- Title
- Systematics and phylogeography of mormyrid fishes in South Africa
- Creator
- Maake, Pholoshi Abram
- Subject
- Marcusenius
- Subject
- Fishes Morphology
- Subject
- Petrocephalus
- Subject
- Fishes Phylogeny
- Subject
- Phylogeography
- Subject
- Fishes Identification
- Date Issued
- 2015-04-09
- Date
- 2015-04-09
- Type
- Academic theses
- Type
- Doctoral theses
- Type
- text
- Identifier
- http://hdl.handle.net/10962/480323
- Identifier
- vital:78431
- Description
- Two genera of mormyrids have been reognised from South Africa. Marcuseniusis the largest genus of the Mormyridae, comprising 38 species distributed throughout tropical and sub-tropical Africa. In southern and eastern Africa eight species have been recognized, including M. pongolensis from South Africa. Petrocephalus has about 30 species distributed mainly in tropical Africa, and 15 of these were recently identified in southern and eastern Africa. This thesis integrated several techniques, through the collection of complementary, but separate data sets to investigate the phylogeography of M. pongolensis in South Africa, and the systematics, evolutionary history, biogeography of Marcusenius and Petrocephalus fishes in southern and eastern Africa. Mitochondrial and nuclear genetic markers consistently demonstrated strong population structuring and identified three divergent lineages within South Africa. The widespread Pongola Lineage occurs partly in the Limpopo River system, and is very common in the Incomati, Pongola (type locality) and Kosi river systems. The Limpopo Lineage endemic only in the Limpopo River system is monophyletic with the Mhlatuze-Nseleni Lineage which is only known from the Mhlatuze and Nseleni rivers in the south. There was strong indication of historical isolation, in the form of allopatric fragmentation between genetically divergent Limpopo and Mhlatuze-Nseleni lineages. High genetic diversity was observed in the Limpopo River system within the Limpopo Lineage and the Pongola Lineage. The occurrence of the Mhlatuze-Nseleni Lineage in the far south cannot be explained by the hypothesis of confluence of rivers, river capture or episodic drainage connections, as the Mhlatuze and Nseleni Rivers would not have had a common confluence or shared low relief terrain with the Limpopo, Incomati, Pongola or Kosi river systems. Morphological studies of these lineages revealed even more differentiations and were described as: Marcusenius krameri sp. nov. for the Limpopo Lineage, and M. caudisquamatus sp. nov. from the Mhlatuze and Nseleni river systems. The specimens from the Ruvuma River were also well differentiated from all southern and eastern African species of Marcusenius, and were therefore recognised as M. lucombesisp. nov. New diagnosis characters of M. pongolensis were re-described and a key to the southern and eastern African species of Marcusenius was also provided. The results of all phylogenetic approaches that included all known southern and eastern African Marcusenius species are highly congruent and provided very strong support for recognizing Marcusenius species from these regions as a monophyletic assemblage that evolved from a single common ancestor. The southern and eastern African Petrocephalus is divided into two deeply mitochondrial and nuclear divergent Western and Eastern groups that are separated by the Victoria Falls. The phylogenetic relationships within each group were not supported and future studies incorporating more molecular characters and species will likely help to resolve the relationships. Speciation within Marcusenius and Petrocephalus ranges in the focus of at least 0.8-5 Million years ago in agreement with geological data, which suggested that vicariant events associated with the formation of the major river systems played a major role in the evolution and distribution of both genera in southern and eastern Africa. The high degree of genetic differentiation and at least four previously undescribed lineages recovered in this study suggested that mormyrid diversity within southern and eastern Africa may be underestimated. Possible threats to the studied mormyrid species and lineages and other freshwater-dependent species were identified during the course of this study. When described, the unidentified lineages would further increase the species diversity of both Marcusenius and Petrocephalus, and, therefore, the southern and eastern African ichthyofauna.
- Description
- Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2025
- Format
- computer
- Format
- online resource
- Format
- application/pdf
- Format
- 1 online resource (226 pages)
- Format
- Publisher
- Rhodes University
- Publisher
- Faculty of Science, Ichthyology and Fisheries Science
- Language
- English
- Rights
- Maake, Pholoshi Abram
- Rights
- Use of this resource is governed by the terms and conditions of the Creative Commons "Attribution-NonCommercial-ShareAlike" License (http://creativecommons.org/licenses/by-nc-sa/2.0/)
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| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details Download | SOURCE1 | MAAKE-PhD-TR15-22_embargo 2 years extended to Jul 2018.pdf | 5 MB | Adobe Acrobat PDF | View Details Download |