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Nothrotherium maquinense, an extinct sloth species that existed alongside other megafauna during the Pleistocene, has been a subject of intense debate regarding various aspects of its life. This study integrates an examination of specific forearm bone fracture (paleopathology) with forelimb functional indices (paleoecology) in N. maquinense in order to infer its likely mode of locomotion and substrate preferences. Our findings provide compelling evidence suggesting that N. maquinense possessed climbing abilities and likely had a semi-arboreal lifestyle. Additionally, we report the first occurrence of calcium pyrophosphate deposition disease (CPPD) in this species, indicating that this type of arthritic condition was present in this sloth. [ABSTRACT FROM AUTHOR]

Mylodon darwinii is an extinct terrestrial species of sloth with a wide fossil record in South America, the record of the skin and hairs found from "La Cueva del Milodón", Chile. More than a century after the first studies on its hair, we aimed to redescribe the morphological characteristics of the hairs of M. darwinii by applying modern protocols of trichology and microscopy. Hair patterns were also compared with those of two other extinct species of sloths available in the literature. Hairs from mummified specimen housed in Museo de La Plata (Argentina) were analyzed through light and scanning electron microscopy to identify their cuticular and medullary patterns. Guard hairs lack medulla and have a wavy cuticle with irregular scale orientation, while underhairs have an amorphous cuticle pattern and no medulla. Hence, the former ones help in the diagnosis of the hair morphology of the species, while the latter ones do not. Differences found in the final product of each microscopy technique are discussed and should be considered in future research. The outcomes presented herein are a step further toward the understanding of evolutionary processes within Xenarthra, providing important data for such a poorly studied group that has only been recorded in Central and South America. [ABSTRACT FROM AUTHOR]

Relationships between species and their habitat are strongly related to their feeding habits making its description essential for understanding the species' biology and plan their conservation. This study describes the diet of giant anteaters (Myrmecophaga tridactyla), a specialist insectivorous mammal, and evaluates potential sex-related intraspecific variation. We analyzed fecal matter from live individuals and from road-kills (N = 29 individuals) collected from October 2018 to April 2020 in the Cerrado savanna of Mato Grosso do Sul, Brazil. Anteater's diet was described by the relative frequency (RF; proportion of the sample mass represented by the prey item) and the frequency of occurrence (FO; proportion of samples in which the item was detected) of each prey item, which was classified to the lowest taxonomic level possible. The diet was composed of 14 morphotypes of termites (Blattodea), 28 morphotypes of ants (Formicidae) and grass seeds (Poacea). They fed primarily on termites (FO = 89.65%; RF = 75.85%) and ants (FO = 100%; RF = 23.08%), with no significant differences between sexes. Termites of the genus Syntermes (RF = 75.55%) represented most of the dietary sample mass, and ants of the genus Pheidole represented the most frequent item found in the samples (FO = 96.55%). M. tridactyla is a myrmecophagous specialist that consumes a great richness of prey species associated with multiple habitats. Hence, the preservation of the natural heterogeneity of the Cerrado landscape and their habitats is essential for the conservation of this vulnerable species. [ABSTRACT FROM AUTHOR]

The lesser anteater Tamandua tetradactyla is possibly the most common member of the order Pilosa and occurs in almost all tropical environments in South America. Although commonly recorded in mammal inventories, this species is not abundant, and little is known about its ecology. The food habits of the species are mainly based on ants, but the type and contribution of other arthropods to the diet, especially termites, remains a subject little discussed in the literature. In the present study, we carried out a comprehensive assessment of stomach contents of 16 roadkilled anteaters found in grassland ecosystems in the Brazilian Pampa. We found 73,890 prey, with ant and termite species being the most representative dietary resources. Ants were present in 100% of the stomachs and represented more than 85% of all items consumed, totaling 34 species. Termites were present in 62.5% of the stomachs and represented 14.6% of all items consumed and, summed up five species. We also found six other arthropod taxa but with an insignificant proportion of the biomass intake. Our results contribute to increase knowledge on T. tetradactyla feeding habits in the subtropical grasslands of Southern Brazil. [ABSTRACT FROM AUTHOR]

Cabassous tatouay occurs in moist forests, savannas, and grasslands of south, central, and northeastern Brazil, eastern Paraguay, northeastern Argentina, and Uruguay. Despite its wide distribution range, C. tatouay is scarcely recorded in some regions. This study aimed to: present new records of C. tatouay; compile the localities where the species was recorded according to published scientific accounts; and model its distribution range along South America. We present five new records of C. tatouay from Goiás and Minas Gerais states, Brazil. The review of published accounts resulted in 99 studies, which provided 279 occurrences of C. tatouay to Brazil, Argentina, Paraguay, and Uruguay. The great majority of records are from Brazil, mainly from the Atlantic Forest (119), Cerrado (52), and Pampas (49) biomes. Most records from the Cerrado are placed close to or in transition zones with the Atlantic Forest. Five records are within the Caatinga, but restricted to humid montane forest enclaves. The species distribution models indicate that C. tatouay is probably absent to Amazonia and Pantanal. The higher suitability for the species occurs in eastern Paraguay, northeastern Argentina, and south central Brazil, specifically in the Pampas, Atlantic Forest, and the southern part of the Cerrado. [ABSTRACT FROM AUTHOR]

Simple Summary: This article demonstrates that computed tomography combined with the use of contrasts for imaging examinations can provide a general and comprehensive topographic view of the vasculature, structures, and organs in frozen and glycerinated cadavers of Bradypus variegatus. The objective is to present an alternative technique to the anatomical study of preserved frozen and glycerinated cadavers using computed tomography. The study concludes by highlighting that computed tomography allowed a general and comprehensive view of the anatomical structures of frozen and glycerinated cadavers of B. variegatus, such as the topographic location of bone structures, organs, and vessels, with soft tissues better visualized after intravenous or oral administration of contrast. Bradypus variegatus has unique anatomical characteristics, and many of its vascular and digestive tract aspects have yet to be clearly understood. This lack of information makes clinical diagnoses and surgical procedures difficult. The aim of this study was to evaluate the anatomical aspects of frozen and glycerinated corpses of B. variegatus using computed tomography (CT), emphasizing vascular and digestive contrast studies. Nine corpses that died during routine hospital were examined via CT in the supine position with scanning in the craniocaudal direction. In frozen cadavers, the contrast was injected into a cephalic vein after thawing and, subsequently, was administered orally. In addition to bone structures, CT allowed the identification of organs, soft tissues, and vascular structures in specimens. Visualization of soft tissues was better after contrast been administered intravenously and orally, even without active vascularization. Furthermore, the surfaces of the organs were highlighted by the glycerination method. With this technique, it was possible to describe part of the vascularization of the brachial, cervical, thoracic, and abdominal regions, in addition to highlighting the esophagus and part of the stomach. CT can be another tool for the evaluation of B. variegatus cadavers by anatomists or pathologists, contributing to the identification of anatomical structures. [ABSTRACT FROM AUTHOR]

This report is a continuation of the work published a decade ago on the status of specimens assigned in the literature and museum records to the megalonychid sloth Eucholoeops from the early--middle Miocene Santa Cruz Formation (- 18 to 15.6 Ma, Santacrucian Age) of Argentine Patagonia. This previous report concluded that several species (i.e., E. latirostris, E. externus, and E. curtus) are junior synonyms of E. ingens, but the authors were unable to analyze several other species and remains assigned to this genus. Here, analysis of these other species and remains suggest that E. fronto and E. lafonei are also junior synonyms of E. ingens. Included in the current report is a specimen recently recovered from the field of E. ingens that preserves, for the first time, an ectotympanic of Eucholoeops. In addition to the mainly cranial skeletal features analyzed here, consideration of postcranial remains indicate that the medial and lateral distal articular condyles of the femur are both contiguous with the patellar trochlea, in contrast to the previously reported condition of a separate lateral articular condyle in E. ingens. The authors further conclude that several features of E. latifrons suggest that this species is indeed distinct from E. ingens and that some specimens assigned in the literature to E. ingens cannot be so assigned with confidence. [ABSTRACT FROM AUTHOR]

