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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Revisão taxonômica e filogenia da Seção Myzorhynchella de Anopheles (Nyssorhynchus) (Diptera: Culicidae) / Taxonomic review and phylogeny of Myzorhynchella Section of Anopheles (Nyssorhynchus) (Diptera: Culicidae).

Nagaki, Sandra Sayuri 09 December 2015 (has links)
Anopheles é o gênero da família Culicidae mais estudado devido sua importância médica. Atualmente o gênero Anopheles compreende 472 espécies válidas que estão divididas em sete subgêneros. Os principais vetores de plasmódio da Malária no Brasil pertencem ao subgênero Nyssorhynchus, que inclui 39 espécies oficialmente reconhecidas e um número crescente de complexos de espécies crípticas que estão distribuídas em três Seções: Myzorhynchella, Albimanus e Argyritarsis. Atualmente a Seção Myzorhynchella é formada por seis espécies: An. lutzii, An. parvus, An. nigritarsis, An. guarani, An. antunesi e An. pristinus. Para o desenvolvimento da análise morfológica, observou-se material-tipo depositado em diferentes coleções, espécimes depositados na coleção entomológica da FSP/USP, além de outros obtidos em coletas realizadas durante o presente estudo em diferentes localidades do Brasil. As análises moleculares foram desenvolvidas a partir de espécimes obtidos nas coletas. Revisão taxonômica da Seção Myzorhynchella é apresentada, incluindo-se descrições de quatro novas espécies e redescrições das demais, informações sobre bionomia, importância médica, caracterização molecular, distribuição geográfica, estado de preservação do material-tipo, além de chaves de identificação de adultos, larva de quarto estádio e genitália masculina. Os resultados das análises filogenéticas utilizando sequências de ITS2, COI e Catalase indicam a existência de pelo menos doze espécies dentro da Seção Myzorhynchella, os espécimes que vêm sendo identificados como An. antunesi constitui um complexo formado por possíveis cinco espécies e aqueles de An. parvus e An. pristinus também podem representar complexos de espécies. As sequências de ITS2 podem ser utilizadas como marcador diagnóstico para espécies da Seção Myzorhynchella. Contudo, o estudo ainda demonstra que pouco se conhece sobre a diversidade de espécies de Anopheles que ocorrem em ambientes onde a malária ocorre em baixa endemicidade. Pelo número de espécies novas encontradas e pela escassez de trabalhos com espécies da Seção, fica evidente a necessidade de mais estudos. / Anopheles is the Culicidae Family genus most studied because of its medical importance. The genus currently comprises 472 valid species that are divided into seven subgenus. The main vectors of plasmodium malaria in Brazil belong to the subgenus Nyssorhynchus, that includes 39 valid species and a growing number of cryptic species complexes that are divided in three Sections: Myzorhynchella, Albimanus and Argyritarsis. Myzorhynchella Section currently consists of six species: An. lutzii, An. parvus, An. nigritarsis, An. guarani, An. antunesi and An. pristinus. For the morphological analysis, type material deposited in different collections were studied, specimens deposited in the entomological collection of FSP/USP, and other obtained from field collections in different localities in Brazil during this study. The molecular analyzes were taken from specimens obtained in field collections. Taxonomic review of Myzorhynchella Section is presented, including descriptions of four new species and redescriptions of the others, information on bionomics, medical importance, molecular characterization, geographical distribution, preservation status of type material, as well as identification keys of adults, fourth instar larvae and male genitalia. The results of phylogenetic analysis using sequences of ITS2, COI and Catalase indicate the existence of at least twelve species within Myzorhynchella Section, the specimens which have been identified as An. antunesi is a species complex formed by possible five species and those of An. parvus and An. pristinus may also represent species complexes. The ITS2 sequences can be used as a diagnostic marker for species of Myzorhynchella Section. However, the study also shows that little is known about the diversity of Anopheles species that occur in environments where malaria occurs in low endemicity. By the number of new species found and the lack of studies with species of the Section, it is evident the need for further studies.
62

