Xenarthran Species Research Articles

Exon capture museomics deciphers the nine-banded armadillo species complex and identifies a new species endemic to the Guiana Shield.

The nine-banded armadillo (Dasypus novemcinctus) is the most widespread xenarthran species across the Americas. Recent studies have suggested it is composed of four morphologically and genetically distinct lineages of uncertain taxonomic status. To address this issue, we used a museomic approach to sequence 80 complete mitogenomes and capture 997 nuclear loci for 71 Dasypus individuals sampled across the entire distribution. We carefully cleaned up potential genotyping errors and cross contaminations that could blur species boundaries by mimicking gene flow. Our results unambiguously support four distinct lineages within the D. novemcinctus complex. We found cases of mito-nuclear phylogenetic discordance but only limited contemporary gene flow confined to the margins of the lineage distributions. All available evidence including the restricted gene flow, phylogenetic reconstructions based on both mitogenomes and nuclear loci, and phylogenetic delimitation methods consistently supported the four lineages within D. novemcinctus as four distinct species. Comparable genetic differentiation values to other recognized Dasypus species further reinforced their status as valid species. Considering congruent morphological results from previous studies, we provide an integrative taxonomic view to recognise four species within the D. novemcinctus complex: D. novemcinctus, D. fenestratus, D. mexicanus, and D. guianensis sp. nov., a new species endemic of the Guiana Shield that we describe here. The two available individuals of D. mazzai and D. sabanicola were consistently nested within D. novemcinctus lineage and their status remains to be assessed. The present work offers a case study illustrating the power of museomics to reveal cryptic species diversity within a widely distributed and emblematic species of mammals.

Spermatogenesis in the giant anteater (Myrmecophaga tridactyla)

The giant anteater (superorder Xenarthra) is listed as Vulnerable by the International Union for Conservation of Nature (IUCN) and a low reproductive rate is considered one of the factors contributing to population decline of the species. Nevertheless, little is known on reproductive features in male giant anteaters and, in this regard, microscopic testis morphology and spermatogenesis were studied in roadkill specimens in Brazil. Characteristics of germ cell populations resembled descriptions in other eutherian mammals including other xenarthran species. Furthermore, eight stages of the seminiferous epithelium cycle could be defined. The proposed staging system offers baseline data for assessing impairments or seasonal changes in spermatogenesis and thus allows future studies on reproductive health and reproductive seasonality in male giant anteaters.

Integrative Phylogeography Reveals Conservation Priorities for the Giant Anteater Myrmecophaga tridactyla in Brazil

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.

Effect of captivity on the vertebral bone microstructure of xenarthran mammals.

Captive specimens in museum collections facilitate study of rare taxa, but the lifestyles, diets, and lifespans of captive animals differ from their wild counterparts. Trabecular bone architecture adapts to in vivo forces, and may reflect interspecific variation in ecology and behavior as well as intraspecific variation between captive and wild specimens. We compared trunk vertebrae bone microstructure in captive and wild xenarthran mammals to test the effects of ecology and captivity. We collected μCT scans of the last six presacral vertebrae in 13 fossorial, terrestrial, and suspensorial xenarthran species (body mass: 120 g to 35 kg). For each vertebra, we measured centrum length; bone volume fraction (BV.TV); trabecular number and mean thickness (Tb.Th); global compactness (GC); cross-sectional area; mean intercept length; star length distribution; and connectivity and connectivity density. Wild specimens have more robust trabeculae, but this varies with species, ecology, and pathology. Wild specimens of fossorial taxa (Dasypus) have more robust trabeculae than captives, but there is no clear difference in bone microstructure between wild and captive specimens of suspensorial taxa (Bradypus, Choloepus), suggesting that locomotor ecology influences the degree to which captivity affects bone microstructure. Captive Tamandua and Myrmecophaga have higher BV.TV, Tb.Th, and GC than their wild counterparts due to captivity-caused bone pathologies. Our results add to the understanding of variation in mammalian bone microstructure, suggest caution when including captive specimens in bone microstructure research, and indicate the need to better replicate the habitats, diets, and behavior of animals in captivity.

