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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

Phylogenetic and morphological analysis of the Afroedura nivaria (Reptilia: Gekkonidae) species complex in South Africa

Makhubo, Buyisile Getrude 03 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: The Afroedura nivaria complex is one of the six recognized species complexes within a southern African endemic genus, Afroedura. The A. nivaria complex is a morphologically conservative group of medium-sized geckos endemic to South Africa though they are unevenly distributed in the Eastern Cape, Free State and KwaZulu-Natal provinces. The complex comprises the following five species: A. nivaria (Boulenger 1894), A. amatolica (Hewitt 1925), A. karroica (Hewitt 1925), A. tembulica (Hewitt 1926) and A. halli (Hewitt 1935). These nocturnal and rupicolous geckos shelter in narrow rock crevices on outcrops. It is currently unknown whether a) the described species are valid and b) if additional lineages are present on isolated outcrops. I investigated the hypothesis that endemics with a narrow distribution, that is, A. amatolica and A. tembulica are valid species but that isolated populations in the widespread species (A. nivaria, A. karroica and A. halli) demonstrate genetic variation at the species level. Fragments of two mitochondrial genes (16S rRNA and ND4) and a single nuclear marker (KIAA) were sequenced and analysed using Bayesian inference, maximum parsimony and maximum likelihood. All analyses strongly supported the genetic distinctiveness of the described species. The A. nivaria complex is not monophyletic, A. karroica appeared to be outside the species complex and A. pondolia (thought to be outside the A. nivaria complex) consistently nested within A. nivaria complex. Additional clades recovered in the phylogeny within A. halli and A. nivaria had large genetic divergences and no spatial overlap. Narrowly distributed A. amatolica showed to have two highly diverged clades. Clades recovered in the phylogeny highlight geographical structuring. These findings suggest the existence of up to four additional cryptic lineages within the complex. I used morphometric data (ecologically relevant morphological traits) to investigate whether the genetic lineages would present morphological conservatism. Multivariate analyses of 19 variables showed variation within the A. nivaria species complex was accounted for mostly by differences in locomotor apparatus (limbs and feet) and head dimensions. These traits are mostly related to microhabitat usage and/or dietary specialization in lizards. There were no significant differences for body dimensions between species within the complex, indicative of morphological conservatism. It appears genetic divergence has been achieved among the different clades within A. nivaria complex, but with much similarity in phenotype being retained because of fragmented but similar habitats occupied. / AFRIKAANSE OPSOMMING: Die Afroedura nivaria kompleks is een van ses herkende spesies komplekse binne die endemiese suidelike Afrika genus, Afroedura. Die A. nivaria kompleks is ‘n morfologiese konserwatiewe groep bestaande uit medium grootte geitjies endemies tot Suid Afrika, alhoewel hulle oneweredig verspreid is in die Oos Kaap, Vrystaat en Kwazulu-Natal provinsies. Die kompleks bestaan uit die volgende vyf spesies: A. nivaria (Boulenger 1894), A. amatolica (Hewitt 1925), A. karroica (Hewitt 1925), A. tembulica (Hewitt 1926) and A. halli (Hewitt 1935). Hierdie geitjies kom snags voor en skuil tussen nou skeure op klip koppies. Dit is tans onbekend of a) die beskryfde spesies geldig is en b) of die addisionele afstammelinge voorkom op geisoleerde koppies. Met die studie het ek die hipotese ondersoek dat endemiese spesies met ‘n noue verspreiding (A. amatolica en A. tembulica) geldige spesies is, maar dat spesies met ‘n wye verspreiding (A. nivaria, A. karroica and A. halli) genetiese variasie op spesie vlak wys. Fragmente van twee mitochondriale gene (16S rRNA and ND4) en ‘n enkele nuklêre merker (KIAA) se basispaaropeenvolgingsdata was verkry en geanaliseer deur Bayesian inferensie, maksimum parsimonie en maksimum waarskynlikheid. Alle analise het die genetiese kenmerkendheid van die beskryfde spesies sterk ondersteun. Die A. nivaria kompleks is monofileties, A. karroica het geblyk om buite die spesies kompleks voor te kom en A. pondolia (voorheen beskryf as buite die A. nivaria kompleks) het voortdurend binne die A. nivaria kompleks voorgekom. Addisionele klades afkomstig vanaf die filogenië van A. halli en A. nivaria het vir beide spesies groot genetiese divergensie met geen ruimtelike oorvleuling gewys. Afroedura amatolica, met sy noue verspreiding, het twee hoogs divergente klades getoon. Die klades onthul deur die filogenie beklemtoon ‘n geografiese struktuur. Hierdie bevindings blyk die bestaan van tot vier ekstra kriptiese afstammelinge binne die kompleks. Ek het morfometriese data (ekologiese relevante morfologiese eienskappe) gebruik om vas te stel of die genetiese afstammelinge morphologies konserwatief sal wees. Meerveranderlike analises op 19 veranderlikes het variasie binne die A. nivaria spesies kompleks getoon. Hierdie veranderinge was meestal gevind in die beweeglikheidsapparatuur (ledemate en voete) en kop dimensies. Die verskeie eienskappe hou meestal verband met die mikrohabitatte wat gebruik word en/of dieët spesialisering in akkedisse. Daar was geen noemenswaardige verskille in liggaamsdimensies tussen spesies in die kompleks nie, beduidend op ‘n konserwatiewe morfologie. Dit wil blyk of genetiese divergensie tussen die verskeie klades van die A. nivaria kompleks bewerkstellig is met ooreenstemming in die fenotipes as gevolg van gefragmenteerde maar soortgelyke habitat verbruik.
2