Combining morphological and molecular characters through Bayesian total-evidence dating allows inferring the phylogenetic and timescale framework of both extant and fossil taxa, while accounting for the stochasticity and incompleteness of the fossil record. Such an integrative approach is particularly needed when dealing with clades such as sloths (Mammalia: Folivora), for which developmental and biomechanical studies have shown high levels of morphological convergence whereas molecular data can only account for a limited percentage of their total species richness. Here, we propose an alternative hypothesis of sloth evolution that emphasizes the pervasiveness of morphological convergence and the importance of considering the fossil record and an adequate taxon sampling in both phylogenetic and biogeographic inferences. Regardless of different clock models and morphological datasets, the extant sloth Bradypus is consistently recovered as a megatherioid, and Choloepus as a mylodontoid, in agreement with molecular-only analyses. The recently extinct Caribbean sloths (Megalocnoidea) are found to be a monophyletic sister-clade of Megatherioidea, in contrast to previous phylogenetic hypotheses. Our results contradict previous morphological analyses and further support the polyphyly of "Megalonychidae," whose members were found in five different clades. Regardless of taxon sampling and clock models, the Caribbean colonization of sloths is compatible with the exhumation of islands along Aves Ridge and its geological time frame. Overall, our total-evidence analysis illustrates the difficulty of positioning highly incomplete fossils, although a robust phylogenetic framework was recovered by an a posteriori removal of taxa with high percentages of missing characters. Elimination of these taxa improved topological resolution by reducing polytomies and increasing node support. However, it introduced a systematic and geographic bias because most of these incomplete specimens are from northern South America. This is evident in biogeographic reconstructions, which suggest Patagonia as the area of origin of many clades when taxa are underrepresented, but Amazonia and/or Central and Southern Andes when all taxa are included. More generally, our analyses demonstrate the instability of topology and divergence time estimates when using different morphological datasets and clock models and thus caution against making macroevolutionary inferences when node support is weak or when uncertainties in the fossil record are not considered. [ABSTRACT FROM AUTHOR]

Simple Summary: Anteaters are insectivores, consuming diets consisting primarily of termites and ants in the wild; therefore, feeding them under human care has been a challenge and frequently leads to nutritional disorders. Through analysis of free-ranging giant anteaters' stomach content, the findings of this study provide valuable information for optimizing anteater nutrition in zoological institutions and rehabilitation centers causing a significant impact on the welfare of the species. Using the stomach contents of 24 wild road-killed giant anteaters as proxies for their diet, we found that estimated wild diets were much lower in calcium (about ten times less) and phosphorus compared with manufactured feeds commonly fed to anteaters under human care. Indicators of soil consumption, such as ash, iron, and manganese were higher in the stomach contents than in either wild termites or manufactured diets, likely due to high levels of soil ingestion during feeding in the wild. Protein and fat levels in insects, stomach contents, and commercial diets all met carnivore recommendations. Both giant anteaters and tamanduas in managed care often develop hypercalcemia, perhaps because these taxa have an enhanced ability to retain calcium allowing them to survive on such low calcium diets. Results from this study indicate that, for anteaters in managed care, it is important to keep dietary calcium and vitamins D and K within recommended levels to prevent nutritional diseases such as hyper- and hypocalcemia and vitamin K deficiency. [ABSTRACT FROM AUTHOR]

The sloths that dispersed into Central and North America were most likely derived from tropical taxa, as indicated by their high occlusal surface area (OSA) in comparison with body mass, as in South American tropical species. Relative muzzle width and hypsodonty indices were used to infer the dietary adaptation of several Late Pleistocene/Early Holocene giant ground sloths from the Americas. Nothrotheriidae and Megatheridae taxa were adapted to a browser or browsing mixedfeeder diet, Mylodontidae taxa to a variety of dietary types, and Megalonychidae taxa to a browsing mixedfeeder diet. However, these are generalized dietary adaptations and do not necessarily reflect the consumption of specific food resources. In general, Megalonychidae and Nothrotheriidae were climbing species, Mylodontidae were digging species, and Megatheriidae were fully terrestrial species. [ABSTRACT FROM AUTHOR]

Anthropogenic disturbances affecting forest areas can increase disease prevalence and susceptibility in several species of arboreal mammals, such as sloths. Thus, this study aimed to evaluate the most common conditions in body systems of free-ranging sloths admitted at the Wildlife Triage and Rehabilitation Center of Amazonas of the Institute of Environment and Renewable Natural Resources. A total of 227 individuals (139 retrospective cases from 2015 to 2019, and 88 prospective cases from July 2020 to July 2021) were evaluated over a six-year period. Cases from the genus Bradypus showed involvement of the following body systems: 44% respiratory, 29% integumentary, 15% musculoskeletal, 5% digestive, 3% visual, 2% auditory, 1% circulatory and 1% genitourinary, while that distribution in the genus Choloepus was: 39% musculoskeletal, 27% integumentary, 19% respiratory, 9% digestive, 3% circulatory, 1% visual, 1% auditory and 1% genitourinary. The results reveal significant differences between the condition detected and the genus (Bradypus and Choloepus), age and case outcome. These results can provide data for future investigations of sloth diseases, confirming lesions, as well as motivating and suggesting adequate management methods. [ABSTRACT FROM AUTHOR]

We inferred the annual isotopic diet (δ13C) of an individual of the giant ground sloth Eremotherium laurillardi found in Toca dos Ossos (Ourolândia, Bahia, Brazil) through the extension of its third inferior molar. This individual lived in the region at 40,779-39,617cal yr BP. One year of its life was recorded in a length of 67 mm in the tooth. Two years were recorded in this molariform, during which the diet and climate did not change much, and substantial precipitation occurred during the middle of the year, which is in opposition to the modern pattern. The mean carbon (μδ13C=-13.9 ± 1.8‰) and oxygen (μδ18O = 22.5 ± 2.9‰) isotopic values were similar to values for other individuals of the species found in the same cave but different from the values found in other localities of the Brazilian Intertropical Region, which allows us to suggest that this region had more precipitation and lower temperatures in comparison to today. The oxygen isotopic values found in dated fossils of E. laurillardi and from two other taxa found in the same cave (Toxodon platensis, and Notiomastodon platensis) could help in the understanding of the climatic variation that occurred in the region. [ABSTRACT FROM AUTHOR]

The pelvis, formed by the ilium, ischium and pubis, forms the coxal, which is the largest of the flat bones of the skeleton, with an important role in the physiology of birth. Vastly studied in domestic animals, there is still much to be investigated regarding the anatomical classification in wild animals, mainly aiming to improve the understanding of the reproductive management of the species. Tamandua tetradactyla is one of these species in which morphological studies are still scarce, especially when it comes to reproductive aspects. In this context, we carried out the pelvimetry of T. tetradactyla using radiographic images to anatomically and obstetrically classify the pelvis of this species, classifying it as dolicopelvic, with evidence of homoscedasticity of the samples. Verification of the existence of a relationship between the variables studied by the statistical method of Pearson coefficients showed positive correlations of high intensity for the diameters studied (P < 0.01). Thus, we believed that our findings may support future reproductive studies in this species. [ABSTRACT FROM AUTHOR]

The sedimentological characteristics and fossil vertebrates studies are notoriously increasing in the earth sciences field, as a way to infer reliable information about the biota and the paleoenvironmental and paleoclimatic context. In this framework, we establish relationships among the flora, fauna and the depositional environment during the Late Miocene in Northwestern Argentina. The sedimentology features are described in detail from sediments collected in the Quebrada Salta section, and the Xenarthra Cingulata Kraglievichia paranensis (Pampatheriidae) and Cranithlastus xibiensis (Glyptodontidae) are recorded for the first time in the Palo Pintado Formation (Salta Province, Argentina). The sedimentary observations support the presence of a sinuous sandy-gravel fluvial system with swamps and lacustrine, under a wet tropical climate. In this environment, the vertebrates here described would have inhabited open zones close to these freshwater bodies, predominated by xeric vegetation, mainly represented by grasses and sedges with scarce arboreous elements. [ABSTRACT FROM AUTHOR]