Locomotory Adaptations in 3D Humerus Geometry of Xenarthra: Testing for Convergence

Three-dimensional (3D) models of fossil bones are increasingly available, thus opening a novel frontier in the study of organismal size and shape evolution. We provide an example of how photogrammetry can be combined with Geometric Morphometrics (GMM) techniques to study patterns of morphological convergence in the mammalian group of Xenarthra. Xenarthrans are currently represented by armadillos, sloths, and anteaters. However, this clade shows an incredibly diverse array of species and ecomorphotypes in the fossil record, including gigantic ground sloths and glyptodonts. Since the humerus is a weight-bearing bone in quadrupedal mammals and its morphology correlates with locomotor behavior, it provides an ideal bone to gain insight into adaptations of fossil species. A 3D sample of humerii belonging to extant and fossil Xenarthra allowed us to identify a significant phylogenetic signal and a strong allometric component in the humerus shape. Although no rate shift in the evolution of the humerus shape was recorded for any clade, fossorial and arboreal species humerii did evolve at significantly slower and faster paces, respectively, than the rest of the Xenarthran species. Significant evidence for morphological convergence found among the fossorial species and between the two tree sloth genera explains these patterns. These results suggest that the highly specialized morphologies of digging taxa and tree sloths represent major deviations from the plesiomorphic Xenarthran body plan, evolved several times during the history of the group.

Space use by the giant anteater (Myrmecophaga tridactyla): a review and key directions for future research

Understanding the use of space is essential to promote effective conservation actions, particularly to xenarthran species that are threatened by habitat loss, poaching, and other environment degradation. Information regarding the use of space by the giant anteater (Myrmecophaga tridactyla), a large and vulnerable Neotropical mammal, is sparse and sometimes inconsistent in the scientific literature. Our aims are (1) to present an updated overview of giant anteater use of space; (2) to identify knowledge gaps; and (3) to recommend the next steps to advance this knowledge. We compiled information from 53 publications regarding the key aspects of space use: movement patterns, home range size and overlap, and habitat use. We identified the following research priorities: (a) the need of studies on different populations throughout the species’ range, including continuous native forest areas, and different spatial scales; (b) to develop research on dispersal by the individuals; (c) to understand movement patterns based on trajectory-related methods; (d) to comprehend home range overlap and territoriality ecological meaning; and (e) habitat selection and movement patterns on human-modified landscapes.

NEOTROPICAL XENARTHRANS: a data set of occurrence of xenarthran species in the Neotropics.

Xenarthrans-anteaters, sloths, and armadillos-have essential functions for ecosystem maintenance, such as insect control and nutrient cycling, playing key roles as ecosystem engineers. Because of habitat loss and fragmentation, hunting pressure, and conflicts with domestic dogs, these species have been threatened locally, regionally, or even across their full distribution ranges. The Neotropics harbor 21 species of armadillos, 10 anteaters, and 6 sloths. Our data set includes the families Chlamyphoridae (13), Dasypodidae (7), Myrmecophagidae (3), Bradypodidae (4), and Megalonychidae (2). We have no occurrence data on Dasypus pilosus (Dasypodidae). Regarding Cyclopedidae, until recently, only one species was recognized, but new genetic studies have revealed that the group is represented by seven species. In this data paper, we compiled a total of 42,528 records of 31 species, represented by occurrence and quantitative data, totaling 24,847 unique georeferenced records. The geographic range is from the southern United States, Mexico, and Caribbean countries at the northern portion of the Neotropics, to the austral distribution in Argentina, Paraguay, Chile, and Uruguay. Regarding anteaters, Myrmecophaga tridactyla has the most records (n=5,941), and Cyclopes sp. have the fewest (n=240). The armadillo species with the most data is Dasypus novemcinctus (n=11,588), and the fewest data are recorded for Calyptophractus retusus (n=33). With regard to sloth species, Bradypus variegatus has the most records (n=962), and Bradypus pygmaeus has the fewest (n=12). Our main objective with Neotropical Xenarthrans is to make occurrence and quantitative data available to facilitate more ecological research, particularly if we integrate the xenarthran data with other data sets of Neotropical Series that will become available very soon (i.e., Neotropical Carnivores, Neotropical Invasive Mammals, and Neotropical Hunters and Dogs). Therefore, studies on trophic cascades, hunting pressure, habitat loss, fragmentation effects, species invasion, and climate change effects will be possible with the Neotropical Xenarthrans data set. Please cite this data paper when using its data in publications. We also request that researchers and teachers inform us of how they are using these data.

