego, lo cual indica que los paisajes pirodiversos promovieron la diversidad de reptiles. Un cambio esperado hacia incendios más frecuentes sesgará la distribución de la edad del fuego hacia una predominancia de etapas tempranas, y esto será perjudicial para las comunidades de reptiles.

Antifouling Diterpenoids from the Sponge Dendrilla antarctica.

Two nor-diterpenes, 9,11-dihydrogracilin A (1) and the previously unreported 9,11-dihydrogracillinone A (2), were isolated from the sponge Dendrilla antarctica. The sponge was collected by trawling at a depth of 49 m, from the research vessel Puerto Deseado, near the coast of Tierra del Fuego, farther north than the reported habitat for this species. Since these compounds were particularly abundant and the sponge was free from epibionts, both 1 and 2 were included in soluble-matrix paints and tested for antifouling activity in the ocean. The results obtained from these experiments clearly indicated a potent antifouling activity for both compounds against a variety of colonizing organisms, and established a probable role as natural antifoulants for these abundant secondary metabolites and other structurally related compounds previously isolated from Dendrilla spp.

Predicting habitat use by the Argentine hake Merluccius hubbsi in a warmer world: inferences from the Middle Holocene.

Fish skeletal remains recovered from two archaeological sites dated in the Middle Holocene of Tierra del Fuego (Argentina) were analysed to describe habitat use patterns by hake in the past and predict changes in a warmer world. Mitochondrial DNA was successfully extracted and amplified from 42 out of 45 first vertebra from ancient hake and phylogenetic analysis assigned all haplotypes to Argentine hake (Merluccius hubbsi). According to osteometry, the Argentine hake recovered from the archaeological site were likely adults ranging 37.2-58.1 cm in standard length. C and N stable isotope analysis showed that currently Argentine hake use foraging grounds deeper than those of Patagonian blenny and pink cusk-eel. Argentine hake, however, had a much broader isotopic niche during the Middle Holocene, when a large part of the population foraged much shallower than contemporary pink cusk-eel. The overall evidence suggests the presence of large numbers of Argentine hake onshore Tierra del Fuego during the Middle Holocene, which allowed exploitation by hunter-gatherer-fisher groups devoid of fishing technology. Interestingly, average SST off Tierra del Fuego during the Middle Holocene was higher than currently (11 °C vs 7 °C) and matched SST in the current southernmost onshore spawning aggregations, at latitude 47 °S. This indicates that increasing SST resulting from global warming will likely result into an increased abundance of adult Argentine hake onshore Tierra del Fuego, as during the Middle Holocene. Furthermore, stable isotope ratios from mollusc shells confirmed a much higher marine primary productivity during the Middle Holocene off Tierra del Fuego.

Distribution of maternal lineages in hunter-gatherer societies of the southern coast of Tierra del Fuego, Argentina.

OBJECTIVES: The aim of this work is to explore the maternal genetic diversity of hunter-gatherers of the southern Tierra del Fuego, specifically the north coast of Beagle Channel, the Península Mitre, and Isla de los Estados through ancient mitochondrial DNA analysis. MATERIALS AND METHODS: The hypervariable regions 1 and 2 of the mitochondrial genome of five individuals from the north coast of Beagle Channel, six individuals from Península Mitre, and one individual from Isla de los Estados were analyzed. Through diversity statistics, Analysis of Molecular Variance (AMOVA), and Median Joining networks analyses, maternal relationships in the region were evaluated and phylogenetic similarities between ancient and contemporary populations of Tierra del Fuego were determined. RESULTS: The mitochondrial DNA lineages from the ancient individuals analyzed reveals the presence of subclades C1b and D1g. Pattern of decreasing genetic diversity toward the South is observed. The AMOVAs performed found no statistically significant differences between individuals of the north coast of Beagle Channel and Península Mitre-Isla de los Estados, and modern Yámana populations. Median joining network of haplotypes of clades C1 and D1g, show the same results. DISCUSSION: Ethnohistoric and ethnographic records of Península Mitre show that this region was occupied during the 19th century by Haush or Manekenk populations, although their biological, cultural, and subsistence characterization is unclear. We explore their maternal lineages and encounter low levels of genetic diversity and the absence of population differentiation with modern Yámana groups. We suggest that Península Mitre-Isla de los Estado was part of the same hunting and gathering populations as those of the Beagle Channel.

