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Evidence of cryptic lineages within a small South American crocodilian: The Schneider's dwarf caiman Paleosuchus trigonatus (Alligatoridae: Caimaninae)
Get PDFSchneider's dwarf caiman Paleosuchus trigonatus is one of the smallest living crocodilians. Due to its broad distribution, cryptic behavior, and small home range, the species is well suited for the study of phylogeographic patterns on a continental scale. Additionally, this species is under threat due to habitat loss, trade and harvest, but is considered at low conservation risk by the IUCN. In the present study we test the hypothesis that P. trigonatus is comprised of geographically structured lineages. Phylogenetic reconstructions of the mitochondrial cytochrome b gene and single locus species discovery methods revealed the existence of two well-supported lineages within P. trigonatus-an Amazonian and Guianan lineage. Fossil calibrated divergence of these lineages was estimated to have occurred in the Late Miocene (7.5 Ma). The hypothesis that the Atlantic coast drainages might have been colonized from the southeast or central Amazon is supported by demographic metrics and relatively low genetic diversity of the Coastal and upper Branco populations when compared to the Amazon basin populations. The Amazon basin lineage is structured along an east-west gradient, with a sharp transition in haplotype frequencies to the east and west of the Negro and Madeira rivers. These lineages are already under anthropogenic threat and, therefore, are conservation dependent. Recognition of these lineages will foster discussion of conservation future of P. trigonatus and these lineages. © 2019 Bittencourt et al
Variabilidade Genética e Influência da Temperatura e CO2 em Populações de Aedes aegypti na Cidade de Manaus, por Meio do Gene Kdr e Marcadores RAPD.
No full textThe Influence of Organic Fertilizer on the Seedling Growth of an Oleaginous Species from the Amazon: Andiroba (Carapa Procera Aubl.)
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Determinantes físicos e ecológicos que afetam as assembleias de aves no sudeste da Amazônia: o papel da história na distribuição das espécies
Get PDFAmazonian rivers have been proposed to act as geographic barriers to species dispersal, either driving allopatric speciation or defining current distribution limits. The strength of the barrier varies according to the species ecological characteristics and the river physical properties. Environmental heterogeneity may also drive compositional changes, but have hardly been assessed in Amazonia. Aiming to understand the contributions of riverine barriers and environmental heterogeneity in shaping compositional changes in Amazonian forest bird assemblages, we focus on the Tapajós River. We investigate how spatial variation in species composition is related to physical barriers (Tapajós and Jamanxim rivers), ecological characteristics of the species (distinct guilds) and environmental heterogeneity (canopy reflectance, soils and elevation). We sampled birds through point counts and mist nets on both sides of the Tapajós and Jamanxim rivers. To test for relationships between bird composition and environmental data, we used Mantel and partial Mantel tests, NMDS and ANOVA + Tukey HSD. The Mantel tests showed that the clearest compositional changes occurred across the Tapajós River, which seems to act unequally as a significant barrier to the bird guilds. The Jamanxim River was not associated with differences in bird communities. Our results reinforce that the Tapajós River is a biogeographical boundary for birds, but environmental heterogeneity determines compositional variation within interfluves. These results contrast with diversity patterns described for other vertebrates, suggesting that upland forest birds singularly respond to large rivers as barriers in Amazonia, leading to erroneous extrapolations for interpreting biogeographic results for other Amazonian organisms.Amazonian rivers have been proposed to act as geographic barriers to species dispersal, either driving allopatric speciation or defining current distribution limits. The strength of the