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.

Here we present a commented list of mammals registered in the Serra da Bocaina National Park. Three field trips (February, 2010, and May and July, 2011) were accomplished along the RJ-165 highway in the Municipality of Paraty, State of Rio de Janeiro, Brazil. Forty-eight species belonging to nine orders were recorded. The local mammal fauna could be considered diverse and rich, with some species regarded as biological indicators of habitat quality. Endangered and rare rodent species like Blarinomys breviceps, Juliomys rimofrons, and Thaptomys nigrita were captured. Road and hunting impacts on mammals are discussed.

a b s t r a c tWe present the first quantitative description of postural behaviour of a free ranging metatherian, the bare-tailed woolly opossum, Caluromys philander. Postural behaviour was observed using 10 camera traps set in front of artificial nests, located in the understory of an Atlantic forest site in Rio de Janeiro, Brazil. Seven locomotory and positional modes were identified, with a predominance of diagonal couplets. Individuals used three types of grasp as observed in captivity, but the frequency of digital grasping was higher in the wild. The tail was used as an additional grasping limb, preventing falls and freeing hands to other activities, but the tail was also used to carry leaves for nest building. The use of camera traps may represent a breakthrough in the study of positional behaviours in the wild.

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Movement by mammals generally increases with body size, described by a positive exponent scaling with either home range area or day range distances. Below ca. 100 g, however, interspecific comparisons suggest a negative scaling, increasing movement with decreasing body size. Such a pattern is expected from the rising costs of thermoregulation below ca. 100 g, implying that it should also be observed in intraspecific comparisons. We tested this hypothesis by investigating the scaling exponent of daily home range with body mass for a small (< 100 g) marsupial, the gray slender mouse opossum, Marmosops incanus. We tracked 85 opossums (56 M, 29 F) with a spool-and-line device between August 1998 and October 2005 in the Serra dos Órgãos National Park, a region of Atlantic Forest in the State of Rio de Janeiro, Brazil. Individual paths were mapped and daily home ranges quantified by the minimum convex polygon encompassing each path. We formulated linear models and compared them using Akaike information criteria. The best-supported model for females had only climatic season as a main determinant of daily home range, whereas the best model for males had body mass and reproductive season as the main effects. As predicted, the scaling exponent of daily home range with body mass of males was negative, in contrast with positive intraspecific exponents for opossums > 100 g estimated in a previous study. The inversion in scaling relationships around 100 g in opossums supports the rising costs of thermoregulation as the main cause of this general pattern in mammals. Effects of body mass are generally weak in intraspecific comparisons, but might still be detected after standardizing other effects, opening new possibilities for testing macroecological models at smaller scales. Espera-se que a quantidade de movimento de mamíferos aumente com o tamanho corporal, descrita por um expoente de escala positivo, tanto para área de vida quanto para distâncias diárias de deslocamento. Abaixo de ca. 100 g, comparações interespecíficas sugerem um expoente negativo, áreas de movimento aumentando com menores tamanhos de corpo. Este padrão é apoiado pelo custo crescente de termorregulação abaixo de ca. 100 g, que implica que também ocorreria em comparações intraespecíficas. Testamos esta hipótese investigando o expoente de escala da área de vida diária com a massa corporal em um pequeno (< 100 g) marsupial, Marmosops incanus. Indivíduos foram rastreados com carretel-de-rastreamento entre agosto de 1998 e outubro de 2005, no Parque Nacional da Serra dos Órgãos, uma região de Mata Atlântica no Estado do Rio de Janeiro, Brasil. Trajetórias individuais foram mapeadas e sua área de vida diária medida pelo polígono convexo mínimo envolvendo cada trajetória. Oitenta e cinco indivíduos foram rastreados, sendo 29 fêmeas e 56 machos. Modelos lineares foram formulados e comparados com o Critério de Informação de Akaike. O modelo com maior suporte para fêmeas teve apenas estação climática como determinante principal da área de vida diária, enquanto o melhor modelo para machos teve massa corporal e estação reprodutiva como efeitos principais. O expoente de escala de área de vida diária com massa corporal de machos foi negativo, contrastando como os expoentes positivos para marsupiais > 100 g estimados em um estudo anterior. A inversão de relações de escala em torno de 100 g nestes marsupiais apoia que custos crescentes de termorregulação sejam a causa principal deste padrão geral em mamíferos. Os efeitos da massa corporal são geralmente fracos em comparações intraespecíficas, mas podem ser detectados após a exclusão de outros efeitos, abrindo novas possibilidades para testar modelos macroecológicos em escalas menores.

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