Wits Evolutionary Studies Institute (ESI)

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Browsing Wits Evolutionary Studies Institute (ESI) by School "School of Geosciences"

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    A new middle Permian burnetiamorph (Therapsida: Biarmosuchia) from the South African Karoo filling a gap in the biarmosuchian record
    (The Evolutionary Studies Institute, 2024-09) Matlhaga, Fonda; Benoit, Julien; Rubidge, Bruce S
    Biarmosuchia, the most basal therapsid clade, is represented by relatively few specimens known from Permian deposits in Russia and southern Africa. In both the Guadalupian (middle Permian) and Lopingian (late Permian), biarmosuchians represent less than 1% of the fossil record at the specimen level. Here, we describe a new burnetiamorph biarmosuchian, Impumlophantsi boonstrai, based on a partial skull and associated postcrania from the upper Tapinocephalus Assemblage Zone. It is characterized by the presence of a low nasal crest with a unique morphology among burnetiamorphs. Inclusion of this taxon in an updated phylogenetic analysis of biarmosuchians indicates that this specimen is one of the most basal burnetiamorphs, representing the only record of this grade from the middle Permian.
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    Cranial morphology of Jonkeria truculenta (Therapsida, Dinocephalia) and a taxonomic reassessment of the family Titanosuchidae
    (The Evolutionary Studies Institute, 2024-06) Jirah, Sifelani; Rubide, Bruce S; Abdala, Fernando
    Titanosuchidae are a group of herbivorous, long-snouted dinocephalians with definitive records known only from the middle Permian Tapinocephalus Assemblage Zone of the Beaufort Group (Karoo Supergroup) of South Africa. Here, the taxonomy of this family is revised; of the nine species currently recognized, only two are found to be valid: Titanosuchus ferox and Jonkeria truculenta, which can be distinguished on the basis of appendicular proportions. Jonkeria boonstrai, J. haughtoni, J. ingens, J. parva, J. rossouwi, and J. vanderbyli are synonymized with Jonkeria truculenta, and J. koupensis is considered a nomen dubium (Titanosuchidae indet.). Several new cranial features are described for J. truculenta, such as pachyostosis of the prefrontals, postorbitals and parietals, and an ontogenetic series for the species is presented.
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    On the importance of using standardized anatomical terminology in palaeoanthropology: The missing StW 431 pubic body
    (The Evolutionary Studies Institute, 2024-09) VanSickle, Caroline; Zipfel, Bernhard
    In 1987, a partial right pubic bone, StW 431ef, was unearthed with hominin skeletal remains at Sterkfontein Cave, South Africa. It preserved the lateral portion of the superior pubic ramus, yet has been described in the literature as a “pubic body”. We confirmed that no medial pubic fragments were discovered with this fossil and sought to explain why it has been described this way. We found that international anatomical terminology guidelines for humans define the pubic body with medial elements, while veterinary guidelines associate it with the portion near the acetabulum We suggest that as a hominin, the StW 431ef pubis should be described based on the human standards, and is thus the lateral portion of a superior pubic ramus. This case illustrates the importance of palaeoanthropologists agreeing on which international standard to follow to ensure clarity and accuracy across disciplines and over time.