Band 89, Heft 6

Studies on diet differences between and within species help explain how natural history variation and environmental changes affect ecological interactions. This study aimed to investigate the diet of nine didelphid species captured in different environments (humid, semi-deciduous, liana forests, and agroforestry systems) in eastern Brazilian Atlantic Forest. It was hypothesized that diet variation would occur between species, individuals of the same species in different environments, and between sexes. The richness and composition of food items were compared among six species, with diet comparisons across environments and sexes for four species. Results showed a high frequency of arthropods in the diet, especially Formicidae and Termitidae. Larger species exhibited more diverse diets, overlapping with those of smaller species. Marmosa murina showed greater richness of consumed items in agroforests, with Formicidae as the most frequent. No differences were observed between sexes, possibly due to high temporal variability in the data, which may limit detection of sex-related patterns. These findings help fill knowledge gaps on didelphid diet and highlight the importance of investigating dietary variation between and within species.

Habitat loss and fragmentation are the main threats to biodiversity conservation worldwide. The tuco-tuco-do-lami ( Ctenomys lami ) is an endangered subterranean rodent species endemic to the Pampa biome in southern Brazil. The species needs studies to understand how anthropic changes influence ecological patterns over time. Thus, in this study, we aimed to: i) evaluate how persistence is influenced by the hypotheses of habitat amount and configuration at multiple scales; and ii) analyze the extent of occurrence and area of habitat. By applying a multiscale landscape approach, we revealed that habitat configuration is a stronger predictor of persistence than habitat amount at finer spatial scales. Our results demonstrate a clear scale effect, with habitat configuration emerging as the best predictor at the 500 m spatial scale. These findings reinforce the importance of incorporating multiscale analyses in conservation planning, especially for subterranean and habitat specialist species. Furthermore, the species had a reduction in the extent of occurrence and habitat amount, representing a setback compared to recent years. Our study demonstrated how anthropic changes affect the ecological patterns of an endangered species.

Pteromys volans is asocial; however, individuals temporarily form communal nesting groups in tree cavities during winter. It was anticipated that behavioural keys could be identified to facilitate the transition between living a solitary and gregarious lifestyle. Understanding the processes of formation, maintenance, and dissolution of a nesting group of P. volans may help to resolve the dynamics of communal nesting in rodents. We tracked the nesting behaviour of P. volans in two cavity nests from September to April in 2020–2021 and 2021–2022 using passive integrated transponder tags and infrared video cameras. Twelve males and nine females used these nests, and the nesting group originated from the presence of at least one male and one female. The nesting group was maintained from autumn to early spring. Although the group members changed frequently, causing fluctuations in group composition, stable principal individuals were retained. The nesting group dissolved during March–April, suggesting that this may be related to mating behaviour. These findings provide valuable insight into the sociality of P. volans .

The composition of the bat assemblage in the middle course of the Uruguay river (Argentina) was studied and compared with other assemblages along this same river. A total of 55 individuals belonging to 11 species from the families Molossidae (4), Phyllostomidae (3) and Vespertilionidae (4) were captured using mist nets at different sites. These species belong to six trophic guilds; the highest specific richness correspond to the insectivorous guild, but the most common bat was the frugivorous Sturnira lilium . Additionally, we reported the southernmost record in Argentina for the frugivorous bat Artibeus lituratus . Finally, we discussed the conservation, importance and distribution of these mammals in riparian environments.

Tapirus kabomani is a little-studied species, making new records essential for understanding its geographic distribution, ecology and conservation. We document new records of T. kabomani in at Cristalino State Park, Mato Grosso, Brazil. These records significantly expand the known range of the species. Our findings highlight the importance of protected areas for the conservation of species such as T. kabomani and reinforce the need for continuous monitoring in the Amazon to ensure the preservation of these populations in the face of increasing deforestation and habitat fragmentation.

Caluromys comprises three species of Neotropical marsupials distributed from Mexico south to Argentina. In Colombia, Caluromys derbianus and Caluromys lanatus have been reported, and the presence of Caluromys philander is expected but not validated yet. Based on photographs of a male individual, we confirmed the presence of C. philander in the Japurá–Solimoes–Negro Moist Forests ecoregion of the Amazon region of Colombia. This record extends the distribution 538 km south-west from the closer locality in Amazonas, Venezuela, increasing the number of marsupials distributed in Colombia to 42 species (40 Didelphimorphia and 2 Paucituberculata).

This study aimed to investigate the species distribution of the Barbary ground squirrel within Tindouf Cultural Park, an arid region where no prior occurrence records for this species existed. Additionally, we assessed the species’ potential range by modelling its bioclimatic niche. Our field trips conducted on 2023 to various habitats in the Tindouf cultural park have confirmed the presence of the Barbary ground squirrel in nine sites, primarily in rocky, mountainous areas with water sources. Vegetation in these areas is diverse, with a dominance of Acacia and Argan trees. The squirrels showed a preference for argan fruits. Using GBIF data, 2,133 geo-referenced observations were collected, showing an increase in occurrences from the 2000s. Due to the nature of the data collected (presence only) we used Maxent for modelling Barbary ground squirrel bioclimatic niche and distribution. The model used proved to be excellent, with an AUC value of 0.977. The Jackknife test identified the minimum temperature of the coldest month, the precipitation of the coldest quarter, and the average diurnal range as the main influencing variables on the presence of the Barbary ground squirrel. The predictive distribution map shows that the squirrel could potentially inhabit a larger area in Algeria than what is currently observed.

Records of bats with coloration anomalies has increased in the last years in South America, with few records from the Amazon. Here, we report new records of coloration anomalies in phyllostomid bats from Brazilian Amazon. We captured one species with leucism: Artibeus planirostris and ten species with piebaldism: Dermanura gnoma , Hsunycteris thomasi , Glossophaga bakeri , Glossophaga soricina , Lionycteris spurrelli , Lophostoma silvicola , Phyllostomus elongatus , Phyllostomus hastatus , Trachops cirrhosus , and Tonatia maresi . The impact of coloration anomalies in bats and other vertebrates has been a topic of debate, with some authors suggesting that these alterations increase the risk of predation and intraspecific conflicts, thereby reducing survival and fitness. Our findings may indicate that even with color anomalies, bats can survive, and bats reach adulthood.

Gracilinanus aceramarcae is a small opossum distributed in the montane forests from northern Peru to northern Bolivia. This species has been proposed as a species complex; but no study has included specimens from its full distributional range to assess its taxonomic status. Here, we present a review of specimens identified as G. aceramarcae (including new records) based on morphological, morphometric, and phylogenetic analyses using cytochrome b sequences. Our results suggest that G. aceramarcae comprises a Bolivian morphotype (which include the holotype) and seven Peruvian morphotypes distributed allopatrically throughout the Peruvian montane forests. These morphotypes are distinguished by a combination of external and craniodental traits and different position in the morphospace. Five of them were recovered monophyletic in our molecular analyses and were genetically distinct from each other in a range of 6.03–14.13 %. The other two morphotypes were not phylogenetically resolved due to lack of tissues. In conclusion, G. aceramarcae sensu stricto is redescribed, and evidence is provided that the Peruvian morphotypes might constitute putative new taxa. Additionally, we suggest that important rivers such as Marañón, Huallaga, Apurímac, and Limbani have influenced the diversification of these taxa.