Bone cortical compactness in 'tree sloths' reflects convergent evolution.

Bone remodeling, one of the main processes that regulate bone microstructure, consists of bone resorption followed by the deposition of secondary bone at the same location. Remodeling intensity varies among taxa, but a characteristically compact cortex is ubiquitous in the long bones of mature terrestrial mammals. A previous analysis found that cortical bone in a few 'tree sloth' (Bradypus and Choloepus) specimens is heavily remodeled and characterized by numerous immature secondary osteons, suggesting that these animals were remodeling their bones at high rate until late in their ontogeny. This study aims at testing if this remodeling is generally present in 'tree sloths', using a quantitative analysis of the humeral cortical compactness (CC) among xenarthrans. The results of the investigation of humeral diaphyseal cross-sections of 26 specimens belonging to 10 xenarthran species including specimens from both extinct and extant species indicate that in 'tree sloths' the CC is significantly lower than in the other sampled xenarthrans. No significant difference was found between the CC of the two genera of 'tree sloths'. Our results are consistent with the hypothesis that the cortical bone of 'tree sloths' in general undergoes intense and balanced remodeling that is maintained until late (possibly throughout) in their ontogeny. In the light of xenarthran phylogeny, low CC represents another convergence between the long-separated 'tree sloth' lineages. Although the exact structural and/or functional demands that are associated with this trait are hitherto unknown, several hypotheses are suggested here, including a relationship to their relatively low metabolism and to the mechanical demands imposed upon the bones by the suspensory posture and locomotion, which was independently acquired by the two genera of 'tree sloths'.

Resolving the phylogenetic position of Darwin's extinct ground sloth (Mylodon darwinii) using mitogenomic and nuclear exon data.

Mylodon darwinii is the extinct giant ground sloth named after Charles Darwin, who first collected its remains in South America. We have successfully obtained a high-quality mitochondrial genome at 99-fold coverage using an Illumina shotgun sequencing of a 12 880-year-old bone fragment from Mylodon Cave in Chile. Low level of DNA damage showed that this sample was exceptionally well preserved for an ancient subfossil, probably the result of the dry and cold conditions prevailing within the cave. Accordingly, taxonomic assessment of our shotgun metagenomic data showed a very high percentage of endogenous DNA with 22% of the assembled metagenomic contigs assigned to Xenarthra. Additionally, we enriched over 15 kb of sequence data from seven nuclear exons, using target sequence capture designed against a wide xenarthran dataset. Phylogenetic and dating analyses of the mitogenomic dataset including all extant species of xenarthrans and the assembled nuclear supermatrix unambiguously place Mylodon darwinii as the sister-group of modern two-fingered sloths, from which it diverged around 22 million years ago. These congruent results from both the mitochondrial and nuclear data support the diphyly of the two modern sloth lineages, implying the convergent evolution of their unique suspensory behaviour as an adaption to arboreality. Our results offer promising perspectives for whole-genome sequencing of this emblematic extinct taxon.

