Wits Evolutionary Studies Institute (ESI)

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End date: 2019Subject: search.filters.subject.biostratigraphy

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    First occurrence of the dicynodont Digalodon (Therapsida, Anomodontia) from the Lopingian upper Madumabisa Mudstone Formation, Luangwa Basin, Zambia
    (Evolutionary Studies Institute, 2019-04) Angielczyk, Kenneth D.
    Digalodon is a rare emydopoid dicynodont first described from upper Permian rocks in the Karoo Basin of South Africa. During fieldwork in the upper Madumabisa Mudstone Formation of the Luangwa Basin (Zambia) in 2014, a small dicynodont skull was discovered that conforms very well to the recently revised diagnosis of Digalodon rubidgei, although some minor differences between the Zambian and South African specimens are apparent. The Zambian occurrence of Digalodon expands the known geographic range of the genus, which was previously limited to a small set of localities in the vicinity of the town of Graaff-Reinet (Eastern Cape). Based on historical specimens, Digalodon is thought to have a comparatively short stratigraphic range in the Balfour Formation that spans the boundary between the Cistecephalus and Daptocephalus assemblage zones. This observation may allow refinement of biostratigraphic correlations between the Karoo and Luangwa Basins, but discovery of more precisely-provenanced specimens in the Karoo is needed to fully assess Digalodon’s biostratigraphic utility.
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    Biesiespoort revisited: a case study on the relationship between tetrapod assemblage zones and Beaufort lithostratigraphy south of Victoria West
    (Evolutionary Studies Institute, 2018-12) Day, Michael O.; Rubidge, Bruce S.
    The relationship between the tetrapod assemblage zones of the South African Karoo Basin and the lithostratigraphic divisions of the Beaufort Group is well-established, and provides an independent means of dating fossil occurrences. However, this relationship may not be consistent across the basin; a discrepancy exists between the historical tetrapod assemblages in the vicinity of Victoria West, Northern Cape Province, and the expected tetrapod assemblage zones based on mapped geology. In order to examine this disconnect, we collected fossils at two localities close to Biesiespoort railway station, a locality that was visited on a number of occasions by Robert Broom. Our fossil samples support the biostratigraphic determinations of Broom and thus confirmthat the stratigraphic extent of the biozones at these localities differs from their type areas further south. The reasons for this are unclear but could be related to the northward younging of the lithological units, implying complex depositional processes, or result from difficulties in mapping. Nevertheless, caution should be exercised when using mapped geology near Victoria West as a guide to the age of fossils found there.
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    Permo-Triassic fossil woods from the South African Karoo Basin
    (Bernard Price Institute for Palaeontological Research, 1999) Bamford, Marion K
    The Karoo Basin extends over more than half of the South African land surface and incorporates sediments deposited over a period of more than 100 million years, from the Upper Carboniferous to the Lower Jurassic. Biozones have been established on the basis of the abundant vertebrate fauna. Fossil plant deposits are numerous but best represented by the Lower Permian Glossopteris floras and Middle to Upper Triassic Dicroidium floras. Fossil woods occur throughout the sequence. In this paper previously described woods are discussed, newly collected woods are described and an attempt is made to correlate the woods with the Formations and vertebrate biozones. Prototaxoxylon africanum (Walton) Krausel and Dolianiti is common but restricted to the Permian (Ecca and Lower Beaufort Groups). Prototaxoxylon uniseriale Prasad has the same distribution but is rare. Australoxylon teixeirae Marguerier extends from the Ecca to the middle Beaufort. Araucarioxylon occurs throughout the Karoo but there are several species that have different ranges. Araucarioxylon africanum Bamford sp. nov. occurs throughout the Beaufort and into younger deposits. Araucarioxylon karooensis Bamford sp. nov. occurs in the Normandien Formation of the Beaufort Group. Woods with podocarpacean affinities, recognized as Mesembrioxylon, first occur in the uppermost Beaufort and extend into the Cretaceous. The woods can, therefore, be used as broadscale biostratigraphic indicators but further data need to be collected.
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    A new find of Trematosuchus (Amphibia, Temnospondyli) from the Cynognathus Zone of South Africa
    (Bernard Price Institute for Palaeontological Research, 1994) Shishkin, Michael A; Welman, Johann
    Some aspects of the cranial morphology of Trematosuchus sobeyi, a temnospondylous Trematosaurid amphibian from the South African Cynognathus Zone, are described in detail for the first time from a new fossil find referred to this form. The new specimen is similar in size to that of the holotype of Trematosuchus sobeyi but differs in the more moderate elongation of the snout. Apart from the presence of the septomaxilla, the validity of the genus Trematosuchus is reconfirmed inter alia by its much larger size and the position of the supraorbital sensory groove alongside the lachrymal margin rather than crossing this bone. This last characteristic differentiates Trematosuchus from all other trematosauroids. T. Sobeyi is of particular importance since it represents the only purely freshwater Gondwanan form closely comparable to the European Trematosaurus. The presence of T. Sobeyi in the lowermost strata of the Cynognathus Zone in South Africa, in association with some other forms related to the Upper Olenekian (Middle Buntsandstein) tetrapod assemblage of Europe, indicates that these strata belong to the Scythian in contrast to the higher strata of the Cynognathus Zone which are Anisian.