Revisão taxonômica e filogenia do gênero Balgus Fleutiaux, 1920 (Coleoptera, Elateridae, Thylacosterninae) / Taxonomic revision and phylogeny o genus Balgus Fleutiaux, 1920 (Coleoptera, Elateridae, Thylacosterninae)

Barbosa, Felipe Francisco 24 April 2015 (has links)
Balgus Fleutiaux, 1920 possui atualmente nove espécies: B. tuberculosus (Dalman, 1823); B. eganensis (Bonvouloir, 1875); B. humilis (Bonvouloir, 1875); B. obconicus (Bonvouloir, 1875); B. subfasciatus (Bonvouloir, 1875); B. albofasciatus (Bonvouloir, 1875); B. eschscholtzi (Laporte, 1835); B. rugosus (Blanchard, 1843) e B. schnusei (Heller, 1914), mais uma subespécie. Espécies deste gênero podem ser facilmente diferenciadas das espécies dos outros gêneros de Thylacosterninae pela presença de tubérculos no disco pronotal. O presente trabalho teve como objetivos: realizar a revisão taxonômica das espécies do gênero; e realizar a reconstrução filogenética do gênero, por meio de caracteres morfológicos e moleculares. Apenas uma espécie, B. subfasciatus (Bonvouloir, 1875), não foi analisada. Para as extrações do rDNA 16S foi utilizado um protocolo adaptado de Gilbert et al. (2007) para espécimes conservados em via seca. Os dados foram analisados por meio do critério de máxima parcimônia (MP) e por meio da inferência bayesiana (BI). Em sua versão final a matriz de caracteres contém 55 caracteres. Para a BI com dados morfológicos, foi utilizado o modelo Mkv para dados discretos morfológicos, com taxa de distribuição Gamma (). No caso dos dados moleculares, foi utilizado o alinhamento e busca de árvores por meio do método de alinhamento direto por Tree alignment (homologia dinâmica). O gênero Balgus foi redescrito, assim como todas as espécies do gênero analisadas. Todas as espécies se mantiveram válidas e a subespécie B. schnusei cayennensis Chassain, 2003 se tornou inválida. Foi gerada uma chave de classificação para todas as espécies do gênero. O cladograma preferível foi o gerado por MP com morfologia, devido ao fato de ter sido o cladograma mais bem resolvido: (Lissomus(C. mutabilis(P. bimaculatus((B. obconicus(B. humilis+B. schnusei))(B. eganensis(B. tuberculosus(B. eschscholtzi(B. albofasciatus+B. rugosus)))))))). São necessários novos estudos taxonômicos que visem B. subfasciatus (Bonvouloir, 1875), novos caracteres morfológicos sejam amostrados e, principalmente, que outros genes sejam sequenciados, para as espécies amostradas e não amostradas. / Balgus Fleutiaux 1920 currently has nine species: B. tuberculosus (Dalman, 1823); B. eganensis (Bonvouloir, 1875); B. humilis (Bonvouloir, 1875); B. obconicus (Bonvouloir, 1875); B. subfasciatus (Bonvouloir, 1875); B. albofasciatus (Bonvouloir, 1875); B. eschscholtzi (Laporte, 1835); B. rugosus (Blanchard, 1843) and B. schnusei (Heller, 1914), further one subespecies. Species of this genus can be easily distinguished from species of other genera of Thylacosterninae by the presence of tubercles in pronotal disk. This study aimed to: the taxonomic revision of the genus; and the phylogenetic reconstruction of the genus, based on morphological and molecular characters. The examination of type material of two species, B. tuberculosus and B. rugosus was performed. Only one species, B. subfasciatus (Bonvouloir, 1875), was not analyzed. The extractions of rDNA 16S were performed using a protocol adapted from Gilbert et al. (2007) for samples preserved in a dry route. Data were analyzed using the maximum aarsimony (MP) and by bayesian inference (BI). The final version of the character matrix contains 55 characters. For BI with morphological data, the model Mkv was used for morphological discrete data with a distribution rate Gamma (). In the case of molecular data, we used the method of Tree alignment (dynamic homology). The Balgus genus was redescribed, as well as all species of the genus which were analyzed. All species remained valid and the subspecies B. schnusei cayennensis Chassain, 2003 are now invalid. A classification key to all species of the genus was generated. The preferred cladogram was generated by MP with morphology due to the fact that it was the most well-resolved cladogram: (Lissomus(C. mutabilis(P. bimaculatus((B. obconicus(B. humilis+B. schnusei))(B. eganensis(B. tuberculosus(B. eschscholtzi(B. albofasciatus+B. rugosus)))))))). New taxonomic studies, aimed B. subfasciatus (Bonvouloir, 1875), are necessary, new characters must be sampled and especially new genes must be sequenced for non-sampled species as well as for those which were already sampled.
63

