Browsing by Author "Zipfel, Bernhard"

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    An investigation into high gear and low gear propulsion in human gait and its relation to metatarsal diaphyseal geometric cross-sectional properties
    (University of the Witwatersrand, Johannesburg, 2023-06) Reyneker, Mark Brenden; Carlson, Kristian J.; Zipfel, Bernhard
    This study investigates the relationship between metatarsal bone form, as quantified by cross-sectional geometric properties, and its relationship to high (medial forefoot loading) versus low gear (lateral forefoot loading) push-off during the propulsion phase of the gait cycle. The objective being to assess whether forefoot loading may be variable or whether high gear loading occurs in higher frequencies, as depicted in theoretical foot function models. The study sample (n=53), made up of three broad groups, include Later Stone Age southern Africans, post-industrial individuals from South Africa, and the Jomon of Japan. Metatarsals 1-5 cross-sectional geometric properties (CSA, Ix, Iy, Imin, Imax, Zx, Zy, Zp, Zmin, Zmax) taken from CT scans at 25%, 35%, 50% and 65% metatarsal diaphyseal biomechanical lengths are grouped into high gear (metatarsal 1-2) and low gear (metatarsal 2-5) for comparison. The combined population analysis reveals that the high gear metatarsal diaphysis exhibit significantly higher strength and rigidity driven mainly by the post-industrial individuals from South Africa and the Later Stone Age southern Africans. In contrast, the Jomon of Japan, exhibit no significant differences between high and low gear metatarsals except for CSA, Imax, and Zmax. Furthermore, metatarsal 1 and 5 differ far less in cross-sectional geometric properties in the Jomon of Japan compared to the other populations except for medial-lateral strength (Zy) and torsional and average bending strength (Zp) where metatarsal 5 is significantly higher. The study findings indicate that forefoot loading demonstrates variability during the propulsion phase of gait, while also suggesting a higher frequency of occurrence for high gear push-off. This challenges current theoretical models of foot function that emphasise high gear push-off as typical and normal for striding bipedalism.
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    A case of vertebrate fossil forgery from Madagascar
    (Bernard price Institute for Palaeontological Research, University of the Witwatersrand, 2010-12) Zipfel, Bernhard; Yates, Celeste; Yates, Adam M.
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    Genetic data and radiocarbon dating question Plovers Lake as a Middle Stone Age hominin-bearing site
    (Elsevier, 2019) Lombard, Marlize; Malmstrom, Helena; Schlebusch, Carina Maria; Svensson, Emma M.; Gunther, Torsten; Coutinho, Alexandra; Edlund, Hanna; Zipfel, Bernhard; Jakobsson, Mattias
    We have sampled five out of the eleven previously identified human specimens and some faunal remains from the Plovers Lake site in the Cradle of Humankind, South Africa, for ancient DNA. We were successful in obtaining positive results for three of the human individuals and three ‘buffalo’ teeth. Based on ages obtained for flowstone and one bovid tooth, the site was interpreted previously as a hominin-bearing Middle Stone Age site of more than 60 000 years old. Our work, however, revealed that not all the material accumulated during the Pleistocene. Instead, the sampled humans and bovids most likely represent a Bantu-speaking Iron Age population (mtDNA haplogroup L3d) and their Nguni cattle. Newly obtained radiocarbon dates confirmed that these remains are probably no older than the last 500 years bp. This study demonstrates the usefulness of inter-disciplinary investigation into the human past, and the depositional and stratigraphic complexities that researchers in the Cradle of Humankind need to contend with before interpreting their assemblages.
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    The inner craniodental anatomy of the Papio specimen U.W. 88-886 from the Early Pleistocene site of Malapa, Gauteng, South Africa
    (Evolutionary Studies Institute, 2019-04) Bouchet, Florian; Ribéron, Alexandre; Heaton, Jason L.; Hoffman, Jakobus; Bam, Lunga; Jakata, Kudakwashe; Tawane, Mirriam; Tenailleau, Christophe; Zipfel, Bernhard; Beaudet, Amélie
    Cercopithecoids represent an essential component of the Plio-Pleistocene faunal assemblage. However, despite the abundance of the cercopithecoid fossil remains in African Plio-Pleistocene deposits, the chronological and geographic contexts from which the modern baboons (i.e. Papio hamadryas ssp.) emerged are still debated. The recently discovered Papio (hamadryas) angusticeps specimen (U.W. 88-886) from the Australopithecus sediba-bearing site of Malapa, Gauteng, South Africa, may represent the first modern baboon occurrence in the fossil record. Given the implication of U.W. 88-886 for the understanding of the papionin evolutionary history and the potential of internal craniodental structures for exploring evolutionary trends in fossil monkey taxa, we use X-ray microtomography to investigate the inner craniodental anatomy of this critical specimen. Our goal is to provide additional evidence to examine the origins of modern baboons. In particular,we explore (i) the tissue proportions and the dentine topographic distribution in dental roots and (ii) the endocranial organization. Consistent with the previous description and metrical analyses of its external cranial morphology, U.W. 88-886 shares internal craniodental anatomy similarities with Plio-Pleistocene and modern Papio, supporting its attribution to Papio (hamadryas) angusticeps. Interestingly, average dentine thickness and distribution in U.W. 88-886 fit more closely to the extinct Papio condition, while the sulcal pattern and relative dentine thickness are more like the extant Papio states. Besides providing additional evidence for characterizing South African fossil papionins, our study sheds new light on the polarity of inner craniodental features in the papionin lineage.