New remains of a relatively plesiomorphic nothrotheriid sloth have been recovered from upper Miocene-aged deposits near the village of Achiri in the Altiplano of Bolivia. The new specimens appear allied to other middle and late Miocene remains from Argentina and Bolivia that have been assigned to the pseudo-genus 'Xyophorus'. 'Xyophorus' has not previously been recognised as a distinct genus because of the paucity of material it encompasses. The new specimens, however, include a well-preserved squamosal with attached auditory region and an isolated astragalus. These elements, which are described in detail, provide a sufficient number of distinctive characters to place the previous fossils assigned to 'Xyophorus' into a new monotypic genus. Beyond exhibiting a suite of distinctive autapomorphies which justify its formal taxonomic designation, the new taxon not only shares several synapomorphies with more derived members of Nothrotheriidae but also retains a number of plesiomorphies characteristic of basal megatherioid taxa and shows a number of intermediate features. Although the new taxon is too incomplete to justify a full phylogenetic analysis, it appears to represent a basal member of Nothrotheriidae. Resolution of the taxonomic status of the genus Xyophorus awaits a better understanding of the taxonomy of early Miocene-aged basal megatherioids. [ABSTRACT FROM AUTHOR]

Armadillos are bitten by several species of flea. Females of the genus Tunga penetrate the epidermis and when in place are fertilised by males, after which the abdomen swells enormously to form a 'neosome'. Within the penetrans group, T. perforans, makes lesions that perforate the osteoderms within the integument to form ~3 mm diameter cavities occupied by a discoid neosome. We examined these lesions in carapace material from animals which had died in the wild to see whether we could recruit evidence as to how they may be generated, either by the insect or by the host. We studied one species without such lesions, the nine‐banded armadillo Dasypus novemcinctus, and two species with, the greater hairy armadillo Chaetophractus villosus and the southern three‐banded armadillo Tolypeutes matacus, both showing the characteristic 'flea bite' holes in the external surfaces of the osteoderms. Samples were studied by three‐dimensional backscattered electron mode scanning electron microscopy and X‐ray microtomography. Both methods showed resorption pit complexes in the external surfaces of the osteoderms characteristic of those made by osteoclasts in active bone resorption. Lesions involved both the syndesmoses (sutures) between adjacent bones and the central regions of the osteoderms. Many lesions showed extensive repair by infilling with new bone. We conclude that the T. perforans neosome creates a local host response which causes bone resorption, creating the space in which it can grow. [ABSTRACT FROM AUTHOR]

The giant anteater (Myrmecophaga tridactyla) is the largest of the Neotropical vermilinguans. This animal is the second mammal most frequently run over on the roads of Cerrado biome, Brazil. Therefore, it is pivotal to know the anatomy of this species to contribute to the clinical care of these animals. Thus, the aim of this study was to identify the anatomical structures in the abdominal region of the giant anteater using computed tomography (CT). For this, the tomographic analysis was performed in sequential order in the craniocaudal direction in five giant anteaters. Moreover, four giant anteater corpses were used for anatomical studies, where two corpses were sectioned in cross sections of approximately 3 cm each, and two animals were dissected to identify the abdominal organs. The association between CT and anatomical study allowed the visualization of anatomical structures found in the abdominal cavity, such as the topographic anatomy facilitates the identification of organs on CT images. The findings of this study demonstrated that CT is a good technique to provide detailed information about the anatomical structures in the abdominal cavity and that this study can be used as CT and anatomical reference for veterinarians who care for wild animals. [ABSTRACT FROM AUTHOR]

Sloths are among the most specialized arboreal species and have evolved a suite of anatomical features that support suspensory behaviors. While sloths generally show a reduction in skeletal muscle mass, the digital flexor musculature (i.e., the muscles associated with grip strength) remains relatively large. It may therefore be inferred that grip strength represents an important selective criterion for sloths. However, no in vivo data are available to assess the validity of this hypothesis. In this study, we explore how grip force varies as a function of substrate diameter, sidedness, and between the forelimb and hindlimb in brown‐throated three‐toed sloths (Bradypus variegatus; N = 5). Grip force was measured using a custom‐built support, comprising two semi‐circular prisms, the lower half of which was instrumented with a medium‐load force plate. Maximum recorded grip forces exceeded 100% bodyweight. While no differences were observed between the fore‐ and hindlimb pairs, both substrate diameter and sidedness significantly influenced grip strength. Specifically, B. variegatus exhibited the greatest grip force potential on the left side of their body and on large‐diameter supports. Equal gripping performance between the fore‐ and hindlimbs may be attributable to previous observations in sloths of a near‐equal distribution of bodyweight support between the limbs during suspensory locomotion. Moreover, a tendency to produce the greatest grip forces on large‐diameter substrates agrees with their ecological substrate preferences. The consistent tendency for left sidedness across the individuals studied was unexpected, and future work should explore the potential ecological and anatomical correlates of such a finding. [ABSTRACT FROM AUTHOR]

We present a taxonomic revision of maned sloths, subgenus Bradypus (Scaeopus), a taxon endemic to the Brazilian Atlantic Forest and currently composed of a single species, the vulnerable Bradypus torquatus. Our review is based on coalescent species delimitation analyses using mitochondrial and nuclear DNA, morphological analyses, and field observations. Our integrative approach demonstrates that two species of maned sloth can be recognized: the northern maned sloth (Bradypus torquatus Illiger, 1811) occurring in the Brazilian states of Bahia and Sergipe, and the southern maned sloth (Bradypus crinitus Gray, 1850), occurring in Rio de Janeiro and Espirito Santo states. The two species diverged in the Early Pliocene and are allopatrically distributed. We discuss the biogeographic pattern of the two maned sloth species, comparing it with other Atlantic Forest mammals. We also suggest that the conservation status of both maned sloths needs to be reassessed after this taxonomic rearrangement. [ABSTRACT FROM AUTHOR]

Climate change and habitat loss have been identified as the main causes of species extinction. Forest regeneration and protected areas are essential to buffer climate change impacts and to ensure quality habitats for threatened species. We assessed the current and future environmental suitability for the maned sloth, Bradypus torquatus , under both future climate and forest restoration scenarios, using ecological niche modeling. We compared environmental suitability for two Evolutionarily Significant Units (ESUnorth and ESUsouth) using two climate change scenarios for 2070, and three potential forest regeneration scenarios. Likewise, we evaluated the protection degree of the suitable areas resulting from the models, according to Brazilian law: PA—Protected Areas; PPA—Permanent Protection Areas (environmentally sensitive areas in private properties); and LR—Legal Reserves (natural vegetation areas in private properties). Finally, we calculated the deficit of PPA and LR in each ESU, considering the current forest cover. Forest regeneration might mitigate the deleterious effects of climate change by maintaining and increasing environmental suitability in future scenarios. The ESUnorth contains more suitable areas (21,570 km²) than the ESUsouth (12,386 km²), with an increase in all future scenarios (up to 45,648 km² of new suitable areas), while ESUsouth might have a significant decrease (up to 7,546 km² less). Suitable areas are mostly unprotected (ESUnorth—65.5% and ESUsouth—58.3%). Therefore, PPA and PA can maintain only a small portion of current and future suitable areas. Both ESUs present a high deficit of PPA and LR, highlighting the necessity to act in the recovery of these areas to accomplish a large-scale restoration, mitigate climate change effects, and achieve, at least, a minimum forested area to safeguard the species. Notwithstanding, a long-term conservation of B. torquatus will benefit from forest regeneration besides those minimum requirements, allied to the protection of forest areas. [ABSTRACT FROM AUTHOR]

