105 resultados para On the Origin of Species


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Tontelea fuliginea differs from other species whose stamens alternate with undivided stigma-lobes by its profusely ramified, many flowered, and densely dirty-brown puberulous inflorescences. This paper also provides a synopsis and key of the group of species with alternate stamens and 3-lobed stiomas with undivided lobes (T. attenuata group). Four lectotypes are designated for previously published names: Tontelea longifolia, Tontelea micrantha, Tontelea corrugulata, and Salacia micrantha var. lancifolia.

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Ten species of Hyla with 2n = 30 from Brazilian fauna were analysed cytogenetically. Hyla minuta is the unique presenting all bi-armed metacentric or submetacentric chromosomes in the karyotype, therefore, with the highest FN = 60. The remaining species have a variable number of uni-armed telocentric or subtelo-centric chromosomes: H. cruzi, H. elianeae, and H. rubicundula with three pairs (FN = 54), H. berthalutzae, H. elegans, H. microps, and H. nana with four pairs (FN = 52), and H. nahdereri and H. sanborni with five pairs (FN = 50). The uni-armed elements are among pairs 5, 6, 7, 11, 14, and 15, which also appeared with metacentric or submetacentric morphology. The remaining chromosome pairs 1, 2, 3, 4, 8, 9,10, 12, and 13 were never found to be telocentric or subtelocentric. AgNOR patterns are species-specific, the majority of the species exhibiting a single pair with AgNORs, with the exception of H. elegans and H. nana with more than one chromosome pair bearing this cytological marker. C banding was obtained in H. berthalutzae, H. cruzi, H. elegans, H. elianeae, H. microps, H. minuta, H. nahdereri, and H. nana, which showed positively stained centromeric heterochromatin. Our analysis confirms the great karyotypic diversity in the species of Hyla with 2n = 30, with no species sharing identical karyotypes.

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We review the information currently available on the reproduction of the Amphisbaenia and provide original data on the reproductive biology of four Neotropical species: Amphisbaena alba; A. mertensi; Cercolophia roberti, and Leposternon infraorbitale. In total, we compiled data for 22 species: 17 Amphisbaenidae, 1 Rhineuridae, 3 Bipedidae, and 1 Trogonophidae. The majority of the species were oviparous with the exceptions of Loveridgea ionidesii, Monopeltis anchietae, M. capensis, and Trogonophis wiegmanni. Viviparity was interpreted as a derived trait that evolved independently for at least 3 times within the Amphisbaenia. In most species, reproduction is synchronized with the hot and rainy season and seems to vary with latitude. Although Amphisbaenia eggs have been found in ant nests, it remains disputable whether this is an obligatory or even a preferable location for egg-laying. Incubation time in A. mertensii lasts 59 days and this is the first report encompassing egg-laying to hatching for any Amphisbaenia species. Nonetheless, a two months incubation period seems to be the common rule for oviparous Amphisbaenia. The general pattern of reproductive output in Amphisbaenia is characterized by a low number of eggs/embryos per clutch whose individual size is comparatively large in relation to adult body size. Eggs are markedly elongated on the long axis and arranged in-line within the abdominal cavity possibly to prevent/diminish biomechanic drawbacks of egg bearing. Hatchlings of A. mertensi possess an egg-tooth implanted at the upper jaw, exhibit positive geotropism, and display defensive behaviors known to be present in adults. Our review shows that our current knowledge of Amphisbaenia reproduction is fragmentary, often based on the examination of small samples, and heavily dependent on the publication of anedoctal observations. Future publications on this subject are encouraged.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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A molecular phylogenetic analysis of the Hyla pulchella species group was performed to test its monophyly, explore the interrelationships of its species, and evaluate the validity of the taxa that were considered subspecies of H. pulchella. Approximately 2.8 kb from the mitochondrial genes 12s, tRNA valine, 16s, and Cytochrome b were sequenced. The analysis included 50 terminals representing 10 of the 14-15 species currently recognized in the H. pulchella group, including samples from several localities for some taxa, several outgroups, as well as two species previously suspected to be related with the group (Hyla guentheri and Hyla hischoffi). The results show that the H. pulchella and Hyla circumdata groups are distantly related, and, therefore, should be recognized as separate groups. As currently defined, the H. pulchella group is paraphyletic with respect to the Hyla polytaenia group; therefore, we recognize the Hyla polytaenia clade in the H. pulchella group. Two subspecies of H. pulchella recognized by some authors are considered full species including Hyla pulchella riojana because it is only distantly related to H. pulchella, and Hyla pulchella cordobae because molecular and non-molecular evidence suggests that it is specifically distinct. With the inclusion of the H. polytaenia clade, H. guentheri, and H. bischoffi, and the recognition of the two former subspecies of H. pulchella as distinct species, the H. pulchella group now comprises 25 described species. All representatives of the H. pulchella group with an Andean distribution are monophyletic and nested within a clade from the Atlantic forest from south-southeastern Brazil/northeastern Argentina, and Cerrado gallery forest from central Brazil. (C) 2004 Elsevier B.V. All rights reserved.

