7 resultados para molecular systematics

em Biblioteca Digital da Produção Intelectual da Universidade de São Paulo (BDPI/USP)


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Two new species of Gracilariopsis from the Indian Ocean are proposed-Gracilariopsis (Gp.) mclachlanii Buriyo, Bellorin et M. C. Oliveira sp. nov. from Tanzania and Gracilariopsis persica Bellorin, Sohrabipour et E. C. Oliveira sp. nov. from Iran-based on morphology and DNA sequence data (rbcL gene and SSU rDNA). Both species fit the typical features of Gracilariopsis: axes cylindrical throughout, freely and loosely ramified up to four orders, with an abrupt transition in cell size from medulla to cortex, cystocarps lacking tubular nutritive cells and superficial spermatangia. Nucleotide sequence comparisons of rbcL and SSU rDNA placed both species into the Gracilariopsis clade as distinct species from all the accepted species for this genus, forming a deeply divergent lineage together with some species from the Pacific. The new species are very difficult to distinguish on morphological grounds from other species of Gracilariopsis, stressing the importance of homologous molecular marker comparisons for the species recognition in this character-poor genus.

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Aim We present a molecular phylogenetic analysis of Brotogeris (Psittacidae) using several distinct and complementary approaches: we test the monophyly of the genus, delineate the basal taxa within it, uncover their phylogenetic relationships, and finally, based on these results, we perform temporal and spatial comparative analyses to help elucidate the historical biogeography of the Neotropical region. Location Neotropical lowlands, including dry and humid forests. Methods Phylogenetic relationships within Brotogeris were investigated using the complete sequences of the mitochondrial genes cyt b and ND2, and partial sequences of the nuclear intron 7 of the gene for Beta Fibrinogen for all eight species and 12 of the 17 taxa recognized within the genus (total of 63 individuals). In order to delinetae the basal taxa within the genus we used both molecular and plumage variation, the latter being based on the examination of 597 skin specimens. Dates of divergence and confidence intervals were estimated using penalized likelihood. Spatial and temporal comparative analyses were performed including several closely related parrot genera. Results Brotogeris was found to be a monophyletic genus, sister to Myiopsitta. The phylogenetic analyses recovered eight well-supported clades representing the recognized biological species. Although some described subspecies are diagnosably distinct based on morphology, there was generally little intraspecific mtDNA variation. The Amazonian species had different phylogenetic affinities and did not group in a monophyletic clade. Brotogeris diversification took place during the last 6 Myr, the same time-frame as previously found for Pionus and Pyrilia. Main conclusions The biogeographical history of Brotogeris implies a dynamic history for South American biomes since the Pliocene. It corroborates the idea that the geological evolution of Amazonia has been important in shaping its biodiversity, argues against the idea that the region has been environmentally stable during the Quaternary, and suggests dynamic interactions between wet and dry forest habitats in South America, with representatives of the Amazonian biota having several independent close relationships with taxa endemic to other biomes.

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The generic identity of Odontophrynus moratoi is controversial since the original description due to the presence of intermediate morphological features between the genera Odontophrynus and Proceratophrys. Herein we performed molecular analyses of three genes (16S, cyt b and Rag-1) and recovered O. moratoi deeply imbedded inside a clade containing only Proceratophrys species, appearing as the sister group of Proceratophrys concavitympanum. Therefore, this study formally transfers the species O. moratoi to the genus Proceratophrys [Proceratophrys moratoi (Jim & Caramaschi 1980) comb. nov].

