Marsupials are an important but typically neglected group of mammals that have been overlooked in many comparative analyses of vertebrate ecology and life history evolution. In order to address this knowledge bias, we have developed The Marsupial Database. The Marsupial Database contains traits for a phylogenetically diverse set of 414 extant and recently extinct (last 200 years) species from all seven modern marsupial orders (Dasyuromorphia, Didelphimorphia, Diprotodontia, Microbiotheria, Notoryctemorphia, Paucituberculata, Peramelemorphia) native to 34 countries in the Americas and Australasia. The database comprises 11,054 records of 35 traits describing anatomical, physiological, phenological, and reproductive characteristics, as well as information on species' ecology and current conservation status. Data were collected from 41 sources, comprising published databases and other relevant sources of information. By providing a centralized repository of marsupial ecological and life history traits, The Marsupial Database facilitates analyses of ecological and evolutionary patterns within the group, and also encourages inclusion of marsupials in comparative studies of mammals, vertebrates, and the entire animal kingdom. The Marsupial Database is free from copyright or proprietary restrictions. Please cite this data paper when using the data in publications or scientific presentations.

Opossums (Didelphidae) are American marsupials traditionally known for their generalized morphology and generalist feeding habits. They include a diversity of similar items in their diets, but the proportion of types of items consumed varies between taxa. Thus, feeding ecology shows varying degrees of omnivory or food preference that cannot be distinguished into strict dietary categories. With few exceptions, the anatomical and functional relationship between the masticatory muscles and variation in food resources used in opossums is unknown. Here we provide comparative descriptions of the jaw adductor muscle anatomy and architecture of nine Didelphidae genera. The muscles were dissected, weighed, and chemically digested for separation and measurement of the muscle fascicles. We estimated the potential physiological cross-sectional area (pPCSA) of the muscles and used 2D lever arm mechanics to calculate the potential bite force on the canine and first molar. We tested the allometric relationships of muscle variables and bite forces and the correlation of bite forces with diet and diet mechanical challenge (relative frequency of hard items). The adductor muscles were represented by the m. temporalis and m. masseter, with two layers (superficial and deep) each, and m. pterygoideus medialis across the sample. The m. zygomaticomandibularis was also identified in most genera, except for Didelphis and Lutreolina. Muscle anatomy is conserved but varies in the extent of the attachment areas, in part due to differences in skull morphology. The anatomical diversification and relationships between muscles corresponded to a generalized pattern in most genera, which proved to be efficient for adding different items to the diet. The mass, average fascicle length, and pPCSA of the adductor muscles scaled isometrically with size. Bite forces on the canine and first molar also scaled isometrically and were not correlated with diet or diet mechanical challenge. Therefore, the variation in quantitative myological data and bite force was consistent with size, and the increase in bite force supports dietary diversification associated with increased size in opossums.

Science communication initiatives bring people closer to scientific knowledge, stimulate the desire to learn, and foster an understanding of how science is produced. The traveling, interactive, and multisensory exhibition “Getting to Know the Biodiversity of the Caatinga,” part of SNCT 2024, brought specimens of mammals, birds, reptiles, and amphibians from the Caatinga, as mounted or study skins, or fluid-preserved, so that the public, from children to the elderly, could touch them and feel the textures of their fur, feathers, skin, and scales. Games and banners complemented the learning experience, addressing adaptations, ecological functions, and extinction risks. The exhibition, presented at various venues including schools, museums, and parks, reached diverse audiences, reduced prejudices, and stimulated awareness on conservation, demonstrating the effectiveness of sensory experiences in building scientific culture. Additionally, it highlighted the importance of zoological collections for research and science communication, thus fulfilling its role of bringing society closer to science.

Nectar-feeding bats of the genus Hsunycteris are endemic to the Neotropical region and currently include four recognized species: Hsunycteris thomasi, H. cadenai, H. pattoni, and H. dashe. Hsunycteris thomasi is considered a common nectar-feeding bat in Amazonia, where it is widely distributed, with presumed large subpopulations in Brazil. Based on five misidentified Hsunycteris specimens previously housed in scientific collections and recently surveyed specimens, we report eight new records that represent notable range extensions and provide the first Cytb sequence of Hsunycteris for the Atlantic Forest biome. These records include the first documentation of the genus in the Atlantic Forest biome, the Cerrado-Atlantic Forest transition zone, and the fourth record for the Cerrado biome. Among these, we present the first occurrence of the genus in the Brazilian states of Pernambuco, Alagoas, and Minas Gerais, the second occurrence in Mato Grosso, and the first record for the Cerrado of Maranh & atilde;o state. Further field efforts in the northeastern Atlantic Forest allowed us to obtain tissue samples for genetic analysis, leading to the identification of a new lineage within the H. thomasi species complex in the Atlantic Forest. Phylogenetic analysis based on the Cytb gene reveals that Hsunycteris forms a monophyletic group comprising six clades. Hsunycteris dashe was recovered as a sister to a clade containing H. cadenai, H. pattoni, and three distinct lineages of H. thomasi. The H. thomasi lineages were recovered as paraphyletic, with lineage I diverging first within the clade, lineage II as a sister to H. pattoni, and lineage III as a sister to H. cadenai. Genetic distances among the H. thomasi lineages range from 7.4% to 8.6%. These results show that the specimens reported here are part of a newly recovered lineage, representing a putative new species, evincing that the diversity of the genus is higher than previously thought.

