Browsing by Author "Da Silva, Maria Nazareth F."
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Item Mammals of the Rio Juruá and the evolutionary and ecological diversification of Amazonia. Bulletin of the AMNH ; no. 244([New York] : American Museum of Natural History, 2000) Patton, James L.; Da Silva, Maria Nazareth F.; Malcolm, Jay R.We describe the nonvolant mammal fauna of the Rio Juruá of the western Amazon of Brazil, based on collections made during a year-long survey of the river. We, along with our colleagues Drs. Claude Gascon and Carlos Peres, designed the field project to examine the effects of the river on the differentiation among terrestrial vertebrates (mammals, birds, and amphibians and reptiles) at both the community and population levels. This monograph examines only the patterns of geographic variation and community structure of the small-bodied mammals. Species inventories were made at 16 primary trapping localities divided into eight pairs of cross-river sites, with two pairs in each of four regions from near the mouth to the headwaters of the Rio Juruá. A total of 81 species of nonvolant mammals were obtained, including nine new to science. Four of these are described herein; the others have been described elsewhere. We used a standardized trapping protocol to assess community structure at each of the 16 localities that included terrestrial and canopy trap stations in floodplain (várzea) and upland (terra firme) forest formations. Supplemental trapping was done in secondary habitats at all sites. We describe these sites, the trap effort expended, and the placement of trap stations relative to local habitats. We also describe each species of marsupial, sciurid rodent, murid rodent, and echimyid rodent encountered; comment on their systematics; and summarize aspects of habitat use, life history, geographic distribution, and geographic differentiation based on morphological and molecular traits. We examine patterns of differentiation in the mitochondrial cytochrome-b gene for samples of 41 of the 45 species of marsupials and rodents obtained within the Rio Juruá Basin, and discuss these patterns from the perspective of the entire Amazon and, in some cases, the Mata Atlantica of coastal Brazil. We also examine patterns of community organization within the Rio Juruá basin and throughout Amazonia, drawing attention to the geographic distribution of what appear to be major faunal units that are independent of habitat differences. Finally, we use principles of phylogeography to analyze patterns of geographic differentiation among the nonvolant mammals with regard to the Riverine Barrier Hypothesis. We show that, while there are few examples of taxa for which the Rio Juruá is apparently a barrier, most taxa either are largely undifferentiated throughout the basin or are sharply divided into reciprocally monophyletic mtDNA haplotype clades separable into upriver and downriver units. We argue that the concordance in the geographic placement of clade boundaries suggests a common history; moreover, both the age of these clades and their geographic position in relation to underlying geological features suggest that landform evolution has been an important, but underappreciated component of diversification within western Amazonia.Item Revisionary notes on neotropical porcupines (Rodentia, Erethizontidae). 2, A review of the Coendou vestitus group with a description of two new species from Amazonia. American Museum novitates ; no. 3351(New York, NY : American Museum of Natural History, 2001) Voss, Robert S.; Da Silva, Maria Nazareth F.Neotropical porcupines of the Coendou vestitus group consist of four small-bodied species from northwestern South America that are hypothesized to form a clade on the basis of their unique dorsal pelage composition. In addition to soft wool and barbed quills--hair types widely shared by other erethizontids--the dorsal pelage of vestitus-group porcupines includes what may be called bristle-quills: long, thin, unbarbed quills with flexible tips. The group includes Coendou vestitus Thomas, 1899; C. pruinosus Thomas, 1905; and two new species. The latter provide the first documented records of small porcupines from western Amazonia, where only large porcupines (C. prehensilis and C. bicolor) were previously known. Other small porcupines probably remain to be discovered in Amazonia, where hydroelectric dam projects offer unique (if unfortunate) faunal-sampling opportunities.Item Systematics of neotropical spiny mice, genus Neacomys Thomas, 1900 (Rodentia: Cricetidae), from southeastern Amazonia, with descriptions of three new species. (American Museum novitates, no. 3958)(American Museum of Natural History., 2020-09-05) Semedo, Thiago Borges Fernandes; Da Silva, Maria Nazareth F.; Gutiérrez, Eliécer E.; Ferreira, Daniela Cristina; Nunes, Mario Da Silva; Mendes-Oliveira, Ana C.; Farias, Izeni Pires; Rossi, Rogério V.Species of Neacomys are small cricetid rodents that occur in forested habitats of Central and South America, from eastern Panama to central Bolivia and central/western Brazil. In order to assess species diversity of this poorly known genus, we obtained cytochrome b gene sequences from the most comprehensive taxonomic and geographic sampling analyzed to date. We also conducted morphological analyses on a large series of specimens housed in 15 museums, including types of 10 out of 14 nominal taxa. Our analyses of the genetic data recovered 17 lineages clustered in four distinct clades. Among these lineages, 11 correspond to species currently recognized as valid, and the remaining six are putative new species. In southeastern Amazonia--the geographical scope of this report--four undescribed species were discovered, three of which are named herein: Neacomys marajoara, sp. nov., from the Island of Marajó, Pará state; Neacomys vossi, sp. nov., restricted to the Tapajós center of endemism (between the Tapajós and Xingu rivers); and Neacomys xingu, sp. nov., restricted to the Xingu center of endemism (between the Xingu and Araguaia/Tocantins rivers). The new species can be discriminated from other Neacomys species by the morphology of the nasal bones, zygomatic plate, interorbital region, subsquamosal fenestra, paraoccipital process, incisive foramina, auditory bullae, anterocone and anteroloph of the first upper molar, carotid circulation pattern, and karyotype. Our results substantially improve our understanding of the genus Neacomys by providing morphological, morphometric, and novel molecular insights about these poorly known rodents and demonstrate that the diversity of small Amazonian mammals is still poorly known, even in the relatively accessible southeastern part of the biome.