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.

Thesis (Ph. D.)--University of Chicago, Dept. of Organismal Biology and Anatomy. / Includes bibliographical references. Also available on the Internet.

A dissertation submitted to the Faculty of Science, University of Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science. / Dinocephalians form an important part of the Upper Permian therapsid faunas of South Africa and Russia, and have also recently been reported from China and Brazil, and even more recently a diverse dinocephalian fauna has been described from Zimbabwe. This thesis reports a new primitive tapinocephalid dinocephalian, NHMB 1556, from the Upper Madumabisa Mudstone Formation in Zimbabwe. NHMB 1556 is considered to be closely related to Avenantia and it possesses primitive tapinocephalid characters, but is more derived than Tapinocaninus, the most primitive tapinocephalid dinocephalian known. NHMB 1556 is distinguished from other tapinocephalines by having a groove on the squamosal below its dorsal contact with the parietal, a low squamosal-parietal suture on the posterior border of the temporal fenestra, a vomer which extends posteroventrally and forms the anterior margin of the interpterygoidal vacuity and basisphenoid, which is semi-circular anteroventrally. / AC2017

A Dissertation submitted to the Faculty of Science University of the Witwatersrand, .Johannesburg for the Degree of Master of Science. / A detailed morphological study of two skulls of Emydops was undertaken by using the serial grinding technique. Graphical, wax modeI and computer-3D reconstructions of various aspects of the skulls were made. The internal structures are described in detail and compared to other small dicyncdonts such as Eodicmodort, Pristerodon, Tropidostpma, Cistecepnalus and Diictodon. The structure of the skull of Emydops conforms within the limits of variation known for this genus, to descriptions given in the literature. It was found that Emydops is different from other dicynoconts in that the parasphen and has a definite suture with the pterygoid anterior to the pterygoidbasisphenoid suture, which is not noticed and mentioned for other dicynodonts, except for Emydops (Olson, 1944). / Andrew Chakane 2018

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science. Johannesburg, 2014. / Anteosaurs (Therapsida: Dinocephalia: Anteosauria) were the dominant terrestrial predators during the late Middle Permian period and became extinct at the close of the Tapinocephalus Assemblage Zone. Only two genera of anteosaurs, Australosyodon and Anteosaurus, are recognised from the Karoo rocks of South Africa. A newly discovered small anteosaurid skull from the Abrahamskraal Formation is fully described. Because of its relatively large orbits, the unfused nature of its sutures, and the lack of replacement teeth in the dental alveoli, the specimen is considered to be a juvenile Anteosaurus magnificus. A full computer-aided 3-D reconstruction of the skull enabled cranial measurements to be taken for an allometric analysis which included twenty-three measurements and eleven specimens. Positive allometry was found for four of the measurements suggesting fast growing in the temporal region, and a significant difference in the development of the postorbital bar and suborbital bar between juveniles and adults. Phylogenetic research shows that the Russian anteosaurids to be forerunners to Anteosaurus, and because the juvenile Anteosaurus (BP/1/7074) manifests many features of both Syodon and Titanophoneus, it is suggested that ontogenetic growth of Anteosaurus follows Haeckel’s Law.

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the Degree of Master of Science. Johannesburg, 2016. / Pareiasaurs were abundant, large, herbivorous parareptiles of the middle and late Permian which had a global distribution. The most basal pareiasaurs are found only in the middle Permian of South Africa, suggesting a Gondwanan origin for the group. Despite their relative abundance, most pareiasaurs are poorly known, especially the large middle Permian South African taxa that went extinct at the end of the Tapinocephalus Assemblage Zone. Historic taxonomic confusion was reduced with studies by Lee (1995, 1997a) that addressed the alpha-taxonomy of all pareiasaurs. He reduced the middle Permian South African pareiasaurs from 11 to four species: Bradysaurus baini, B. seeleyi, Embrithosaurus schwarzi and Nochelesaurus alexanderi. However this revision did not include detailed anatomical descriptions of any of the middle Permian South African Tapinocephalus Assemblage Zone taxa. The first detailed cranial description of Embrithosaurus schwarzi is presented in this contribution. Within the middle Permian pareiasaurians, Embrithosaurus has unique wide, short and stubby teeth with nine marginal cusps arranged more regularly. A cranial taxonomic reassessment of all middle Permian pareiasaurs has confirmed the validity of the four taxa identified by Lee and produced updated cranial diagnoses for each species. Diagnostic features noted by Lee and retained include an autapomorphic large distinctive maxillary boss on a strongly buckled or bent maxilla for B. baini, distinctive horizontally flat and pointed bosses on the posterior margin of the quadratojugal for Nochelesaurus and the smallest cheek flanges for B. seeleyi. Using the updated diagnoses, re-identification of 39 specimens out of 108 studied has produced updated biostratigraphic ranges for the middle Permian species. B. seeleyi is the first to make an appearance, in the middle Koornplaats Member of the Abrahamskraal Formation. B. baini first appears in the upper iii Koornplaats Member, Nochelesaurus in the Swaerskraal Member, and Embrithosaurus in the lower Moordenaars Member of the Abrahamskraal Formation. All taxa disappear by the top of the Karelskraal Member of the Abrahamskraal Formation, confirming that all the middle Permian pareiasaur species went extinct at the end of the Tapinocephalus Assemblage Zone. / MT2017

