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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.
1

Diversity of the genus Seira (Collembola: Entomobryidae: Seirinae) in the Fynbos and Southern Afrotemperate forest

Liu, Wing Pui Amy 12 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Soil is one of the most complex and understudied terrestrial habitats, and it comprises a wide range of organisms that affect the functioning of terrestrial ecosystems. Despite the importance of these below-ground fauna, our understanding of this diversity remains limited, especially in the Cape Floristic Region (CFR), where higher plants and other more conspicuous invertebrates have been better represented in the literatures. The main aim of this thesis is to provide the first insights into the taxonomic, cryptic and spatial diversity of one of the more diverse Collembola genera, Seira (Collembola: Entomobryidae: Seirinae), in the Fynbos and Southern Afrotemperate forest habitats of the CFR. Collembola constitute an important component of terrestrial biodiversity and are essential for ecosystem functioning. The thesis is divided into two data chapters. The first data chapter examines the mitochondrial barcoding COI (Cytochrome-c oxidase subunit I) gene of 496 Seira specimens from 41 Fynbos and forest sites. Discrete Molecular Operational Taxonomic Units (MOTUs) are identified within Seira. Furthermore, divergence times are estimated and tentatively used to propose historical triggers for the diversification of Seira. Habitat specificity of Seira is assessed through phylogenetic reconstruction using Parsimony and Bayesian analyses based on the nucleotide and amino acid sequences. Genetic divergence indicates that Seira is composed of at least 91 MOTUs, suggesting that morphological taxonomy has vastly under-estimated the richness of this genus by at least four folds. Most of the MOTUs are highly habitat specific and geographically localised. The reconstruction of an evolutionary time frame of these lineages reveals several deep diversifications in the Miocene and a spate of more recent radiations in the Pleistocene and Holocene. Palaeo-environmental fluctuations and vegetation composition shifts are hypothesised as having increased the environmental complexity of the region and this may have influenced the diversification patterns of Seira. In the second data chapter, the spatial variation of Seira diversity is examined and compared between and within two major habitat types, Fynbos and forest, across nine study sites. Abiotic variables were recorded and compared for the investigation of environmental differences among habitat types. The habitat specificity of Seira is assessed, as well as the relative effects of habitat types and study sites on assemblage structure. Species richness of Seira is higher in Fynbos than in forest, and this could be due to the high heterogeneity of niches and resources created by the steep environmental and floristic gradients in the Fynbos habitats. Perhaps one of the most striking results is the high levels of beta diversity exhibited by Seira. The spatial turnover of the Seira assemblage is complete or nearly complete among and within habitat types across study sites within the CFR. Low dispersal abilities and consequently isolated evolutionary histories may account for the strong assemblage differences within the same habitat type of different study sites. However, the substantial differences in assemblage composition between adjacent habitat types in the same site are likely to be the result of the contrasting abiotic conditions exhibited by the Fynbos and forest habitats, as found by this study. Overall, the results of this thesis suggest that Seira species richness is much greater than previously thought. It follows similar diversity patterns to the well-described and hyper-diverse plant communities of the CFR. Here, for both CFR plants and Seira, the spectacular regional diversity displayed is not the result of high alpha diversity, but rather of substantial beta diversity. Because of the high beta diversity and the fact that only two CFR vegetation types were sampled from a limited number of study sites, I predict that the Seira species richness presented here is but the tip of the iceberg. / AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar
2

Descri??o de novas esp?cies de Entomobryoidea, Womersley, 1934 (Collembola, Hexapoda) em remanescentes urbanos de mata atl?ntica no Estado do Rio Grande do Norte