Natural history collections serve as crucial infrastructure for both basic and applied scientific research, providing temporal and spatial specimen data needed to understand biodiversity, environmental change, and emerging pathogens. This study surveyed mammal collections across South America to assess the scope and quality of this infrastructure. A detailed questionnaire was distributed to curators and collection managers from May 2021 to February 2022, gathering information on institutional characteristics, collection size, taxonomic and geographical scope, preservation methods, genetic resource availability, percentage digitization, financial support, and challenges such as funding limitations. Our survey identified 141 collections; more than twice the number reported by the American Society of Mammalogists in 2018. South American collections house similar to 746000 catalogued specimens, including 452 primary type specimens, representing only a modest proportion of the vast mammalian diversity of South America. Collections are geographically concentrated in Argentina, Brazil, Colombia, and Peru, with a significant gap in the Guianas region and a decline in responses from Venezuela. The survey highlights four major challenges facing South American collections: staffing shortages, minimal cryogenic infrastructure, incomplete digitization, and sustainability issues. This initiative aims to raise awareness of collections in South America, plan for strategic growth, and strengthen research capacity to address pressing global issues, such as climate change, zoonotic disease transmission, and long-term conservation strategies.

AimUnderstanding the geographic origin of lineages is critical to comprehending their biogeographical and evolutionary histories and the historical connections among biomes. In northeastern Brazil, the Caatinga dry forest represents the largest and most biologically diverse patch of Seasonally Dry Tropical Forest in the Neotropics. Here, using the endemic avian taxa of the Caatinga, we aim to (i) infer their biogeographical origins and timing of diversification, (ii) investigate the relationships with taxa from other Neotropical domains and (iii) understand the processes driving the evolution and diversification of the Caatinga endemic avifauna.LocationNeotropical Region.TaxonBirds.MethodsWe obtained previously published calibrated phylogenies of 40 bird species endemic to the Caatinga to reconstruct their ancestral geographic ranges through the R package BioGeoBEARS to infer and highlight the origins, mode and tempo of evolution of the Caatinga avian endemics.ResultsOur results suggest that most avian endemics (21 taxa) are related to lineages from open habitats, including other dry forests or savannas; less than a quarter of the species (9 taxa) likely colonised the Caatinga from adjacent humid forests; we also highlight in situ origins (6 taxa), and cladogenetic events playing an important role in the colonisation of the domain. Although most of the endemics seem to represent new arrivals from adjacent habitats, we also detected relatively old lineages that likely occupied these dry landscapes since the Miocene. A correlation between the age, origins of Caatinga birds and their degree of threat was also found.Main ConclusionsWe provide a much needed framework for the evolution and biogeographic diversification of the Caatinga Dry Forest. The spatio-temporal patterns recovered here suggest an evolutionary history influenced not only by strict vicariance events but also by episodes of dispersal that likely played an important role in the origin of its avifauna. These events were likely influenced by major climatic and geological events that formed ancient corridors, allowing connections between the Caatinga and both dry and humid forests in South America.