Classificação de rios e sua relação com a comunidade de macroinvertebrados em riachos

Vasconcelos, Márlon de Castro January 2012 (has links)
Nesta tese avaliei a relação entre a classificação de riachos em tipos de rios baseados nas suas características abióticas com a comunidade de macroinvertebrados. Especificamente, avaliei as seguintes questões: 1) Como as escalas de trecho de rio (local) e de bacia hidrográfica (regional) influenciam as comunidades? 2) As classificações de rios baseadas em variáveis abióticas são concordantes com aquelas baseadas em macroinvertebrados? 3) As respostas das comunidades de macroinvertebrados são similares quando diferentes abordagens de classificação são usadas? Por fim, 4) De que forma a resolução taxonômica e o tratamento dos dados influenciam as perguntas 2 e 3? Este estudo foi realizado em 38 riachos, numa área de 282 mil km2 no Rio Grande do Sul. As distâncias entre os riachos variaram entre 15 a 670 km. As variáveis físicas e químicas dos rios foram obtidas em trechos de 50 metros de extensão. A bacia hidrográfica de cada trecho foi delimitada e o uso da terra, tipo de solo e o relevo foram obtidos por meio de SIG. A tese traz uma “Apresentação geral” como Introdução. O capítulo 1 cobre a revisão da literatura e foi publicado na revista Ciência e Ambiente. O capítulo 2 apresenta a relação das variáveis ambientais e do espaço (distância geográfica) com a comunidade de macroinvertebrados. Como principal resultado, observou-se que o ambiente explica a maior parte da variação da distribuição na comunidade de macroinvertebrados, sendo que o efeito do ambiente é dependente da resolução taxonômica utilizada. No capítulo 3 avaliei a concordância entre classificações bióticas e abióticas. Avaliamos concomitantemente o efeito da resolução taxonômica, tipo de dado e da escala (trecho de rio x bacia hidrográfica). Tanto o tipo de dado quanto a resolução taxonômica influenciaram os resultados, sendo a classificação baseada nos dados no nível de família o único concordante com a classificação baseada em dados abióticos (duas escalas juntas). Outro importante resultado obtido foi a observação de que em uso de diferentes escalas, separadamente, verifica-se que a concordância se deu apenas para a escala de bacia hidrográfica, desde que para abundância no nível de gênero e presença/ausência no nível de família. No capítulo 4 verifiquei a relação da comunidade de macroinvertebrados com cinco sistemas de classificações de rios. As duas primeiras são baseadas em hidrorregiões, a terceira, em ecorregiões aquáticas da FEOW, a quarta deriva das ordens dos rios e a quinta é resultado do agrupamento de variáveis ambientais medidas localmente e regionalmente. Os resultados demonstram que a classificação baseada em variáveis ambientais se apresentou como o melhor sistema de classificação dos rios amostrados. Também avaliamos o tipo de dado e resolução taxonômica. Novamente a resolução taxonômica foi importante para os resultados obtidos e os dados de gênero obtiveram os melhores resultados. Por fim, na última parte da tese são apresentadas as considerações finais. / This thesis evaluated the relationships between stream classifications according to their abiotic characteristics and macroinvertebrate stream assemblages. Specifically, I asked the following questions: 1) How the macroinvertebrate communities are related with stream reach and catchment scales ? 2) Are the streams classifications with biotic and abiotic approach congruent? 3) Are there similar responses of macroinvertebrate assemblages when different classification approaches are used? 4) Can the taxonomic resolution and data type (abundance and presence/absence) to influence the results? This study was conducted in 38 streams, with distances among streams ranged from 15 to 670 km at an area of 282.000 km2 in Rio Grande do Sul state. The chemical and physical variables were obtained at a 50 m reach in each stream. The catchment was delimited and land use, soil coverage and relief were obtained using GIS tools. The thesis includes an “overview” as introduction. Chapter 1 covers the literature review and was published on Ciência e Ambiente. The Chapter 2 shows the relationship of environmental variables and space (distance among streams) with macroinvertebrate assemblages. The main result was that the environment accounted for most of the variation on the distribution of macroinvertebrate assemblages and this effect was dependent of the taxonomic resolution. In chapter 3 I evaluated the concordance between the abiotic and biotic classifications as well as the effect of the numerical and taxonomic resolution and the scale (stream reach x catchment). The results are dependent of the taxonomic resolution and dada type. The most important result was the effect of taxonomic resolution on the concordance between biotic and abiotic classifications. The classification based on macroinvertebrate family data was the only biotic classification concordant with the classification based on abiotic data. Another important result is that different scales, when used separately, only catchment classification was concordant with biotic one, and this result was dependent of both taxonomic and dada type. In chapter 4 we assessed the relationship of macroinvertebrate assemblages with five stream classifications. The first two is based on catchments grouped in hydrologic units, the third is based in freshwater ecoregions of FEOW, the fourth is based on stream orders and the fifth is result by cluster of environmental variables get on stream reach and catchment scales. That classification based on environmental variables had the higher scores than others classification by Classification Strength approach. The taxonomic and numeric resolutions were also evaluated. The taxonomic resolution was important to the results obtained, and genera data show the best scores. In the last part of the thesis are presented the conclusion remarks.
64

