Volume 44 December 2009
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Item Palaeontologia africana Volume 44(Bernard Price Institute for Palaeontological Research, 2009)Item Palaeontological Society of Southern Africa - 15th Biennial Meeting, Matjiesfontein, 2008 - Abstracts(Bernard Price Institute for Palaeontological Research, University of the Witwatersrand, 2009-12) VariousItem Partial hominin tibia (StW 396) from Sterkfontein, South Africa(Bernard Price Institute for Palaeontological Research, University of the Witwatersrand, 2009-12) Zipfel, Bernhard; Berger, Lee R.Comparison of a proximal hominin tibial fragment, StW 396 from Sterkfontein Member 4, South Africa, with the StW 514a tibia, also from Member 4 and attributed to Australopithecus africanus, indicates a degree of morphological variability that may represent the extremes of intraspecific variability or even exceed what one would expect from intraspecific variation alone. The morphology of StW 396 is human-like which suggests adaptations towards stability at the knee, whilst that of StW 514a is interpreted as being more mobile and ape-like (Berger & Tobias 1996). Four features separate the two morphological patterns. In StW 514a the attachment area of m. semimembranosus is strongly localized, whereas in StW 396 the posteromedial border is notched near the base of the lateral intercondylar tubercle; thirdly, the lateral tibial condyle of StW 514a is supero-inferiorly thin, whereas in StW 396 the lateral condyle is supero-inferiorly thickened and the contrast between the condyle and the shaft is less pronounced; lastly the articular surface of the medial condyle of StW 396 is anteroposteriorly broad and highly concave as opposed to the narrower, flatter surface of StW 514a. The degree of variability of the two specimens possibly suggests differing functional adaptations and may thus support an hypothesis suggesting that two hominin species may be represented within Sterkfontein Member 4.Item Dicynodont postcrania from the Triassic of Namibia and their implication for the systematics of Kannemeyeriiforme dicynodonts(Bernard Price Institute for Palaeontological Research, University of the Witwatersrand, 2009-12) Govender, Romala; Yates, AdamRecent years have seen a renewed interest in the postcranial anatomy of Triassic dicynodonts from Africa. This study investigates the previously undescribed dicynodont postcrania from the Omingonde Formation of Namibia. Two valid dicynodont species, based upon crania, are known from this formation: Dolichuranus primaevus and Kannemeyeria lophorhinus. Dolichuranus displays a primitive generalized cranial anatomy that has made it difficult to place in Triassic dicynodont phylogeny. Some of the postcranial specimens can be positively identified as D. primaevus on the basis that they were associated with skulls of this species. Two scapula morphologies can be distinguished among the postcranial specimens that are not positively associated with diagnostic cranial remains. One of these shares similarities with the scapula of Kannemeyeria simocephalus from South Africa and is provisionally referred to K. lophorhinus. The other displays unusual characters such as the absence of an acromion and a tubercle on the lateral surface of the scapula at the level where the acromion would be expected. Inclusion of the new postcranial data in a cladistic analysis of Triassic dicynodonts resolves the position of D. primaevus as a member of Sinokannemeyeriidae. It also causes an enigmatic unnamed postcranial taxon from equivalently aged beds in South Africa to fall within the Sinokannemeyeriidae. These results highlight the importance of including postcranial data in analyses of Triassic dicynodont relationships.Item Middle Pliocene Bovidae from Hominid-bearing sites in the Woranso-Mille area, Afar region, Ethiopia(Bernard Price Institute for Palaeontological Research, University of the Witwatersrand, 2009-12) Geraads, Denis; Melillo, Stephanie; Haile-Selassie, YohannesHominid-bearing sites of the northwestern part of the Woranso-Mille research area, dated to between 3.7 and 3.8 Mya, yield 10 species of Bovidae. The evolutionary stages of the most common species fit quite well this radiometric age. The most abundant bovid is a new species of Aepyceros, of large size, with upright, lyrated horn-cores; it is clearly distinct from the impalas of younger sites in the same area, and from those sampled at Hadar. A new species of Tragelaphus is also common; its horn-cores exhibit reduced anterior keel and antero-posterior compression foreshadowing the most common form at Hadar. A single partial Ugandax skull, despite some primitiveness, may fit into the variation range of U. coryndonae from Hadar. Other tribes are rare; the virtual absence of reduncines is a major difference from younger sites, but the occurrence of a cephalophine and of Neotragus is worth noting. This assemblage unambiguously indicates an environment with a significant component of arboreal vegetation.Item Phylogenetic interrelationships and pattern of evolution of the therapsids: testing for polytomy(Bernard Price Institute for Palaeontological Research, University of the Witwatersrand, 2009-12) Kemp, Tom S.There is little agreement on the interrelationships of the major therapsid subtaxa because none of the variously proposed sister-group relationships are supported by clearly defined, unambiguously distributed morphological characters. Rather