The presented study comprises a complete morphological and phylotaxonomic revision of basal Sphenacodontia, designated as the paraphyletic ‘haptodontines’. Ianthodon from the Kasimovian is known from newly identified elements, including most of the skull and particular postcrania. This species is determined as the best model for the initial morphology of the Sphenacomorpha (Edaphosauridae and Sphenacodontia). Remarkably older sphenacodontian remains from the Moscovian indicate a derived, though fragmentarily known form, possibly basal Sphenacodontoidea. The genus Haptodus is conclusively revised, including the revalidation of the type species H. baylei from the Artinskian. Haptodus grandis is renamed as Hypselohaptodus, gen. nov. “Haptodus” garnettensis is not monophyletic with Haptodus, moreover the material assigned to it yielded a greater diversity. Thus, its renaming includes Eohaptodus garnettensis, gen. nov., Tenuacaptor reiszi, gen. et spec. nov., and Kenomagnathus scotti, gen. et spec. nov. Along with Ianthodon and the basal edaphosaurid Ianthasaurus, these taxa from a single assemblage are differentiated by dentition and skull proportions, providing a case study of annidation. Since Ianthodon can be excluded from Sphenacomorpha, the larger, stem-based taxon Haptodontiformes is introduced. More derived ‘haptodontines’ apparently form another radiation, named as Pantherapsida. This new taxon includes Cutleria, Tetraceratops, Hypselohaptodus, the Palaeohatteriidae (Pantelosaurus and Palaeohatteria), and the Sphenacodontoidea. The ‘pelycosaur’-therapsid transition is affirmed as a long-term development. An integrative evolutionary hypothesis of basal sphenacodontians is provided, within which the ghost lineage of Early Permian therapsids can be explained by biome shift.

The presented study comprises a complete morphological and phylotaxonomic revision of basal Sphenacodontia, designated as the paraphyletic ‘haptodontines’. Ianthodon from the Kasimovian is known from newly identified elements, including most of the skull and particular postcrania. This species is determined as the best model for the initial morphology of the Sphenacomorpha (Edaphosauridae and Sphenacodontia). Remarkably older sphenacodontian remains from the Moscovian indicate a derived, though fragmentarily known form, possibly basal Sphenacodontoidea. The genus Haptodus is conclusively revised, including the revalidation of the type species H. baylei from the Artinskian. Haptodus grandis is renamed as Hypselohaptodus, gen. nov. “Haptodus” garnettensis is not monophyletic with Haptodus, moreover the material assigned to it yielded a greater diversity. Thus, its renaming includes Eohaptodus garnettensis, gen. nov., Tenuacaptor reiszi, gen. et spec. nov., and Kenomagnathus scotti, gen. et spec. nov. Along with Ianthodon and the basal edaphosaurid Ianthasaurus, these taxa from a single assemblage are differentiated by dentition and skull proportions, providing a case study of annidation. Since Ianthodon can be excluded from Sphenacomorpha, the larger, stem-based taxon Haptodontiformes is introduced. More derived ‘haptodontines’ apparently form another radiation, named as Pantherapsida. This new taxon includes Cutleria, Tetraceratops, Hypselohaptodus, the Palaeohatteriidae (Pantelosaurus and Palaeohatteria), and the Sphenacodontoidea. The ‘pelycosaur’-therapsid transition is affirmed as a long-term development. An integrative evolutionary hypothesis of basal sphenacodontians is provided, within which the ghost lineage of Early Permian therapsids can be explained by biome shift.:Chapter 1 ‘Haptodontines’ re-examined – An Introduction Chapter 2 New information on the cranial and postcranial anatomy of the early synapsid Ianthodon schultzei (Sphenacomorpha: Sphenacodontia), and its evolutionary significance Chapter 3 Reviewing the question of the oldest therapsid Chapter 4 Revision of the genus Haptodus (Synapsida: Haptodontiformes) and evolutionary implications from the Garnett fossil site Chapter 5 Morphological description and taxonomic status of Palaeohatteria and Pantelosaurus (Synapsida: Sphenacodontia) Chapter 6 Re-description of Cutleria and Tetraceratops (Synapsida, Sphenacodontia), with implications on the radiation of Sphenacodontoidea Chapter 7 Callibrachion and Datheosaurus, two historical and previously mistaken basal Caseasauria (Synapsida) from Europe Chapter 8 Synthesis and perspective