Volume 29 1992
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Item Palaeontologia africana Volume 29(Bernard Price Institute for Palaeontological Research, 1992)Item A method of improving contrast in illustrations of coalified fossils(Bernard Price Institute for Palaeontological Research, 1992) Rayner, Richard JA simple, economic method of enhancing the contrast and, therefore, improving the qual ity of certain palaeontological photographic illustrations is outlined. The technique, which involves the use of polarising filters, in no way alters the negatives or prints. In recommending this technique, it is hoped some of the confusion arising from inadequate illustrations will be removed.Item First record of Triassic Rhynchosauria (Reptilia: Diapsida) from the Lower Zambezi Valley, Zimbabwe(Bernard Price Institute for Palaeontological Research, 1992) Raath, Michael A; Oesterlen, P M; Kitching, James WTrue rhynchosaurids are described from Zimbabwe for the first time. The fossils occur as partially associated skeletons and scattered isolates in upward-fining, micaceous fluvial sandstones of the Pebbly Arkose Formation (late Triassic) in the Western Cabora Bassa Basin, Lower Zambezi Valley. On the grounds that the dentary of the Zimbabwean form possesses a row of small, conical lingual teeth in addition to a palisade row of penicillate teeth on the occlusal surface, it is concluded that the taxon present is Hyperodapedon sp., and that it is closely related to a rhynchosaurid described from Tanzania. One bone identified as a prosauropod dinosaurian femur was found associated with the Zimbabwean rhynchosaurids. The late Triassic age suggested by the presence of advanced rhynchosaurids is supported by the occurrence of the typical Triassic fossil plant genus Dicroidium, and by the general stratigraphy of the beds which contain the fossils (i.e. the fossil-bearing beds are underlain by beds of mid-Triassic age or younger, and are overlain by beds of latest Triassic or early Jurassic age)Item An enigmatic new reptile from the Lower Triassic Fremouw Formation of Antarctica(Bernard Price Institute for Palaeontological Research, 1992) Gow, Chris EThe partial skull of a new reptile from the Lower Triassic of Antarctica is described: It has a distinctive procolophon-like dentition, but other features suggest it is a diapsid. The name Fremouwsaurus geludens is proposed for the new animal. It is not possible to place the new form in any known higher taxon, so it is necessary to establish a new Family Fremouwsauridae to receive it.Item Taxonomic status of the partial calvaria a.l. 333-45 from the Late Pliocene of Hadar, Ethiopia(Bernard Price Institute for Palaeontological Research, 1992) Ferguson, Walter WThe taxonomic status of a partial calvaria, A.L. 333-45, from the late Pliocene of Hadar, in Ethiopia, classified as a hominid and paratype of "Australopithcus afarensis" Johanson, White and Coppens 1978 is reassessed. Its total morphological pattern and adaptive affinities agree with the Pongidae, and do not exhibit a single unequivocal hominid character. The evidence in fact suggests that A.L. 333-45 represents a relatively generalized ape, the only pongid calvaria known from the late Pliocene of Africa: and may be the first skull found of Praeanthropus africanus (Weinert), 1950. Moreover, this indicates that the fossils assigned to "Australopithecus afarensis'' do not represent a single taxon: and that the reconstruction of the skull of a male "A. afarensis" seems to be a composite of pongid and hominid fossils.Item Preparation of fossil bone for histological examination(Bernard Price Institute for Palaeontological Research, 1992) Chinsamy, Anusuya; Raath, Michael APalaeo-histology is the branch of palaeontology concerned with the microscopic structure of fossil bone. Researchers entering the field for the first time become aware of a need for a concise description of a technique to prepare thin sections from fossil bone. This note aims to fill that need by describing the procedure used in a recent palaeohistological study (Chinsamy 1988, 1990, 1991, 1992). The technique described has been successfully applied to the bones of dinosaurs and mammal-like reptiles, as well as to archaeological samples ofhuman bone and also to defatted bone of recent taxa. There is no one 'correct' method of making sections of hard tissues like bones, but all existing techniques share a number of core processes in common (Enlow 1954; Enlow and Brown 1956; Honjo and Fischer 1965; Peabody 1961 ; Macfall and Wollin 1972; Buffrenil, Ricqles, Ray and Domning 1990). Although the method described here is specifically intended for use on bone, thin sections of fossilised wood have also been obtained using the same method.Item Disarticulated remains of an Ordovician metazoan from the Cedarberg Formation, South Africa: a re-interpretation of Eohostimella parva Kovacs(Bernard Price Institute for Palaeontological Research, 1992) Chesselet, PascaleSmall pointed axes previously described as a non-vascular Palaeozoic plant, Eohostimella parva Kovacs 1986, are assigned to Siphonacis parva (Kovacs) Chesselet 1990 n. comb. These carbonaceous compressions are indicator fossils for assemblages of Promissum pulchrum Kovacs 1986, which was initially interpreted as a land plant and is now thought to be a giant conodont. These fossils occur with invertebrates and algae in the Late Ashgillian Soom Shale Member of the Cedarberg Formation, in the Table Mountain Group. E. parva has a distinctive internal structure which invalidates its assignment to Eohostimella Schopf and casts doubt on its placement in the plant kingdom. Presently these small axes are of uncertain affinity although it seems likely that they are the disarticulated remains of a problematic Ordovician metazoan.