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Phylogeographic variation of the Karoo bush rat, Otomys unisulcatus : a molecular and morphological perspective
Thesis (MSc (Botany and Zoology))--Unkiversity of Stellenbosch, 2009.
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| Format: | Thesis |
| Language: | English |
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Stellenbosch : University of Stellenbosch
2009
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| _version_ | 1867613894873186304 |
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| access_status_str | Open Access |
| author | Edwards, Shelley |
| author2 | Matthee, Conrad A. |
| author_browse | Edwards, Shelley Matthee, Conrad A. |
| author_facet | Matthee, Conrad A. Edwards, Shelley |
| author_sort | Edwards, Shelley |
| collection | Thesis |
| dc_rights_str_mv | University of Stellenbosch |
| description | Thesis (MSc (Botany and Zoology))--Unkiversity of Stellenbosch, 2009. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/2108 |
| institution | Stellenbosch University (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:43:24.214Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2009 |
| publishDateRange | 2009 |
| publishDateSort | 2009 |
| publisher | Stellenbosch : University of Stellenbosch |
| publisherStr | Stellenbosch : University of Stellenbosch |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/2108 Phylogeographic variation of the Karoo bush rat, Otomys unisulcatus : a molecular and morphological perspective Edwards, Shelley Matthee, Conrad A. Jansen van Vuuren, Bettine University of Stellenbosch. Faculty of Science. Dept. of Botany and Zoology. Otomys unisulcatus Phylogeography Geometric morphometrics Dissertations -- Zoology Theses -- Zoology Phenotypic plasticity Bush rat -- South Africa -- Karoo -- Geographical distribution Thesis (MSc (Botany and Zoology))--Unkiversity of Stellenbosch, 2009. Phylogeographic genetic structure has been documented for a number of southern African terrestrial taxa. Information regarding geographic population genetic structuring in multiple taxa, with differing life histories, can provide insights into abiotic processes such as vicariance. A fragment of the cytochrome b mitochondrial DNA gene of a plains-dwelling species, Otomys unisulcatus, was sequenced and analysed. Two closely related geographic assemblages were found. The first assemblage (lowland group) contains populations from both the eastern and western parts of the species range, and the second comprises populations from the Little Karoo (central group). The lowland group was shown to be in a state of population expansion after a relatively recent mitochondrial DNA (mtDNA) coalescence, while the genetic signature of the central assemblage was characterized by more genetic diversity indicative of an older lineage/genetic refuge. Areas of higher elevation (namely mountain ranges) appeared to be the main factor limiting gene flow between these two groups. Aridification cycles due to glacial maximum periods probably resulted in increased dispersal leading to the widespread distribution of common haplotypes throughout the lowland group. Morphological variation in skull shape and size has been shown to follow environmental clines in some rodents. Geometric morphometric analyses on the ventral and dorsal views of the craniums of O. unisulcatus were utilised to test whether the population groupings obtained in the genetic analyses would be recovered by morphometric analyses. In addition, it was also investigated which of the environmental factors investigated influenced skull shape and size. The genetic groupings were not recovered for either the cranial shape or size. Size variation in the females correlated positively with annual rainfall, and so by proxy with habitat productivity, indicating that females which inhabited areas with lower rainfall would be larger. The significant relationship between females’ centroid sizes and rainfall was thought to be as a result of the increased nutrient requirement by this gender in the production of offspring. The males did not show a significant correlation between any of the environmental variables and centroid size. There was a significant difference between the skull shapes of the genders, further verifying the sexual dimorphism in the species. Three major clusters were found (according to cranium shape) using a Two-Block Partial Least Squares Analysis (2B-PLS), which relate to the biome boundaries within the species’ range. Variations in shape were attributed to the varying needs for strong masticatory muscles resulting from differing diets. The skull shapes of specimens occurring along the escarpment were intermediate between the first two clusters. Cranial shape in the male dorsal view dataset was significantly correlated with the environmental variables block, possibly due to the much lower minimum temperature in the Sutherland population (a population which was not included in the female analyses). It was concluded that differing diets of individuals in the respective biomes influenced the shape of the cranium of both genders. The sexual dimorphism in the cranium shapes may be as a result of the females digging tunnels (using their teeth) underneath the stick nests. Otomys unisulcatus show high levels of phenotypic plasticity throughout the range and it thus appears that the species can adapt fast to the different environmental variables. 2009-11-17T06:54:05Z 2010-06-01T08:40:39Z 2009-11-17T06:54:05Z 2010-06-01T08:40:39Z 2009-03 Thesis http://hdl.handle.net/10019.1/2108 en University of Stellenbosch application/pdf Stellenbosch : University of Stellenbosch |
| spellingShingle | Otomys unisulcatus Phylogeography Geometric morphometrics Dissertations -- Zoology Theses -- Zoology Phenotypic plasticity Bush rat -- South Africa -- Karoo -- Geographical distribution Edwards, Shelley Phylogeographic variation of the Karoo bush rat, Otomys unisulcatus : a molecular and morphological perspective |
| title | Phylogeographic variation of the Karoo bush rat, Otomys unisulcatus : a molecular and morphological perspective |
| title_full | Phylogeographic variation of the Karoo bush rat, Otomys unisulcatus : a molecular and morphological perspective |
| title_fullStr | Phylogeographic variation of the Karoo bush rat, Otomys unisulcatus : a molecular and morphological perspective |
| title_full_unstemmed | Phylogeographic variation of the Karoo bush rat, Otomys unisulcatus : a molecular and morphological perspective |
| title_short | Phylogeographic variation of the Karoo bush rat, Otomys unisulcatus : a molecular and morphological perspective |
| title_sort | phylogeographic variation of the karoo bush rat otomys unisulcatus a molecular and morphological perspective |
| topic | Otomys unisulcatus Phylogeography Geometric morphometrics Dissertations -- Zoology Theses -- Zoology Phenotypic plasticity Bush rat -- South Africa -- Karoo -- Geographical distribution |
| url | http://hdl.handle.net/10019.1/2108 |
| work_keys_str_mv | AT edwardsshelley phylogeographicvariationofthekaroobushratotomysunisulcatusamolecularandmorphologicalperspective |