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    Permian palynomorphs from the number 5 seam, Ecca Group, Witbank/Highveld coalfields, South Africa
    (Bernard Price Institute for Palaeontological Research, 1994) Aitken, G A
    A palynological study of the number 5 seam in the Ecca group has yielded a wide variety of miospores, with a lateral and vertical consistency in their relative abundance, diversity and composition. Striate bisaccate pollen genera predominate, particularly Protohaploxypinus Samoilovich emend. Morbey 1975, Striatopodocarpites Zoricheva & Sedova ex Sedova emend. Hart 1964 and Weylandites Bharadwaj & Srivastava 1969. On a regional scale the number 5 seam palynomorphs correlate both quantitatively and qualitatively with Biozone F of MacRae (1988) from the Waterberg and Pafuri coal-bearing basins, and Hammanskraal plant locality. Broad palaeoenvironmental inferences drawn from both the palynology and sedimentology of this seam, support a flood plain setting, comprising shallow wide open pans and peat swamps interspersed with wide water-logged mud flats . The surrounding highlands would have been forested mostly by plants adapted to wind dispersal with colonisation of the levees and margins of smaIl ponds by spore producers. The age of the number 5 seam is tentatively suggested as Guadalupian, which in turn is equated with the Tatarian (European Standard usage); Midian to Dzhulfian (Tethys usage).
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    A new vertebrate biozone at the base of the Beaufort Group, Karoo sequence (South Africa)
    (Bernard Price Institute for Palaeontological Research, 1990) Rubidge, Bruce S
    A new vertebrate biozone at the base of the Beaufort Group has been identified. This biozone is the oldest vertebrate biozone of the Beaufort Group and contains fossils of various therapsid genera which are more primitive than previously known related forms from the Karoo. The name Eodicynodon - Tapinocaninus Assemblage Zone is proposed as these two genera of therapsid are the most plentiful from this biozone and have not been found in the rocks of the overlying Dinocephalia Assemblage (Tapinocephalus) Zone.
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    Clarification of Belemnopteris Feistmantel 1876, and description of a leaf of Belemnopteris pellvcida Pant and Choudhury 1977 found amongst a South African Ecca flora
    (Bernard Price Institute for Palaeontological Research, 1990) Kovacs-Endrody, E
    A leaf of Belemnopteris pellucida Pant and Choudhury 1977 was found for the first time in South Africa amongst an Ecca flora near Hammanskraal, about 30km north of Pretoria. The taxonomic status of Belemnopteris Feistmantel 1876 and the biostratigraphic correlation indicated by the presence of this genus is clarified.
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    A new GIS-based biozone map of the Beaufort Group (Karoo Supergroup), South Africa
    (Bernard Price Institute for Palaeontological Research, University of the Witwatersrand, 2010-12) van der Walt, Merrill; Day, Michael; Rubidge, Bruce; Cooper, Antony K.; Netterberg, Inge
    The stratigraphic subdivision of the Karoo Supergroup of South Africa has been addressed for more than a century by various geoscience studies. A lack of good lithostratigraphic markers in the Beaufort Group and the fact that the succession preserves a rich diversity of therapsid fossils for which there is a robust taxonomic scheme, make biostratigraphy the best option for correlation. This is applicable both within the basin and when comparing the Karoo succession to other coeval depositional basins. Published biostratigraphic maps of the Beaufort Group were compiled based on rough estimates of the distribution of zone-defining tetrapod fossil genera throughout the basin. None of these simultaneously utilized all the databases of South African museum collections. The recent application of GIS technology to integrate the vertebrate fossil databases of all South African museums has resulted in a far more precise biozone map which can be continuously updated as new information is received. This digital map introduces an entirely new way of representing the geographical distribution of fossil data, and thus can potentially enhance basin development and tetrapod biogeographic studies.
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    A second specimen of Blikanasaurus (Dinosauria: Sauropoda) and the biostratigraphy of the lower Elliot Formation
    (Bernard Price Institute for Palaeontological Research, university of the Witwatersrand, 2008-04) Yates, Adam M.
    A second specimen of the rare basal sauropod Blikanasaurus cromptoni, is recorded from a site in the Ladybrand district of the Eastern Free State, South Africa. The specimen consists of a right metatarsal 1 that originated from the upper 20mof the lower Elliot Formation. It can be referred to B. cromptoni on the basis of its small size and highly robust proportions, which distinguish this taxon from all other sauropodomorphs. This record extends the geographic distribution of B. cromptoni north into the region of the main Karoo Basin where the Elliot Formation is dramatically thinner. It also extends the known stratigraphic range of B. cromptoni up from the base of the Elliot Formation into a position near the top of the lower member. This new record, combined with other new discoveries, supports the hypothesis that the thin northern part of the lower Elliot Formation is a condensed section that is largely, if not entirely, coeval with the thicker southern sections.
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    A new cynodont record from the Tropidostoma Assemblage Zone of the Beaufort Group: implications for the early evolution of cynodonts in South Africa
    (Bernard Price Institute for Palaeontological Research, University of the Witwatersrand, 2008-04) Botha-Brink, J.; Abdala, F.
    A new specimen of cynodont has been recovered from the lower Upper Permian levels of the Tropidostoma Assemblage Zone of the South African Karoo Basin. A series of characters, including the presence of an interpterygoid opening, triconodont postcanine teeth, which are circular in crown view, a probable lingual cingulum, and most significantly, the presence of a masseteric fossa high on the coronoid process, allows this specimen to be assigned to the Procynosuchidae. However, unlike most procynosuchids, precanine teeth are absent and the incisors are represented by four left and five right upper and probably, three lower teeth. Considering the small size of the new specimen from the Tropidostoma Assemblage Zone we identify it as a juvenile Procynosuchus delaharpeae, the only species currently recognized in the genus. The low number of incisors and absence of precanines in this specimen are interpreted as ontogenetic variation (i.e. juvenile characters). This discovery extends the biostratigraphic range of Procynosuchus, as it is now recorded in three assemblage zones, indicating that this taxon is the longest-lived cynodont in the Karoo Basin. The new specimen of Procynosuchus and the recently described Charassognathus gracilis, are the oldest global records of cynodonts, and indicate an earlier initial radiation of this lineage than was previously thought.