Meira, Michael Jefferson Coelho 20 June 2014 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-02-22T23:19:51Z No. of bitstreams: 1 MichaelJeffersonCoelhoMeira_DISSERT.pdf: 6007089 bytes, checksum: 8193a72146f38df6552ad2f77a6bb3dc (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-02-26T19:06:01Z (GMT) No. of bitstreams: 1 MichaelJeffersonCoelhoMeira_DISSERT.pdf: 6007089 bytes, checksum: 8193a72146f38df6552ad2f77a6bb3dc (MD5) / Made available in DSpace on 2016-02-26T19:06:01Z (GMT). No. of bitstreams: 1 MichaelJeffersonCoelhoMeira_DISSERT.pdf: 6007089 bytes, checksum: 8193a72146f38df6552ad2f77a6bb3dc (MD5) Previous issue date: 2014-06-20 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Col?mbolos s?o microartr?podes comumente reconhecidos em ambientes ed?ficos. Entre as formas mais comuns (e mais vis?veis) destes animais, est?o os Entomobryoidea, um dos grupos mais diversificados de col?mbolos. Embora sejam registradas mais de 8300 esp?cies de Collembola no globo, no Brasil pouco mais de 310 esp?cies s?o registradas, sendo a maioria no Sudeste do pa?s. No Nordeste, em particular no Rio Grande do Norte, esses registros ainda s?o reduzidos, mesmo na Mata Atl?ntica, dom?nio reconhecidamente diverso para esta fauna e de forma espec?fica, para os Entomobryoidea. Assim, este trabalho teve como principal objetivo descrever novas esp?cies de Entomobryoidea em remanescentes urbanos de Mata Atl?ntica no Rio Grande do Norte, especificamente no Parque das Dunas, Natal e na ?rea de Prote??o Ambiental de Genipabu, Extremoz. As coletas foram realizadas nos meses Julho e agosto de 2012 e Janeiro e Fevereiro de 2013. Os esp?cimes foram identificados em laborat?rio e descritos de forma detalhada atrav?s de consulta a literatura espec?fica. Neste trabalho foram descritas quatro novas esp?cies da fam?lia Entomobryidae: Entomobrya sp. nov. 1, Seira sp. nov. 1, Seira sp. nov. 2 e Trogolaphysa sp. nov. 1. Seira sp. nov. 1 possui claras semelhan?as com S. paraibensis, entretanto a quetotaxia do Th. II e Abd. IV distingue ambas as esp?cies. Estas semelhan?as sugere proximidade filogen?tica entre as esp?cies. Seira sp. nov. 2 ? caracterizado por sua quetotaxia, principalmente na regi?o ?M? cef?lica e pelo seu Th II. Existe possibilidade de uma rela??o filogen?tica com S. praiana e S. potiguara devido a algumas semelhan?as. Entomobrya sp. nov. 1 possui poucas semelhan?as com esp?cies brasileiras, entretanto n?o h? para estas ?ltimas detalhes da quetotaxia dorsal, o que pode ocultar rela??es de proximidade evolutiva, entretanto, a principal caracter?stica diagn?stica de Entomobrya sp. nov. 1 frente a outras esp?cies do g?nero ? a quetotaxia do Abd. IV. Trogolaphysa sp. nov. 1 mostrou acentuada diferen?a em sua quetotaxia cef?lica dorsal e ao Th II e Abd. IV. A descri??o de novas esp?cies de col?mbolos, potencialmente end?micas de seus habitats de ocorr?ncia pode ajudar na compreens?o de padr?es morfol?gicos e evolutivos nos t?xons amostrados, assim como na preserva??o dos ambientes nos quais foram encontradas. / Springtails are commonly recognized microarthropods edaphic environments. Among the most common (and most visible) forms of these animals are the Entomobryoidea, one of the most diverse groups of springtails. Although more than 8,300 species of Collembola are registered on the globe, in Brazil a little over 310 species are recorded, mostly in the Southeast. In the Northeast, particularly in Rio Grande do Norte, these records are still reduced, even in the Atlantic Forest domain for this admittedly diverse fauna and specifically, for Entomobryoidea. This study aimed to describe new species of Entomobryoidea in urban remnants of Atlantic Forest in Rio Grande do Norte, specifically in Parque das Dunas, Natal in the Environmental Protection Area Genipabu, Extremoz. The collections were made in the months July and August 2012 and January and February 2013, using entomological vacuums and plastic trays. The specimens were identified in the laboratory and described in detail by looking at the literature. In this paper four new species were described Entomobryidae family: Entomobrya sp. nov. 1, Seira sp. nov. 1, Seira sp. nov. 2 and Trogolaphysa sp. nov. 1. Seira sp. nov. 1 has clear similarities to S. paraibensis, however the chaetotaxy of the mesothorax and abdomen IV distinguishes both species. The number of phylogenetic proximity suggests similarities between species. Seira sp. nov. 2 is characterized by its chaetotaxy, mainly in the 'M' head and his mesothorax. There is possibility of a phylogenetic relationship with S. praiana and S. Potiguara due to some similarities. Entomobrya sp. nov. 1 has little resemblance to Brazilian species, from the point of view of color, however there is for the latter detailing the dorsal chaetotaxy, which might obscure evolutionary relationships of proximity. Even so, the main diagnostic feature Entomobrya sp. nov. 1 compared to other species of the genus is the complexity of the chaetotaxy of the fifth abdominal segment. Descriptions of new species of Collembola, potentially endemic to their habitats of occurrence may help to understand the morphological and evolutionary patterns in the sampled taxa, as well as the preservation of the environments in which they were found.
3

Novas esp?cies de entomobryoidea, Womersley, 1934 (Collembola, Hexapoda) em duas ?reas de caatinga do Rio Grande de Norte