Phenotypic and genetic differentiation between diadromous and landlocked puyen Galaxias maculatus.

This study reports the phenotypic and genetic differences between individuals of puyen Galaxias maculatus from two sites in the same river basin in Tierra del Fuego National Park, southern South America. Individuals from the two sampling sites presented morphometric and genetic differences. The morphometric differences indicated that individuals from Laguna Negra (LN) were short and more robust and had large eyes, whereas those from Arroyo Negro (AN) were thin and elongated and had small eyes. Genetic differences showed that AN individuals had a greater genetic structuration and an older demographic history than LN individuals. The results of this study affirmed that the individuals from the two sampling sites belong to different populations with a high degree of isolation. The demographic history could indicate that the individuals of G. maculatus which migrated to northern areas during the last glaciation settled in the Beagle Channel after its formation. The LN population could have originated after the retreat of the glaciers, migrating from AN.

High nitrogen contribution by Gunnera magellanica and nitrogen transfer by mycorrhizas drive an extraordinarily fast primary succession in sub-Antarctic Chile.

Chronosequences at the forefront of retreating glaciers provide information about colonization rates of bare surfaces. In the northern hemisphere, forest development can take centuries, with rates often limited by low nutrient availability. By contrast, in front of the retreating Pia Glacier (Tierra del Fuego, Chile), a Nothofagus forest is in place after only 34 yr of development, while total soil nitrogen (N) increased from near zero to 1.5%, suggesting a strong input of this nutrient. We measured N-fixation rates, carbon fluxes, leaf N and phosphorus contents and leaf δ15 N in the dominant plants, including the herb Gunnera magellanica, which is endosymbiotically associated with a cyanobacterium, in order to investigate the role of N-fixing and mycorrhizal symbionts in N-budgets during successional transition. G. magellanica presented some of the highest nitrogenase activities yet reported (potential maximal contribution of 300 kg N ha-1  yr-1 ). Foliar δ15 N results support the framework of a highly efficient N-uptake and transfer system based on mycorrhizas, with c. 80% of N taken up by the mycorrhizas potentially transferred to the host plant. Our results suggest the symbiosis of G. magellanica with cyanobacteria, and trees and shrubs with mycorrhizas, to be the key processes driving this rapid succession.

Impacts of tropical forest disturbance on species vital rates.

Tropical forests are experiencing enormous threats from deforestation and habitat degradation. Much knowledge of the impacts of these land-use changes on tropical species comes from studies examining patterns of richness and abundance. Demographic vital rates (survival, reproduction, and movement) can also be affected by land-use change in a way that increases species vulnerability to extirpation, but in many cases these impacts may not be manifested in short-term changes in abundance or species richness. We conducted a literature review to assess current knowledge and research effort concerning how land-use change affects species vital rates in tropical forest vertebrates. We found a general paucity of empirical research on demography across taxa and regions, with some biases toward mammals and birds and land-use transitions, including fragmentation and agriculture. There is also considerable between-species variation in demographic responses to land-use change, which could reflect trait-based differences in species sensitivity, complex context dependencies (e.g., between-region variation), or inconsistency in methods used in studies. Efforts to improve understanding of anthropogenic impacts on species demography are underway, but there is a need for increased research effort to fill knowledge gaps in understudied tropical regions and taxa. The lack of information on demographic impacts of anthropogenic disturbance makes it difficult to draw definite conclusions about the magnitude of threats to tropical ecosystems under anthropogenic pressures. Thus, determining conservation priorities and improving conservation effectiveness remains a challenge.

Towards a methodology for analysing nineteenth-century collecting journeys of science and empire, with Charles Darwin's activities in Tierra del Fuego as a case study.

