Volume 37 2001

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    Carboniferous pycnoxylic woods from the Dwyka Group of southern Namibia
    (Bernard Price Institute for Palaeontological Research, 2001) Bangert, Berthold; Bamford, Marion K
    Glacial deposits of the Dwyka Group between Keetmanshoop and Mariental in southern Namibia have been reinvestigated for palaeontological remains and associated tuff horizons in an attempt to accurately date the deposits. SHRIMP-based dating of juvenile zircons from these tuff horizons provide ages which cumulate in the latest Carboniferous (Gzelian). The pycnoxylic woods Megaporoxylon scherziKrausel and Megaporoxylon kaokense Krausel are described in detail for the first time and are compared with similar permineralised woods from Gondwana. Based on previous fossil wood studies covering the rocks of the main Karoo Basin, these species occur only in the Dwyka and lower Ecca Groups in southern Africa and do not extend to the upper Ecca Group.
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    Cranial anatomy of the giant Middle Triassic temnospondyl Cherninia megarhina and a review of feeding in mastodonsaurids
    (Bernard Price Institute for Palaeontological Research, 2001) Damiani, Ross J
    The skull of Cherninia (,Parotosuchus') megarhina, a giant but poorly known mastodonsaurid temnospondyl from the Upper Horizon of the Middle Triassic N'tawere Formation of the Upper Luangwa Valley, Zambia, is redescribed and refigured in detail for the first time. Cherninia megarhina is highly derived in most aspects of its cranial morphology and is characterised by the presence of a massively broad and elongated snout, relatively tiny orbits that are set well back on the skull roof, small, near-laterally directed tabular horns, an occipital sensory sulcus, and prominent, forked ridges on the skull roof. The palate is characterised by the presence of a ventral exoccipital-pterygoid contact, a short basicranial suture, a narrow parasphenoid body, a broad pterygoid body, and choanae that are placed far forward of the interpterygoid vacuities. The presence in Cherninia megarhina of numerous cranial autapomorphies justifies its separation from Parotosuchus. These autapomorphies are shared with Cherninia (‘Parotosuchus') denwaifrom the Middle Triassic Denwa Formation of India. The lateral orientation of the tabular horns and morphology of the otic region suggests that Cherninia megarhina is slightly more derived than the Indian species. Mastodonsaurids have traditionally been perceived as passive, benthic suction-feeders. However, recent work on the anatomy and functional morphology of the skeleton of mastodonsaurids suggests that they were designed for active swimming and predation. As such, it is hypothesised that prey capture was achieved using sideways sweeps of the head rather than suction-feeding.
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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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    Interpretive problems in a search for micro-invertebrate fossils from a Neoproterozoic limestone in Namibia
    (Bernard Price Institute for Palaeontological Research, 2001) Brain, C K; Hoffman, K -H; Prave, A R; Fallick, A E; Coetzee, J; Botha, A J
    Attention is focussed on a carbonate sequence in the Auros Formation of the Otavi Group in northern Namibia, where several limestone layers are found to have been phosphatised. These contain an abundance of unusual objects, some of which suggest sponge-like microfossils, whereas others superficially resemble bivalved shells. Alternatively they may be pseudofossils - the deceptive products-of a phosphatisation process and subsequent diagenetic effects in the limestone. Since this deposit antedates the ca. 590 million-year-old Ghaub or Marinoan glaciation, the presence of any potential metazoan fossils is worth investigating. The objects in question are described and alternative interpretations are discussed.
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    Locomotor and habitat classifications of cercopithecoid postcranial material from Sterkfontein Member 4, Bolt's Farm and Swartkrans Members 1 and 2, South Africa
    (Bernard Price Institute for Palaeontological Research, 2001) Elton, Sarah
    Much southern African cercopithecoid postcranial material is not associated with craniodental remains. Consequently, this postcranial material cannot be confidently assigned to a particular taxon, with the result that little is known about the locomotor strategies and habitat preferences of specific Plio-Pleistocene cercopithecoids from southern Africa. However, cercopithecoid postcrania can provide important information about habitats that were present at fossil sites, even when the material is not attributed to taxa. In this paper, ecomorphic analysis is used to assign cercopithecoid postcranial material from Sterkfontein Member 4, Bolt's Farm and Swartkrans Members 1 and 2 to one of three habitat/locomotor categories: forest-living arboreal quadrupeds (‘forest arboreal'), open habitat terrestrial quadrupeds (‘open terrestrial') and open habitat cercopithecoids using a mix of arboreal and terrestrial quadrupedalism (‘open mixed'). Cercopithecoids representing all three habitat categories were found in the samples from Sterkfontein Member 4 and Bolt' s Farm, suggesting that monkeys using a range of habitats and locomotor strategies were present at these sites. However, no 'forest arboreal' cercopithecoids were found in the samples from Swartkrans Members 1 and 2, indicating that cercopithecoids at these localities probably depended largely on open habitats. The habitat and locomotor strategy data were also used in combination with locality-based listings of fossil cercopithecoid craniodental remains to suggest possible locomotor strategies for several southern African Plio-Pleistocene cercopithecoid taxa, including Parapapio broomi (possibly 'forest arboreal'), Parapapio jonesi (‘open terrestrial'), Papio robinsoni (‘open terrestrial') and Cercopithecoides williamsi (‘open mixed').