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Transposable elements are major components of plant genomes and they influence their evolution, acting as recombination hot spots, acquiring specific cell functions or becoming part of protein-coding regions. The latter is the subject of the present analysis. This study is a report on the annotation of transposable elements (TEs) in expressed sequences of Coffea arabica, Coffea canephora and Coffea racemosa, showing the occurrence of 383 ESTs and 142 unigenes with TE fragments in these three Coffea species. Based on selected unigenes, it was possible to suggest 26 putative proteins with TE-cassette insertions, demonstrating a likely contribution to protein variability. The genes for two of those proteins, the fertility restorer (FR) and the pyrophosphate-dependent phosphofructokinase (PPi-PFKs) genes, were selected for evaluating the impact of TE-cassettes on host gene evolution of other plant genomes (Arabidopsis thaliana, Oryza sativa and populus trichocarpa). This survey allowed identifying a FR gene in O. sativa harboring multiple insertions of LTR retrotransposons that originated new exons, which however does not necessarily mean a case of molecular domestication. A possible transduction event of a fragment of the PPi-PFK beta-subunit gene mediated by Helitron ATREPX1 in Arabidopsis thaliana was also highlighted.

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Ten species of Hyla with 2n = 30 from Brazilian fauna were analysed cytogenetically. Hyla minuta is the unique presenting all bi-armed metacentric or submetacentric chromosomes in the karyotype, therefore, with the highest FN = 60. The remaining species have a variable number of uni-armed telocentric or subtelocentric chromosomes: H. cruzi, H. elianeae, and H. rubicundula with three pairs (FN = 54), H. berthalutzae, H. elegans, H. microps, and H. nana with four pairs (FN = 52), and H. nahdereri and H. sanborni with five pairs (FN = 50). The uni-armed elements are among pairs 5, 6, 7, 11, 14, and 15, which also appeared with metacentric or submetacentric morphology. The remaining chromosome pairs 1, 2, 3, 4, 8, 9, 10, 12, and 13 were never found to be telocentric or subtelocentric. AgNOR patterns are species-specific, the majority of the species exhibiting a single pair with AgNORs, with the exception of H. elegans and H. nana with more than one chromosome pair bearing this cytological marker. C banding was obtained in H. berthalutzae, H. cruzi, H. elegans, H. elianeae, H. microps, H. minuta, H. nahdereri, and H. nana, which showed positively stained centromeric heterochromatin. Our analysis confirms the great karyotypic diversity in the species of Hyla with 2n = 30, with no species sharing identical karyotypes.

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Chartergellus golfitensis West-Eberhard new species, is described from Central America and compared with C. zonatus Spinola, a species heretofore inadequately described.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Este estudo investigou a importância dos fatores ambientais sobre os padrões de abundância dos decápodos na costa sudeste brasileira. Amostragens foram feitas mensalmente de janeiro/1998 a dezembro/1999 em Ubatumirim e Mar Virado, região de Ubatuba, usando um barco de pesca camaroneiro equipado com redes doublerig. Foram selecionadas seis áreas adjacentes aos costões rochosos. Amostras de água de fundo foram coletadas usando garrafa de Nansen, para mensurar a temperatura e salinidade. Amostras de sedimento foram obtidas utilizando pegador de Van Veen, para determinação da textura e conteúdo de matéria orgânica. A associação dos fatores ambientais com a abundância das espécies foi verificada através da Análise de Correspondência Canônica (α = 0,05). Quarenta e uma espécies de Decapoda foram utilizadas na análise multivariada. A análise indicou que a textura do sedimento (phi) e a temperatura foram os fatores mais fortemente correlacionados (p < 0,05) com a abundância espacial e temporal das espécies. Considerando a região de estudo como zona de transição faunística, incluindo espécies de origem tropical e subantártica, as espécies responderam diferentemente aos fatores ambientais, principalmente à temperatura. Possivelmente os decápodos ajustem sua distribuição de acordo com suas limitações fisiológicas intrínsecas, como resultado dos recursos disponíveis.