The cervicornis species group of Taumacera Thunberg, 1814, endemic to Sri Lanka, is revised. Seven species, including three species new to science, are recognized: Taumacera cervicornis (Baly, 1861), T. lewisi (Jacoby, 1887), T. mirabilis (Jacoby, 1887), T. unicolor (Jacoby, 1887), T. adamskii sp. nov., T. maskeliya sp. nov., and T. sigiriya sp. nov. The representatives of this group are characterized by pectinate antennomeres and by 12-segmented antennae. Antennomeres XI and XII are firmly fused in most species, separated by a distinct suture; however, in T. cervicornis, antennomere XII appears to be moveable. Color photographs of habitus, body details, and aedeagi as well as female genitalia are presented. [ABSTRACT FROM AUTHOR]

Previous studies have suggested species- and individual-specific morphologies of cephalic shields of three-banded armadillos (Tolypeutes spp.). Central cephalic scutes would form discrete lines; the first two posterior lines being composed of one scute (1-1) in Tolypeutes matacus and one followed by two scutes (1-2) in Tolypeutes tricinctus. However, conclusions were limited to a few specimens and the T. tricinctus pattern was later observed in T. matacus. Here, we assessed the potential use of the morphology of the cephalic shield as a species diagnostic trait and individual natural mark in three-banded armadillos by quantifying their patterns in museum (n = 71) and field (n = 82) specimens. In total, 93% of T. matacus and 88% of T. tricinctus specimens presented the respective species' character states. All specimens could be individualized based on a visual comparison of their cephalic shields. Our findings show that the morphology of cephalic shields is a species diagnostic trait and an individual natural mark in three-banded armadillos. Therefore, we add an accessible character for species diagnosis in Tolypeutes and provide an alternative to artificial marks that presents virtually no associated cost and damage to animal welfare and can be reliably applied in ecological and participatory science projects. [ABSTRACT FROM AUTHOR]

Global change imposes multiple challenges on species and, thus, a reliable prediction of current and future vulnerability of species must consider multiple stressors and intrinsic traits of species. Climate, physiology, and forest cover, for example, are required to evaluate threat to thermolabile forest-dependent species, such as sloths (Bradypus spp.; Mammalia: Xenarthra). Here, we estimated future changes in the distribution of three sloth species using a metabolic-hybrid model focused on climate (climatic only, i.e., CO approach) and adding forest cover constraints to distribution of species (climate plus land cover, i.e., CL approach). We used an innovative method to generate estimates of physiological parameters for endotherms, validated with field data. The CF approach predicted a future net expansion of distribution of B. torquatus and B. variegatus, and a future net contraction of distribution of B. tridactylus. The inclusion of forest cover constraints, however, reversed the predictions for B. torquatus, with a predicted net distribution contraction. It also reduced expansion of B. variegatus, although still showing a large net expansion. Thus, B. variegatus is not predicted to be threatened in the future; B. tridactylus emerges as the species most vulnerable to climate change, but with no considerable forest losses, while B. torquatus shows the opposite pattern. Our study highlights the importance of incorporating multiple stressors in predictive models in general. To increase resilience of species to climate change, it is key to control deforestation in the Amazon for B. tridactylus, and to promote reforestation in the Atlantic Forest for B. torquatus. As mudanças globais impõem vários desafios à biodiversidade e uma previsão confiável da vulnerabilidade atual e futura das espécies deve considerar vários estressores e características intrínsecas das mesmas. Clima, fisiologia e cobertura florestal, por exemplo, são necessários para avaliar a ameaça às espécies dependentes da floresta e termolábeis, como as preguiças (Bradypus spp.; Mammalia: Xenarthra). Aqui, estimamos as mudanças futuras na distribuição de três espécies de preguiças usando um modelo híbrido metabólico focado no clima (abordagem apenas climática, CO) e adicionando restrições de cobertura florestal à distribuição das espécies (abordagem de clima mais cobertura florestal, CL). Utilizamos um método inovador para gerar estimativas de parâmetros fisiológicos para endotérmicos, validado com dados de campo. A abordagem CO previu uma expansão líquida futura da distribuição de B. torquatus e B. variegatus, e uma contração líquida futura da distribuição de B. tridactylus. A inclusão de restrições de cobertura florestal, no entanto, reverteu as previsões de B. torquatus, com uma contração da distribuição líquida prevista. A restrição de cobertura florestal também reduziu a expansão de B. variegatus, embora ainda exiba uma grande expansão líquida. Assim, B. variegatus não está previsto para ser ameaçado no futuro; B. tridactylus emerge como a espécie mais vulnerável às mudanças climáticas, mas sem perdas florestais consideráveis, enquanto B. torquatus mostra o padrão oposto. Nosso estudo destaca a importância de incorporar múltiplos estressores em modelos preditivos em geral. Para aumentar a resiliência das espécies às mudanças climáticas, é fundamental controlar o desmatamento na Amazônia para B. tridactylus e promover o reflorestamento na Mata Atlântica para B. torquatus. [ABSTRACT FROM AUTHOR]

Global change imposes multiple challenges on species and, thus, a reliable prediction of current and future vulnerability of species must consider multiple stressors and intrinsic traits of species. Climate, physiology, and forest cover, for example, are required to evaluate threat to thermolabile forest-dependent species, such as sloths (Bradypus spp.; Mammalia: Xenarthra). Here, we estimated future changes in the distribution of three sloth species using a metabolic-hybrid model focused on climate (climatic only, i.e. CO approach) and adding forest cover constraints to distribution of species (climate plus land cover, i.e. CL approach). We used an innovative method to generate estimates of physiological parameters for endotherms, validated with field data. The CF approach predicted a future net expansion of distribution of B. torquatus and B. variegatus , and a future net contraction of distribution of B. tridactylus. The inclusion of forest cover constraints, however, reversed the predictions for B. torquatus , with a predicted net distribution contraction. It also reduced expansion of B. variegatus , although still showing a large net expansion. Thus, B. variegatus is not predicted to be threatened in the future; B. tridactylus emerges as the species most vulnerable to climate change, but with no considerable forest losses, while B. torquatus shows the opposite pattern. Our study highlights the importance of incorporating multiple stressors in predictive models in general. To increase resilience of species to climate change, it is key to control deforestation in the Amazon for B. tridactylus , and to promote reforestation in the Atlantic Forest for B. torquatus. [ABSTRACT FROM AUTHOR]

Simple Summary: Monitoring diseases and lesions in free-ranging and captive wild animals is important for biodiversity conservation and for understanding factors that can impact not only animal health but also human and environmental health. Here, we report for the first time a case of liver cancer in a free-ranging three-toed sloth (Bradypus variegatus) and describe the gross, microscopic, and immunohistochemical features of the lesion. The tumor was identified during the necropsy of a three-toed sloth that had to be euthanized due to serious consequences of an accident in the electrical network. Despite not being related to the cause of death of the animal, the type of tumor observed, a hepatocellular carcinoma (HCC), is one of the most frequent hepatic neoplasms in the liver of humans and domestic animals. The increasing interest of tumors in wildlife is important for biodiversity conservation and for monitoring environmental agents and/or contaminants with potential impact on human health. Here we described the occurrence of hepatocellular carcinoma (HCC) in noncirrhotic liver of a free-ranging three-toed sloth (Bradypus variegatus) from the Atlantic Forest biome in Brazil. The HCC showed a moderate mononuclear inflammatory infiltrate within the tumor tissue but with no inflammation and fibrosis in the adjacent liver tissue. Upon immunohistochemistry, neoplastic cells were diffusely positive for HepPar-1 and glutamine-synthetase presenting an irregular and random immunostaining pattern; β-catenin was positive in the cytoplasmic membrane of malignant hepatocytes; and cytokeratin 19 immunostaining was restricted to bile duct epithelial cells. The liver tissue was negative for HBV-like and HCV-like viruses assessed by molecular tests. The potential similarity of pathogenesis may reinforce the need for research on environmental and/or infectious agents associated with HCC that may contribute to the understanding of cancer in wildlife. [ABSTRACT FROM AUTHOR]