Opossums (marsupials of the Didelphidae family) retain a generalized masticatory apparatus and tribosphenic molars, often used as models to understand the evolution of mastication in early therian mammals. Like all marsupials, their growth goes through a stage when pups complete their development while permanently attached to the mother's teats before weaning and starting feeding on their own. Yet, while the masticatory muscles of adults are known, as is the ontogeny of the cranium and mandible, the ontogenetic changes in the masticatory muscles remain unknown. Here we describe for the first time the changes in the masticatory muscles observed in lactating pups, and weaned juveniles, subadults, and adults in the White-eared opossum, Didelphis albiventris, through dissection of 25 specimens and quantification of relative muscle masses, lines of actions and mechanical advantages whenever possible. We also assessed the scaling patterns of muscle masses and mechanical advantages through ontogeny. The main changes, as expected, were found between suckling and weaned specimens, although some changes still occurred from juveniles to adults. The adult adductor musculature is similar to the other Didelphis species already known, with a dominant m. temporalis that originates on the lateral wall of the skull, up to the sagittal and nuchal crests, and fills the zygomatic arch when inserting into the lateral and medial surfaces of the coronoid process, respectively through the pars superficialis and pars profunda. The m. masseter is also subdivided in superficial and deep bundles which originate posteriorly in the maxilla and zygomatic arch, and insert into the angular process and masseteric fossa in the mandible. The m. pterygoideus medialis originates from the palatine, the pterygoid bone and the alisphenoid, and it inserts on the angular process medially. Suckling pups showed muscles with more restricted attachments, reduced muscle lines of action, and less diversity in the fiber orientation. The absence of the postorbital constriction also resulted in a distinct morphology of the m.temporalispars profunda, through two bundles, one anterior and one posterior, which insert more inferiorly into the mandible. These major changes can be related to the onset of mastication and to size-related changes in growing weaned age classes. In general, all adductor muscles grew with positive allometry, and increased their fixation areas through, in part, the development of specific regions of the cranium and mandible. Their lines of action also increase and diversify along ontogeny. These changes can be related to the functional requirements for fixation during lactation, which shift to adduction and mastication movements after weaning.

Knowledge of Didelphidae taxonomy and diversity has increased steadily over the last decades, mainly due to increasing collection efforts and revisionary works. Yet, especially for mouse opossums, a proper appraisal of morphological variation is still incipient. Thylamys karimii occurs in the Brazilian biomes of Caatinga and Cerrado, and specimens with two different shades of dorsal coloration (brown and gray) were recently documented in sympatry in the Parque Nacional (PARNA) do Catimbau (Caatinga biome). We used qualitative and morphometric data from skulls and skins (n = 7 from PARNA Catimbau and n = 26 from other localities) to compare these two coat color morphotypes and characterize the morphological diversity and taxonomic status of the Caatinga populations. We used Student's t-tests to compare sexes and morphotypes' measurements. We found at least three well-defined coat color morphotypes distinguishable by dorsal and ventral coloration and not restricted to PARNA Catimbau. Variation of the other morphological traits suggests that these morphotypes are more likely a case of intraspecific variation in the Brazilian northeastern region. Morphometric differences, particularly between coat color morphotypes, might be better elucidated in larger samples. Additionally, these specimens represent an important extension of the species' known distribution reaching the Atlantic Forest borders.

A dissecção possibilita o conhecimento de características anatômicas e funcionais dos diferentes grupamentos musculares, e constitui uma das técnicas clássicas que permitem entender a forma e função dos mamíferos. A adição de novas técnicas à dissecção fornece mais informações em que funções podem ser estimadas. Os locais de origem e inserção, os tamanhos e arquitetura interna (da fibra) dos músculos podem corresponder ao desempenho de comportamentos, especialmente quando diferentes ou especializados. A capacidade dos músculos de se estender, de produzir força, ou quão rápido se contraem, está associada à arquitetura de fibra. As fibras musculares estão organizadas nos fascículos e o arranjamento dos fascículos dentro do músculo influencia seu comprimento e a quantidade. Quanto maior o número de fibras no músculo, maior a sua capacidade de produção de força. A área de secção transversal fisiológica (PCSA, sigla baseada no termo em inglês) é uma medida proporcional à força muscular pois representa a quantidade de fibras. Nosso objetivo aqui, é apresentar métodos acessíveis associados a dissecção muscular clássica para medição dos fascículos musculares e estimativa da PCSA. Com isso e a possibilidade de amostragens amplas em coleções e museus científicos, ou mesmo na recepção de novos espécimes que podem representar oportunidades únicas, esperamos aumentar o interesse em explorar os músculos através de uma combinação de estimativas que contribuem para a compreensão da evolução morfológica e funcional da musculatura dos mamíferos.

Didelphid marsupials are considered a morphologically unspecialized group with a generalist diet that includes vertebrates, invertebrates, and plant matter. While cranium and scapula variation has already been examined within Didelphidae, variation in mandible shape, usually associated with diet or phylogeny in other mammalian groups, has not yet been properly assessed in the family. We evaluated the variation in mandible shape and size of didelphids (2470 specimens belonging to 94 species) using 2D geometric morphometrics. We classified the diet of the didelphids into four broad categories to assess whether morphospace ordination relates to dietary habits. We also provided the most comprehensive phylogeny for the family (123 out of the 126 living species) using 10 nuclear and mitochondrial genes. We then mapped mandible size and shape onto that phylogeny for 93 selected taxa and ancestral size and shapes were reconstructed by parsimony. We found phylogenetically structured variation in mandible morphology between didelphid groups, and our results indicate that they have a significant phylogenetic signal. The main axis of shape variation is poorly related to size, but the second is strongly allometric, indicating that allometry is not the main factor in shaping morphological diversity on their mandibles. Our results indicate that the shape and size of the ancestral mandible of didelphids would be similar to that of the current species of the genus Marmosa.