The interests of Charles Darwin and Alfred Russel Wallace in natural history and evolution took them to remote parts of the globe on hazardous, multi-sensory journeys that were ultimately about collecting. This paper introduces a methodology for exploring these complex experiences in more detail, informed by historical geography, anthropology, textual analysis and the geo-humanities. It involves looking for evidence of the richly stimulating and often challenging sensory dynamics within which they collected and connected data, observations, images, specimens, memories and ideas. Darwin's exploits in Tierra del Fuego are examined as a case study, with a particular focus on the collection of 'Fuegian' body paints in 1833. This type of analysis provides a fresh insight into the multi-sensory entanglement of encounter with people and place involved in the collecting process. It helps us to understand better the experiences that shaped what was collected and brought back to Britain, and the personal observations associated with these collections that sowed the seeds for Darwin's work on the origin of species.

Eco-geographic adaptations in the human ribcage throughout a 3D geometric morphometric approach.

OBJECTIVES: According to eco-geographic rules, humans from high latitude areas present larger and wider trunks than their low-latitude areas counterparts. This issue has been traditionally addressed on the pelvis but information on the thorax is largely lacking. We test whether ribcages are larger in individuals inhabiting high latitudes than in those from low latitudes and explored the correlation of rib size with latitude. We also test whether a common morphological pattern is exhibited in the thorax of different cold-adapted populations, contributing to their hypothetical widening of the trunk. MATERIALS AND METHODS: We used 3D geometric morphometrics to quantify rib morphology of three hypothetically cold-adapted populations, viz. Greenland (11 individuals), Alaskan Inuit (8 individuals) and people from Tierra del Fuego (8 individuals), in a comparative framework with European (Spain, Portugal and Austria; 24 individuals) and African populations (South African and sub-Saharan African; 20 individuals). RESULTS: Populations inhabiting high latitudes present longer ribs than individuals inhabiting areas closer to the equator, but a correlation (p < 0.05) between costal size and latitude is only found in ribs 7-11. Regarding shape, the only cold adapted population that was different from the non-cold-adapted populations were the Greenland Inuit, who presented ribs with less curvature and torsion. CONCLUSIONS: Size results from the lower ribcage are consistent with the hypothesis of larger trunks in cold-adapted populations. The fact that only Greenland Inuit present a differential morphological pattern, linked to a widening of their ribcage, could be caused by differences in latitude. However, other factors such as genetic drift or specific cultural adaptations cannot be excluded and should be tested in future studies.

Quantitative discrimination of deformation in Fueguian crania.

OBJECTIVES: Artificial deformation of the cranium in humans has been related to powerful environmental-cultural stimuli that modify vectors of growth and development when the cranium is still malleable. Osteological differentiation into deformed and nondeformed remains enables the morphological information of individuals that make up ethnic groups or populations to be separately contrasted, the invariant measurements of deformation to be identified, the information provided by archeological remains to be placed in a social context, the cranial variation to be related to genetic variation (individuals without deformation), and predictions to be made (in the absence of direct genetic information). METHODS: With samples of reduced size and many variables, we propose a decision rule based on: (a) pre-selecting variables (Kruskal-Wallis and Λ-Wilks test); (b) applying logistic regression to obtain the optimal classification criterion; and (c) defining a multi-criterion decision rule to bring about greater robustness. RESULTS: After applying the decision rule to a sample of 180 crania (71 from the Selknam, 74 from the Yamana, and 35 from the Alakaluf ethnic groups), it was possible to identify the Selknam men with frontal deformation and the Yamana women with flattening of the parietal regions at the height of the bregma. CONCLUSIONS: From there on with the information provided by the graphical representation of the populations in the most informative dimensions and the homogeneity contrast between sexes, we related the frontal deformation in Selknam men to dragging firewood, vegetable matter, domestic utensils, and heavy pieces of meat from the hunt. On the other hand, the flattening of the parietal areas at the height of the bregma in Yamana women is related to loading and transporting vegetables and animals in baskets or leather sacks.

Fueguian crania and the circum-Pacific rim variation.

