Navegando por Orientadores "ALEIXO, Alexandre Luis Padovan"

Agora exibindo 1 - 13 de 13

Acesso aberto (Open Access)
Filogeografia comparada de aves com distribuição trans-amazônica e trans-andina
(Universidade Federal do Pará, 2015-05-28) MIRANDA, Leonardo de Sousa; ALEIXO, Alexandre Luis Padovan; http://lattes.cnpq.br/3661799396744570
Acesso aberto (Open Access)
Filogeografia de Phaethornis bourcieri (Aves:Trochilidae): implicações taxonômicas e biogeográficas
(Universidade Federal do Pará, 2012) SILVA, Lucas Eduardo Araújo; ALEIXO, Alexandre Luis Padovan; http://lattes.cnpq.br/3661799396744570
The Straight-billed Hermit Phaethornis bourcieri inhabits the understory of upland terra-firme forest, being distributed through most of the Amazon. Currently, two allopatric taxa considered valid and, regarded as subspecies, are included in P. bourcieri: P. b. bourcieri and P. b. major. Nonetheless, these taxa have their validity, inter-specific limits, and evolutionary history not fully elucidated. Here, we used morphological and molecular characters to review the taxonomy and propose a phylogenetic hypothesis for populations and taxa grouped under Phaethornis bourcieri. Our results showed that P. bourcieri is part of the straight-billed Hermit clade, along with P. philippii and P. koepckeae, and that the subspecies major is closer to the latter two species rather than populations grouped under nominate bourcieri. Our phylogenetic hypotheses recovered three main reciprocally monophyletic clades under nominate bourcieri separated by the Negro and Solimões rivers. These clades (along with the distantly related major) are best treated as valid phylogenetic and biological species, for which only three valid names are applicable. The diversification of the straight-billed Hermit clade (P. bourcieri, P. philippii, and P. koepckeae) is centered in the Amazon and appears to be tightly linked with the formation of the modern Amazon drainage during the Plio-Pleistocene.
Acesso aberto (Open Access)
Filogeografia de três espécies de Passeiriformes (Suboscines) na região do Baixo Tocantins - Ilha do Marajó - Pará
(Universidade Federal do Pará, 2008) FACCIO, Maya Sonnenschein; ALEIXO, Alexandre Luis Padovan; http://lattes.cnpq.br/3661799396744570
The area of the lower Tocantins river - Marajó Island is an excellent place to carry out a study integrating geological and biological data to understand processes responsible for the diversification of species in the Amazon. Population genetics and phylogenetic analyses of populations of three selected bird species (Xiphorhynchus spixii and Glyphorynchus spirurus - Dendrocolaptidae and Willisornis poecilinotus - Thamnophilidae) were carried out employing the mitochondrial gene ND2, and related to the geological scenario proposed for the landscape evolution in the area. Estimates based on maximum likelihood and Bayesian inference where used to infer intraespecific phylogenies and haplotype networks, in addition to tests for deviation of neutrality R2, AMOVA, F ST e Nm, which were employed in population genetic analyses of the three selected species. Xiphorhynchus spixii showed no phylogeographic structure and high levels of gene flow among all populations analyzed. The phylogenetic trees recovered for G. spirurus populations presented one group of haplotypes endemic to the Marajó Island (IM) sister to a second group with the remaining haplotypes belonging to all three areas analyzed; these topologies imply an apparent secondary contact between isolated endemic populations of IM with those of the continent. The tree obtained for W. poecilinotus was similar to that of G. spirurus, indicating that the formation of IM might have affected in a similar way populations of those two species sharing similar dispersion abilities. On the other hand, the lack of phylogeographic structure detected for X.spixii might have been caused by a higher dispersal capacity, thus leading to a different response to the same set of vicariant events. Molecular clock estimates for the node separating haplotypes endemic to IM from those found in ali three areas were 747.000 years BP in G. spirurus and 798.000 years BP in W. poecilinotus thus older than the estimated separation of the IM from the continent (near 10.000 years BP) based on geological data.
