Volume 30 1993
Permanent URI for this collectionhttps://wiredspace.wits.ac.za/handle/10539/15933
Browse
Search Results
Item Palaeontologia africana Volume 30(Bernard Price Institute for Palaeontological Research, 1993)Item Statistical analysis of skulls of Triassic proterosuchids (Reptilia, Archosauromorpha) from South Africa(Bernard Price Institute for Palaeontological Research, 1993) Welman, Johann; Fleming, AlexSize-related differences have previously been considered to be important in distinguishing the four proterosuchian archosauromorph species described from South Africa. Previous authors hypothesized that these differences were due to allometric growth. In this study, a statistical analysis of 85 parameters measured in 12 skulls, including all the type specimens, has been carried out. The results show that all the specimens can be fitted into a growth series, supporting a hypothesis expressed by Cruickshank (1972). Variation in the growth rate of parts of the proterosuchid skull and the possible functional significance of such allometric growth patterns are investigated. On the basis of specimens measured in this study and assuming that they all belong to a single species, it would appear that the South African proterosuchids did not display a strong degree of sexual dimorphism.Item Variability in shape of the dental arcade of Homo sapiens in Late Pleistocene and modern samples from southern Africa(Bernard Price Institute for Palaeontological Research, 1993) Thackeray, J Francis; Kieser, J AMandibles are among the most common skeletal elements of Late Pleistocene specimens of Homo sapiens from southern African sites (notably Klasies River Mouth and Border Cave). For this reason mandibles have been selected for study to compare with samples drawn from modem populations (including South African negroes, Khoisanoid "Bushmen" and caucasoids). An analysis of shape of the dental arcade, based on the spatial distribution of molars, premolars and canines, indicates that several of the Late Pleistocene samples (including KRM 41815) are outside the range of variation found in modem African and caucasoid populations, and in this respect, cannot be described as "anatomically modem", sensu strictu. There appears to be a trend in the process of modernisation, from very flared dental arcades (notably in the case of the Kabwe skull, representing "archaic" H. sapiens), through moderately flared arcades (as found in Late Pleistocene "nearly modem" samples) towards a less flared condition which is found in modern Africans and caucasoids.Item 7th Biennial Conference of the Palaeontological Society of South Africa 6th-9th September 1992 Programme(Bernard Price Institute for Palaeontological Research, 1993)Item Taxonomic and evolutionary affinities of Papio izodi fossils from Taung and Sterkfontein(Bernard Price Institute for Palaeontological Research, 1993) McKee, Jeffrey KPapio izodi is an extinct papionin found at Taung and Sterkfontein. The taxonomic status of southern African fossils sometimes referred to P. izodi is clarified here in order to verify the existence of the species at Sterkfontein and define the morphological characteristics distinguishing it from P. angusticeps, a later species of similar size. P. izodi may be the earliest known species of the genus Papio in southern Africa, as the putative contemporary presence of the derived species Papio hamadryas robinsoni cannot be confirmed at Sterkfontein. P. izodi retains some of the primitive features found in Parapapio broomi, suggesting a close evolutionary link between the two species.Item Sensitivity of xylem vessel size and frequency to rainfall and temperature: implications for palaeontology(Bernard Price Institute for Palaeontological Research, 1993) February, EdBased on the xylem vessel size and frequency in fossil wood, a number of studies have developed theories on climate change through time. The basic premise of these studies is that xylem vessel size decreases while vessel frequency increases with intensifying aridity. In this paper the relationship between rainfall and xylem vessel size and frequency is examined in two extant tree species. The results indicate that rainfall is related positively to vessel diameter and negatively to vessel frequency in Combretum apiculatum and Protea caffra. Xylem vessel size of both species is between 50 and 100 µm. However, the two species exhibit different responses to rainfall in that P. caffra has much smaller diameter vessels than C. apiculatum in high rainfall areas. These differences indicate that the potential for using xylem anatomy as a palaeoclimatic indicator has not been fully utilised. A more precise picture of climate change through time is possible with a more refined statistical analysis of reliably identified fossil wood.Item Fossil wood from the Brandvlei area, Bushmanland as an indication of palaeoenvironmental changes during the Cainozoic(Bernard Price Institute for Palaeontological Research, 1993) de Wit, Michiel C J; Bamford, Marion KRemnants of Cainozoic fluvial deposits occur along the northerly flowing Sak River in Bushmanland, between Brandvlei and Sak River Station. The terraces can be subdivided into older and younger