Much evidence suggests that Amazonia and the Atlantic Forest were connected through at least three dispersion routes in the past: the Eastern route, the central route, and the Western route. However, few studies have assessed the use of these routes based on multiple species. Here we present a compilation of mammal species that potentially have dispersed between the two forest regions and which may serve to investigate these connections. We evaluate the present-day geographic distributions of mammals occurring in both Amazonia and the Atlantic Forest and the likely connective routes between these forests. We classified the species per habitat occupancy (strict forest specialists, species that prefer forest habitat, or generalists) and compiled the genetic data available for each species. We found 127 mammalian species presently occurring in both Amazonia and the Atlantic Forest for which, substantial genetic data was available. Hence, highlighting their potential for phylogeographic studies investigating the past connections between the two forests. Differently from what was previously proposed, the present-day geographic distribution of mammal species found in both Amazonia and the Atlantic Forest points to more species in the eastern portion of the dry diagonal (and adjoining forested habitats). The Central route was associated with the second most species. Although it remains to be seen how this present-day geography reflects the paleo dispersal routes, our results show the potential of using mammal species to investigate and bring new insights about the past connections between Amazonia and the Atlantic Forest.

A ordem Didelphimorphia é composta somente pela família Didelphidae, exclusiva do continente americano. Esta família é amplamente distribuída na região Neotropical, ocupando grande variedade de hábitats. A literatura registra 68 espécies de didelfídeos no Brasil, das quais 24 delas têm ocorrência confirmada para a Bacia do Alto Paraguai (BAP). As espécies presentes nessa região pertencem a três subfamílias – Glironiinae (1 gênero, 1 espécie), Caluromyinae (1, 2) e Didelphinae (11, 21) – e, dentre elas, inclui-se Monodelphis saci, espécie há pouco descrita, bem como outras três, recentemente validadas em nível de espécie, Gracilinanus peruanus, Philander canus e Marmosa rapposa, e duas espécies ameaçadas de extinção, Thylamys karimii e T. macrurus. A proposta deste artigo foi fazer um levantamento de todas as espécies de marsupiais registradas na BAP até o presente momento, trazendo, na medida da disponibilidade de dados, uma breve descrição morfológica de cada uma das 24 espécies, bem como a comparação com espécies congêneres ou assemelhadas, a revisão dos dados de ecologia e de história natural e informações específicas de suas populações e de seus graus de ameaça. Por fim, este estudo traz informações inéditas que podem ser utilizadas para a tomada de decisões em políticas públicas e para o norteamento de pesquisas básicas para esse grupo zoológico nessa região tão pouco conhecida e fortemente ameaçada.

A ordem Rodentia representa aproximadamente 39% da diversidade mundial de mamíferos, sendo que para o Brasil são reconhecidos atualmente 76 gêneros e 263 espécies. Para a Bacia do Alto Paraguai (BAP), foi registrada a ocorrência de 42 espécies, distribuídas em oito famílias: Sciuridae (2 gêneros, 2 espécies), Cricetidae (15, 27), Caviidae (3, 3), Ctenomyidae (1, 1), Cuniculidae (1, 1), Dasyproctidae (1, 1), Erethizontidae (1, 1) e Echimyidae (5, 6). Dentre as espécies registradas na BAP, duas foram recentemente descritas, Akodon kadiweu e Oecomys matogrossensis, uma revalidada em nível de espécie, Coendou boliviensis, e três são alvo de caça, Cuniculus paca, Dasyprocta azarae e Hydrochoerus hydrochaeris. A proposta deste artigo foi fazer um levantamento de todas as espécies de roedores registradas na BAP até o presente momento, trazendo, na medida da disponibilidade de dados, a descrição morfológica de cada uma das 42 espécies, bem como a comparação com espécies congêneres ou assemelhadas, a revisão dos dados de ecologia e de história natural e informações específicas de suas populações e de seus graus de ameaça. Por fim, este estudo traz informações inéditas, que podem ser utilizadas para a tomada de decisões em políticas públicas e para o norteamento de pesquisas básicas para esse grupo zoológico nessa região tão pouco conhecida e fortemente ameaçada.