Mammalian Diversity and Matses Ethnomammalogy in Amazonian Peru Part 2: Xenarthra, Carnivora, Perissodactyla, Artiodactyla, and Sirenia

This report continues our monographic analysis of mammalian diversity and Matses ethnomammalogy in the Yavari-Ucayali interfluvial region of northeastern Peru. Based primarily on specimens collected in the region from 1926 to 2003, interviews with Matses hunters, and published sight surveys of large mammals, we document the local occurrence of 33 species of xenarthrans, carnivores, perissodactyls, artiodactyls (including cetaceans), and sirenians. All of the species in these groups, with the exception of the Amazonian manatee (Trichechus inunguis), are recognized and named by the Matses, from whom we recorded extensive accounts of mammalian natural history.The local xenarthran fauna consists of nine species (Cabassous unicinctus, Priodontes maximus, Dasypus novemcinctus, D. pastasae, Bradypus variegatus, Choloepus hoffmanni, Cyclopes didactylus, Myrmecophaga tridactyla, Tamandua tetradactyla), all of which are represented by examined specimens. Only two xenarthrans (D. pastasae and C. hoffmanni) are primary game species for the Matses, who are familiar with many aspects of their biology that were previously unrecorded in the scientific literature. However, Matses interviews also provide important new information about the behavior of D. novemcinctus (a secondary game species) and M. tridactyla, neither of which has previously been studied in rainforested environments.The local carnivore fauna consists of 16 species (Atelocynus microtis, Speothos venaticus, Leopardus pardalis, L. wiedii, Panthera onca, Puma concolor, Pu. yagouaroundi, Eira barbara, Galictis vittata, Mustela africana, Lontra longicaudis, Pteronura brasiliensis, Bassaricyon alleni, Nasua nasua, Potos flavus, Procyon cancrivorus), most of which are represented by examined specimens; six species without preserved voucher material are known from camera-trap photographs and/or unambiguous sightings by Matses hunters and field biologists. Although the coati (N. nasua) is the only carnivore occasionally hunted by the Matses for food, Matses interviews are richly informative about the natural history of other species, notably including S. venaticus, Leopardus spp., Pa. onca, Puma spp., and E. barbara.All of the local ungulates (Tapirus terrestris, Pecari tajacu, Tayassu pecari, Mazama americana, M. nemorivaga) are hunted by the Matses for food, and the hunters we interviewed are correspondingly well informed about the natural history of most of these species, with the exception of the seldom-encountered gray brocket (M. nemorivaga). Both species of local cetaceans (Inia geoffroyi, Sotalia fluviatilis) are familiar to the Matses, although neither is eaten.The xenarthrans, carnivores, ungulates, and aquatic mammals that inhabit the Yavari-Ucayali interfluve are all widespread species, so this component of the regional fauna, as currently understood, is not biogeographically distinctive, nor is it extraordinarily diverse (by western Amazonian standards). Although we discuss several noteworthy taxonomic and nomenclatural issues relevant to these taxa, the principal contribution of this report consists in the natural history information compiled from our Matses informants and the resulting overview of local community structure as defined by diurnal activity, locomotion, social behavior, and trophic relationships.

Genome-Wide Screening of Retroviral Envelope Genes in the Nine-Banded Armadillo (Dasypus novemcinctus, Xenarthra) Reveals an Unfixed Chimeric Endogenous Betaretrovirus Using the ASCT2 Receptor

