Wits Evolutionary Studies Institute (ESI)

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Now showing 1 - 10 of 597
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    Discovering Hominins - Application of Medical Computed Tomography (CT) to Fossil-Bearing Rocks from the Site of Malapa, South Africa.
    (Public Library of Science, 2015-12-18) Smilg, J.S.; Berger, L.R.; Smilg, Jacqueline S.
    In the South African context, computed tomography (CT) has been used applied to individually prepared fossils and small rocks containing fossils, but has not been utilized on large breccia blocks as a means of discovering fossils, and particularly fossil hominins. Previous attempts at CT imaging of rocks from other South African sites for this purpose yielded disappointing results. For this study, 109 fossil- bearing rocks from the site of Malapa, South Africa were scanned with medical CT prior to manual preparation. The resultant images were assessed for accuracy of fossil identification and characterization against the standard of manual preparation. The accurate identification of fossils, including those of early hominins, that were not visible on the surface of individual blocks, is shown to be possible. The discovery of unexpected fossils is reduced, thus lowering the potential that fossils could be damaged through accidental encounter during routine preparation, or even entirely missed. This study should significantly change the way fossil discovery, recovery and preparation is done in the South African context and has potential for application in other palaeontological situations. Medical CT imaging is shown to be reliable, readily available, cost effective and accurate in finding fossils within matrix conglomerates. Improvements in CT equipment and in CT image quality are such that medical CT is now a viable imaging modality for this palaeontological application.
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    manual
    (DURASPACE, 2005-08-17) Diol, Joe
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    Youngest dinocephalian fossils extend the Tapinocephalus Zone, Karoo Basin, South Africa.
    (Academy of Science of South Africa (ASSAf), 2015-03-01) Day, M.O.; Guven, S.; Abdala, F.; Jirah, S.; Rubidge, B.; Almond, J.
    The dinocephalians (Synapsida, Therapsida) were one of the dominant tetrapod groups of the Middle Permian (Guadalupian Epoch, ∼270-260 million years ago) and are most abundantly recorded in the Tapinocephalus Assemblage Zone (AZ) of the Main Karoo Basin, South Africa. Dinocephalians are thought to have become extinct near the top of the Abrahamskraal Formation of the Beaufort Group and their disappearance is one criterion used to define the base of the overlying Pristerognathus AZ. Because of the abundance of fossils in the Karoo, the Beaufort Group biozones form the biostratigraphic standard for later Permian terrestrial tetrapod ecosystems, so their stratigraphic delineation is of great importance to Permian palaeobiology. We report two new specimens of the rare tapinocephalid dinocephalian Criocephalosaurus from the lowermost Poortjie Member, which makes them the youngest dinocephalians known from the Main Karoo Basin and extends the Tapinocephalus AZ from the Abrahamskraal Formation up into the Teekloof Formation. The extension of the Tapinocephalus AZ relative to the lithostratigraphy potentially affects the biozone or biozones to which a fossil species can be attributed; this extension has implications for biostratigraphic correlations within the Main Karoo Basin as well as with other basins across Gondwana. These discoveries also indicate that a population of herbivorous tapinocephalids survived as rare constituents of the tetrapod fauna after most generic richness within the clade had already been lost.
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    Use of wood anatomy to identify poisonous plants: Charcoal of Spirostachys africana.
    (Academy of Science of South Africa (ASSAf), 2015-03-01) Lennox, S.J.; Bamford, M.