deposits, and occur approximately 60m and between 20m and 30m above the present-day river respectively. The older deposits are found to the east of the Sak River in the Geelvloer palaeo-valley. Most of the older 'terraces' are either hill-slope deposits or fans, and represent reworked fluvial sediments. A rounded vertebrate bone and several pieces of sub-rounded fossil wood were found in these deposits, which indicate a mid Miocene age for the original older deposits. Some of the fossil-wood samples have been positively identified as extant angiospermous families. The occurrence of fagaceous wood in two samples is of great interest biogeographically. Both the vertebrate fossil and the wood suggest that the mid Miocene climate was subtropical. At the end of the Miocene the wet period changed to arid conditions, and mature calcretes developed. This dry period was interrupted by pluvials during which the younger gravels were deposited. These alluvial terraces are interpreted as an aggradational sequence of braid bars associated with a wandering river, deposited under semi-arid conditions. Two well-rounded fossil-wood clasts, presumably reworked from the older terraces, were found in these sediments. One of which is identified as Polygalaceae. Based on similarities of lithofacies and style of diagenesis with the Van Wyksvlei sequence to the east, the younger terraces are probably Plio-Pleistocene in age.Item Palaeontology and the National Monuments Council(Bernard Price Institute for Palaeontological Research, 1993) Deacon, JanetteThe National Monuments Council is the only statutory body that actively protects the palaeontological resources in South Africa. It does this in three ways: by issuing permits for excavation, collection and export of palaeontological material; by declaring sites of particular scientific importance national monuments; and by compiling a register of conservation-worthy property that can include palaeontological sites. It is important that palaeontologists in South Africa are aware of the terms of the National Monuments Act and that they assist the National Monuments Council in drawing up policy and guidelines. Close co-operation between the PSSA and the NMC can be of mutual benefit with regard to formulating principles and criteria for evaluating permit applications, identifying sites that may be affected by development, and predicting the implications that promoting palaeontology may have for site protection and management.Item Undescribed suid remains from Bolt's Farm and other Transvaal cave deposits(Bernard Price Institute for Palaeontological Research, 1993) Cooke, H B SAlthough individual suid specimens from other sites have been described, only Makapansgat has been treated comprehensively, but much new material has come to light in the past three decades. The University of California African Expedition worked several sites of different ages at Bolt's Farm and the material recovered includes a virtually complete, slightly compressed, skull of Phacochoerus modestus (= P. antiquus Broom 1948) from Pit 3, associated with Antidorcas recki, and also several cranial and dental fragments from Pit 14 that belong to the typical Makapansgat Potamochoeroides shawi. Bolt's Farm was the source of a cranial specimen described by Broom as "Notochoerus meadowsi" (= Metridiochoerus andrewsi); other specimens referred to this taxon and described by Shaw as from "Sterkfontein Lime Works" more probably came from Bolt's Farm as well. Broom's cranium and a pair of mandibles have closer resemblances to Metridiochoerus jacksoni of East Africa. Swartkrans has yielded both described and undescribed material referred to Phacochoerus modestus and to Metridiochoerus. Discounting Shaw's material, only one small specimen has come from the Sterkfontein Type Site, a mandible fragment of a juvenile with an incompletely formed third molar in alveolus but it can be matched remarkably closely with a specimen from Makapansgat and there is very little doubt that it belongs to Potamochoeroides shawi. An undescribed third molar from the pink breccia at Makapansgat is comparable with early Notochoerus scotti from East Africa. The status of Notochoerus capensis is reconsidered.Item Dicynodont (Therapsida) bone histology: phylogenetic and physiological implications(Bernard Price Institute for Palaeontological Research, 1993) Chinsamy, Anusuya; Rubidge, Bruce SThe bone histology of humeri of a number of taxonomically well established and easily definable dicynodont genera is described and compared. The bone of Aulacephalodon, Cistecephalus, Dicynodon, Endothiodon, Lystrosaurus, Kannemeyeria and Oudenodon consists of alternating fibro-lamellar and lamellated bone tissue, while that of Diictodon consists only of fibro-lamellar tissue. The presence of fibro-lamellar bone in all the genera studied, indicates that the bone was deposited rapidly, but the occurrence of lamellated bone tissue suggests that all the genera except Diictodon, also had intermittent periods of slow growth. This is the first time that a comparative study of bone histology of different dicynodont genera has been attempted by using one particular bone element to standardise intergeneric comparisons.