Retroviruses enter host cells through the interaction of their envelope (Env) protein with a cell surface receptor, which triggers the fusion of viral and cellular membranes. The sodium-dependent neutral amino acid transporter ASCT2 is the common receptor of the large RD114 retrovirus interference group, whose members display frequent env recombination events. Germ line retrovirus infections have led to numerous inherited endogenous retroviruses (ERVs) in vertebrate genomes, which provide useful insights into the coevolutionary history of retroviruses and their hosts. Rare ERV-derived genes display conserved viral functions, as illustrated by the fusogenic syncytin env genes involved in placentation. Here, we searched for functional env genes in the nine-banded armadillo (Dasypus novemcinctus) genome and identified dasy-env1.1, which clusters with RD114 interference group env genes and with two syncytin genes sharing ASCT2 receptor usage. Using ex vivo pseudotyping and cell-cell fusion assays, we demonstrated that the Dasy-Env1.1 protein is fusogenic and can use both human and armadillo ASCT2s as receptors. This gammaretroviral env gene belongs to a provirus with betaretrovirus-like features, suggesting acquisition through recombination. Provirus insertion was found in several Dasypus species, where it has not reached fixation, whereas related family members integrated before diversification of the genus Dasypus >12 million years ago (Mya). This newly described ERV lineage is potentially useful as a population genetic marker. Our results extend the usage of ASCT2 as a retrovirus receptor to the mammalian clade Xenarthra and suggest that the acquisition of an ASCT2-interacting env gene is a major selective force driving the emergence of numerous chimeric viruses in vertebrates. Retroviral infection is initiated by the binding of the viral envelope glycoprotein to a host cell receptor(s), triggering membrane fusion. Ancient germ line infections have generated numerous endogenous retroviruses (ERVs) in nearly all vertebrate genomes. Here, we report a previously uncharacterized ERV lineage from the genome of a xenarthran species, the nine-banded armadillo (Dasypus novemcinctus). It entered the Dasypus genus >12 Mya, with one element being inserted more recently in some Dasypus species, where it could serve as a useful marker for population genetics. This element exhibits an env gene, acquired by recombination events, with conserved viral fusogenic properties through binding to ASCT2, a receptor used by a wide range of recombinant retroviruses infecting other vertebrate orders. This specifies the ASCT2 transporter as a successful receptor for ERV endogenization and suggests that ASCT2-binding env acquisition events have favored the emergence of numerous chimeric viruses in a wide range of species.

Morphological convergence in the pubis of slow-moving primates and xenarthrans.

Determining the functional significance of pubic rami is important for reconstructing locomotor behavior of fossil species. The slow loris pelvis, characterized by long pubic rami, is unusual among primates. Long pubic rami may be related to increasing the moment arm of the abdominal musculature during ventroflexion after the termination of hindlimb suspension, which is a common component of slow arboreal quadrupedalism (AQ). Some extant xenarthran species are also slow AQ taxa, and provide an ideal group to test hypotheses of morphologically convergent adaptations to slow AQ. A model relating abdominal moment arms to pubic morphology is tested in three genera of slow-moving xenarthrans (Bradypus, Choloepus, and Cyclopes) and two species of slow loris (Nycticebus coucang and Perodicticus potto), using a comparative sample of 37 species of primates and xenarthrans. Phylogenetic analyses of variance and regression were performed on pubic dimensions (superior and inferior pubic ramus length, pubic symphysis length). As a locomotor group, slow-moving xenarthrans and lorises share superior pubic rami that are longer than all other locomotor groups; at the species level, there is some overlap among slow AQ and non-slow-AQ taxa. Inferior pubic ramus and pubic symphysis lengths also differ according to locomotor category, but multiple comparisons among locomotor groups are non-significant. These results support the hypothesis that superior pubic ramus length is functionally related to slow, suspensory locomotion by increasing the leverage of the ventral abdominal musculature, and demonstrates morphological convergence among two phylogenetically distant groups of mammals that have evolved adaptations for slow, suspensory locomotion.

Cognitive Function Related to the Sirh11/Zcchc16 Gene Acquired from an LTR Retrotransposon in Eutherians.

Gene targeting of mouse S ushi- i chi-related r etrotransposon h omologue 11 / Z inc finger CCHC domain-containing 16 (Sirh11/Zcchc16) causes abnormal behaviors related to cognition, including attention, impulsivity and working memory. Sirh11/Zcchc16 encodes a CCHC type of zinc-finger protein that exhibits high homology to an LTR retrotransposon Gag protein. Upon microdialysis analysis of the prefrontal cortex region, the recovery rate of noradrenaline (NA) was reduced compared with dopamine (DA) after perfusion of high potassium-containing artificial cerebrospinal fluid in knockout (KO) mice. These data indicate that Sirh11/Zcchc16 is involved in cognitive function in the brain, possibly via the noradrenergic system, in the contemporary mouse developmental systems. Interestingly, it is highly conserved in three out of the four major groups of the eutherians, euarchontoglires, laurasiatheria and afrotheria, but is heavily mutated in xenarthran species such as the sloth and armadillo, suggesting that it has contributed to brain evolution in the three major eutherian lineages, including humans and mice. Sirh11/Zcchc16 is the first SIRH gene to be involved in brain function, instead of just the placenta, as seen in the case of Peg10, Peg11/Rtl1 and Sirh7/Ldoc1.