The use of digital technologies is undoubtedly allowing new approaches in the study of mammal morphology, behavior, and evolution and the availability of 3D models of mammal skulls is increasing regularly. Brazil harbors currently 776 mammal species, but there are no estimates on the coverage of this species diversity as 3D cranial models in repositories worldwide. Our goal here was to survey these repositories and create a list of 3D models of Brazilian mammals with direct links, as a tool for teaching activities and as an auxiliary tool for possible preliminary morphological identification of skeletal remains. We found 3D models for about one-third of all Brazilian mammal species and models for congeneric species for ca. 50% of all other species. The distribution of models found for Brazilian mammals is uneven, with a few orders and families with good coverages but most still poorly sampled or lacking any model altogether. We hope that this initial step ignites a collective effort to cover all the Brazilian mammal fauna.

The contraction of the amount of suitable habitat due to climate change can result in a species becoming threatened with extinction. Strong evidence supports that this effect will be pronounced for several species of small mammals in the near future. We address these issues using the ensemble technique to generate potential distribution models for Neotropical marsupials associated with aquatic environments, Chironectes minimus and Lutreolina crassicaudata, and predict the effects of climate change on the distribution of these two species. We later evaluate the effectiveness of the Fully Protected Areas for the two species in the present and future scenarios. Based on our models, we recommend priority areas for the conservation of these species, emphasizing conservation efforts across borders between countries. Our results indicated that both species will suffer a significant restriction of their potential distributions until 2050. Our models predicted that the loss of suitable areas will be greater for C. minimus, with only ~33% of the original distribution area remaining. The models also indicated that the current system of Fully Protected Areas in the Neotropical region will protect L. crassicaudata in a small area of its current and future potential distribution, inserted in climatically stable areas (~14%). These scenarios for these species support strong impacts on the biodiversity protection in aquatic environments in the Neotropical region. We strongly recommend the priority planning and implementation of transboundary Fully Protected Areas in stable areas of distribution of these species to maintain the protection of these marsupials and the ecosystems to which they are associated.

Environmental pressures challenge the survivorship of wildlife, and adaptive ability is key to their success and establishment. However, it remains unclear how changes in environmental conditions affect the phenotypic plasticity of some species. Studies that consider the effect of the environment (e.g., climate changes) on species morphology are essential to better understand his potential resilience. Thus, Diptera species appear as an excellent model. Here we investigated the effect of environmental conditions on wing size and shape within and between one native and one invasive blowfly species populations, along an ecoregional gradient in Brazil. For native species, wing size was affected by almost all environmental variables, while wing shape was unaffected. For invasive species, humidity best explained both wing size and wing shape variation. Our results show a differentiation between populations for both species, but a transversal comparison reveals that invasive species do not seem to be affected in the same way as the native species by climatic variations in the field. Temperature and humidity are the most significant environmental variables associated with differences in wing size and shape for invasive species, indicating an elevated climate tolerance of this species, which may be associated with its invasive characteristics and adaptive potential. Thus, our findings shed light on the importance of assessing the individual and compound effect of environmental variation and biological invasion on the adaptation of native species, since it is expected to increase 3 °C with a 20% overall reduction in the amount of rainfall in the tropical region of Brazil by 2100.

Aim:Comprehensive, global information on species' occurrences is an essential biodiversity variable and central to a range of applications in ecology, evolution, biogeography and conservation. Expert range maps often represent a species' only available distributional information and play an increasing role in conservation assessments and macroecology. We provide global range maps for the native ranges of all extant mammal species harmonised to the taxonomy of the Mammal Diversity Database (MDD) mobilised from two sources, the Handbook of the Mammals of the World (HMW) and the Illustrated Checklist of the Mammals of the World (CMW). Location:Global. Taxon:All extant mammal species. Methods:Range maps were digitally interpreted, georeferenced, error-checked and subsequently taxonomically aligned between the HMW (6253 species), the CMW (6431 species) and the MDD taxonomies (6362 species). Results:Range maps can be evaluated and visualised in an online map browser at Map of Life (mol.org) and accessed for individual or batch download for non-commercial use. Main conclusion:Expert maps of species' global distributions are limited in their spatial detail and temporal specificity, but form a useful basis for broad-scale characterizations and model-based integration with other data. We provide georeferenced range maps for the native ranges of all extant mammal species as shapefiles, with species-level metadata and source information packaged together in geodatabase format. Across the three taxonomic sources our maps entail, there are 1784 taxonomic name differences compared to the maps currently available on the IUCN Red List website. The expert maps provided here are harmonised to the MDD taxonomic authority and linked to a community of online tools that will enable transparent future updates and version control.