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Thesis (MSc)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: South Africa is known for its high marine invertebrate diversity but the evolutionary histories of these species are largely unknown. The present study contributes to the growing body of phylogeographic studies of southern African coastal species. The main aim is to better understand the colonization and diversification of South African barnacles. To investigate the phylogeographic pattern in the southern African volcano barnacle, Tetraclita serrata, 410 individuals from 20 sampling localities were analyzed. In addition, to understand the colonization and diversification patterns of South African barnacle species, nine taxa were included in a molecular phylogeny derived from the nuclear gene, 18S rRNA. With only a limited number of 18S sequences available on GenBank, a separate phylogenetic tree, for the mitochondrial gene, was constructed to determine whether the genus Tetraclita is monophyletic. Restricted gene flow in some geographical areas was hypothesized for T. serrata based on oceanic circulation patterns; known biogeographic regions; and features such as the Agulhas Bank, which has shaped the population genetic structure of several other South African marine organisms. The population genetic structure was investigated using the mitochondrial cytochrome oxidase subunit 1 (CO1) and nuclear internal transcribed spacer 1 (ITS1) genes. Phylogenetic and population genetic analyses of the CO1 gene revealed two distinct genetic clades with overlapping distributions. The nuclear ITS1 data performed on a subset of individuals drawn from both mtDNA clades revealed a single lineage. The pattern observed can be ascribed to a historical event that may have been responsible for the formation of allopatric lineages that have since come into secondary contact. On the other hand, the pattern observed may be as result of incomplete sorting of nDNA alleles, in which case, given that the two mtDNA clades are not geographically isolated, could be explained by selective pressures acting on the species due to ecological constraints. No clear phylogeographic structure was found within each of these clades and the direction of gene flow of T. serrata individuals can be linked to the oceanographic features found along the South African coast. In contrast to most other South African marine species studied to date, the haplotype network, mismatch distributions and time since expansion suggest that the effective population size of T. serrata was not severely affected by the Last Glacial Maximum. It is proposed that further investigations into the phylogeography of coastal marine species, particularly obligatory sessile species such as barnacles, are required to determine whether the patterns observed in T. serrata is a rare history, or not. Neighbour-joining, maximum parsimony and Bayesian analyses on the CO1 gene provide evidence for the monophyly of the genus Tetraclita; however, Tetraclita species found in South Africa do not share a common ancestry suggesting multiple colonization events. This study has also accidently led to the discovery of an introduced species, Balanus perforatus, native to Europe, and I discuss the potential of the alien becoming invasive on the east coast of South Africa where it was found. / AFRIKAANSE OPSOMMING: Suid-Afrika is bekend vir sy hoë mariene ongewerwelde diversiteit, maar die evolusionêre geskiedenis van hierdie spesies is grootliks onbekend. Hierdie studie is gedoen om by te dra tot die filografiese studies van suider Afrikaanse kus spesies en om die kolonisasie en diversifikasie van die Suid-Afrikaanse eendmossels beter te verstaan. Om die genetiese struktuur van die bevolkings van die vulkaan eendmossel, Tetraclita serrata, wat langs die Suid-Afrikaanse kuslyn voorkom, te bestudeer, was 410 individue van 20 lokaliteite ontleed. Daarbenewens, om die kolonisasie en diversifikasie van Suid-Afrikaanse eendmossels te verstaan, was nege spesies ingesluit in 'n molekulêre filogenie wat gebaseer is op die kern geen, 18s rRNA. Met slegs 'n beperkte aantal 18s DNS volgordes beskikbaar op GenBank,is 'n aparte filogenetiese boom, vir die mitochondriale geen COI, gekonstrueer om te bepaal of die genus Tetraclita monofileties is. Beperkte geen-vloei in sommige geografiese gebiede was verwag vir T. serrrata gebaseer op oseaniese sirkulasiepatrone; bekende biogeografiese streke, en kenmerke soos die Agulhas Bank, wat die filogeografiese struktuur van verskeie ander Suid- Afrikaanse mariene organismes beïnvloed het. Die genetiese struktuurvan die bevolkings is geondersoek met behulp van die mitochondriale sitochroom oksidase subeenheid 1 (COI) en kern interne getranskripeerde spasieërder 1 (ITS1) gene. Geen duidelike bevolkings genetiese struktuur is gevind nie en die rigting van geenvloei van T. serrata individue kan gekoppel word aan die oseanografiese kenmerke wat langs die Suid-Afrikaanse kus voorkom. Filogenetiese en bevolking genetiese ontleding van die COI geen openbaar twee afsonderlike klades maar met oorvleuelende geografiese verspruidings. Die ITS1 data-analise wat uitgevoer was op 'n subset van individue wys op 'n enkele spesie. Die waargenome patroon dui op 'n belangrike historiese verskil tussen die twee klades. 'n Geskiedkundige gebeurtenis was dalk verantwoordelik vir die vorming van twee evolusionêre lyne wat sederdien sekondêre kontak het. Aan die ander kant, kan die patroon waargeneem word as gevolg van die onvolledige sortering van nDNA allele, in welke geval, gegee dat die twee mtDNA clades nie geografies geïsoleer is nie, dit verduidelik kan word deur selektiewe druk wat op die spesie was as gevolg van fisiologiese of ekologiese beperkings. Die statistiese parsimonie netwerk, ongelyksoortige verspreidings en tyd sedert die bevolkingsuitbreiding dui daarop dat T. serrata die laaste ysagtige maksimum tydperk oortleef het. Tot op hede het geen Suid- Afrikaanse mariene spesies so 'n patroon gewys nie. So, verdere ondersoeke in die filogeografie van die kus mariene spesies, veral verpligte sittende spesies soos eendmossels, word vereis om te bepaal of die patroon waargeneem in T. serrata 'n seldsame geskiedenis het, of nie. Buur-aansluiting, maksimum parsimonie en Bayesian afleiding op die CO1 geen het bewyse verskaf vir die monofiletiese afkoms van die genus Tetraclita, maar Tetraclita spesies wat in Suid Afrika gevind is, deel nie ‘n gemeenskaplike afkoms nie, wat weer bewyse verskaf vir verskeie kolonisasie gebeure. Hierdie studie het gelei tot die ontdekking van 'n eksotiese spesie, Balanus perforatus, inheems aan Europa, en die potensiaal van die indringer om ontwykend te raak aan die ooskus van Suid-Afrika waar dit gevind is word bespreek. / The South African National Research Foundation (NRF) and Stellenbosch University