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    A new actinopterygian fish species from the Late Permian Beaufort Group, South Africa
    (Bernard Price Institute for Palaeontological Research, 2001) Bender, Patrick
    A new genus and species of actinopterygian (ray-finned) fish, Bethesdaichthys kitchingi, is described from the Tatarian, Late Permian, Lower Beaufort Group of South Africa. Bethesdaichthys is presently known from three localities, two in the New Bethesda and one in the Victoria West districts of the Karoo region respectively. The fossils were recovered from within the Abrahamskraal Formation Tapinocephalus Assemblage Zone at the Victoria West locality, and from an uncertain Formation possibly closely equivalent to the Balfour Formation, within the Dicynodon Assemblage Zone at the New Bethesda sites. Bethesdaichthys kitchingi is a fusiform fish, up to approximately 300mm in total length, with the skull displaying a moderately oblique suspensorium, and a maxilla with a large sub-rectangular postorbital blade. Furthermore there is a complex of four suborbital bones adjacent to the orbit. The pectoral fin is large relative to body size and the tail is heterocercal with an elongate tapered dorsal body lobe. The anterior midflank scales in particular exhibit a distinctive dermal ornamentation consisting of numerous ganoine ridges. The phylogenetics and interrelationships of Bethesdaichthys kitchingiare examined. It appears to exhibit a relatively conservative morphology similar to that found in possibly related Carboniferous taxa such as the South African taxa Australichthys and Willomorichthys. Bethesdaichthys kitchingiis derived relative to stem-actinopterans such as the Howqualepis and Mimia, and also derived relative to southern African Palaeozoic actinoptyerygians such as Mentzichthys jubbi; and Namaichthys schroeden; but basal to stemneopterygians such as Australosomus, Perleldus and Saurichthys.
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    New evidence of the Giant Hyaena, Pachycrocuta brevirostris (Carnivora, Hyaenidae), from the Gladysvale Cave deposit (Plio-pleistocene, John Nash Nature Reserve, Gauteng, South Africa)
    (Bernard Price Institute for Palaeontological Research, 2001) Mutter, Raoul J; Berger, Lee R; Schmid, Peter
    A well preserved cranium which represents the most complete skull of Pachycrocuta brevirostris (Carnivora, Hyaenidae) discovered in Africa, and a maxillary fragment from the Gladysvale Cave Deposit (John Nash Nature Reserve, Gauteng, South Africa) are described and compared to other fossil and extant hyaenid specimens from South Africa and Europe. In addition, some aspects of functional morphology in the hyaenid dentition are reconsidered and suggested to be directly related to the palaeoecological role of P. brevirostris.
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    New Viverrinae (Carnivora: Mammalia) from the basal Middle Miocene of Arrisdrift, Namibia
    (Bernard Price Institute for Palaeontological Research, 2001) Morales, Jorge; Pickford, Martin; Soria, Dolores; Fraile, Susan
    A new genus and species of viverrid of modern type, Orangic!is gariepensis, is described from the basal Middle Miocene locality of Arrisdrift in southern Namibia. It is the earliest known representative of the subfamily Viverrinae from Africa. Detailed examination of the mongoose-like carnivores of the early Miocene of Africa, hitherto all assigned to the family Viverridae, reveals that none of them are related to this group.
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    Palaeontologia africana Volume 37
    (Bernard Price Institute for Palaeontological Research, 2001)
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    A partial skeleton of the tritheledontid Pachygenelus (Therapsida: Cynodontia)
    (Bernard Price Institute for Palaeontological Research, 2001) Gow, Chris E
    Tritheledontids are advanced cynodonts that are considered the sister group of Mammalia. To date the postcranial skeleton has remained largely unknown, so that cladistic analyses are based on cranial characters only. This paper describes a specimen of the tritheledontid Pachygenelus which has most of the skull and vertebral column, a complete shoulder girdle, and most of the forelimb. The girdle and limb are closely comparable to those of Massetognathusand Eozostrodon, and unlike these elements in tritylodontids, which are more derived for fossorial specialisations.
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    Preliminary phylogenetic analysis and stratigraphc congruence of the dicynodont anomodonts (Synapsida: Therapsida)
    (Bernard Price Institute for Palaeontological Research, 2001) Angielczyk, Kenneth D
    A preliminary phylogenetic analysis of 20 well-known dicynodont taxa was conducted using modern cladistic methods. Many past phylogenetic hypotheses were corroborated, but others conflict with the results of this analysis. Most notably, Diictodon, Robertia, and Pristerodon are reconstructed in more basal positions than previously suggested, whereas Endothiodon and Chelydontops occupy a more crown ward position. These findings are consistent with novel evolutionary scenarios for characters such as the presence of postcanine teeth and anterior palatal ridges. The Relative Completeness Index and Gap Excess Ratio were used to examine the degree of fit between the most parsimonious cladograms of this study and the stratigraphic record of the dicynodonts. Although the results of this analysis suggest that the preferred cladogram is relatively consistent with stratigraphy, the presence of some ghost ranges and ghost lineages imply that the fossil record of dicynodonts is not as complete as is sometimes stated. These findings are important because there is a long tradition of intensive collecting in regions where dicynodont fossils are common; sections of several dicynodont lineages may not be preserved in these areas.