OBJECTIVES: The Fueguians are descendants of the first settlers of America, a 'relict' isolated geographically for 10,000 years. We compared their cranial variation with other Americans, and samples from Asia and Australia to know whether the modern extinct Fueguians can be considered Paleoamericans or not. MATERIALS AND METHODS: Herein we study 176 Fuego-Patagonian skulls, the largest cranial sample to be studied, refined and well documented, using CVA, and the D2 of Mahalanobis. The affinities between populations and sexual dimorphism were jointly studied. RESULTS: Terrestrial hunters (Selknam) have a different cranial morphology from sea canoeists (Yamana, Alakaluf) particularly with regard to cranial size and robustness. In the American context, there are extreme differences between the canoeists of Santa Cruz (California) and the Eskimos and canoeists of Fuego-Patagonia in terms of cranial size, prognathism and development of the frontal region. Fueguian canoeists are cranially closer to the Californian ones than to their Fueguian neighbors, the Selknam. Our results favor the hypothesis of two different flows for the origin of the first populators of Tierra del Fuego. DISCUSSION: We concluded that the robusticity of some Fuegians (Selknam) might be the result of an allometric pattern of overall robusticity expression well as a result of epigenetics or differential reproduction (Larsen, 2015:264) or hypothetical endocrine changes (Bernal et al. in Am J Hum Biol 2006;18:748-765). When compared with three Australian-Melanesian series, the group comprising Amerindians, Ainu, and Eskimos clusters together as they are all extremely different from the former in terms of both cranial size and shape.

Antiquity and geographic distribution of cranial modification among the prehistoric groups of Fuego-Patagonia, Chile.

OBJECTIVES: Nineteenth and twentieth century documents testify that four ethnic groups, generally classified as terrestrial hunters or canoe nomads, inhabited Fuego-Patagonia. Archaeologically, however, their presence and temporal depth remains unknown. This study analyzes the antiquity and geographic distribution of cranial modification, a highly visible symbol of social identity, in Fuego-Patagonia, Chile, to assess whether it expressed ethnic affiliation. MATERIALS AND METHODS: A total of 60 adult skulls from Southern Patagonia (n = 32; 53.3%) and Tierra del Fuego (n = 28; 46.7%) were examined for age-at-death, sex and cranial modification with standard methods. Individuals were further categorized as terrestrial (n = 26; 43.3%), marine (n = 21; 35%) or indetermined hunter-gatherers (n = 13; 21.7%) based on the archaeological site's characteristics, geographic location, and isotopic information. RESULTS: Thirty percent (n = 18) of the skulls in this study were modified, and most of the modified skulls (n = 15) presented a tabular-erect shape. No statistically significant differences were identified between Fuegians and Patagonians, males or females, or between the different types of adaptation and geographic locations. DISCUSSION: Thus, this Late Holocene, widely distributed practice, was not a reflection of ethnicity, but a material expression of information circulation and the complex social relations that these small-size groups had with one another. These results suggest that the emergence of modern ethnic identities in the region is a historic process that resulted from the interaction of local groups with European and Criollos.

Temporal activity and detection rates of chilla (Lycalopex griseus) in Tierra del Fuego, Argentina.

Designing mitigation strategies for invasive species requires a clear understanding of their ecology and behaviour. Chilla (or grey fox; Lycalopex griseus) were introduced to Isla Grande de Tierra del Fuego (Tierra del Fuego Island) in 1951 to control European rabbit (Oryctolagus cuniculus) populations. Although this management strategy was unsuccessful, the chilla spread across the island and are now considered invasive. Despite this, there is a lack of research concerning their ecology and behavioural patterns, particularly on the Argentinian side of the island. We assessed the detection rates and temporal activity patterns of chillas using camera traps in the Argentinian region of Tierra del Fuego Island. Chilla had average detection rates of 61.7 (SD ± 33.3, range = 13.5-105.7) per 100 trap nights. Although analysis by clock time suggested cathemeral activity patterns, when analysed by sun time the chillas exhibited distinct nocturnal activity patterns. These findings offer the first information on the detection rates of chilla on the Argentinian side of Tierra del Fuego Island and reveal new insights into their temporal activity patterns, providing an important basis for future research that may aid the development of more effective management and conservation strategies.