Forest management strategies often compromised the patterns and processes of the naturally dynamic forest ecosystems. As species occurrence and diversity are directly associated with ecological and environment factors, this study evaluated the effect of low-impact forest management on the structure of the anuran community, considering the effects of the environment types generated by the management and the post-exploitation time in the Fazenda Uberlândia, southeastern Amazonia (Portel, Pará, Brazil). Field data were collected in the period of the highest rainfall in the region (February to March 2021) by sampling 84 linear transects (25 m each) at a minimum distance of 500 m between them. The time elapsed since logging that took place in the study sites varied from 2 to 17 years. We analyzed an area without forest management (used as a control) and three environment types formed by logging activities: secondary roads, skid trails, and storage yard. Our results showed no differences in species richness, abundance, and composition of the anuran community with respect to time since exploitation. Meanwhile, we found significant differences across different environment types, suggesting that the observed pattern of richness and abundance may benefit the assembly of anurans in the short term. Still, over a longer period, it may have a homogenizing effect, gradually modifying the anurofauna assemblage in managed areas to favor species adapted to more open environments, resulting in damage to the local diversity of anurans.

Morphology has been used to establish interspecific limits in echimyid rodents. However, using only morphology can be problematic, especially for polymorphic or morphologically cryptic species. Recently, combined data sources have been used to recognize and delimit species and have proven to be especially useful for taxonomic resolutions. Makalata is a taxonomically problematic genus that needs revision. Currently, two species are recognized: M. didelphoides and M. macrura. A third species, M. obscura, is considered questionable. Molecular studies demonstrate that diversity in the genus has been underestimated. In the present study, we identified 14 subclades representing potential species in the genus Makalata using molecular and cytogenetic data. Analysis of species delimitation corroborated this hypothesis. Four lineages in the Guiana Shield, currently considered to be a single taxonomic entity in the literature (M. didelphoides) based only on morphology, were shown to be potential cryptic species, differentiated only by molecular and karyotype data. We verified that the name M. didelphoides cannot be applied to any clade or museum specimen without a genetic approach and sequencing of the holotype. We present an amended diagnosis for M. macrura through examination of the original description, sequencing, and karyotype of topotypic samples allowed us to associate with the name M. macrura represented by subclade I in this study. Karyotype data proved to be a powerful tool in differentiating the Makalata species according to different combinations of diploid number (2n) and fundamental number, as for other genera of spiny tree-rats. Our results demonstrate a heterogeneous status for Makalata, highlighting the importance of using multiple tools to determine the taxonomy of this group and reinforcing the importance of molecular and chromosomal data added to the morphological data to obtain a more accurate picture of the taxonomic diversity of this and other small mammal genera.

The brown or pouchless four-eyed opossums or jupatis represent the genus Metachirus with a wide geographical range in the Neotropics. Recent studies show distinct monophyletic clades with high genetic divergence and recognized two species, Metachirus nudicaudatus and Metachirus myosuros. Nevertheless, there is a need for systematic revision with multiple sources of evidence on the taxonomy of Metachirus, which has never been fully revised. Here we describe a new species of Metachirus for the Brazilian Amazon from the Xingu/Tocantins interfluve using the unification of concepts and evolutionary significant units, morphological, genetic, and geographic data. Our analysis reveals a new species within Metachirus as a differentiated Amazonian clade from the Serra dos Carajás region and the Caxiuanã National Forest, both in the Xingu endemism centre. This new species can be distinguished from the type species, M. nudicaudatus and from M. myosuros through discrete external morphological characters, including cranium and dentition, and molecular data with an average degree of divergence, but ancient divergence time for the mitochondrial cytochrome b gene. The Amazon River delimits the distribution of the new species, which also occurs in areas under strong anthropogenic pressure, reinforcing the importance to guide conservation strategies for the region.