    Spirostachys africana Sond. (tamboti/tambotie) is a woodland tree that is often found near water. It has a poisonous and purgative latex. The archaeological site of Sibudu, a rock shelter in KwaZulu-Natal, has evidence, from well-preserved charcoal and seeds, of past environments and wood use from approximately 77-38 thousand years ago (ka). As their uses and environmental indicators are different, it is critical to confidently distinguish among the three anatomically similar woods of the Euphorbiaceae: Spirostachys africana, Sclerocroton integerrimus and Shirakiopsis elliptica. A detailed anatomical study of reference and archaeological charcoal shows that xylem vessel width increases proportionally as vessel frequency decreases, from Spirostachys africana, Sclerocroton integerrimus to Shirakiopsis elliptica. Crystals of calcium oxalate are present in ray cells of Spirostachys africana, whereas silica bodies are present in ray cells of Sclerocroton integerrimus and Shirakiopsis elliptica. Using these features, the presence of Spirostachys africana was confirmed amongst hearth charcoal of the Spotty Camel layer, with an age of approximately 58 ka and of the Mottled Deposit occupational layer, with an age of approximately 49 ka. The presence of this charcoal, collected from ancient fireplaces or sieved from surrounding sediments, implies that people at Sibudu understood and used this poisonous tree to their advantage. We are encouraged in this view by the presence of many Cryptocarya woodii leaves found on the surface of 77-ka sedge bedding at Sibudu (Wadley L et al., Science. 2011;334:1388-1391). Cryptocarya woodii has insecticidal and larvacidal properties and members of the Laurel family are well known for their medicinal properties.
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    Putting fossils on the map: Applying a geographical information system to heritage resources
    (Academic of Science of South Africa (ASSAf)., 2015-12) Van ver Walt, M.; Cooper, A.K.; Netterberg, I.; Rubidge, B.S.
    A geographical information system (GIS) database was compiled of Permo-Triassic tetrapod fossils from the Karoo Supergoup in South African museum collections. This database is the first of its kind and has great time applicability for understanding tetrapod biodiversity change though time more than 200 million years ago. Because the museum catalogues all differed in recorded information and were not compliant with field capture requirements, this information had to be standardised to a format that could be utilised for archival and research application. Our paper focuses on the processes involved in building the GIS project, capturing metadata on fossil collections and formulating future best practices. The result is a multi-layered GIS database of the tetrapod fossil record of the Beaufort Group of South Africa for use as an accurate research tool in palaeo- and geoscience research with applications for ecology, ecosystems, stratigraphy and basin development.
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    An Acheulean handaxe from Gladysvale Cave site, Gauteng, South Africa.
    (Academy of Science of South Africa (ASSAf), 2006-03) Hall, G.; Pickering, R.; Lacruz, R.; Hancox, J.; Berger, L.R.; Schmid, P.
    WE DESCRIBE A SINGLE HANDAXE FROM fossiliferous breccias at Gladysvale Cave, South Africa. The artefact is the only known tool so far discovered during the controlled excavations conducted at this site over the last decade, and was recovered from decalcified sediments near the stratigraphic interface of two breccia units, making it difficult to assign it with confidence to either. The morphology of the handaxe indicates a middle-late Acheulean industry, and preliminary electron spin resonance and palaeomagnetic dating suggest an age of greater than 780 000 years.
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    A partial skull of Paranthropus robustus from Cooper's Cave, South Africa.
    (Academy of Science of South Africa (ASSAf), 2008-03) Berger, L.R.; Kuhn, B.F.; Steininger, C.
    A partial hominin skull (COB 101) was identified in the fossil collections of the Transvaal Museum, Pretoria, attributed to the Cooper's Cave site in South Africa. The find represents the most complete hominin specimen recovered from localities at this site to date. COB 101 comprises the supraorbital, zygomatic, infraorbital and nasoalveolar regions of the right side, and the right upper third premolar. The specimen has undergone post-depositional distortion that resulted in the flattening of the facial structures. Here we describe and compare COB 101 with other hominin material from Africa and find that this specimen shares numerous diagnostic features with Paranthropus robustus. The discovery of COB 101 augments the number of specimens attributed to this species from other South African sites and other Cooper's Cave localities.
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    3D techniques and fossil identification: An elephant shrew hemi-mandible from the Malapa site.