Why do Xenarthrans matter?: Table 1.

Xenarthrans possess a suite of characteristics that make them among the most unusual of mammals. Understanding the functional significance of these traits is one prominent reason why xenarthrans matter. In addition, Xenarthra is currently considered one of the basal clades of placental mammals, and the only one to originate in South America. Consequently, studies of xenarthrans can provide important insights into the evolution of early placentals. The fossil record contains hundreds of recognized species of xenarthrans but this rich evolutionary history is currently distilled into just 31 extant species. Preserving this heritage through various conservation initiatives is yet another reason why xenarthrans matter. This Special Feature on xenarthrans provides an overview of current work and identifies many areas requiring further study. It is our hope that this Special Feature will raise the profile of xenarthrans among mammalogists and perhaps entice some to consider addressing one or more of the many lin...

Distribución Actual y Potencial deCabassous tatouayyTamandua tetradactylaen el Límite sur de su Distribución: Implicancias para su Conservación en Uruguay

Abstract Cabassous tatouay and Tamandua tetradactyla are the least frequent of the five xenarthran species currently present in Uruguay. Given the scarce records for these species, their potential distribution was modeled using the software Maxent in order to identify the most favorable areas for their presence and assess their occurrence within the National System of Protected Areas (SNAP). Records of the species were obtained through bibliographical searches and revisions of the major scientific collections of the country. Records from hunters and rural inhabitants were also compiled. The obtained maps show that the most favorable areas for T. tetradactyla in Uruguay are located in the Department of Cerro Largo, mainly along the Yaguaron River and Sierra de Rios. Cabassous tatouay showed a favorability value greater than 0.90 within Uruguayan territory, spanning the Departments of Cerro Largo, Treinta y Tres, Lavalleja, and Maldonado. The overlay of the distribution maps and the SNAP protected areas rev...

Distribution and Status of the Extant Xenarthrans (Mammalia: Xenarthra) in the Southern cone Mesopotamian Savanna, Argentina

The Southern Cone Mesopotamian savanna (MS), located in northeastern Argentina, is one of the least protected ecoregions (0.11%) of the country. Five of the seven historically present species of xenarthrans in this region are of conservation concern at the national level. This work reviews, updates and analyzes the current distribution and conservation status of the xenarthrans using a georeferenced database including records from four complementary methods: field surveys, interviews with local stakeholders, participatory monitoring, and bibliography review. Results were then compared with existing distribution maps. In total, 304 occurrence records were documented in 127 localities. Considering their relative presence (number of localities where the species is present divided by the total number of localities), the species with most records were Dasypus novemcinctus (71.7%) and Dasypus hybridus (63%); Euphractus sexcinctus and Tamandua tetradactyla were detected in a lower proportion (48.8 and 35.4%, respectively). Cabassous tatouay and Myrmecophaga tridactyla are rare species in the ecoregion. The extant xenarthrans that inhabit the MS are reviewed and information gaps for certain species are identified. We emphasize the importance of contributions from the local community, who provided 80% of the collected information for this study.

