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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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Amazonian mammal diversity is exceptionally high, yet new taxonomic discoveries continue to be made and many questions remain for understanding its diversification through time and space. Here we investigate the diversification of spiny rats in the genus Makalata, whose species are strongly associated with seasonally flooded forests, watercourses and flooded islands. We use a biogeographical approach based on a mitochondrial cytochrome b gene through divergence time estimation and reconstruction of ancestral areas and events. Our findings indicate an ancient origin of Makalata for the Guiana Shield and Eastern Amazonia as ancestral area. A first cladogenetic event led to a phylogeographic break into two broader clades of Makalata through dispersal, implying a pattern of western/Eastern Amazonian clades coinciding with the Purus Arch (middle Miocene). Most of subclades we infer originated between the late Pliocene to the early Pleistocene, with few recent exceptions in the early Pliocene through dispersal and vicariant events. The hypothesis of rivers as dispersal barriers is not corroborated for Makalata, as expected for mammalian species associated with seasonally flooded environments. We identify two key events for the expansion and diversification of Makalata species: the presence of geologically stable areas in the Guiana and Brazilian shields and the transition from lacustrine conditions in western Amazonia (Acre system) to a river system, with the establishment of the Amazon River transcontinental system and its tributaries. Our results are congruent with older geological scenarios for the Amazon basin formation (Miocene), but we do not discard the influence of recent dynamics on some speciation events and, mainly, on phylogeographic structuring processes. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The Guiana Center of Endemism (GCE) extends across Guyana, Suriname, French Guiana, north of the Amazon River and east of the Negro River in Brazil, and Venezuela to the south of the Orinoco River. Regarding diversity of nonvolant mammals, the Brazilian part of this center is less studied, especially the area corresponding to the north of the State of Pará. Seven field trips lasting 12-15 days each were conducted in five conservation units in northern Pará, in order to assess the nonvolant mammalian fauna. Small mammals were captured using conventional and pitfall traps. Medium-sized and large mammals were recorded through direct observations on diurnal transect censuses, collections, camera traps, indirect evidence, and in some cases, interviews. We recorded 60 species distributed in nine orders. Among other contributions, a recently described species of Monodelphis was collected, and the range distribution of Didelphis imperfecta was extended. In addition, the night monkey Aotus sp. was recorded on the east of the Trombetas River for the first time. The high number of records for game and/or threatened species evidences that the studied area is highly preserved, and the newly created protected areas are strategic for the conservation of mammals in the GCE. [ABSTRACT FROM AUTHOR]

The article offers the authors' views on the study regarding the geographic distribution of marsh deer Blastocerus dichotomus in Northern Brazil particularly at the Nascentes do Rio Parnaíba National Park (NRPNP). They note that various authors confirmed the origin of B. dichotomus in Cerrado, but W. Tomas, M. D. Beccaceci, and L. Pinder asserted the extinction of this species in the region due to hunting and habitat loss. According to C. L. Miranda and G. S. Alencar, traditional hunting is rampant for people residing near the park to provide meat of slaughtered animals to nearby cities. The authors also mentions the habitat changes in Piaui and Maranhâo because of expanding agricultural grasslands. They add that immediate attention for conservation of this species is required.

The article discusses the discovery of species Metachirus nudicaudatus in the state of Piaui, Northeastern Brazil. It refers to the collection of four specimens from a semi-deciduous forest area located at Fazenda Nazareth, which were distinguished through morphological and skull characters. It mentions that the identification has been aided by observations on the agonistic behavior typical of the species. It states that the new record has indicated a significant increase in the species' geographic distribution area.