Freitas, Thiago Fernando Gomes de 31 May 2016 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-02-20T23:49:40Z No. of bitstreams: 1 ThiagoFernandoGomesDeFreitas_DISSERT.pdf: 3334465 bytes, checksum: 45551c8fb5cbb4b77890be34808aa6b4 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-03-02T23:33:33Z (GMT) No. of bitstreams: 1 ThiagoFernandoGomesDeFreitas_DISSERT.pdf: 3334465 bytes, checksum: 45551c8fb5cbb4b77890be34808aa6b4 (MD5) / Made available in DSpace on 2017-03-02T23:33:33Z (GMT). No. of bitstreams: 1 ThiagoFernandoGomesDeFreitas_DISSERT.pdf: 3334465 bytes, checksum: 45551c8fb5cbb4b77890be34808aa6b4 (MD5) Previous issue date: 2016-05-31 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Col?mbolos s?o microartr?podes terrestres que apresentam grande diversidade entre os representantes da fauna ed?fica. Atualmente existem mais de 8 mil esp?cies descritas ao redor do mundo. O Brasil ? considerado um dos pa?ses com uma das maiores diversidades para o grupo, contudo o n?mero de esp?cies descritas no pa?s ainda ? pouco representativo. Atualmente pouco mais de 300 esp?cies foram descritas e a maioria dos registros deriva da regi?o Sudeste. Para a Regi?o Nordeste, especialmente no Bioma Caatinga, o n?mero de estudos ? escasso. Assim, esse trabalho tem como objetivo principal descrever novas esp?cies de Entomobryoidea em duas ?reas de Caatinga do Rio Grande do Norte, especificamente nos munic?pios de Riacho da Cruz e Portalegre, ambos localizados no Oeste Potiguar. As coletas foram realizadas em dois momentos, uma no m?s de novembro de 2013 e outra no m?s junho de 2014. Os esp?cimes foram triados e identificados em laborat?rios e descritos de forma detalhada atrav?s de literatura espec?fica. Foram descritas quatro novas esp?cies, tr?s da fam?lia Entomobryidae: Seira sp. nov. 1, Seira sp. nov. 2, e Lepidocyrtus sp. nov. e uma da fam?lia Paronellidae: Salina sp. nov., Seira sp. nov. 1 foi comparada com tr?s outras esp?cies do g?nero: Seira coroatensis, Seira mendoncea e Seira ritae mostrando diferen?as no n?mero de macrocerdas, diferen?a de espinhos no ?rg?o metatrocanteral e na f?rmula do tri?ngulo labial. Lepidocyrtus sp. nov. comparada com a esp?cie Lepidocyrtus sotoi, apresenta diferen?as na colora??o, f?rmula do tri?ngulo labial, tipos das cerdas prelabrais, n?mero de espinhos no ?rg?o metatrocanteral e altera??o no n?mero de cerdas nos segmentos corporais, Salina sp nov. comparada a Salina maculiflora e Salina colombiana difere na cor, n?mero de espinhos do ?rg?o metatrocanteral e no n?mero de dentes do mucro al?m da vis?vel diferen?a da quetotaxia em todos os segmentos. Seira sp nov. 2, comparada a Seira diamantinae e Seira jiboienses n?o apresenta cerdas na s?rie (a) do mesot?rax, apresenta cinco cerdas intraoculares, sendo uma delas macro, no abd?men IV as cerdas Be2 e Be3 est?o presentes apenas em Seira sp. nov. 2. Este trabalho demonstra a grande diversidade de col?mbolos existentes em ?reas de Caatinga, e al?m do conhecimento de novas esp?cies, pode ajudar a preservar o meio os quais s?o encontrados. / Springtails are land micro arthropods that present huge diversity among the members of edaphic fauna. Nowadays, there are more than 8 thousand species spread around the globe. Brazil is considered one of the countries that has one of the most ranged variety for the group, yet, the number of labelled species in this country is scarcely significant. Currently, the number of labelled species is slightly over 300 and the majority of them derives from the Southwest region. Concerning the Northeast region, specially in the biome Caatinga, the number of studies is scanty. Thus, this paper has as its main goal to describe new species of Entomobryoidea in two Caatinga areas of Rio Grande do Norte, specifically in the municipality of Riacho da Cruz and Portalegre, both located in the west of the city. The collections were made in two disctint moments, the first in November 2013 and the second in June 2014. The specimens were screened and identified in labs and described in details using specific literature. In this piece of work, four new species were described, three from the Entomobryidae family: Seira sp. nov. 1, Seira sp. nov. 2, e Lepidocyrtus sp. nov. and one from the Paronellidae family: Salina sp. nov., Seira sp. nov. 1 was compared to three other species of the same genera: Seira coroatensis, Seira mendoncea e Seira ritae, evidencing differences in the number of macrochaetae, number of spines in the metatrochanteral organ and in the labial triangle setea. Lepidocyrtus sp. nov.compared to the Lepidocyrtus sotoi species, shows differences in colour, labial triangle setea, types of Pre-labral setae, number of spines in the metatrochanteral organ, and change in the number of chaetae in the body segments. Salina sp nov. compared to Salina maculiflora and Salina colombiana evidencing differences in the number of spines of the metatrochanteral organ and in the number of theeth of the mucro and visible difference chaetotaxy in all segments. Seira sp nov. 2, compared to Seira diamantinae and Seira jiboienses does not present chatae in series (a) of mesothorx, it features five intraocular setae, being one macro. In the abdomen IV the chaetae Be2 e Be3 are present only in Seira sp. nov. 2. This paper shows the great diversity of existing collembolans in Caatinga areas, and apart from the knowledge of new species, may aid in the preservation of the environment where they are found.

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