Patterns of variation in hyoid morphology, chromosomal properties and craniodental
characteristics among ten chrysochlorid species from South Africa were studied
to clarify generic relationships among taxa assigned variably to Amblysomus,
Chlorotalpa and Calcochloris by previous authors.
Intra-specific variation in hyoid morphology was negligible, but inter-specific
differences were marked. Similarly, intra-specific karyotypic variation was negligible,
except in A. hottentotus, which displayed three cytotypes. These data supported the
recognition of Chlorotalpa, Calcochloris and Neamblysomus as taxa distinct from
Amblysomus.
Only one (presence/absence of M3) of the seven dental traits used by previous
authors was consistent enough within species to be taxonomically useful in this work.
Dental variability within species appeared to arise from the morphological differences
between deciduous and permanent teeth, which may occur together in the same
toothrow. Intra-specific craniometric variation in most species involved pronounced
sexual size dimorphism, but negligible age-related variation. In the more widespread
species, patterns of geographic variation were dominated by divergence in overall size,
although subtle differences in cranial shape were also evident. Multivariate analyses
confirmed the validity of subspecies in Chlorotalpa sclateri and Calcochloris
obtusirostris, and showed that A. hottentotus (as traditionally recognized) includes: four
cryptic species; five subspecies (including A. h. iris); and several populations that
should be relegated to A. corriae.
Inter-specific morphometric variation was dominated by overall size. The
species fell into two size groups, and eight phena that differed mainly in skull width,
palatal shape, rostrum breadth and claw size. Inter-specific relationships suggested by
phenetic analyses of metric and mixed-mode data were, however, incongruent owing to
discordance between different data suites. Evolutionary relationships inferred by
integrating data suites, using either equal or differential weights, indicated that a strong
phylogenetic signal was present in the data. Phylogenetic analyses showed that the
differentially weighted treatment was more consilient with character-state distributions.
A phylogram based on the differential-weights cladogram was used to derive a revised
phylogenetic classification for the Chrysochloridae. Unlike previous treatments, this
classification affords Carpitalpa and Neamblysomus generic rank, and assigns C.
leucorhina from equatorial Africa to Calcochloris, rather than to Chlorotalpa. / Thesis (Ph.D.)-University of Natal, 1995.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ukzn/oai:http://researchspace.ukzn.ac.za:10413/4006 |
| Date | January 1995 |
| Creators | Bronner, Gary N. |
| Contributors | Meester, Jurgens A. J., Rautenbach, I. L., Cooke, John A., Willan, Ken. |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
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