than pursue a new cladistic analysis here, the hypothesis is explored that the lack of an agreed cladogram is because there was a polytomy at the base of the therapsid radiation that is not amenable to positive testing by conventional morphological cladistics, but that can be tested in four ways. The virtually simultaneous appearance of all the lineages except Cynodontia in the Middle Permian stratigraphic record supports the hypothesis. The palaeogeographic record, which shows a combination of taxa with first occurrences in different parts of Pangaea also supports it, though this is not strong evidence. The palaeoenvironmental record supports the polytomous hypothesis strongly by providing evidence of a coincidence between the start of the therapsid radiation and the appearance of a new suite of ecological opportunities for diversification within higher latitudes. Finally, a functional correlation analysis of the characters associated with feeding, and the reconstruction of lineages of functionally integrated organisms offers strong support by indicating that no two of the four respective lineages, Dinocephalia, Gorgonopsia, Anomodontia and Therocephalia, could have shared a functionally feasible common ancestral stage subsequent to a hypothetical ancestor at a biarmosuchian grade. The exception is Cynodontia and Therocephalia, which are inferred to have shared such a more recent common ancestral stage, and therefore to be sister-groups in the taxon Eutheriodonta.Item The postcranial skeleton of the basal therocephalian Glanosuchus macrops (Scylacosauridae) and comparison of morphological and phylogenetic trends amongst the Theriodontia(Bernard Price institute for Palaeontological Research, University of the Witwatersrand, 2009-12) Fourie, Heidi; Rubidge, Bruce S.The postcranial morphology of the early scylacosaurid therocephalian Glanosuchus macrops from the Pristerognathus Assemblage Zone of the Beaufort Group is described and compared with that of later therocephalians. This database is used as a basis to identify postcranial differences between therocephalians, gorgonopsians and cynodonts in an attempt to increase understanding of the postcranial anatomy of theriodont therapsids. It is demonstrated that some postcranial elements can be used to identify particular theriodont groups. The T-shaped interclavicle, absence of ossified sternum, humerus without shaft area, and large pubic foramen are characteristics of therocephalians from the Tapinocephalus Assemblage Zone of the Beaufort Group of South Africa.Item New Cenozoic fossil-bearing site abbreviations for collections of the University of the Witwatersrand(Bernard price Institute for Palaeontological Research, University of the Witwatersrand, 2009-12) Zipfel, Bernhard; Berger, Lee R.Item A new record of Procynosuchus delaharpeae (Therapsida: Cynodontia) from the Upper Permian Usili Formation, Tanzania(Bernard Price Institute for Palaeontological Research, University of the Witwatersrand, 2009-12) Weide, D. Marie; Sidor, Christian A.; Angielczyk, Kenneth D.; Smith, Roger M.H.Procynosuchus, the best-known Permian cynodont, has a remarkably broad geographic range, with records stretching from southern Africa to Europe. Fossils of Procynosuchus are most common in the Upper Permian Dicynodon Assemblage Zone of South Africa, but also occur in coeval East African rocks. Currently, there is one documented occurrence from the Madumabisa Mudstone Formation of Zambia, and two specimens from the Usili (=Kawinga) Formation of Tanzania. The Tanzanian specimens include a poorly preserved, incomplete skull and a partial cranium originally attributed to Parathrinaxodon proops. The latter is now considered a subjective junior synonym of Procynosuchus delaharpeae. Here we report on a new specimen collected in 2007 near the base of Kingori Mountain in Tanzania. It preserves the postorbital region of the skull and the posterior portions of both lower jaws, each containing several intact teeth. A well-preserved postcanine tooth exhibits the dental hallmarks of Procynosuchus and permits unambiguous referral to this taxon. Recent fieldwork corroborates previous suggestions that the Usili tetrapod fauna includes representatives of the Tropidostoma, Cistecephalus and Dicynodon assemblage zones of South Africa. Moreover, the presence of several endemic Usili taxa (e.g. Katumbia, Kawingasaurus, Peltobatrachus), suggests that a straightforward correlation between the Usili tetrapod fauna and a particular assemblage zone from the Beaufort Group may not be possible.Item Assessing content and bias in South African Permo-Triassic Karoo tetrapod fossil collections(Bernard price Institute for Palaeontological Research, University of the Witwatersrand, 2009-12) Nicolas, Merrill; Rubidge, Bruce S.A standardized taxonomic database as well as a Geographical Information System (GIS) database of all fossil tetrapods collected from the Permo-Triassic Beaufort Group rocks of South Africa has been compiled from a number of South African museum catalogues. The data capture required rigorous evaluation of the accuracy of the original records and the degree of collecting bias. The outcome of this evaluation endorsed the accuracy of the two databases and showed no significant degree of collecting bias. This standardized database, now linked to a new GIS-based database, will be a valuable resource to scientists researching Permo-Triassic biodiversity and faunal distribution patterns.