barrier varies according to the species ecological characteristics and the river physical properties. Environmental heterogeneity may also drive compositional changes, but have hardly been assessed in Amazonia. Aiming to understand the contributions of riverine barriers and environmental heterogeneity in shaping compositional changes in Amazonian forest bird assemblages, we focus on the Tapajós River. We investigate how spatial variation in species composition is related to physical barriers (Tapajós and Jamanxim rivers), ecological characteristics of the species (distinct guilds) and environmental heterogeneity (canopy reflectance, soils and elevation). We sampled birds through point counts and mist nets on both sides of the Tapajós and Jamanxim rivers. To test for relationships between bird composition and environmental data, we used Mantel and partial Mantel tests, NMDS and ANOVA + Tukey HSD. The Mantel tests showed that the clearest compositional changes occurred across the Tapajós River, which seems to act unequally as a significant barrier to the bird guilds. The Jamanxim River was not associated with differences in bird communities. Our results reinforce that the Tapajós River is a biogeographical boundary for birds, but environmental heterogeneity determines compositional variation within interfluves. These results contrast with diversity patterns described for other vertebrates, suggesting that upland forest birds singularly respond to large rivers as barriers in Amazonia, leading to erroneous extrapolations for interpreting biogeographic results for other Amazonian organisms
Chemical compositions of essential oil of piper species from atlantic forest of Amazonia, Brazil
Get PDFEssential oils from the leaves of Piper japurense (Miq.) C. DC., P. coariense Yunk., P. auriculifolium Yunk., P. curtistilum C.DC., P. alatipetiolatum Yunk. and P. brevesanum Yunk. from the Amazon Forest (Brazil) were obtained through hydrodistillation. The chemical composition of the oils was determined using gas chromatography and mass spectrometry, which revealed the presence of 108 compounds representing 95.14%, 95.64%, 95.57%, 92.05%, 96.24% and 91.316% of the oils, respectively. All oils had an abundance of sesquiterpenes, except the oil from P. alatipetiolatum, which had a higher percentage of monoterpenes. The major components were α-eudesmol in the P. japurense (22.05%) and P. coariense (27.33%) oils, premnaspirodiene (32.26%) in the P. auriculifolium oil, caryophyllene oxide (28.69%) in the P. curtistilum oil, linalool (43.88%) in the P. alatipetiolatum oil and β-elemene (12.75%) in the P. brevesanum oil. Although the oils were composed of terpenes, the chemical analysis revealed qualitative and quantitative differences. This is the first report of the chemical composition of these six species of Piper that occur in the Amazonia biome in Brazil. © 2019 ACG Publications. All rights reserved
Cranial morphology and osteology of the sexually dimorphic electric fish, compsaraia samueli albert & crampton (apteronotidae, gymnotiformes), with comparisons to C. Compsa (Mago-Leccia)
No full textSexual dimorphism of the snout has evolved independently in at least four separate clades of the gymnotiform family Apteronotidae. This phenomenon may help identify sex, except in the absence of mature individuals, and has led to confused taxonomy for several species. We examined a large collection of Compsaraia samueli collected during the breeding season from a remote stream in the Rio Negro drainage. This collection contains a wide range of sizes of both sexes, but most individuals were easily identified as mature. To quantify the sexual dimorphism of these specimens, 15 measurements were taken from the head and the body. In addition, some specimens were cleared-and-stained to study cranial osteology. We found that long-snouted males of C. samueli span a wide range of body sizes. As the snout length increases the distance between the eye and the occiput does not increase at the same rate, suggesting that it is only the anterior portion of the head that has an increased allometry. Skeletal anatomy differs between the sexes in that the lower jaw is more triangular in females and more linear in males. The coronomeckelian is small and round in females in contrast to being longer and pointed in males. There is strong interlacing of the dentary and anguloarticular bones in males, whereas this contact is not as extensive in females. We also discuss the implications of sexual dimorphism for identification of this species relative to its congener (C. compsa), and for the evolution of sexual dimorphism in the family. Copyright © 2019 Magnolia Press