Timing of cranial suture closure in placental mammals: Phylogenetic patterns, intraspecific variation, and comparison with marsupials

Used as markers of postnatal growth closure sequences of 22 ectocranial sutures and synchondroses were recorded in a sample of 1161 skulls belonging to 38 species from all major placental clades: Afrotheria, Xenarthra, Laurasiatheria and Euarchontoglires (Boreoeutheria). The maximum closure level, which is not significantly correlated to body mass, is higher in Afrotheria and Xenarthra than in Boreoeutheria. Only the basioccipito-basisphenoid and the basioccipito-exoccipital synchondroses close in all species sampled, the supraoccipito-exoccipital and the inter-parietal sutures do in most species. Parsimov retrieved more heterochronic shifts for Afrotheria and Xenarthra than for Boreoeutheria. The amount of intraspecific variation differs among the species sampled being high among xenarthran species and low among afrotherians. Specimens (162) representing 12 marsupial genera were also analysed. Placentals exhibit a larger number of suture closures than marsupials and in both groups the sutures at the base of the skull are the first to fuse starting with the basioccipito-exoccipital.

Field Metabolic Rate, Water Flux and Food Consumption by Free-Living Silky Anteaters (Cyclopes didactylus) in Panama

Wild silky anteaters (Cyclopes didactylus) were studied in Panama during the dry season using doubly-labeled water (DLW) to measure field metabolic rates (FMR) and water intake rates (WIR), and to estimate feeding rates. Their daily requirements for energy, food and water were low: only one- to two-thirds of those of typical eutherian mammals with the same body size. Anteaters' body-size-adjusted requirements were similar to, but higher than, those of sympatric three-toed sloths, another xenarthran species. Xenarthrans in general may have unusually low metabolic intensities and nutritional needs. Silky anteaters were strictly nocturnal, arboreal and myrmecophagous, and had relatively low body temperatures (31.5 °C).Se estudiaron serafines del platanar (Cyclopes didactylus) en Panamá durante la estación seca con agua doblemente marcada (DLW) para medir las tasas metabólicas de campo (FMR), la tasa de ingesta de agua (WIR) y para estimar las tasas de alimentatión. Sus requerimientos diarios de energía, alimento y agua fueron bajos: correspondían a uno a dos tercios de los valores típicos para mamíferos euterios de tamaño corporal similar. Los requerimientos de los serafines, ajustados por el tamaño corporal, fueron similares pero más altos que los registrados en otra especie de Xenarthra simpátrica, el perezoso de tres dedos. Los xenartros en general pueden tener intensidades metabólicas y necesidades nutricionales inusualmente bajas. Los serafines del platanar fueron estrictamente nocturnos, arbóreos y mirmecófagos, y tenían una temperature corporal relativamente baja (31,5 °C).

Range shifts under climate change and the role of protected areas for armadillos and anteaters

The planning of protected areas take into consideration the current distributions of target species, disregarding possible future range shifts under climate change. This study tested potential shifts in the distribution of three xenarthran species (the giant anteater, Myrmecophaga tridactyla; the giant armadillo, Priodontes maximus; and the three-banded armadillo, Tolypeutes tricinctus) due to the effects of climate change under different dispersal scenarios. In addition, we tested the adequacy of the current Brazilian protected areas in preserving these species under future climate changes (future distribution for the year 2050), under full and null dispersal scenarios. The final occurrence maps were then confronted with two Brazilian reserve systems for the year 2010: one consisting of reserves for integral protection only (IPCU), and one that included also reserves for sustainable use and indigenous reserves (SUCU). In the IPCU system, none of the species have or will have ⩾10% of their distributions protected, under neither dispersal scenario. Including SUCU, however, M. tridactyla and P. maximus already are, and will still be, adequately protected in the future. T. tricinctus, which is endemic to the Brazilian semi-arid, will not reach the 10% goal under neither dispersal scenario, even under the SUCU system. We stress the need for management actions in the northeastern and central parts of Brazil. Opportunities for the creation of more reserves are highlighted, considering the potential range shifts and the natural habitats still present in these regions.

Distribution of extant xenarthrans (Mammalia: Xenarthra) in Argentina using species distribution models

Fil: Abba, Agustin Manuel. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Division Zoologia de Vertebrados; Argentina