Abstract
An impressive body of literature has recently investigated a number of key questions on the phylogenetic patterns of extinction risk: how the tree of life would be pruned as a result of the ongoing extinction crisis? How much evolutionary diversity is at risk? How lineages have accumulated over million years? In the vertebrate group, these questions focus almost exclusively on mammals, and more recently, on amphibians, birds and reptiles. Unfortunately, similar efforts are yet to focus on fish, particularly in Africa’s freshwater ecosystems. Interestingly, recent methodological approaches have improved our ability, in the absence of complete DNA data, to reconstruct complete phylogenies. In the present thesis, the main aim is to explore those questions (mentioned above) for fish, to fill the existing knowledge gap. Specifically four objectives were set. Firstly, DNA barcode, the CO1 marker, was tested for its efficacy in assigning specimens of African Cyprinidae to their correct species. There was evidence for discriminatory power of CO1 ranging from 79% to 92%, depending on the methods used. This provides additional support for the CO1 as a good barcode for the African Cyprinidae. The second objective was to investigate what CO1 can reveal in terms of the evolutionary history of Cyprinidae in Africa. The macro-evolutionary analysis of CO1 data reveals that, in Africa, the family Cyprinidae evolves through a non-constant diversification pattern over time. In particular, two significant speciation events in the last 10 million years were found, and these events coincided with major geologic and paleo-climatic events in Africa, suggesting that they may have mediated the diversification of Cyprinidae on the continent. What is the current conservation status of these species that have been accumulated through these macro-evolutionary events? To investigate this question, the cumulative link mixed effect models were fitted to ecological and biological data of the African Cyprinidae. Five categories of...
Ph.D. (Zoology)