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Parsimony-based phylogenetic analyses of the neotropical tribe Helieae (Gentianaceae) are presented, including 22 of the 23 genera and 60 species. This study is based on data from morphology, palynology, and seed micromorphology (127 structural characters), and DNA sequences (matK, trnL intron, ITS). Phylogenetic reconstructions based on ITS and morphology provided the greatest resolution, morphological data further helping to tentatively place several taxa for which DNA was not available (Celiantha, Lagenanthus, Rogersonanthus, Roraimaea, Senaea, Sipapoantha, Zonanthus). Celiantha, Prepusa and Senaea together appear as the sister clade to the rest of Helieae. The remainder of Helieae is largely divided into two large subclades, the Macrocarpaea subclade and the Symbolanthus subclade. The first subclade includes Macrocarpaea, sister to Chorisepalum, Tochia, and Zonanthus. Irlbachia and Neblinantha are placed as sisters to the Symbolanthus subclade, which includes Aripuana, Calolisianthus, Chelonanthus, Helia, Lagenanthus, Lehmanniella, Purdieanthus, Rogersonanthus, Roraimaea, Sipapoantha, and symbolanthus. Generic-level polyphyly is detected in Chelonanthus and Irlbachia. Evolution of morphological characters is discussed, and new pollen and seed characters are evaluated for the first time in a combined morphological-molecular phylogenetic analysis.

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Most Neotropical lowland forest taxa occur exclusively on one side of the Andes despite the availability of appropriate habitat on both sides. Almost all molecular phylogenies and phylogenetic analyses of species assemblages (i.e. area cladograms) have supported the hypothesis that Andean uplift during the Late Pliocene created a vicariant barrier affecting lowland lineages in the region. However, a few widespread plant and animal species occurring in lowland forests on both sides of the Andes challenge the generality of this hypothesis. To understand the role of the Andes in the history of such organisms, we reconstructed the phylogeographic history of a widespread Neotropical flycatcher (Mionectes oleagineus) in the context of the other four species in the genus. A molecular phylogeny based on nuclear and mitochondrial sequences unambiguously showed an early basal split between montane and lowland Mionectes. The phylogeographic reconstruction of lowland taxa revealed a complex history, with multiple cases in which geographically proximate populations do not represent sister lineages. Specifically, three populations of M. oleagineus west of the Andes do not comprise a monophyletic clade; instead, each represents an independent lineage with origins east of the Andes. Divergence time estimates suggest that at least two cross-Andean dispersal events post-date Andean uplift.

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Morphological and molecular studies were carried out on Palisada papillosa and P. perforata from the Canary Islands (type locality of P. perforata), Mexico and Brazil. The two species have been distinguished by features of their external morphology such as size and degree of compactness of the thalli, presence or absence of arcuate branches, branching pattern and basal system. A detailed morphological comparison between these taxa showed that none of the vegetative anatomical or reproductive characters was sufficient to separate these species. The presence or absence of cortical cells in a palisade-like arrangement, also previously used to. distinguish these species, is not applicable. The species present all characters typical of the genus, and both share production of the first pericentral cell underneath the basal cell of the trichoblast, production of two fertile pericentral cells (the second and the third additional, the first remaining sterile), spermatangial branches produced from one of two laterals on the suprabasal cell of trichoblasts, and the procarpbearing segment with four pericentral cells. Details of the procarp are described for the species for the first time. The phylogenetic position of these species was inferred by analysis of the chloroplast-encoded rbcL gene sequences from 39 taxa, using one other Rhodomelacean taxon and two Ceramiaceae as outgroups. Relationships within the clade formed by P. papillosa and P. perforata have not been resolved due to the low level of genetic variation in their rbcL sequences (0-0.4%). Considering this and the morphological similarities, we conclude that P. papillosa is a taxonomic synonym of P. perforata. The phylogenetic analyses also supported the nomenclatural transfer of two species of Chondrophycus to Palisada, namely, P. patentiramea (Montagne) Cassano, Senties, Gil-Rodriguez & M.T. Fujii comb. nov. and P. thuyoides (Kutzing) Cassano, Senties, Gil-Rodriguez & M.T. Fujii comb. nov.

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Croton laceratoglandulosus, a new species from the dry forests of the Brazilian states of Piaui, Ceara, Bahia and Minas Gerais, and the Bolivian department of Santa Cruz, is described and illustrated here. Molecular sequence data demonstrate that it is most closely related to the taxa of Croton section Cascarilla, and not to sections Medea or Barhamia, which also have glandular calyces and laciniate stipules. (C) 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158, 493-498.