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The article "TOWARDS A NEW CATEGORIZATION OF ARGENTINA'S MAMMALS" informs about the categorization of mammals in Argentina according to their risk of extinction. The "Red List" published in 2019 by SAREM and the National Environment Secretariat updated the taxonomy and distribution of mammal species in Argentina, as well as the threats they face. It was found that 24% of mammals in Argentina are endangered. This categorization has influenced other South American countries and has driven research on introduced mammals in the country. A new categorization will be carried out in 2024, maintaining principles of plurality, participation, technical robustness, and free dissemination of results. A procedure from the IUCN will also be incorporated to classify introduced species, and a new web platform will be developed to present the data. SAREM plays an important role in the knowledge and management of mammals in Argentina. [Extracted from the article]

Past and current climatic and environmental changes have contributed to configure actual species distributions and abundances. Knowing their evolution over time allows discrimination between natural and anthropogenic causes in current composition of faunal communities. We evaluate the changes in small mammal assemblages from the north-central Patagonian Andean forests since the Late-Holocene to recent times and their relationship with the environmental modifications driven by human activities. A bone sequence from Población Anticura archaeological site (lower Manso river valley, Río Negro province, Argentina) was studied, which encompasses a time span from the early Late-Holocene (3350 ± 100–2270 ±80 years BP) to final Late-Holocene (1420 ± 70–530 ±50 years BP) and Historical times (480 ± 70–280 ±40 years BP). The species composition indicates that forest environment established in the area from at least the Late-Holocene (dominance of Loxodontomys micropus, with subordinate frequencies of Abrothrix olivacea, A. hirta, Geoxus valdivianus, Irenomys tarsalis, and Paynomys macronyx), with patches of (or near to) open environments (presence of Reithrodon auritus and cavids). It is remarkable the presence of cavids, which increased their abundance in the sequence towards Historical times but disappeared nowadays. The low frequencies (<10%) of the rodent Oligoryzomys longicaudatus along the entire sequence is also relevant, since this rodent is the reservoir of the Andes strain of the Hantavirus (ANDV), which causes pulmonary syndrome. This mouse dominates the small mammal assemblages from forests and ecotonal shrublands of northwestern Patagonia (abundances exceed 50% in owl pellets recently collected from the study area). Current configuration of forest and ecotonal assemblages, particularly the high abundance of O. longicaudatus, should be mainly linked to anthropogenic causes, including the introduction of cattle, land clearing, and the advance of introduced plant species such as the sweet briar (Rosa eglanteria). Particularly, this exotic shrub offers shelter and additional food for O. longicaudatus, turning their shrublands into spaces of high epidemiological risk. [ABSTRACT FROM AUTHOR]

The studies of the small mammal fossil and recent assemblages from the Limay river basin (Northwestern Patagonia) have strongly increased during the last decade. Taxonomic, taphonomic, and paleoecological information about small rodents and marsupials recovered from fossil sites offers the opportunity to discuss the periods of change and stability in the conformation of their communities through the Anthropocene. Here, we used two large data matrix of fossil and recent small mammal samples. As starting point, we considered the small mammal record of Epullán Grande cave (LL thereafter), which covers the Early Holocene/Post-hispanic Period, in order to assess the impact of anthropic activities on the small mammal communities during the Anthropocene. The taphonomic analysis performed on the newest samples from LL confirms the predatory activity of Tyto furcata on sigmodontines and human consumption on caviomorphs (mostly for the last ca. 1000 years). The analysis of manganese oxide staining suggested higher levels of moisture during the earliest formation of the LL sequence. The taxonomic results indicate a major diversity in the small mammal fossil assemblages to the later periods of LL and other fossil sequences of the Limay basin of the Anthropocene. Conversely, opportunistic sigmodontines (Abrothrix olivacea, Calomys musculinus, Eligmodontia spp. and Oligoryzomys longicaudatus) experienced a growth in the recent samples. Some stenoic and specialist species (Euneomys spp., Lestodelphys halli, Loxodontomys micropus and Reithrodon auritus) were abundant in the temporal units associated with the Anthropocene, but now are in retraction. Additionally, the drop in the diversity of recent assemblages supports a restructuration of small mammal communities from Limay river basin occurred in the 20th century. [ABSTRACT FROM AUTHOR]