The lesser anteater (Tamandúa tetradactyla) is a mammal of the family Myrmecophagi-dae, which is part of the Superordem Xenarthra. It is found in South America and is distributed in all the Brazilian biomes. The ecologic aspects of the morphology of the lesser anteater are still little known. This study used 12 specimens of Tamandua tetradactyla with unknown gender; a specimen of dog (Canis lupus familiaris) male; a specimen of cat (Felis catus) female; a specimen of sheep (Ovis aries) with unknown gender. The grac-ilis muscle was dissected, evidencing its origin and insertion. This paper describes the origin and insertion of the gracilis muscle in Tamandua tetradactyla. Knowledge about biomechanical aspects of terrestrial and arboreal species is essential in ecomorphologi-cal studies. The lesser anteater is a climber who actively uses its hind limbs in adduction when climbing trunks and trees. [ABSTRACT FROM AUTHOR]

The giant anteater (Myrmecophaga tridactyla) is a strictly myrmecophagous xenarthran species that ranges from Honduras to northern Argentina, occupying various habitats, from grassland and floodplains to forests. According to the IUCN, it is a vulnerable species mainly threatened by poaching, habitat loss and fragmentation, and road kills. Here, we investigate the phylogeography, distribution, ecology, and historical demography of Brazilian populations of the giant anteater. We analysed two mitochondrial (mtDNA) and three nuclear (nDNA) markers in 106 individuals from the Cerrado, Pantanal, Atlantic Forest, and Amazon Forest biomes through analyses of population structure and demography, phylogeography, and ecological niche modelling. Two divergent mtDNA clusters were found, one in the Amazon (AM) and another in the Cerrado, Pantanal, and Atlantic Forest biomes (CEPTAF). At the population level, CEPTAF presented higher mtDNA haplotype richness than AM and a unidirectional mtDNA gene flow was identified from AM to CEPTAF, which could be linked to more favourable habitat conditions for the species in Cerrado and Pantanal. Paleodemographic reconstructions with mtDNA and nDNA data indicate a large population expansion of the species starting at the end of the Pleistocene. Finally, the integrative phylogeographic analyses of giant anteater populations reinforce the importance of the Brazilian Cerrado as a priority biome for the species' conservation. [ABSTRACT FROM AUTHOR]

Identifying ecomorphological convergence examples is a central focus in evolutionary biology. In xenarthrans, slow arboreality independently arose at least three times, in the two genera of 'tree sloths', Bradypus and Choloepus, and the silky anteater, Cyclopes. This specialized locomotor ecology is expectedly reflected by distinctive morpho-functional convergences. Cyclopes, although sharing several ecological features with 'tree sloths', do not fully mirror the latter in their outstandingly similar suspensory slow arboreal locomotion. We hypothesized that the morphology of Cyclopes is closer to 'tree sloths' than to anteaters, but yet distinct, entailing that slow arboreal xenarthrans evolved through 'incomplete' convergence. In a multivariate trait space, slow arboreal xenarthrans are hence expected to depart from their sister taxa evolving toward the same area, but not showing extensive phenotypical overlap, due to the distinct position of Cyclopes. Conversely, a pattern of 'complete' convergence (i.e., widely overlapping morphologies) is hypothesized for 'tree sloths'. Through phylogenetic comparative methods, we quantified humeral and femoral convergence in slow arboreal xenarthrans, including a sample of extant and extinct non-slow arboreal xenarthrans. Through 3D geometric morphometrics, cross-sectional properties (CSP) and trabecular architecture, we integratively quantified external shape, diaphyseal anatomy and internal epiphyseal structure. Several traits converged in slow arboreal xenarthrans, especially those pertaining to CSP. Phylomorphospaces and quantitative convergence analyses substantiated the expected patterns of 'incomplete' and 'complete' convergence for slow arboreal xenarthrans and 'tree sloths', respectively. This work, highlighting previously unidentified convergence patterns, emphasizes the value of an integrative multi-pronged quantitative approach to cope with complex mechanisms underlying ecomorphological convergence. [ABSTRACT FROM AUTHOR]

Very little information is available to zoo managers on the nutritional preferences of the lesser anteater, a highly specialized predator. By studying lesser anteater feeding behavior, we expect to contribute to improved management decisions and individual welfare experiences. We studied the response of zoo-housed lesser anteaters (n = 7) to feeders with live ants (Acromyrmex lundi) and termites (Cortaritermes fulviceps), and we also evaluated the nutritional values of these prey. We individually evaluated each lesser anteater (3 sessions), recording activities by camera. We ground insect samples into a coarse meal and evaluated in vitro biochemical parameters (humidity, lipids proteins, ash, and carbohydrates). Lesser anteaters spent more time with termites than with ants and consumed more termites. Ant meal presented a higher protein and lipid content than termite meal (35.28 ± 0.18% vs. 18.19 ± 0.34% and 16.95 ± 0.13% vs. 6.54 ± 0.31%, respectively), and carbohydrate digestibility was higher in termites. These findings indicate an association between the level of insect consumption and nutritional and digestibility values. This is the first exploration of lesser anteater responses to the presence of social insects in feeders and may serve to guide the study of food preferences in captivity. [ABSTRACT FROM AUTHOR]

Tamandua is a neotropical mammal genus that belongs to the superorder Xenarthra. The thoracic limbs of Tamandua have anatomical adaptations that widely differ from other mammals, and there are frequently specimens in wildlife care centers with traumas in their limbs. However, there are few studies describing the radiographic and morphometric anatomy of the humerus in Tamandua, or describing partially the bone reliefs. Thus, the main objective of this study was to describe the characteristics of the humerus of Tamandua mexicana based on gross dissections, radiographies and measurements comparing with other studies in the three Vermilingua genera, and establishing more suitable terminology. Twelve thoracic limbs of six death specimens of Tamandua mexicana were analyzed. The bone reliefs, ligaments, muscles and neurovascular structures related to the humerus were identified, and the suitable terminology to the humerus of Tamandua was established. Morphometric measurements of each bone relief were taken, and the data were statistically analyzed with the Wilcoxon non-parametric test for functional proposes. The humerus of Tamandua has anatomical characteristics mainly to offer greater areas to the muscles that act on the shoulder flexion and hand movements. Even the articular reliefs are lesser than the adjacent non-articular reliefs, the muscles and ligaments are the anatomical structures that give more stabilization to the shoulder and elbow joints. The deltosupracondylar ligament can be partially ossified in older adult specimens, and neurovascular structures pass through the supracondylar foramen. These anatomical characteristics must be accounted for in the radiological diagnosis and surgical approaches. [ABSTRACT FROM AUTHOR]

Chaetophractus villosus (Desmarest, 1804) is commonly known as the large hairy armadillo. It is one of two living species of Chaetophractus. Like all armadillos, it bears a dorsal carapace of ossified dermal scutes covered by epidermal scales. Dorsal hair is sparse, long, and black and brown. This semifossorial armadillo inhabits grasslands, savannas, steppes, forests, and even degraded areas such as agroecosystems of Argentina, the "Gran Chaco" of Bolivia and Paraguay, and southern Chile. Chaetophractus villosus is omnivorous–carnivorous. It is listed as "Least Concern" (LC) on the International Union for Conservation of Nature Red List of Threatened Species, and is mainly affected by hunting, persecution as an agricultural pest, and vehicle collisions. [ABSTRACT FROM AUTHOR]