Revisão taxonômica de Octostruma Forel, 1912 (Formicidae, Myrmicinae) / Taxonomic revision of Octostruma Forel, 1912 (Formicidae: Myrmicinae).

Prado, Lívia Pires do 19 February 2016 (has links)
O gênero de formigas Octostruma Forel 1912 (Formicidae: Myrmicinae) está restrito à região Neotropical; suas espécies ocorrem do México até a Argentina, são predadoras de pequenos artrópodes e podem nidificar no solo, serapilheira e em epífitas. No presente trabalho, a taxonomia do gênero é revista com base no exame de cerca de 4.000 exemplares. Reconheço 43 espécies de Octostruma, 34 espécies previamente conhecidas são consideradas válidas e redescritas e, portanto, nove são reconhecidas como novas. Além disso, indivíduos de castas e sexos ainda não registrados (machos, gines e ergatóides) são aqui descritos pela primeira vez para diferentes espécies. Novos registros de localidades expandem a distribuição geográfica conhecida para parte das espécies e informações sobre a biologia das espécies a partir de dados de rótulo e observações de campo, somados às poucas informações encontradas na literatura são compiladas neste trabalho. Uma chave de identificação para as operárias de todas as espécies do gênero é fornecida. / The ant genus Octostruma Forel 1912 (Myrmicinae: Attini) is restricted to the Neotropics; their species occur from Mexico to Argentina, are predators of small arthropods and may nest in the soil, leaf litter and epiphytes. In the present work, the taxonomy of the genus is reviewed based in the examination of about 4.000 specimens. Recognize 43 Octostruma species, 34 species previously known are considered valid and redescribed and nine are recognized as new. Moreover, castes and sex of individuals not yet recorded (males, gynes and ergatoids) are described here for the first time for different species. New records expand the distribution known for most species and information about the biology of the species from label data and field observations, added to the little information in the literature are compiled in this work. A key to the worker of all species of the genus is provided.
65

