One of the most commonly used sampling techniques to capture leaf litter amphibians, lizards and small mammals is a set of pitfall traps with drift fences. However, there are still many speculations concerning the effectiveness of different designs of pitfall traps and the most adequate size of each trap. To address this problem, we conducted the first standardized comparison of patterns of species richness, rank-abundance, and community structure of leaf litter amphibians, lizards and small mammals for two trap designs (I and Y format) and three bucket sizes (35, 62, and 100 L) in a Neotropical forest. Results are very similar for the herpetofauna, regardless of the pitfall trap design or size used, while for small mammals values of species richness were higher for 100 L pitfall traps, as compared to the smaller traps. Therefore, the use of 100 L pitfall traps is recommended to sample the terrestrial vertebrate fauna, in multidisciplinary studies. For surveys aiming only the herpetofauna the use of smaller (35 L) traps is acceptable, taking into consideration the cost-benefits obtained by the smaller traps, in comparison to the larger ones
Neacomys (Sigmodontinae) comprises 8 species mainly found in the Amazonian region. We describe 5 new karyotypes from Brazilian Amazonia: 2 cytotypes for N. paracou (2n = 56/FNa = 62-66), 1 for N. dubosti (2n = 64/FNa = 68), and 2 for Neacomys sp. (2n = 58/FNa = 64-70), with differences in the 18S rDNA. Telomeric probes did not show ITS. We provide a phylogeny using Cytb, and the analysis suggests that 2n = 56 with a high FNa is ancestral for the genus, as found in N. paracou, being retained by the ancestral forms of the other species, with an increase in 2n occurring independently in N. spinosus and N. dubosti. Alternatively, an increase in 2n may have occurred in the ancestral taxon of the other species, followed by independent 2n-reduction events in Neacomys sp. and in the ancestral species of N. tenuipes, N. guianae, N. musseri, and N. minutus. Finally, a drastic reduction event in the diploid number occurred in the ancestral species of N. musseri and N. minutus which exhibit the lowest 2n of the genus. The karyotypic variations found in both intra- and interspecific samples, associated with the molecular phylogeny, suggest a chromosomal evolution with amplification/deletion of constitutive heterochromatin and rearrangements including fusions, fissions, and pericentric inversions.
Amazonia National Park is located in southwestern Pará State in central Amazonia. The 10,707 km 2 park is one of the largest protected areas in Brazil and is covered with pristine forests, but the region is threatened by dam construction projects. An incomplete mammal biodiversity inventory was conducted in the area during the late 1970s. Here, we present results of sampling from 7,295 live-trap nights, 6,000 pitfall-trap nights, more than 1,200 km of walking transect censuses, and approximately 3,500 camera-trap days, all conducted between 2012 and 2014. These sampling efforts generated a list of 86 known species of nonvolant mammals, making the park the single most species-rich area for nonvolant mammals both in the Amazon Basin and in the Neotropics as a whole. Amazonia National Park is a megadiverse site, as is indicated by its mammalian richness, which includes 15 threatened mammal species and 5 to 12 new species of small mammals. As such, it merits being a high-conservation priority and should be an important focus of Brazilian authorities' and the international scientific community's conservation efforts. A comprehensive conservation plan is urgently needed, especially given the ecological threats posed by dam construction.
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
Little is known about the genus Neusticomys , one of the most poorly represented sigmodontine rodents in scientifi c collections. In this report, we provide new records of Neusticomys ferrerai and N. oyapocki in the Brazilian Amazonia and discuss possible limits for their geographic distributions. Three individuals of N. ferreirai were recorded during three distinct survey events. The fi rst record extends the range of the species approximately 100 km westward, and the other two extend it approximately 1000 km northeastward. For N. oyapocki , our record extends the currently known range of the species approximately 300 km westward. All specimens were collected in primary forests by 60-liter pitfall traps. Considering our records of N. ferreirai and the ecoregions associated with them, we argue that the species range may extends north along the interfl uves Xingu-Tocantins and Madeira-Tapaj ó s and west to the Guapor é River. Similarly, the limits of the range of N. oyapocki may coincide with the Amazon river at south, the Negro river at west and the transition zones between the Guianan forests and savannas or coastal vegetation at east and north. Larger series of Neusticomys in collections are expected to be available in the future, as more inventories using pitfall traps are carried out in Amazonia.
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.
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