The Magnorder Xenarthra includes recent and fossil forms of Cingulata, Vermilingua, and Folivora. Folivora consist of extant and extinct sloths, presenting a great diversification in terms of size and habits. To analyse endocranial morphological variation in sloths, we measured digital endocrania of representatives of both fossil and extant Xenarthrans, and compiled measurements from the literature for a variety of mammals representing different orders, sizes, and habits. A Principal Component Analysis combining both datasets revealed a conservative covariance structure among mammalian orders, with the arrangement of scores along the first principal component summarising nearly 93% of morphometric variation, related in an almost isometric trend. A second analysis held only for endocranial measurements from Xenarthran endocrania, produced second and third principal components scores showing a variation trend among sloths related to relative dimensions of the olfactory bulb and the hypophysis. Interpolation of these scores also revealed an overlapping between Folivora and Vermilingua representatives and the separation of Cingulata, related to the dimensions of the olfactory bulbs. These results suggest that the endocranial structures exhibit a conservative pattern, varying according to the overall size of the encephalon, but also point to some convergence related to fossorial and arboreal habitat uses. [ABSTRACT FROM AUTHOR]

The skeletal anatomy of the anterior narial region in mammals is complex, comprised of several bony and cartilaginous elements. Because it includes many cartilaginous components, preservation of this area in extant and extinct specimens is often incomplete. This, along with its complexity, means that this region of the cranium is generally understudied, with the exception of humans and a few select mammal species. The present study began with a cranial specimen of the extant Hoffmann's two-toed sloth, Choloepus hoffmanni (Xenarthra, Folivora, Megalonychidae), that possessed several unusual well-preserved narial anomalies. In order to determine whether such features are present in other extant sloths, and if so, how frequently, we examined two- and three-toed sloth specimens from a variety of museum collections. Additionally, we examined museum specimens of extinct sloths known to possess unusual osseous narial structures, with the goal of better understanding the anatomy of the anterior opening of the nasal cavity in all sloths, living and extinct. A diverse series of unusual narial elements were found, including an internasal bone, an ossified anterior nasal septum, an os nariale, an ossified processus lateralis ventralis of the nasal capsule, and an internarial bar of varying composition and completeness. All of these features are present in Choloepus, although they are preserved in museum skulls infrequently, but none were found to be present in the three-toed sloth, Bradypus. An internarial bar, anteriorly elongated ossified nasal septum, and ossified processus lateralis ventralis were observed in several species of extinct mylodontid and megatheriid sloths, and an os nariale was recorded in the extant vermilinguan anteaters Cyclopes and Tamandua. It is not known how much of the variation we document in these features is genuine and how much is due to preservation issues. Given such uncertainty, it is difficult to assess the phylogenetic or functional significance of these features. We believe, however, that this is an area of the skull in Pilosa (sloths and anteaters) that merits further study. [ABSTRACT FROM AUTHOR]

The northern naked-tailed armadillo (Cabassous centralis) is a small, poorly known armadillo species. We update the state of knowledge on this species, provide information on its current and potential distribution, and assess its conservation status and threats. We reviewed the existing literature and obtained georeferenced records from publications, online databases, and field researchers. A total of 174 documents mentioning C. centralis have been published between 1855 and 2019, about half of which (83) provided information on its distribution. The majority of publications came from Colombia. About 10% of publications included information about its ecology, concluding that it is a rare species that mainly occurs in areas with secondary vegetation. It seems to prefer complex habitats, as it is rarely found in fragmented or modified habitats. Consequently, it is possible that its ability to adapt to land use change is low. A total of 224 confirmed records allowed us to extend the species range to the northern Lacandona Forest in Mexico, the Andes of Colombia and southwards in Ecuador. Nevertheless, a distribution model suggests that the species could be even more widely distributed. C. centralis is listed in a threatened category in two countries, whereas more than half of the range countries have not assessed its conservation status. We consider its current global listing as Data Deficient to be appropriate, as many aspects of its ecology, reproduction, population size and trend, and the degree of impact of potential threats remain unknown. [ABSTRACT FROM AUTHOR]

Vestigial organs are historical echoes of past phenotypes. Determining whether a specific organ constitutes a functional or vestigial structure can be a challenging task, given that distinct levels of atrophy may arise between and within lineages. The mammalian pineal gland, an endocrine organ involved in melatonin biorhythmicity, represents a classic example, often yielding contradicting anatomical observations. In Xenarthra (sloths, anteaters, and armadillos), a peculiar mammalian order, the presence of a distinct pineal organ was clearly observed in some species (i.e., Linnaeus's two-toed sloth), but undetected in other closely related species (i.e., brown-throated sloth). In the nine-banded armadillo, contradicting evidence supports either functional or vestigial scenarios. Thus, to untangle the physiological status of the pineal gland in Xenarthra, we used a genomic approach to investigate the evolution of the gene hub responsible for melatonin synthesis and signaling. We show that both synthesis and signaling compartments are eroded and were probably lost independently among Xenarthra orders. Additionally, by expanding our analysis to 157 mammal genomes, we offer a comprehensive view showing that species with very distinctive habitats and lifestyles have convergently evolved a similar phenotype: Cetacea, Pholidota, Dermoptera, Sirenia, and Xenarthra. Our findings suggest that the recurrent inactivation of melatonin genes correlates with pineal atrophy and endorses the use of genomic analyses to ascertain the physiological status of suspected vestigial structures. [ABSTRACT FROM AUTHOR]

Extinct sloths (Xenarthra, Folivora) are morphologically diverse, despite some similarities among some Pleistocene genera. Cranial and diagnostic postcranial elements (especially limb bones) are taxonomically informative but the axial postcranial skeleton can prove difficult to classify, as in cases with only vertebral remains or when closely related taxa are found together. Here, 24 linear and angular measurements of presacral axial skeletons from eight genera of Pleistocene ground sloths were analysed through multivariate methods for assigning their vertebrae to a genus and to a position along the vertebral column. Both isolated vertebrae and vertebrae associated with partial and complete skeletons of each genus were included. Principal components and linear discriminant analyses show a high percentage (over 90%) of correct taxonomic reclassification. For the position of vertebrae, the accuracy increased significantly when cervical, thoracic and lumbar regions were separately considered instead of the whole column, misclassifying the position of the vertebrae only by a few positions in most cases. Our database is useful for confidently assigning isolated vertebrae of extinct sloths to a specific genus and position, showing that beyond the apparent homogeneity in the axial postcranial skeleton of ground sloths, quantitative studies allow the evaluation of diversity and variation between groups. [ABSTRACT FROM AUTHOR]

Osteoderms are present in most tetrapod lineages with considerable lineage-specific variation. It has been hypothesized that osteoderms are a case of "deep homology" in craniates, but the embryonic origin of osteoderms -and other related postcranial exoskeletal elements- is still under debate. Most authors support its mesodermal origin, while others suggest that osteoderms are derived from neural crest scleroblastic cells in sauropsids. The armadillos (Xenarthra, Cingulata) are the only living mammals and the only extant synapsids with osteoderms. Here, we aim to identify skeletogenic neural crest cells in the dorsal skin of armadillos in order to assess if osteoderms have a neuroectodermal origin in mammals, similar to what is observed in sauropsids. For this purpose, skin samples from fetuses and newborn specimens of Dasypus hybridus were processed and the embryological development of osteoderms was characterized using different immunohistochemical markers (HNK-1, PDGFR α, S-100, and C5). For the first time, we report cell populations that were reactive to skeletogenic neural crest markers, indicating an ectomesenchymal origin of the mammalian osteoderms. Our results demonstrate similar molecular expression for mammals as in sauropsids and, therefore, this strongly suggests that osteoderms in both groups would have a homologous embryonic origin. [ABSTRACT FROM AUTHOR]