The Commerson's dolphin as Subantarctic sentinel of POPs: Insights into the pollutant status in one of the southernmost coastal areas of the globe.

Persistent organic pollutants (POPs) are halogenated contaminants found globally. Cetaceans are impacted by these pollutants, and nowadays, it is essential to understand their presence to mitigate their impacts. This study aimed to establish baseline levels of POPs in the blubber of Commerson's dolphins (Cephalorhynchus commersonii) within the Subantarctic ecosystem. A wide range of POPs concentrations were measured among individuals: ΣPCBs from 289.5 to 15264 ng g-1 lw and ΣDDTs from 540.4 to 17657 ng g-1 lw. Levels of HCB and mirex ranged from 48 to 1703.7 ng g-1 lw and 5.1-1917.4 ng g-1 lw, respectively. The predominant POPs were mid-to high molecular weight PCBs (hexa-PCBs), consistent with other findings in cetaceans of the southern hemisphere. The mean ratio of ΣDDT/ΣPCB was 0.44, with p,p'-DDE/ΣDDT at 0.56, indicating p,p'-DDE as the dominant DDT isomer. Furthermore, differences in POP concentrations were observed based on sexual maturity, with mature males exhibiting higher levels of Æ©PCBs, HCB, Æ©DDT, and mirex. Age and total body length of animals were strongly correlated with POP concentrations. Our study provides valuable insights into the pollutant status of POPs in the Subantarctic population of Commerson's dolphins inhabiting the southernmost coastal regions of South America.

Spinal gunshot wounds: A retrospective, multicenter, cohort study. / [Artículo traducido] Lesiones vertebrales por proyectil de arma de fuego: estudio de cohorte retrospectivo, multicéntrico.

INTRODUCTION AND OBJECTIVE: To describe the demographic and clinical characteristics and treatment of patients with spinal gunshot wounds across Latin America. MATERIAL AND METHODS: Retrospective, multicenter cohort study of patients treated for gunshot wounds to the spine spanning 12 institutions across Latin America between January 2015 and January 2022. Demographic and clinical data were recorded, including the time of injury, initial assessment, characteristics of the vertebral gunshot injury, and treatment. RESULTS: Data on 423 patients with spinal gunshot injuries were extracted from institutions in Mexico (82%), Argentina, Brazil, Colombia, and Venezuela. Patients were predominantly male civilians in low-risk-of-violence professions, and of lower/middle social status, and a sizeable majority of gunshots were from low-energy firearms. Vertebral injuries mainly affected the thoracic and lumbar spine. Neurological injury was documented in 320 (76%) patients, with spinal cord injuries in 269 (63%). Treatment was largely conservative, with just 90 (21%) patients treated surgically, principally using posterior open midline approach to the spine (79; 87%). Injury features distinguishing surgical from non-surgical cases were neurological compromise (P = 0.004), canal compromise (P < 0.001), dirty wounds (P < 0.001), bullet or bone fragment remains in the spinal canal (P < 0.001) and injury pattern (P < 0.001). After a multivariate analysis through a binary logistic regression model, the aforementioned variables remained statistically significant except neurological compromise. CONCLUSIONS: In this multicenter study of spinal gunshot victims, most were treated non-surgically, despite neurological injury in 76% and spinal injury in 63% of patients.

Reassessment of the use of fire as a management tool in deciduous forests of eastern North America.

