The taxonomy and biogeography of the southern African pheasant shell fauna are poorly
known. Thirty–one nominal taxa referable to Phasianelloidea have been described or
recorded in this region, but no systematic revision of these has ever been undertaken.
Morphological evidence suggests that 16 taxa represent valid species, 13 are synonyms and
two represent incorrect identifications. DNA sequence data from mitochondrial COI and 16S
markers are used to assess the validity of the described nominal southern African Tricolia
species. Phylogenetic analyses recovered seven distinct clades. Tricolia adusta, T. elongata,
T. formosa, T. kochii, T. saxatilis and T. neritina were recovered as distinct species. Tricolia
africana and T. capensis are genetically indistinguishable. However, morphological
characters of the shell are clearly diagnosable. This could be due to incomplete sorting
(ancestral polymorphism) reflecting recent speciation with rapid morphological and
ecological divergence co–incident with geographical separation. Similarly, there is little
genetic differentiation between T. bicarinata, T. insignis and T. kraussi. In this case the
similarity is also supported by morphological data as the three species are conchologically
close with intergrading shell characters, and might even be one species exhibiting
ecogeographic variation in shell form. Monophyly of the southern African Tricolia species is
not supported as well as the relationship between these and the European Tricolia pullus. In
the last chapter a molecular phylogeny based on sequence data from mtDNA (COI and
16S), nuclear (18S and 28S) and the combined data (COI, 16S, 18S and 28S) is presented
for the Phasianelloidea. Bayesian inference analyses performed on the combined data
support the monophyly of Tricolia sensu stricto, Eulithidium and Phasianella. Tricolia sensu
lato is not monophyletic, as its southern Australian and Indo–West Pacific species do not
cluster with its southern African and Eastern Atlantic representatives. The position of Hiloa
and Gabrielona within the Phasianelloidea is unresolved. Phylogenetic reconstructions using
bayesian inference support monophyly of the Phasianelloidea. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ukzn/oai:http://researchspace.ukzn.ac.za:10413/10852 |
| Date | January 2010 |
| Creators | Nangammbi, Tshifhiwa Constance. |
| Contributors | Herbert, David., Brothers, Denis J., Bowie, Rauri., Teske, Peter. |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
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