Gorgonopsia represent a group of specialised carnivorous therapsids that filled the role of apex predator during the Late Permian of Gondwana. Skull size in the Gorgonopsia ranges from that of a cat, to larger than any extant, terrestrial predator. Despite this degree of size variation, the observed morphological variation in the skull is relatively conservative. This study set out to better understand the extent of size and morphological variation among species attributed to the South African genus, Aelurognathus, with the aim of possibly refining the taxonomy of the genus. Aelurognathus was chosen, as it contains the largest number of described specimens (16) of any of the Rubidgeinid genera. Previous work has led to numerous revisions to the taxonomic assignment of each specimen, at both the generic and specific levels. All available specimens were studied and morphological differences at both the intraspecific and interspecific levels noted. Morphological variations allowed for the division of the six previously recognised species into three morphotaxa based on the character state of the preparietal and the extent of contact by the frontal on the supraorbital margin. Both characters have been shown to vary among individuals of extant taxa. Taking this into account, a hypothesis that all 16 specimens represent a single taxon, exhibiting a high degree of morphological variation, was tested using allometric techniques. Linear measurements of the skull were selected, such that variation in skull size and shape was accounted for in all dimensions. Results of the bivariate analyses showed a high level of correlation with the bivariate fitted lines plotted, supporting the single taxon hypothesis. While Aelurognathus has previously been divided into six species, using morphological characters, this study has shown that the characters used in the past have been unreliable. As such it is proposed that all species attributed to Aelurognathus be synonymised with the type, Aelurognathus tigriceps.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/12361 |
| Date | 01 February 2013 |
| Creators | Norton, Luke Allan |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf |
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