Acesso aberto (Open Access)
Filogeografia e limites inter-específicos em Dendrocolaptes certhia (Aves:Dendrocolaptidae)
(Universidade Federal do Pará, 2012) BATISTA, Romina do Socorro da Silva; ALEIXO, Alexandre Luis Padovan; http://lattes.cnpq.br/3661799396744570
The systematics of the polytypic species Dendrocolaptes certhia (Aves: Dendrocolaptidae) has been studied so far only through morphological characters, which have been unable to resolve relationships and provide consistent diagnoses for many described taxa grouped under this species. Molecular characters thus become a potential tool to provide a higher degree of resolution concerning the evolutionary history of this polytypic species. We used a multilocus database combining two mitochondrial and three nuclear genes from different loci, which was analyzed with different approaches (Bayesian, coalescent, and population genetics), to propose the first phylogeographic hypothesis for this polytypic species. The molecular data indicate that traditional taxonomy contrasts strongly with the evolutionary history of Dendrocolaptes certhia, with the recognition of seven diagnosable independent species rather than a single polytypic species. These seven species are distributed coincidentally with the main areas of endemism in the Amazon, and their diversification appears to be strongly correlated with the formation of the modern Amazonian drainage during Plio-Pleistocene times.
Acesso aberto (Open Access)
Revisão sistemática e biogeografia da espécie politípica campylorhamphus procurvoides
(Universidade Federal do Pará, 2007-11-10) PORTES, Carlos Eduardo Bustamante; ALEIXO, Alexandre Luis Padovan; http://lattes.cnpq.br/3661799396744570
The latest review of the genus Campylorhamphus (which dates back to 1934 by Zimmer), recognized the polytypic species C. procurvoides as grouping the following taxa whose reciprocal diagnosis is difficult and based mostly on plumage characters: C. p. procurvoides, C. p multostriatus, C. p. probatus, C. p. sanus e C. p. successor. The goal of this study is to review the systematics of the polytypic C. procurvoides through the critical evolution of the geographic variation and diagnosis of its taxa based on a combined analysis of morphological and molecular characters. All molecular phylogeny estimates produced showed with strong statistical support that C. procurvoides, as currently defined, represents a polyphyletic species since its taxa are found in three separate clades with disparate phylogenetic affinities within the genus Campylorhamphus. The combined analysis of molecular and morphological characters allowed objective diagnoses for the taxa procurvoides, multostriatus, probatus and sanus, but not successor, which was synonymzed with a taxon grouped under a different polytypic species (C. trochilirostris notabilis); the combined analysis further supported the recognition of two additional taxa not previously recognized, which are treated here as taxon novum 1 and taxon novum 2. Based on their phylogenetic relationship and consistent reciprocal diagnoses, each taxa considered valid according to the present review and formerly treated as subspecies of C. procurvoides, are recognized as species based on the General Lineage Species Concept.
Acesso aberto (Open Access)
Revisão sistemática e filogeografia de Deconychura longicauda (Aves - Dendrocolaptidae)
(Universidade Federal do Pará, 2010) BARBOSA, Ivã; ALEIXO, Alexandre Luis Padovan; http://lattes.cnpq.br/3661799396744570
The interspecific limits of the polytypic specie Deconychura longicauda (Dendrocolaptidae) were investigated by a combined analysis including molecular, morphological, and vocal characters. A total of 1,108 base pairs of mitochondrial genes Cyt b and ND2 were used to build phylogenetic hypotheses, whereas the morphological and vocal characters were analyzed with univariate and multivariate statistical methods. All recovered trees indicated high levels of genetic differentiation and phylogeographic structure in Deconychura longicauda, with the recognition of four major groups well-supported statistically and geographically consisting of birds from (1) the Guiana area of endemism in northeastern South America, (2) the Amazon basin excluding the Guianan shield, (3) the eastern slope of the Andes and (4) trans-Andean South America and Central America. The levels of genetic divergence between these clades reach 6-8% (among birds from Guianan, non-Guianan, eastern slope of the Andes and, trans-Andean birds). Although morphological characters contribute little to the diagnoses among Deconychura, loudsongs, consistently distinguish them. Based on those analyzes, we recommend the splitting of D. longicauda into the following phylogenetic and biological species based on their molecular and vocal unequivocal diagnoses: Deconychura longicauda, D. pallida, D. zimmeri, D. connectens, D. typica and one yet unnamed taxon endemic to the eastern slope of the Andes.