Estudo taxonômico de Achilixiidae Muir, 1923 (Hemiptera: Auchenorrhyncha: Fulgoroidea) no Brasil
Get PDFAchilixiidae is a small family including 24 species distributed into two genera: Achilixius Muir, 1923 (16 species) from Oriental region and Bebaiotes Muir, 1924 (8 species) from the Neotropical region. Bebaiotes is distinguished from Achilixius by the frons lacking the median carina, vein R without ramification close to the anterior margin, veins CuA1 and CuA2 not fused close to the posterior margin, and a pair of lateral abdominal processes forming three pits. None species of Achilixiidae has been registered for Brazil so far, with only Bebaiotes registered for Panama, Ecuador, and Guiana in the Neotropics. The material studied was obtained from national zoological collections and photos were provided by some foreign collections. An identification key, maps with geographical records, descriptions, and redescriptions of the species were provided. Four new species were revised and their distribution widen: Bebaiotes banksi (Metcalf, 1938) (Brazil - Amazonas and Pará; Panama); Bebaiotes dorsivittata Fennah, 1947 (Brazil - Amapá, Amazonas, Pará, Rondônia and Roraima; Ecuador; Peru; Bebaiotes guianesus (Fennah, 1947) (Brazil - Amazonas; Guiana); Bebaiotes pulla Muir, 1934 (Brazil - Acre and Amazonas; Ecuador) and it have been added eight new species for the genus for Brazil: Bebaiotes amazonica sp. nov. (Amazonas, Pará, Rondônia and Roraima); Bebaiotes bia sp. nov. (Acre); Bebaiotes dichromata sp. nov. (Amazonas); Bebaiotes macroptera sp. nov. (Amazonas and Amapá); Bebaiotes parallela sp. nov. (Amazonas); Bebaiotes pennyi sp. nov. (Amazonas and Maranhão); Bebaiotes tigrina sp. nov. (Amazonas); Bebaiotes wilsoni sp. nov. (Amazonas). The distribution of the family and genus were expanded for Brazil, being centered in Northern and Northeastern regions.Achilixiidae é uma família com 24 espécies divididas em dois gêneros: Achilixius Muir, 1923 (16 espécies) da região Oriental e Bebaiotes Muir, 1924 (8 espécies) da região Neotropical. Bebaiotes é distinto de Achilixius por possuir fronte sem carena mediana, asa anterior com veia R sem ramificação próxima a margem anterior, veias CuA1 e CuA2 não fusionadas próximo a margem posterior e um par de processos na lateral do abdômen formando três fossas. Até o momento nenhuma espécie de Achilixiidae tinha sido registrada para o Brasil, havendo registro apenas do gênero Bebaiotes para o Panamá, Equador e Guiana no neotrópico. O material estudado foi obtido a partir de coleções zoológicas nacionais e fotografias fornecidas por algumas coleções estrangeiras. Chave de identificação, mapas com registros geográficos, descrições e redescrições de espécies foram fornecidas. Quatro espécies foram revisadas e suas distribuições foram ampliadas: Bebaiotes banksi (Metcalf, 1938) (Brasil - Amazonas e Pará; Panamá – Barro Colorado); Bebaiotes dorsivittata Fennah, 1947 (Brasil - Amapá, Amazonas, Pará, Rondônia e Roraima; Equador - Feltons; Peru - Madre de Dios); Bebaiotes guianesus (Fennah, 1947) (Brasil - Amazonas; Guiana - New River); Bebaiotes pulla Muir, 1934 (Brasil – Acre e Amazonas; Equador - Feltons) e foram acrescentadas oito espécies novas ao gênero para o Brasil: Bebaiotes amazonica sp. nov. (Amazonas, Pará, Rondônia e Roraima); Bebaiotes bia sp. nov. (Acre); Bebaiotes dichromata sp. nov. (Amazonas); Bebaiotes macroptera sp. nov. (Amazonas e Amapá); Bebaiotes parallela sp. nov. (Amazonas); Bebaiotes pennyi sp. nov. (Amazonas e Maranhão); Bebaiotes tigrina sp. nov. (Amazonas); Bebaiotes wilsoni sp. nov. (Amazonas). A distribuição da família e do gênero foi ampliada para o Brasil, sendo concentrada na região Norte e Nordeste