This thesis examines the political thought of Achille Mbembe. It deploys decolonial critical analysis to unmask traces of coloniality with regard to the African existential conditions foregrounded in the conception of the African subject, its subjection, and subjectivity. The theoretical foundation of this thesis is decolonial epistemic perspective—the epistemic intervention that serves as a lens to understand Mbembe’s work and—that is the theoretical foundation outside the Euro-North American “mainstream” canon foregrounded in coloniality. Decolonial epistemic perspective in this thesis is deployed to expose three kinds of coloniality in Mbembe’s work, namely: coloniality of power, coloniality of knowledge and coloniality of being. The thrust of this thesis is that Mbembe’s political thought is inadequate for the understanding of the African existential condition in that it does not fully take coloniality into account. In order to acknowledge the existence of coloniality through decolonial critical analysis, the political thought of Mbembe is examined in relation to modes of self-writing, power in the postcolony, the politics of violence in Africa, Frantz Fanon’s political thought, and the idea of South Africa as major themes undertaken in this thesis. Decolonial critical analysis deals with foundational questions that have relevance to the existential condition of the African subject and the manner in which such an existential crisis can be brought to an end. These foundational questions confront issues like—who is speaking or writing, from where, for whom and why? This thesis reveals that Mbembe is writing and thinking Africa from outside the problematic ontology of the African subject and, as such, Mbembe precludes any form of African subjectivity that challenges the Euro-North American canon. This then reveals that Mbembe is not critical of coloniality and this has the implications in that subjection is left on the wayside and not accounted for. Having explored the genealogy, trajectory and horisons of decolonial critical analysis to understand the political thought of Mbembe, this thesis highlights that it is essential to take a detour through the shifting of the geography of reason. Herein lies the originality of this thesis, and it is here that Africa is thought from within a standpoint of decolonial critical analysis and not Africa that is thought from the Euro-North American canon. Therefore, the shifting of the geography of reason is necessary for the authorisation of the subjectivity of the African subject in order to combat subjection. / Political Sciences / D. Litt. et Phil. (African Politics)

This thesis examines the political thought of Achille Mbembe. It deploys decolonial critical analysis to unmask traces of coloniality with regard to the African existential conditions foregrounded in the conception of the African subject, its subjection, and subjectivity. The theoretical foundation of this thesis is decolonial epistemic perspective—the epistemic intervention that serves as a lens to understand Mbembe’s work and—that is the theoretical foundation outside the Euro-North American “mainstream” canon foregrounded in coloniality. Decolonial epistemic perspective in this thesis is deployed to expose three kinds of coloniality in Mbembe’s work, namely: coloniality of power, coloniality of knowledge and coloniality of being. The thrust of this thesis is that Mbembe’s political thought is inadequate for the understanding of the African existential condition in that it does not fully take coloniality into account. In order to acknowledge the existence of coloniality through decolonial critical analysis, the political thought of Mbembe is examined in relation to modes of self-writing, power in the postcolony, the politics of violence in Africa, Frantz Fanon’s political thought, and the idea of South Africa as major themes undertaken in this thesis. Decolonial critical analysis deals with foundational questions that have relevance to the existential condition of the African subject and the manner in which such an existential crisis can be brought to an end. These foundational questions confront issues like—who is speaking or writing, from where, for whom and why? This thesis reveals that Mbembe is writing and thinking Africa from outside the problematic ontology of the African subject and, as such, Mbembe precludes any form of African subjectivity that challenges the Euro-North American canon. This then reveals that Mbembe is not critical of coloniality and this has the implications in that subjection is left on the wayside and not accounted for. Having explored the genealogy, trajectory and horisons of decolonial critical analysis to understand the political thought of Mbembe, this thesis highlights that it is essential to take a detour through the shifting of the geography of reason. Herein lies the originality of this thesis, and it is here that Africa is thought from within a standpoint of decolonial critical analysis and not Africa that is thought from the Euro-North American canon. Therefore, the shifting of the geography of reason is necessary for the authorisation of the subjectivity of the African subject in order to combat subjection. / Political Sciences / D. Litt. et Phil. (African Politics)