Divergence in forelimb morphology is often associated with functional habits exhibited within the Xenarthra, ranging from terrestrial-digging in armadillos to arboreal-suspension in sloths. We hypothesized that quantitative differences in hind limb form also will be predictive of the diverse lifestyles observed in this small clade. A total of 26 morphofunctional indices were calculated from 42 raw measurements of bone length/width/depth in a sample of N = 76 skeletal specimens (18 species). Index data for each species were categorized by substrate preference and use and then evaluated using a combination of stepwise Discriminant Function Analysis (DFA) and Principal Component Analysis (PCA) to determine significant osteological correlates (traits) among extant taxa. Additionally, character states of the morphometric data were inferred using a recent hypothesis of xenarthran phylogeny. DFA determined 14 distinct morphofunctional indices relating to femur robustness, hip/ankle/limb mechanical advantage, and foot and claw length as the most discriminating features. PCA clearly separated armadillos from sloths in morphospace based on overall robustness versus gracility, as well as proximal versus distal lengths of skeletal elements (including the claws), whereas these characteristics were intermediate in the hind limbs of anteaters and selected armadillos having either a larger greater trochanter or modified foot/claw proportions. Two-toed and three-toed sloths showed further separation from each other in morphospace primarily driven by proportions of their tibia and hind feet despite evidence of convergence for numerous functional traits. Moreover, the majority of the traits measured had significant phylogenetic signal and several of these indicated clear patterns of convergent and divergent evolution in xenarthrans by evaluation of their tip states. Our assessments expand functional interpretations of xenarthran limb form and identify potentially conserved and secondarily modified traits related to fossoriality across taxa, including in three-toed sloths, demonstrate possible morphological trade-offs between digging and climbing habits, and suggest derived traits adapted for arboreal lifestyle and suspensory function. [ABSTRACT FROM AUTHOR]

Despite the ubiquity of parasitism, the knowledge regarding fossil parasites remains fragmentary. As an example, South American clade Xenarthra was a predominant group of mammals during the Cenozoic; however, its paleoparasitological knowledge has many gaps, with only a few reports in armadillos and fewer in ground sloths. Darwin’s ground sloth (Mylodon darwini) was a mega mammal widely distributed in the Neotropics; however, its parasitic fauna is poorly known with the sole report of unidentified nematode eggs. Thus, this study aimed to determine additional host-parasite associations and to discuss its possible role as a reservoir of zoonotic parasites. Fifty-two coprolites from Cueva del Milodón Natural Monument were analyzed through coprological analysis to determine the presence of parasites. From these, 18 (34.62%) coprolites had parasitic helminth eggs belonging to 6 taxa: Calodium sp., Ascaridida, Hymenolepididae, Anoplocephalidae, Taeniidae, and Digenea. All these findings are new records for this sloth; also, two of them, Calodium sp. and Anoplocephalidae, have represented a risk for the health of ancient humans. Eggs of Calodium were similar to those previously isolated from ancient humans in Patagonia. Thus, Darwin’s ground sloth has represented a potential reservoir of zoonotic helminths, which is interesting considering this species was in close contact with humans in ancient Patagonia. Thus, additional collaboration with paleontologists is highlighted considering the incipient development of paleoparasitology in Chile, which could elucidate the presence of important pathogens, contributing to a better understanding of the evolution and changes in the distribution and virulence of certain parasites through time. [ABSTRACT FROM AUTHOR]

The earliest widely accepted presence of humans in America dates to approximately 17.5 cal kyr BP, at the end of the Last Glacial Maximum (LGM). Among other evidence, this presence is attested by stone tools and associated cut-marks and other bone surface modifications (BSM), interpreted as the result of the consumption of animals by humans. Claims of an older human presence in the continent have been made based on the proposed anthropogenic modification of faunal remains; however, these have been controversial due to the highly subjective nature of the interpretations. Here, we employ advanced deep learning algorithms to objectively increase the accuracy of BSM identification on bones.With several models that exhibit BSM classification accuracies greater than 94%, we use ensemble learning techniques to robustly classify a selected sample of BSM from the approximately 30 kyr BP site of Arroyo del Vizcaíno, Uruguay. Our results confidently show the presence of cut-marks imparted by stone tools on bones at the site. This result supports an earlier presence of humans in the American continent, expanding additional genetic and archaeological evidence of a human LGM and pre-LGM presence in the continent. [ABSTRACT FROM AUTHOR]

Glyptodonts (Mammalia, Xenarthra, Glyptodontidae) represent a diversified radiation of large armored herbivores, mainly related to open biomes in South America, with an extensive fossil history since the late Eocene (ca. 33 Ma) until their extinction in the latest Pleistocene-earliest Holocene. During the Pliocene and Pleistocene, glyptodonts arrived in Central and North America as part of the Great American Biotic Interchange. Within glyptodont diversity, one of the most enigmatic groups (and also one of the least known) are the Doedicurinae, mainly recognized by the enormous Pleistocene Doedicurus, with some specimens reaching ca. two tons. Almost nothing is known about the Neogene evolutionary history of this lineage. Some very complete specimens of the previously scarcely known Eleutherocercus solidus, which in turn becomes the most complete Neogene Doedicurinae, are here described in detail and compared to related taxa. The materials come from the Andalhuala and Corral Quemado formations (north-western Argentina), specifically from stratigraphic levels correlated to the Messinian-Piacenzian interval (latest Miocene-Pliocene). The comparative study and the cladistic analysis support the hypothesis that Doedicurinae forms a well supported monophyletic group, located within a large and diversified clade mostly restricted to southern South America. Within Doedicurinae, the genus Eleutherocercus (E. antiquus + E. solidus) is the sister group of the Pleistocene Doedicurus. Unlike most of the late Neogene and Pleistocene lineages of glyptodonts, doedicurins show along its evolutionary history a latitudinal retraction since the Pleistocene, ending with the giant Doedicurus restricted to the Pampean region of Argentina, southernmost Brazil, and southern Uruguay. This hypothetic relationship between body mass and latitudinal distribution suggests that climate could have played an active role in the evolution of the subfamily. [ABSTRACT FROM AUTHOR]

Glyptodonts (Mammalia, Xenarthra, Glyptodontidae) represent a diversified radiation of large armored herbivores, mainly related to open biomes in South America, with an extensive fossil history since the late Eocene (ca. 33 Ma) until their extinction in the latest Pleistocene-earliest Holocene. During the Pliocene and Pleistocene, glyptodonts arrived in Central and North America as part of the Great American Biotic Interchange. Within glyptodont diversity, one of the most enigmatic groups (and also one of the least known) are the Doedicurinae, mainly recognized by the enormous Pleistocene Doedicurus, with some specimens reaching ca. two tons. Almost nothing is known about the Neogene evolutionary history of this lineage. Some very complete specimens of the previously scarcely known Eleutherocercus solidus, which in turn becomes the most complete Neogene Doedicurinae, are here described in detail and compared to related taxa. The materials come from the Andalhuala and Corral Quemado formations (north-western Argentina), specifically from stratigraphic levels correlated to the Messinian-Piacenzian interval (latest Miocene-Pliocene). The comparative study and the cladistic analysis support the hypothesis that Doedicurinae forms a well supported monophyletic group, located within a large and diversified clade mostly restricted to southern South America. Within Doedicurinae, the genus Eleutherocercus (E. antiquus + E. solidus) is the sister group of the Pleistocene Doedicurus. Unlike most of the late Neogene and Pleistocene lineages of glyptodonts, doedicurins show along its evolutionary history a latitudinal retraction since the Pleistocene, ending with the giant Doedicurus restricted to the Pampean region of Argentina, southernmost Brazil, and southern Uruguay. This hypothetic relationship between body mass and latitudinal distribution suggests that climate could have played an active role in the evolution of the subfamily. [ABSTRACT FROM AUTHOR]