Acesso aberto (Open Access)
Sistemática e diversificação dos gêneros Hylopezus e Myrmothera (Aves:Grallariidae)
(Universidade Federal do Pará, 2015-03-31) CARNEIRO, Lincoln Silva; ALEIXO, Alexandre Luis Padovan; http://lattes.cnpq.br/3661799396744570
Acesso aberto (Open Access)
Sistemática molecular e filogeografia do gênero Phoenicircus Swainson, 1832 (Aves: Cotingidae)
(Universidade Federal do Pará, 2012) MARTINS, Denise Mendes; ALEIXO, Alexandre Luis Padovan; http://lattes.cnpq.br/3661799396744570
Many hypotheses have been erected to attempt to explain the origin and maintenance of the Amazon‟s high biodiversity, although few can been tested under a phylogeographic approach. We evaluated patterns of temporal and spatial genetic diversity of two endemic bird species in the Brazilian Amazon, which have allopatric populations restricted to different areas of endemism and limited by the main rivers of the Amazon basin. Sequences of two mitochondrial genes (ND2 and cytb) and two nuclear (βf7 and G3PDH intron 11) were obtained from 30 individuals, throughout the range of the genus Phoenicircus comprising the two currently-recognised species P. carnifex and P. nigricollis. The use of phylogeographic tools, in combination with population genetics and molecular dating allowed us to reconstruct the spatial and temporal context of the diversification of this genus in the Amazon region, as well as make predictions about its evolutionary history and geographical environment. Our data revealed the existence of four genetically distinct groups, demonstrating the paraphyletic status of P. carnifex and reciprocal monophyly between the two allopatric populations of P. nigricollis. These discoveries necessitate a revision of the current two-species arrangement of the genus Phoenicircus. The group‟s evolutionary history is defined by two types of vicariant events, initially by the formation of the main rivers of the Amazon during the Plio-Pleistocene, and more recently as a result of neotectonics activity in the central Amazon, highlighting the importance of historical processes when modeling the present Amazonian biota.
Acesso aberto (Open Access)
Sistemática molecular e implicações para a conservação de uma linhagem endêmica da Amazônia: o gênero Hylexetastes Sclater, 1889 (Aves: Dendrocolaptidae)
(Universidade Federal do Pará, 2017-03-07) RODRIGUEZ, Roxiris Auxiliadora Azuaje; SILVA, Sofia Alexandra Marques; http://lattes.cnpq.br/0062405368911898; ALEIXO, Alexandre Luis Padovan; http://lattes.cnpq.br/3661799396744570
The genus Hylexetastes is endemic to the Amazon rainforest. Currently, two species are accepted in the genus (H. perrotti and H. stresemannii), each one divided into three subspecies. Nevertheless, some authors defend that the subspecies of H. perrotti should be considered as full species. In particular, H. p. brigidai is an endemic taxon from Pará and Mato Grosso and seems to have the smallest distribution area. This lineage is distributed by the most deforested region within the biome and thus its taxonomic status is of particular concern for conservation. So far, only morphological characters have been evaluated for taxonomic definition of this genus. Therefore, in this study we present a molecular phylogenetic hypothesis to help solve the taxonomic uncertainties within the genus. Fragments of two mitochondrial markers (Cytb and ND2) and three nuclear markers (BF5, G3PDH and MUSK) were sequenced on 58 Hylexetastes specimens. In addition, ecological niche modeling was developed for each of the identified strains to evaluate their potential distribution area, climatic requirements and their vulnerability to deforestation. The phylogenetic analyzes support the designation of H. perrotti, H. uniformis and H. brigidai as full species, and H. perrotti seems to be a sister species of H. stresemanni and not of the other taxa considered co-specific. In addition, it was possible to distinguish the presence of two Significant Evolutionary Units within H. uniformis. Each of these taxa are distributed in different interfluvial / endemic areas of the Amazon basin. In particular, it confirms the status of full species for H. brigidai, endemic to the second area of Amazonian endemism with greater deforestation. Thus, we suggest the continued in-depth evaluation of its conservation status to promote its preservation.