Prescribed burning is increasingly being used in the deciduous forests of eastern North America. Recent work suggests that historical fire frequency has been overestimated east of the prairie-woodland transition zone, and its introduction could potentially reduce forest herb and shrub diversity. Fire-history recreations derived from sedimentary charcoal, tree fire scars, and estimates of Native American burning suggest point-return times ranging from 5-10 years to centuries and millennia. Actual return times were probably longer because such records suffer from selective sampling, small sample sizes, and a probable publication bias toward frequent fire. Archeological evidence shows the environmental effect of fire could be severe in the immediate neighborhood of a Native American village. Population density appears to have been low through most of the Holocene, however, and villages were strongly clustered at a regional scale. Thus, it appears that the majority of forests of the eastern United States were little affected by burning before European settlement. Use of prescribed burning assumes that most forest species are tolerant of fire and that burning will have only a minimal effect on diversity. However, common adaptations such as serotiny, epicormic sprouting, resprouting from rhizomes, and smoke-cued germination are unknown across most of the deciduous region. Experimental studies of burning show vegetation responses similar to other forms of disturbance that remove stems and litter and do not necessarily imply adaptation to fire. The general lack of adaptation could potentially cause a reduction in diversity if burning were introduced. These observations suggest a need for a fine-grained examination of fire history with systematic sampling in which all subregions, landscape positions, and community types are represented. Responses to burning need to be examined in noncommercial and nonwoody species in rigorous manipulative experiments. Until such information is available, it seems prudent to limit the use of prescribed burning east of the prairie-woodland transition zone.

Evaluating population histories in Patagonia and Tierra del Fuego, Chile, using ancient mitochondrial and Y-chromosomal DNA.

OBJECTIVES: This study aims to characterize the genetic histories of ancient hunter-gatherer groups in Fuego-Patagonia (Chile) with distinct Marine, Terrestrial, and Mixed Economy subsistence strategies. Mitochondrial (mtDNA) and Y-chromosome data were generated to test three hypotheses. H0: All individuals were drawn from the same panmictic population; H1: Terrestrial groups first populated the region and gave rise to highly specialized Marine groups by ~7,500 cal BP; or H2: Marine and Terrestrial groups represent distinct ancestral lineages who migrated independently into the region. METHODS: Ancient DNA was extracted from the teeth of 50 Fuegian-Patagonian individuals dating from 6,895 cal BP to after European arrival, and analyzed alongside other individuals from previous studies. Individuals were assigned to Marine, Terrestrial, and Mixed Economy groups based on archeological context and stable isotope diet inferences, and mtDNA (HVR1/2) and Y-chromosome variation was analyzed. RESULTS: Endogenous aDNA was obtained from 49/50 (98%) individuals. Haplotype diversities, FST comparisons, and exact tests of population differentiation showed that Marine groups were significantly different from Terrestrial groups based on mtDNA (p < 0.05). No statistically significant differences were found between Terrestrial and Mixed Economy groups. Demographic simulations support models in which Marine groups diverged from the others by ~14,000 cal BP. Y-chromosome results showed similar patterns but were not statistically significant due to small sample sizes and allelic dropout. DISCUSSION: These results support the hypothesis that Marine and Terrestrial economic groups represent distinct ancestral lineages who diverged during the time populations were expanding in the Americas, and may represent independent migrations into Fuego-Patagonia.

Biotopes of the intertidal zone in Clarence Island (south of the Strait of Magellan).

Background: The characteristics of the Strait of Magellan promote the formation of unique environments, with diverse habitats and marine organisms. This fragmentation of the landscape generates diverse little-explored ecological associations, especially in the zone of sub-Antarctic islands of the Tierra del Fuego archipelago. One way to address this lack of knowledge is through the biotope characterization methodology, with ecological units composed of the habitat and the communities associated with these environments, obtaining data and information on the dominant and incidental taxonomic groups. This is a good research model to conduct baseline studies in coastal benthic marine environments. New information: A data set in Darwin Core standard is presented of the species that make up the intertidal biotopes of Clarence Island (Tierra del Fuego Archipelago, south of the Strait of Magellan). This includes 50 identified species and the specific coordinates for each sampled location, with a total of 1400 georeferenced records. Mollusks were the most diverse taxon with 21 species, followed by algae (14 species). Sessile organisms such as the barnacles Elminiuskingii and Austromegabalanuspsittacus predominate in these ecosystems, followed by bivalve mollusks such as Choromytiluschorus and Mytiluschilensis, which together with Nacellamagellanica and the alga Hildenbrandia sp. make up more than 50% of the total records. The inclusion of biotope patterns in this study complements the information on benthic marine flora and fauna in the intertidal zone, including new records for the coast in the Clarence Island area, which is within the boundary of the Kawésqar National Park.