The drastic reduction of the Brazilian Cerrado has transformed this savanna hotspot into vast swaths of commodity-based agriculture fields, mainly soybean, sugarcane, and beef-production pasturelands. The resulting habitat loss and fragmentation are the principal factors underlying population decline of native species inhabiting the Cerrado, particularly those with a high demand for space, low population density, and specialized diet, such as the endangered giant anteater (Myrmecophaga tridactyla). Although the species has been studied in protected areas, we know much less about its ability to endure in disturbed landscapes. Here, we analyzed camera-trapping data to estimate a proxy of habitat use (⁠ ψ ^ ⁠ ; occupancy) and detection probabilities of the giant anteater, identifying environmental covariates influencing these parameters in landscapes with intensive agriculture and commercial forestry. We found this species using about half of the study area (model average ψ ^ = 0.51, CI = 0.40–0.62), with two predictors strongly influencing habitat use: protected areas and unpaved roads. In turn, detection probability correlates positively with area of open Cerrado and negatively with area of settlements. The species is more likely to use unpaved roads inside protected areas (⁠ ψ ^ = 0.90, CI = 0.47–0.75), compared to off road sites in the surrounding areas (⁠ ψ ^ = 0.19, CI = 0.10–0.34). Our findings indicate that giant anteaters are dependent on nature reserves and native vegetation areas existing on private properties, whose protection is regulated by the Brazilian Native Vegetation Protection Law. Given the relative paucity of state-owned protected areas in the Brazilian Cerrado, increasing the adherence of rural owners to this law is, therefore, key for the conservation of the giant anteater. The intense use of unpaved roads might reflect travelling and/or foraging optimization, a behavioral response that, nevertheless, may compound this species' susceptibility to suffer mortality from roadkill. [ABSTRACT FROM AUTHOR]

As the ungual phalanges of tetrapods are the first structures that interact with the substrate, studying them is of great importance when wanting to know the locomotor behaviour of different species. In this work, we analyse the ungual phalanges of the third finger from the manus of several Pleistocene sloths: G. robustum, L. armatus, M. jeffersonii, M. americanum, S. leptocephalum; and of a wide range of extant xenarthrans and other mammals. The third finger of the manus was chosen because of its larger size and nearly perfect bilateral symmetry, which enhances the possibility to observe functional differences between taxa. The analysis performed on them were of the inner and external curvature and the finite element method. By comparing the results obtained for the fossils and the extant species we were able to indicate possible habits for these Pleistocene ground sloths. Through these analyses the three mylodontid sloths: G. robustum, L. armatus and S. leptocephalum showed a preference for strenuous activities such as digging. On the contrary, M. jeffersonii and M. americanum, although they showed similar resistant structures, they learned more towards a less specific locomotor habit, such as generalised terrestrial mammals. [ABSTRACT FROM AUTHOR]

Summary: The aim of this study was to identify the anatomical structures in the head region of the giant anteater (Myrmecophaga tridactyla) using computed tomography. For this, three giant anteater corpses, adult and female, were used. The tomographic analysis was performed in sequential order in rostrocaudal direction. Subsequently, the heads of these animals were sectioned in cross sections of approximately 1.5 cm each. Tomographic images were compared with anatomical sections. The association between computed tomography and anatomical sections allowed the visualization of anatomical structures found in the nasal, oral, cranial, pharyngeal and ear cavities. An elongated oral cavity delimited by the elongated mandible was observed. The oral cavity was mainly occupied by a thin and elongated tongue formed mainly by the union of the sternoglossal muscles. The nasopharynx and oropharynx extended up to the neck at the level of the fifth cervical vertebra. The findings of this study suggest that the giant anteater has a head with structures morphologically adapted to its feeding habits, such as an elongated skull, tongue, styloid bones and mandible. In addition, based on the results of this study, it is possible to suggest that computed tomography is a pivotal tool for the veterinary routine of wild animals, since it allowed the identification of anatomical structures found in the head of the giant anteater. [ABSTRACT FROM AUTHOR]

Xenarthra, one of the major clades of placentals, comprises two different lineages (sloths and anteaters, and armadillos) with extant representatives showing strongly different morphologies and life habits. Sloths are arboreal herbivores, anteaters are insectivores with digging/climbing abilities, and armadillos are terrestrial diggers with varied diets. The ulna is one of the forelimb elements that exhibits distinct morphological specializations for different abilities (e.g., digging and climbing). A sample of xenarthrans was analyzed in this work from a functional and ecological perspective, using 2-D geometric morphometry. The analyses performed were a Principal Components Analysis (PCA), a regression of the shape on the centroid size, and a PCA with the residuals from the regression. The first PCA shows that the morphospace is strongly influenced by differences in length of the olecranon with respect to the shaft between the three clades. Allometry was detected for the whole sample. In the residual PCA, the allometry-free morphospace allows the differentiation between the ecological categories of substrate preference: armadillos and giant anteaters (terrestrial) are located towards the negative side of PC1, while sloths and silky anteaters (arboreal) are located near the positive end, with collared anteaters (semiarboreal) placed near the center. The terrestrial taxa present a more robust diaphysis, and a comparatively long, diaphysis-aligned olecranon, while the arboreal taxa show a relatively long ulna with an anteriorly curved shaft and an anteriorly deflected carpal facet. The ulnar curvature has biomechanical implications in relation to the bone response to different loadings produced in the context of posture and locomotion in each substrate. [ABSTRACT FROM AUTHOR]

Chaetophractus villosus (Desmarest, 1804) is commonly known as the large hairy armadillo. It is one of two living species of Chaetophractus. Like all armadillos, it bears a dorsal carapace of ossified dermal scutes covered by epidermal scales. Dorsal hair is sparse, long, and black and brown. This semifossorial armadillo inhabits grasslands, savannas, steppes, forests, and even degraded areas such as agroecosystems of Argentina, the "Gran Chaco" of Bolivia and Paraguay, and southern Chile. Chaetophractus villosus is omnivorous–carnivorous. It is listed as "Least Concern" (LC) on the International Union for Conservation of Nature Red List of Threatened Species, and is mainly affected by hunting, persecution as an agricultural pest, and vehicle collisions. [ABSTRACT FROM AUTHOR]

Mylododontidae (Xenarthra: Folivora) includes ground sloths of medium to large size. Lestodon armatus is a mylodontid that have been found in Pleistocene fossiliferous deposits of South America, with most of its records at the southern portion of the continent. Here, we reported a new specimen assigned to this species recovered from a Quaternary deposit in Caçapava do Sul, southern Brazil. The specimen is composed of cranial fragments, vertebrae, articulated hind limb and pes, as well as other post-cranial elements. We described the post-cranial morphology of this specimen, including some elements not yet described for this species, such as the ossified meniscus, cyamo-fabella, and the fusion of the tibia and fibula. The new record contributes to the knowledge on the anatomy of L. armatus as well as to the study of the diversity of the extinct mammalian fauna from southern Brazil. [ABSTRACT FROM AUTHOR]

Basic knowledge of species biology and ecology is essential for the assessment of species conservation status and planning for efficient conservation strategies; however, this information is not always readily available. Here we use movement behavior to understand the ecology and social biology of the poorly known southern three-banded armadillo (Tolypeutes matacus). We used VHF and GPS telemetry to monitor 26 individuals from two sites in the Pantanal wetlands of Brazil. We characterized armadillo activity patterns, evaluated the relationship between sex and body mass with home range size and mean daily distance traveled, and examined home and core range overlap. Three-banded armadillos were active on average for 5.5 ± 2.8 h/day, with most of their activity concentrated in the first half of the night. Adult males were heavier and had larger home ranges than adult females. Home range size scaled positively with body mass for males, but not for females. Core ranges for females overlapped little (< 1%) regardless of age, but home ranges for males overlapped both with other males (12%) and females (18%). Our data suggest that three-banded armadillos are mainly a nocturnal species. Home range and spacing patterns point to a generally asocial behavior and a polygynous or promiscuous mating system. We hope that the data generated as a result of this project will contribute to this species' conservation in Brazil and elsewhere by guiding future management and research efforts. [ABSTRACT FROM AUTHOR]