    (Academy of Science of South Africa (ASSAf), 2011-11-07) Val, A.; Carlson, K.J; Kibii, J.M.; Steininger, C.; Churms, C.; Kuhn, B.F.; Berger, L.R.
    Conventional methods for extracting fossilised bones from calcified clastic sediments, using air drills or chemical preparations, can damage specimens to the point of rendering them unidentifiable. As an alternative, we tested an in silico approach that extended preparation and identification possibilities beyond those realisable using physical methods, ultimately proving to be crucial in identifying a fragile fossil. Image data from a matrix-encased hemi-mandible of a micromammal that was collected from the Plio-Pleistocene site of Malapa, Cradle of Humankind, South Africa, were acquired using microtomography. From the resultant images, a 3D rendering of the fossil was digitally segmented. Diagnostic morphologies were evaluated on the rendering for comparison with extant comparative specimens, positively identifying the specimen as an elephant shrew (Elephantulus sp.). This specimen is the first positively identified micromammal in the Malapa faunal assemblage. Cutting-edge in silico preparation technology provides a novel tool for identifying fossils without endangering bone integrity, as is commonly risked with physical preparation.
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    Cranial description and taxonomic re-evaluation of Kannemeyeria argintinensis (Therapsida: Dicynodontia)
    (Bernard Price Institute for Palaeontological Research, 2001) Renaut, Hancox, PJ AJ
    Examination of the holotype skull of the Triassic dicynodont Kannemeyeria argentinensis Bonaparte reveals that many of purported diagnostic characters are distortion-related. A redescription of the holotype indicates that its inclusion in the genus Kannemeyeria cannot be supported. Several characters are, however, identical to the Argentine taxon Vinceria, and we suggest that the two taxa may be congeneric. This finding challenges the validity of a global Kannemeyeria-biochron, but not necessarily the relationships of tetrapod faunal groups in South America and Africa.
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    Traditional glue, adhesive and poison used for composite weapons by ju/'hoan san in nyae nyae, Namibia. implications for the evolution of hunting equipment in prehistory.
    (Public Library of Science, 2015-10) Wadley, L.; Trower, G.; Backwell, L.; D'Errico, F.
    Ju/'hoan hunters from Nyae Nyae, near Tsumkwe in Namibia, demonstrate the manufacture of three fixative pastes made from plant extracts, and poison made from grubs and plant extracts. Ammocharis coranica and Terminalia sericea produce simple glue. Ozoroa schinzii latex mixed with carbonized Aristeda adscensionis grass is a compound adhesive. Composite poison is made from Chrysomelid grub viscera mixed with salivary extracts of Acacia mellifera inner bark and the tuber sap of Asparagus exuvialis. In order to document potential variability in the chaîne opératoire, and to eliminate inherent biases associated with unique observations, we studied manufacturing processes in three separate Nyae Nyae villages. Although there are methodological similarities in the Nyae Nyae area, we observed a few differences in contemporary traditions of poison manufacture. For example, some hunters make powder from Asparagus exuvialis tuber sap by boiling, reducing, hardening and grinding it, while others simply use heated sap. The Ju/'hoan hunting kit provides insights for archaeologists, but we must exercise caution when looking for continuity between prehistoric and historical technical systems. Some traditions have been lost to modern hunters, while others are new. We should also expect variability in the Stone Age because of geographically restricted resources. Simple glue, compound adhesive, and poison recipes identified in the Stone Age have no modern equivalents. By about 60,000 years ago at Diepkloof, simple glue was used for hafting tools, but at similarly-aged Sibudu there are recipes that combine red ochre powder with plant and/or animal ingredients. At Border Cave, novel poisons and compound adhesives were used in the Early Later Stone Age. It is possible that the complexity that we record in the manufacture of fixative pastes and poison used by Ju/'hoan hunters represents a hafting system both similar to and different from that observed at the Stone Age sites of Diepkloof, Sibudu, and Border Cave.