Barn owls are the most widely distributed group of owls in the world and are among the most common accumulators of small vertebrate remains at archeological and paleontological sites. Despite its importance as a bone remains accumulator and predictor of paleoenvironmental conditions due to its generalist habits, the vertebrate prey of this raptor has been scarcely studied from an ecological community perspective, especially considering the diverse range of prey it captures. Archeological, paleontological, and taphonomic studies typically reveal taxon-specific patterns, focusing primarily on small rodents. In order to overcome this problem, we studied an assemblage of vertebrate bones from barn owl pellets in the central Monte Desert of Argentina. Our analysis included the full range of prey taxa, including rodents, marsupials, birds, and reptiles, addressed from both an ecological and neo-taphonomic perspective. We compare the taxonomic and taphonomic findings with those from regional small vertebrate records obtained from various sampling types over the past 50 years to explore recent environmental changes within the Anthropocene. The assemblage of small vertebrate prey presented here comprises five species of cricetids, one species from the Caviidae family, and at least one ctenomyid rodent species. Additionally, the assemblage includes one species of didelphid marsupial, one reptile species, and at least six passeriform bird species that belong to separate families. The overall taphonomic trends are consistent with the typical barn owl pattern. However, our analysis identified a larger percentage of postcranial elements exhibiting signs of digestion compared to pellet-derived vertebrate bone assemblages previously documented. Furthermore, it is important to note that a significant proportion of avian bone fragments exhibit distinct signs of digestion. [ABSTRACT FROM AUTHOR]

Information on dietary ecology plays a key role in a wide array of biological research and conservation decisions, but its availability is biased towards large and charismatic taxa, whereas small mammals are underrepresented. Of the scarce publications on the Neotropical sigmodontine rodents, most are concentrated in central-eastern Argentina and, up until now, no revision of the totality of these data has been made available. In this work, we performed a thorough review of the dietary information from over 50 publications on 22 species, finding omissions and errors propagated up to the present time. This resulted in a robust database, the proposal of a posteriori dietary categories, and a list of the species that have been neglected in feeding ecology research. In turn, we used that database to test whether the patterns which associate diet and morphology in medium-sized and large mammals could be replicated in these small rodents, despite their overall generalist habits and the restrictions characteristic to their size. We found that larger species tend towards a low-protein diet. Additionally, we identified some stomach types that are restricted to specific diets. These results are consistent with the observations for larger species and shed light on the biology of small mammals. Key words: small mammals, feeding ecology, size, digestive system, Neotropics, Pampas, Rodentia. Si l'information sur l'écologie alimentaire joue un rôle clé dans une vaste gamme de recherches en biologie et décisions concernant la conservation, sa disponibilité est biaisée vers les grands taxons charismatiques, les petits mammifères y étant sous-représentés. Des rares publications sur les rongeurs sigmodontinés néotropicaux, la plupart portent sur le centre-est de l'Argentine et, à ce jour, aucune révision de l'entièreté de ces données n'a été rendue disponible. Nous avons réalisé un examen exhaustif de l'information sur l'alimentation tirée de plus de 50 publications portant sur 22 espèces et relevé des omissions et erreurs qui se sont propagées jusqu'à aujourd'hui. L'examen a produit une base de données robuste, la proposition de catégories de régimes alimentaires a posteriori et une liste d'espèces négligées dans la recherche en écologie de l'alimentation. Nous avons ensuite utilisé cette base de données pour vérifier si les motifs qui associent le régime alimentaire et la morphologie chez les mammifères de taille moyenne et les grands mammifères peuvent être reproduits chez ces petits rongeurs, malgré leurs habitudes globalement généralistes et les restrictions propres à leur taille. Nous constatons que les espèces plus grandes ont tendance à présenter un régime alimentaire faible en protéines. Nous cernons en outre certains types d'estomacs qui sont limités à des régimes alimentaires précis. Ces résultats concordent avec les observations sur des espèces plus grandes et jettent un meilleur éclairage sur la biologie des petits mammifères. [Traduit par la Rédaction] Mots-clés : petits mammifères, écologie de l'alimentation, taille, système digestif, Néotropique, pampas, rongeurs., Introduction Dietary information plays a key role in a varied array of biological studies. As morphological, physiological, and behavioral traits are influenced by diet, this kind of data is useful [...]