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    Morphological variation in the metatarsal bones of selected recent and pre-pastoral humans from South Africa
    (2006-03-23) Zipfel, Bernhard
    The study of the human metatarsals reveals frequent morphological variations from the typical descriptions. Pathologies of these bones in contemporary humans are common, and it has been suggested that some of these may be associated with some of these variants. Within this context, it was not clear to what extent footwear and other environmental factors such as modern substrates have influenced metatarsal morphology. This study essentially consists of three parts. First a preliminary morphometric study of the first, second and fifth metatarsals, to demonstrate the broad patterns of discrimination between selected hominoidea, namely humans, gorillas, chimpanzees and orangutans. In addition, the SKX 5017 first metatarsal fossil thought to be of Paranthropus robustus was included. Second, a primary morphometric investigation into the patterns of morphological discrimination in the five metatarsals of selected humans from South Africa, namely Sotho, Zulu, European and pre-pastoral subgroups. The contemporary human subgroups are associated with modern lifestyles and the pre-pastoral individuals represent habitually unshod forager societies from the western and southern Cape, dated 9750 - 2000 B.P. Third, a non-metric investigation into the patterns of variation in epigenetic and pathological variants of the metatarsus of the four human subgroups. A suite of existing metrical data was utilized for the preliminary hominoid study, and a suite of metrical and non-metrical data was collected for the primary human study from appropriate skeletal collections. Univariate analysis of these iv samples revealed important, though simplistic trends in morphology. Subsequent multivariate analyses utilizing principal components and canonical variates analysis were undertaken. Multivariate analysis of the hominoid samples revealed large scale variation between the species. This discrimination was on the basis of genetics, locomotor function and geography. Multivariate analysis of the human metrical data revealed very subtle morphological discrimination within and between the subgroups. Most of this discrimination appears to be genetic, followed by a functional or life-style based discrimination suggesting a broad discrimination between recent humans and the habitually unshod pre-pastoral subgroup. The epigenetic traits reveal considerable variation within groups, with similar trends between them. All subgroups have an appreciable number of identifiable pathological changes, with the recent human subgroups having the most and the prepastoral subgroup the least. In all subgroups, the hallucal metatarsal displays by far the greatest frequency in osseous modification. The main conclusions of this study are: 1.) The general patterns of morphological discrimination between the metatarsals of the human subgroups are very subtle. The non-metric traits are very variable, but do not discriminate between any of the subgroups. 2.) Both recent and ancient human groups present with similar patterns of pathological changes, but the frequency is different, these changes are to a great extent influenced by lifestyle. Regardless of temporal context, no clear correlation between morphological variation and pathological changes could be found.
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    New Cenozoic fossil-bearing site abbreviations for collections of the University of the Witwatersrand
    (Bernard price Institute for Palaeontological Research, University of the Witwatersrand, 2009-12) Zipfel, Bernhard; Berger, Lee R.
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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.
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    Partial hominin tibia (StW 396) from Sterkfontein, South Africa
    (Bernard Price Institute for Palaeontological Research, University of the Witwatersrand, 2009-12) Zipfel, Bernhard; Berger, Lee R.
    Comparison of a proximal hominin tibial fragment, StW 396 from Sterkfontein Member 4, South Africa, with the StW 514a tibia, also from Member 4 and attributed to Australopithecus africanus, indicates a degree of morphological variability that may represent the extremes of intraspecific variability or even exceed what one would expect from intraspecific variation alone. The morphology of StW 396 is human-like which suggests adaptations towards stability at the knee, whilst that of StW 514a is interpreted as being more mobile and ape-like (Berger & Tobias 1996). Four features separate the two morphological patterns. In StW 514a the attachment area of m. semimembranosus is strongly localized, whereas in StW 396 the posteromedial border is notched near the base of the lateral intercondylar tubercle; thirdly, the lateral tibial condyle of StW 514a is supero-inferiorly thin, whereas in StW 396 the lateral condyle is supero-inferiorly thickened and the contrast between the condyle and the shaft is less pronounced; lastly the articular surface of the medial condyle of StW 396 is anteroposteriorly broad and highly concave as opposed to the narrower, flatter surface of StW 514a. The degree of variability of the two specimens possibly suggests differing functional adaptations and may thus support an hypothesis suggesting that two hominin species may be represented within Sterkfontein Member 4.
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    Size and shape of the human foot bone from Klasies River main site, South Africa
    (Bernard Price Institute for Palaeontological Research, University of the Witwatersrand, 2008-04) Zipfel, Bernhard; Kidd, Robert S.
    Rightmire et al. (2006) recently described three human metatarsal bones of Middle Stone Age antiquity from Klasies River Mouth (KRM) main site, South Africa. One of these, a complete adult left first metatarsal is broadly similar to Late Stone Age (LSA) Holocene skeletons from the southern coastal margins of the Cape, and based on size, was suggested to be from a male. Our analysis subjected the KRM first metatarsal and comparative human samples to selected morphometric analyses, in an attempt to test the hypothesis regarding shape associated sexual dimorphism as a means to estimate sex in the KRM individual. The results support earlier suggestions that it falls within the range of early Holocene variation, this being very narrow both in size and shape. The size-independent shape-associated morphology, however, suggests that the individual may be female. Even though these findings imply that the KRM individual may have been female based on sexually dimorphic shape-associated discrimination in LSA Holocene people, they are not conclusive and that this individual could probably be assigned to either sex.