Volume 28 1991

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Browsing Volume 28 1991 by Keyword "taphonomy"

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    Palaeo-ecology of the Sterkfontein hominids: a review and synthesis
    (Bernard Price Institute for Palaeontological Research, 1991) McKee, Jeffrey K
    Excavations at the Sterkfontein hominid fossil site have yielded a rich and revealing faunal assemblage. Evolutionary transitions are evident in early hominids and associated fauna between the times represented by Members 4 and 5. Member 4 has yielded a large and variable sample of Australopithecus africanus as well as evidence of considerable species diversity among the artiodactyls, carnivores and primates. The appearance of early Homo along with stone and bone tools in Member 5 coincides with a reduction of species representation in the orders of larger mammals as well as with the occurrence of new derived species and apparent extinctions. Three hypotheses have been suggested to account for the trends seen in the hominid-bearing members of the Sterkfontein Formation. The 'Climatic Change Hypothesis' accounts for the evolutionary trends by the causal factors of global and local cooling and aridification with evidence of savanna-grasslands supplanting an earlier environment with a denser cover of vegetation. The 'Taphonomic Hypothesis' explains changes in relative species representation at Sterkfontein in terms of the bone-accumulating agents; in Member 4 primary carnivores were largely responsible for the deposition of large mammalian fauna, whereas the scavenging activities of early Homo would have accounted for much of the bone and all of the artefacts found in Member 5. A third proposition is the 'Species Interaction Hypothesis', a derivative of the ' Red-Queen Hypothesis'; here the dynamics of species interaction, including competition and commensalism among hominids, carnivores and cercopithecids, propel the evolutionary changes and cause the extinctions. These hypotheses are not mutually exclusive, but the relative effects of the factors involved must be verified or refuted with better chronological controls and further analyses of the African fossil sites. The Sterkfontein Formation represents a microcosm in which various scenarios of African mammalian evolution can be tested.
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    The palaeontology of Haasgat a preliminary account
    (Bernard Price Institute for Palaeontological Research, 1991) Keyser, Andre W
    Haasgat is a cave on the steep western slope of the upper reach of the Witwatersrand Spruit, on the farm Leeuwenkloof 480 lQ, in the Brits District. It was heavily mined for flowstone (calcite). The cave contains a deposit offossiliferous cave silt and breccia that was partially removed by the miners and dumped on the steep slopes of the valley. The original entrance was probably a shallow inclined pit, leading into an upper chamber and then into the preserved depository. Both porcupines and carnivores served as accumulating agents for the bones. Fossils of the primates Parapapio and Cercopifhecoides, hyaena (Chasmaporthetes), fox, porcupines, several species of bovids and two species of Hyrax have been recovered. An insufficient number of fossils have been prepared to determine the age of the deposit with certainty. The deposit was provisionally thought to be of Pliocene age because of the occurrence of Parapapio. At this stage it would be unwise to correlate this occurrence with any other caves in this age range. It is concluded that the cave silts were deposited by flash floods, under a wetter climatic regime than that of the present.