Taxonomic or Thematic: Categorization of Familiar Objects by Preschool-Aged Children

Calhoun, David Owen 01 May 1995 (has links)
To acquire language, children must learn how to categorize objects on the basis of the meanings that cultures have assigned to the objects. A series of six experiments tested how preschool-aged children categorize familiar objects. Each experiment used a matching-to-sample format in which children matched pictures of familiar objects (comparisons) to a sample stimulus picture. The sample and one comparison related taxonomically (on the basis of function) from which the children were to find another stimulus that was the same as the sample. Each experiment was a systematic replication of published research and of the prior experiment. In all six experiments, these pre-school-aged children demonstrated a statistically significant preference for the taxonomic stimulus. No statistically significant differences were found between genders. The results of these six experiments did not support the development trend described in the majority of the extant literature. These findings are also contrary to the research literature, with one noted exception.
66

Lexical organization in Mandarin-speaking children: insights from the semantic fluency task

Chen, Su-Mei 01 December 2012 (has links)
Our purpose was to explore developmental changes in the organization and access to the mental lexicon between the ages of three-, five-, and seven years. Six-hundred and seventy three Mandarin-speaking participants listed all exemplars of animals and foods that came to mind within two one-minute intervals. Compared to younger participants, the older children demonstrated more correct responses and fewer errors, suggesting that they have greater knowledge of category-relevant vocabulary. They produced more subcategories, many of which involved embedding and overlapping, which suggests they have more sophisticated lexical-semantic organization. Also, they produced fewer and less closely spaced repetitions, suggesting they could more effectively monitor retrieval responses. We conclude that between the ages of three to seven, children expand and refine the organization of their mental lexicons. Improved monitoring may reflect growth in executive functioning.
67

Classificação taxonômica de sequências obtidas com meta-ômicas por meio de integração de dados / Taxonomic classification of sequences obtained with meta-omics by data integration

Lima, Felipe Prata 20 August 2019 (has links)
Comunidades microbianas possuem papéis importantes em processos que ocorrem em diversos ambientes, tais como solos, oceanos e o trato gastrointestinal dos seres humanos. Portanto, é de interesse a compreensão da estrutura e do funcionamento dessas comunidades. A estrutura dessas comunidades, em termos de organismos componentes, pode ser determinada com o uso do sequenciamento de nova geração em conjunto com as técnicas meta-ômicas e pela análise taxonômica das sequências obtidas com programas de classificação taxonômica. Se por um lado diversos programas estão disponíveis, por outro lado eles cometem erros, como a identificação parcial dos organismos presentes na amostra e a identificação de organismos que não estão presentes na amostra (os falsos positivos - FPs). Algumas abordagens foram propostas para a melhoria das classificações taxonômicas obtidas por esses programas com a redução desses FPs, porém elas abordam apenas um tipo de meta-ômica, a metagenômica. Neste trabalho, propomos uma nova abordagem através da integração de diferentes meta-ômicas - metagenômicas shotgun e de amplicons de 16S, e metatranscritômica. Exploramos os resultados de classificações de dados simulados e mocks para a extração de variáveis e desenvolvemos modelos de classificação para discriminação de predições de espécies de bactérias classificadas como corretas ou incorretas. Comparamos o desempenho dos resultados obtidos entre as meta-ômicas individuais e os obtidos através da integração observando o balanceamento entre a precisão e a sensibilidade. De acordo com as medidas calculadas com nossos conjuntos de dados, nossa abordagem demonstrou melhorias na classificação com a redução de FPs e aumentos para a medida F1, quando comparada com abordagens não integrativas, inclusive com o uso de métodos de combinação de classificadores. Para facilitar seu uso, desenvolvemos o Gunga, uma ferramenta que incorpora a abordagem desenvolvida em formato de pacote do R, com funcionalidades para a integração de dados de classificação taxonômica com diferentes meta-ômicas e a classificação das predições incorretas. / Microbial communities play important roles in processes that occur in diverse environments, such as soils, oceans, and the gastrointestinal tract of humans. Therefore, it is of interest to understand the structure and functioning of these communities. The structure of these communities, in terms of component organisms, can be determined by the use of the next generation sequencing in conjunction with the meta-omics techniques and by the taxonomic analysis of the sequences obtained with taxonomic classification programs. If on the one hand several programs are available, on the other hand they make mistakes, such as the partial identification of the organisms present in the sample and the identification of organisms that are not present in the sample (the false positives - FPs). Some approaches have been proposed to improve the taxonomic classifications obtained by these programs with the reduction of these FPs, but they address only one type of meta-omics, the metagenomics. In this work, we propose a new approach by integrating different meta-omics - shotgun and 16S amplicon metagenomics, and metatranscriptomics. We explored the classifications results of simulated data and mocks for variable extraction and developed classification models for discriminating predictions of bacterial species classified as correct or incorrect. We compared the performance of the results obtained between the individual meta-omics and the obtained through the integration observing the balance between precision and sensitivity. According to the measures calculated with our data sets, our approach has shown improvements in the classification with the reduction of the FPs and increases for the F1 measure, when compared to non-integrative approaches, including the use of classifiers combination methods. To facilitate its use, we developed the Gunga, a tool that incorporates the developed approach in R package format, with features for the integration of taxonomic classification data with different meta-omics and the classification of the incorrect predictions.
68