Acesso aberto (Open Access)
Sistemática molecular, biogeografia e taxonomia do gênero Megascops kaup, 1848 (Aves, Strigidae)
(Universidade Federal do Pará, 2013-06-28) DANTAS, Sidnei de Melo; ALEIXO, Alexandre Luis Padovan; http://lattes.cnpq.br/3661799396744570
Acesso aberto (Open Access)
Sistemática, filogenia e biogeografia do gênero Campylorhamphus (Aves: Dendrocolaptidae)
(Universidade Federal do Pará, 2014) PORTES, Carlos Eduardo Bustamante; ALEIXO, Alexandre Luis Padovan; http://lattes.cnpq.br/3661799396744570
Acesso aberto (Open Access)
Variação morfológica, vocal e genética na espécie politípica Lepidocolaptes albolineatus (Aves – Dendrocolaptidae)
(Universidade Federal do Pará, 2008) RODRIGUES, Elinete Batista; ALEIXO, Alexandre Luis Padovan; http://lattes.cnpq.br/3661799396744570
Lepidocolaptes albolineatus (Aves: Dendrocolaptidae) is a polytypic biological species including the following taxa: L. a. albolineatus occurring in the Guiana Area of Endemism (hereafter AE), L. a. duidae (Imeri AE), L. a. fuscicapillus and L. a. madeirae (both in the Rondônia AE), and L. a. layardi (Tapajós, Xingu, and Belém AEs). The main goals of the present study were: (1) review the validity and diagnoses of the taxa grouped under L. albolineatus based on a combination of morphological, vocal, and molecular characters, and (2) re-evaluate inter-specific limits between among those taxa. A total of 150 specimens deposited in Brazilian and North American collections were measured. In the molecular analysis a total of 940 bp of the mitochondrial gene ND2 belonging to 35 individuals representing all taxa of L. albolineatus was sequenced. PAUP 4.0 b 10 and MrBayes 3.1 were used to generate phylogenetic trees under parsimony, maximum likelihood, and Bayesian approaches. Morphological and molecular data strongly supported the existence of five natural populations (clades) within L. albolineatus: clade 1 (grouping populations from the Rondônia AE), clade 2 (including populations of the Belém, Xingu, and Tapajós AEs), clade 3 (including specimens from the Inambari AE), clade 4 (grouping specimens from the Imeri AE), and clade 5 (including specimens of the Guiana AE). All clades corresponded to already named taxa, except clade 3, which has no valid name yet since the name fuscicapillus is in fact applicable to clade 1, and therefore must be considered the senior synonymous of madeirae. The main genetic and morphological separation in L. albolineatus occurs between the nominate taxon (clade 5) and all remaining taxa and clades, although each clade recognized in the analysis can be regarded as a separate species under the General Lineage Species Concept, since they are all mutually diagnosed based on a combination of morphological, vocal, and genetic characters.
Acesso aberto (Open Access)
Variação morfológica, vocal e molecular em Hylopezus macularius (Temminck, 1830) (Aves, Grallariidae)
(Universidade Federal do Pará, 2009) CARNEIRO, Lincoln Silva; GONZAGA, Luiz Antonio Pedreira; http://lattes.cnpq.br/7163872808115319; ALEIXO, Alexandre Luis Padovan; http://lattes.cnpq.br/3661799396744570
A systematic revision of the polytypic Spotted Antpitta (Hylopezus macularius, Grallariidae) based on morphometric, plumage, vocal, and molecular characters is presented. Morphological and vocal analyses were based, respectively, on 45 specimens and 104 recordings. Molecular phylogenies were inferred based on ca. 1.371 bp of the mitochondrial DNA genes 16S, ND2, and cyt b belonging to 26 specimens, including several outgroups. Our results revealed the existence of an undescribed taxon endemic to the Madeira – Xingu interfluve, cryptically similar in morphology to paraensis, but vocally and genetically readily distinguished from the latter and any other taxon grouped under H. macularius. Molecular trees obtained recovered with strong support the reciprocal monophyly among four main lineages of the Spotted Antpitta, three corresponding to already named taxa (dilutus, macularius, and paraensis), and one to the unnamed taxon, which is described herein. We show that those four taxa are also mutually diagnosed by a combination of both vocal and morphological features, and therefore recommend treating them as separate species. Dating of the molecular trees indicated that splits among species of the Spotted Antpitta complex took place between 2.92 and 0.78 mya, with the older splits concentrated in northwestern Amazonia (across the Negro and upper Amazon rivers) and the most recent ones in the southeastern part of the basin (across the Xingu river).