The evolutionary ecology and population systematics of day geckos (Phelsuma) in the Seychelles

Gardner, Andrew Somerville January 1984 (has links)
The evolutionary ecology and population sytematics of the genus Phelsuma (Gekkonidae) were studied in the Seychelles. The distributions of all 18 Seychelles lizard species are described. These give little evidence for species turnover or the equilibrium model of island biogeography. Aspects of Phelsuma behaviour, social systems and reproduction were investigated. Phelsuma can digest pollen, which, with nectar may constitute a large part of the diet. On Praslin, P.sundbergi and P.astriata breed throughout the year, and partition their macro-habitat, micro-habitat and food resource dimensions such that P.sundbergi mainly occupies nectiferous and polliniferous palms and larger hardwood trees, whilst the smaller P.astriata is found on non-flowering palms and smaller trees. Interspecific competition is demonstrated by population density and habitat shifts between populations on islands in sympatry and allopatry. The biomass of Phelsuma geckos supported by coconut plantations in sympatric and allopatric situations tends to be relatively constant, such that there are either more small geckos or fewer large geckos. It is suggested that large body size is an adaptation to the defence of predictable and defensible food sources, such as palm flowers. Racial differention was investigated by multivariate morphometrics of shape, scalation and colouration, using appropriate techniques to negate ontogenetic effects. In the granitic islands, three phenetic aggregations of island populations were identified in the P.madagascariensis group, and two aggregations in the P.astriata group. Conventional taxonomic methods have failed to illustrate these patterns of phenetic variation, and new classification of island populations is proposed. Primary patterns of racial differentiation appear to have arisen from the sectioning of pre-existing clinal variation by rising Holocene sea levels, while secondary patterns relate to recent ecological selection pressures. P.abbotti populations on Aldabra and Assumption are sub-specifically distinct and not conspecific with granitic island forms. P.laticauda on the Farquhar group are probably not subspecifically distinct from Madagascan populations. All other coralline island populations appear to be recent introductions from the granitic islands.
3

Ecologia e hist?ria natural de popula??o Hemidactylus agrius (Squamata: Gekkonidae) em ?rea de Caatinga, com avalia??o da distribui??o das esp?cies nativas do g?nero no nordeste do Brasil