Isolation and Characterization of Uncultured Freshwater Bacterioplankton from Lake Ekoln and Lake Erken through Dilution-to-Extinction Approach and Molecular Analysis Tools

Zhang, Jiazhuo January 2012 (has links)
Not many of the abundant freshwater bacterial groups have a representative cultured isolate. In this master thesis project, some abundant bacterioplankton from two lakes (Lake Ekoln and Lake Erken) could be isolated by a dilution-to-extinction approach. Sterilized lake water which was obtained through an ultrafiltration system was used resembling a natural medium. Specific fragments of 16s rRNA of the isolates were amplified by universal bacterial primers (27f and 1492r, 341f and 805r.) for genotyping against a freshwater sequence database and RDP training set (Version 7). A total of 33 isolates from the two lakes were taxonomically classified and revealed the isolation of typical and abundant freshwater bacteria. Original bacterial community of Lake Ekoln was also analyzed by 16S rRNA clone library construction for diversity study. Phylogenetic trees were built through neighbor-joining method by Mega (Version 5) to reveal the evolutionary relationships among database entries, obtained isolates and clones.
69

The Search for the Missing Mantles of Differentiated Asteroids: Evidence from Taxonomic A-class Asteroids and Olivine-Dominated Achondrite Meteorites

Lucas, Michael Peter 01 January 2011 (has links)
The apparent rarity of taxonomic A-class asteroids poses a significant paradox for understanding asteroid differentiation and the dynamical evolution of the early solar system. Based on results from asteroid taxonomic surveys, and on the abundances and mineralogy of different achondrite meteorites, it appears that olivine-dominated mantle remnants are missing from both the asteroid population and in meteorite collections. Several scenarios to explain this paradox have been proposed: (1) olivine mantle material has been stripped away by collisions and only remains as small fragments (< ~5 km), (2) A-class asteroids are abundant but have been altered in some way masking their presence, or (3) differentiated asteroids did not form thick olivine-rich mantles. We have approached these questions through the collection of taxonomic and observational data on known A-class asteroids, and the geochemical characterization of olivine grains from pallasite and ureilite igneous meteorites. Examination of four taxonomic surveys reveals discrepancies in the classification of A-class objects. Recent data with spectral coverage to 2.45 μm have reclassified some asteroids previously thought to belong to the class. Data complied from these taxonomies reveal only 17 A-class asteroids out of ~2100 individual objects surveyed (<1%). Physical and orbital characteristics of A-class asteroids indicate that the majority are small (<13 km) collisional fragments that reside in orbits interior to, or within the inner main-belt. Photometric observations of five A-class asteroids obtained during this study have constrained the rotational periods of, 246 Asporina, 289 Nenetta, 446 Aeternitas, 1600 Vyssotsky, and the Mars-crossing asteroid 1951 Lick. Robust photometric data for 446 Aeternitas collected over three apparitions yielded a precise rotation period (15.737496 ± 0.000005 h) and a pole orientation of Β = 49º, and λ = 342º. A shape model produced from these data revealed that 446 Aeternitas has a distinctly angular shape suggestive of a collisional fragment. Olivine compositions between our pallasite meteorites span a narrow range (Fa10.5 - Fa13.4), while the ureilite olivine compositions, generally more