Detection and analysis of Shiga toxin producing and enteropathogenic Escherichia coli in cattle from Tierra del Fuego, Argentina.

Shiga toxin producing Escherichia coli (STEC) and enteropathogenic E. coli (EPEC) are pathovars that affect mainly infants' health. Cattle are the main reservoir of STEC. Uremic hemolytic syndrome and diarrheas can be found at high rates in Tierra del Fuego (TDF). This study aimed to establish the prevalence of STEC and EPEC in cattle at slaughterhouses in TDF and to analyze the isolated strains. Out of 194 samples from two slaughterhouses, STEC prevalence was 15%, and EPEC prevalence was 5%. Twenty-seven STEC strains and one EPEC were isolated. The most prevalent STEC serotypes were O185:H19 (7), O185:H7 (6), and O178:H19 (5). There were no STEC eae + strains (AE-STEC) or serogroup O157 detected in this study. The prevalent genotype was stx2c (10/27) followed by stx1a/stx2hb (4/27). Fourteen percent of the strains presented at least one stx non-typeable subtype (4/27). Shiga toxin production was detected in 25/27 STEC strains. The prevalent module for the Locus of Adhesion and Autoaggregation (LAA) island was module III (7/27). EPEC strain was categorized as atypical and with the ability to cause A/E lesion. The ehxA gene was present in 16/28 strains, 12 of which were capable of producing hemolysis. No hybrid strains were detected in this work. Antimicrobial susceptibility tests showed that all strains were resistant to ampicillin and 20/28 were resistant to aminoglycosides. No statistical differences could be seen in the detection of STEC or EPEC either by slaughterhouse location or by production system (extensive grass or feedlot). The rate of STEC detection was lower than the one reported for the rest of Argentina. STEC/EPEC relation was 3 to 1. This is the first study on cattle from TDF as reservoir for strains that are potentially pathogenic to humans.

Presence of Echinococcus granulosussensulato in the endoparasitic fauna of feral dogs in Tierra del Fuego, Argentina.

The feral dog population from Tierra del Fuego (Argentina) has affected provincial sheep production, and is responsible for the decrease of 43% of the sheep stock. In addition, feral dogs preys on the native fauna, especially the guanaco (Lama guanicoe), a species protected by law. Except for some data on the aforementioned impact, very little is known about feral dogs features in this region, such as distribution, abundance, diet, reproduction, health status, among others. Therefore, a descriptive observational study was carried out in the period 2018-2021 in Tierra del Fuego, with the aim to recognize the endoparasitic fauna of these dogs, with emphasis on Echinococcus granulosus sensu lato (s.l.). Feces samples were collected from 83 feral dogs captured in 15 farms, which were evaluated using flotation and sedimentation coproparasitological techniques, and optical microscope observation. These qualitative methods showed that 66.3% of the samples were positive. Nine parasitic forms were found, including eggs of taenids, Toxocara canis and Toxascaris leonina, and Sarcocystis spp. oocysts and Giardia spp. cysts. Samples with more than one parasitic form were also observed, among which the Taenia/Sarcocystis spp. association was the most frequent. For the diagnosis of canine echinococcosis, the detection of Echinococcus spp. antigens by Copro-ELISA and the molecular confirmation by Copro-PCR were performed. The Copro-ELISA test was positive in 10/80 (12.5%) of the samples processed, while 11 samples (13.8%) were positive by Copro-PCR. Their distribution showed that 9 (81.8%) corresponded to farms with sheep farming, and 2 (18.2%) with cattle farming. The presence of E. granulosus s.l. in feral dogs from Tierra del Fuego is the most relevant finding in this study. These results confirm that feral dogs have access to viscera infected with hydatid cysts. However, the intermediate hosts involved (sheep, cattle or guanacos) should be investigated. Its impact on the transmission of cystic echinococcosis in this region should be evaluated, as well as the adequacy of the disease prevention and control actions implemented in Tierra del Fuego should be considered. Finally, the existence of a wild cycle of the disease should be evaluated, in which feral dogs would act as a source of infection for other animals and humans.