Andrade, Maria Jaqueline Monte de 13 May 2014 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2015-12-04T19:15:27Z No. of bitstreams: 1 MariaJaquelineMonteDeAndrade_DISSERT.pdf: 2265638 bytes, checksum: 9f30624d051acb090d637ee2530e2a96 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2015-12-09T23:02:07Z (GMT) No. of bitstreams: 1 MariaJaquelineMonteDeAndrade_DISSERT.pdf: 2265638 bytes, checksum: 9f30624d051acb090d637ee2530e2a96 (MD5) / Made available in DSpace on 2015-12-09T23:02:07Z (GMT). No. of bitstreams: 1 MariaJaquelineMonteDeAndrade_DISSERT.pdf: 2265638 bytes, checksum: 9f30624d051acb090d637ee2530e2a96 (MD5) Previous issue date: 2014-05-13 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / O g?nero Hemidactylus Oken, 1817 tem distribui??o cosmopolita e, no Brasil, ocorrem tr?s esp?cies, sendo duas nativas, H. brasilianus e H. agrius, e uma ex?tica, H. mabouia. Tomando como base os estudos sobre ecologia de lagartos efetuados na Esta??o Ecol?gica do Serid?, de 2001 a 2011, este trabalho buscou reavaliar a ocorr?ncia das esp?cies do g?nero Hemidactylus nesta ESEC, analisar aspectos ecol?gicos e biol?gicos da popula??o de H. agrius; e investigar a distribui??o atual e potencial das esp?cies nativas do g?nero na regi?o nordeste, analisando a adequabilidade da ESEC para este t?xon. Para os dois primeiros objetivos, uma ?rea de amostragem constitu?da por cinco transectos de 200 m x 20 m, foi inspecionada em turnos alternados por tr?s dias consecutivos, de agosto de 2012 a agosto de 2013. Para a ?ltima perspectiva, foram consultados pontos de ocorr?ncia de H. agrius e H. brasilianus na literatura e no banco de dados da Cole??o Herpetol?gica da Universidade Federal do Rio Grande do Norte para constru??o de mapas preditivos, atrav?s do algoritmo de M?xima Entropia (MaxEnt). Na ESEC Serid? foram coletados 62 H. agrius (25 f?meas, 18 machos e 19 juvenis) e dois rec?m-nascidos foram obtidos a partir de um ninho comunal incubado em laborat?rio, nenhum registro foi feito para as demais esp?cies do g?nero. Hemidactylus agrius demostrou ser uma esp?cie noturna com especialidade a h?bitats com Afloramentos Rochosos, no entanto, generalista quanto ao uso de microh?bitats. Nesta popula??o as f?meas possuem comprimento corporal m?dio maior que o dos machos e apresentaram maiores frequ?ncias de autotomia caudal. Em rela??o ? dieta, H. agrius ? uma esp?cie moderadamente generalista, que consome artr?podes, principalmente Aranae, Orthoptera e Isoptera; e vertebrados, al?m de ter constatado um caso de canibalismo. Quanto ? sazonalidade foram registradas diferen?as apenas para o n?mero dos itens alimentares consumidos. A dieta foi similar entre os sexos, por?m diferen?as ontogen?ticas foram registradas para o volume total e comprimento m?ximo dos itens alimentares. Rela??es significativas foram constatadas entre o tamanho do corpo e da cabe?a dos esp?cimes com o comprimento m?ximo das presas consumidas. Casos de polidactilia e de bifurca??o caudal foram registrados na popula??o com frequ?ncias de 1,6 % e 3,1%, respectivamente. Em rela??o ?s localidades de ocorr?ncia das esp?cies nativas, foram constatados 27 pontos, sendo 14 para H. agrius e 13 para H. brasilianus; a primeira apresentou distribui??o restrita, enquanto que a segunda demonstrou ampla distribui??o. Em ambos os modelos gerados a ?rea da ESEC Serid? apresentou de m?dia a alta adequabilidade. Os resultados deste trabalho confirma a aus?ncia de H. brasilianus e H. mabouia nesta ESEC e confere a H. agrius condi??o de esp?cie canibal oportunista. Al?m disso, confirma os padr?es de distribui??o exibidos pelas esp?cies nativas de Hemidactylus e aponta a ESEC Serid? como ?rea de prov?vel ocorr?ncia para as esp?cies do g?nero, constatando, assim, que o estabelecimento de H. brasilianus e de H. mabouia, possivelmente, ? limitado por fatores bi?ticos, ainda pouco esclarecidos. / The genus Hemidactylus Oken, 1817 has cosmopolite distribution, with three species occurring in Brazil, two of them native, H. brasilianus and H. agrius, and one exotic, H. mabouia. Considering the studies about ecology of lizards conducted in the Ecological Station of the Serid?, from 2001 to 2011, this study aimed (1) to re-evaluate the occurrence of the species of Hemidactylus in this ESEC; (2) to analyze ecological and biological aspects of the H. agrius population; and (3) to investigate the current and potential distribution of the native species of the genus in northeastern Brazil, analyzing the suitability of ESEC to this taxon. For the first two objectives, a sampling area consisting of five transects of 200 x 20 m, was inspected in alternating daily shifts for three consecutive days, from August 2012 to August 2013. For the latter objective, occurrence points of H. agrius and H. brasilianus from literature and from the database of Herpetological Collections of the UFRN and the UNICAMP were consulted to build predictive maps via the Maximum Entropy algorithm (MaxEnt). In ESEC Serid?, 62 H. agrius individuals were collected (25 females, 18 males and 19 juveniles), and two neonates were obtained from a communal nest incubated in the laboratory. No record was made for the other two species of the genus. Hemidactylus agrius demonstrated to be a nocturnal species specialized in habitats with rocky outcrops; but this species is generalist regarding microhabitat use. In the population studied, females had an average body length greater than males, and showed higher frequencies of caudal autotomy. Regarding diet, H. agrius is a moderately generalist species that consumes arthropods, especially insect larvae, Isoptera and Araneae; and vertebrates, with a case of cannibalism registered in the population. With respect to seasonal differences, only the number of food items ingested differed between seasons. The diet was similar between sexes, but ontogenetic differences were recorded for the total volume and maximum length of the food items. Significant relationships were found between lizard body/head size measurements and the maximum length of prey consumed. Cases of polydactyly and tail bifurcation were recorded in the population, with frequencies of 1.6% and 3.1%, respectively. In relation xv to the occurrence points of the native species, 27 were identified, 14 for H. agrius and 13 for H. brasilianus. The first species presented restricted distribution, while the second showed a wide distribution. In both models generated, the ESEC Serid? area showed medium to high suitability. The results of this study confirm the absence of H. brasilianus and H. mabouia this ESEC, and reveal H. agrius as a dietary opportunist and cannibal species. Further, the results confirm the distribution patterns shown by native species of Hemidactylus, and point ESEC Serid? as an area of probable occurrence for the species of the genus, the establishing of H. brasilianus and H. mabouia are probably limited by biotic factors, a fact yet little understood
4

Examining the Relationships between Form, Function, Environment, and Behavior in Adhesive Pad-bearing Lizards

Garner, Austin Michael 16 July 2021 (has links)
No description available.

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