fayalitic, display wide variations in the eight examined meteorites (Fa8.5 - Fa22.1). Major and trace element behavior in olivines from pallasite meteorites is consistent with a model of slow, in situ cooling and crystallization, allowing for near-equilibrium exchange between crystallizing olivines and coexisting silicate and FeNi melt, preserving near-uniform olivine major element compositions, and limited trace element variation. Trace element signatures of ureilite silicates (olivine and pigeonite) show large variations, consistent with residual solids from fractional melting processes. Ureilite olivines are uniformly more enriched in both compatible lithophile and siderophile elements (Ca, Li, Sc, V, Cr, Ni, and Mn) than pallasite olivines. corroborating models for ureilite petrogenesis as low-degree partial melting residues in the absence of an FeNi melt phase. Uniformity of elemental signatures among different pallasites point to a chemically homogeneous parent body.
70

A taxonomic and anatomic assessment of the extinct Zygodactylidae (Aves) from the Green River Formation of Wyoming and placement of Zygodactylidae within Aves

DeBee, Aj McLellan 19 November 2013 (has links)
Birds are the most diverse extant group of terrestrial vertebrates, and relationships amongst major extant and extinct avian lineages remain hotly debated. A clade of Aves which has received limited attention is the extinct Zygodactylidae, a species-rich group of perching birds that possess a foot with a retroverted fourth toe, an elongate tarsometatarsus and a large intermetacarpal process in the wing. Specimens currently included within Zygodactylidae previously were thought to be sister taxa to songbirds (Passeriformes) or woodpeckers and allies (Piciformes). Zygodactylids were most abundant during the Eocene in North America and Europe and persisted to the Early Miocene. Five exceptionally preserved fossils from the Early Eocene Green River Formation of Wyoming are described, and provide insights into the interrelationships of zygodactylid taxa and the position of the clade within Aves. In an attempt to resolve systematic relationships within zygodactylids, and the position of the clade within Aves, I conducted two sets of phylogenetic analyses. The first focused on clarifying relationships within Zygodactylidae. Each taxon was evaluated for 37 morphological characters. Resulting strict consensus cladograms yield topologies in which two of the new Green River specimens are positioned in a clade within Zygodactylus, a taxon previously known only from the Early Oligocene and Early Miocene of Europe. The second set of analyses sought to assess which extant avian lineage is most closely allied with Zygodactylidae. Those analyses used a dataset of 135 characters evaluated for 57 species and a supraspecific terminal, Zygodactylidae. Scoring of Zygodactylidae was based on morphological observations from all described taxa within Zygodactylidae. The extant species sample was chosen to evaluate previously proposed hypotheses of relationships between Zygodactylidae and other avian clades and included songbirds, parrots and 43 species from the coraciiform-piciform clade (e.g., woodpeckers, galbulids, rollers and motmots). Outgroup species were iteratively swapped to determine if outgroup choice affected recovered estimates of zygodactylid relationships within Aves. Zygodactylidae is the sister taxon to songbirds in the resultant tree topologies. These results forward our understanding of the relationship between Zygodactylidae and Passeriformes within Aves. / text

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