Volume 50 April 2016
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Item Complete volume 50(Evolutionary Studies Institute, 2016-04)Item Two unrecognised burnetiamorph specimens from historic Karoo collections(2016-03) Kammerer, Christian F.Two historical specimens from Permian rocks of the Karoo Basin represent previously unrecognised members of the rare therapsid group Burnetiamorpha. These specimens cannot be referred to any existing burnetiamorph species, but are left in open nomenclature because of their incompleteness (both are isolated skull roofs). The first specimen is from the Tapinocephalus Assemblage Zone (AZ) and is characterized by heavily pachyostosed supraorbital bosses and a low nasal crest. The second specimen is from the Tropidostoma AZ and is generally similar to the Malawian taxon Lende, but is unique among described burnetiamorphs in having a frontoparietal ‘dome’ that surrounds the pineal foramen. Phylogenetic analysis of burnetiamorphs recovers support for a split between Proburnetia and Burnetia-like burnetiids, here named Proburnetiinae subfam. nov. and Burnetiinae Broom, 1923.Item New specimens of the basal ornithischian dinosaur Lesothosaurus diagnosticus Galton, 1978 from the Early Jurassic of South Africa(2016-03) Barrett, Paul M.; Butler, Richard J.; Yates, Adam M.; Baron, Matthew G.; Choiniere, Jonah N.We describe new specimens of the basal ornithischian dinosaur Lesothosaurus diagnosticus Galton, 1978 collected from a bone bed in the Fouriesburg district of the Free State, South Africa. The material was collected from the upper Elliot Formation (Early Jurassic) and represents the remains of at least three different individuals. These individuals are larger in body size than those already known in museum collections and offer additional information on cranial ontogeny in the taxon. Moreover, they are similar in size to the sympatric taxon Stormbergia dangershoeki. The discovery of three individuals at this locality might imply group-living behaviour in this early ornithischian.Item Palynostratigraphy, palynofacies and thermal maturation of the Nsukka Formation from an excavation site in Okigwe, Southeastern Nigeria(2016-03) Durugbo, Ernest UzodimmaaThere is a dire need to assess the petroleum generating potential of the Nigerian inland basins. The Nigerian Federal Government has in the last few years demarcated the inland basins, of which little is known palynologically, for oil and gas exploration activities. An input from Nigeria concerning events of the Cretaceous -Paleogene boundary would broaden our knowledge of the global event. This palynological study of the Nsukka Formation from an excavation site in Okigwe, Southeastern Nigeria, revealed abundant records of pollen, spores and dinoflagellate cysts. Palm pollen Longapertites marginatus, L. vaneendenburgi, L. microfoveolatus, Spinizonocolpites echinatus, S. baculatus and Foveomonocolpites bauchiensis dominated the microfloral assemblage with common dinoflagellate cysts, especially Ifecysta spp., Cordosphaeridium spp., Fibrocysta spp., Senegalinium spp., Cerodinium spp., Phelodinium spp., Spiniferites spp. and Hafniasphaera spp., indicating alternating shallow to marginal marine depositional environments. The already published ranges of the palynostratigraphically important taxa such as Buttinia andreevi, Monocolpopollenites sphaeroidites, Rugulatisporites caperatus, Zlivisporis blanensis, Cingulatisporites ornatus, and the earliest Danian dinoflagellate cyst markers Damassadinium californicum, Carpatella cornuta, Hafniasphaera septate and Senegalinium bicavatum, enabled the delineation of the age as Late Maastrichtian-Middle Paleocene. The studied Nsukka sequences consist of alternating successions of fine grained sandstones, well bedded dark and sandy shales. The samples were dominated by terrestrial organic components, especially structured phytoclasts, black debris and unstructured phytoclasts/degraded wood elements, indicating deposition in predominantly nearshore environments, coupled with the dominance of peridinoids over gonyaulacoids. However, the basal samples were characterized by common amorphous organic matter co-occurring with dinoflagellate cysts suggesting brief periods of marine transgressions. Using Deltoidospora adriennis as an index, the spore colouration index (SCI), ranged from 4 (golden yellow) to 4.5 (deep yellow) which correlates to vitrinite reflectance values of 0.4 - < 0.5, indicating that the sediments were immature for oil and gas generation.Item Petroleum of the Deep: Palynological proxies for palaeoenvironment of deep offshore upper Miocene-Pliocene sediments from Niger Delta, Nigeria(2016-03) Olayiwola, Moshood A.; Bamford, Marion K.Better understanding of the palaeoenvironments under which the lithologies of the deepwater petroleum systems were deposited is necessary to unravel the problem surrounding the deep offshore petroleum exploration and production. Therefore, the integration of palynological, lithological and gamma ray log data of ditch-cutting samples from wells A and B from the Niger Delta region are utilized to delineate the upper Miocene-Pliocene depositional environments. The detailed palynological analysis revealed diverse and abundant palynomorph assemblages, which consisted of angiosperm pollen 85.7 %, monolete spores 5 %, fungal elements 4 %, trilete fern spores 4 %, freshwater algae 1 % and marine elements 0.3 %. Eight informal palynological assemblage zones (PAZ I-PAZ VIII) with corresponding eustatic sea level changes are delineated in Wells A and B. Four lithofacies, namely sandstones, siltstones, claystones and mudstones, are recognized in association with three depositional environments in the studied wells. Distributary channels are characterized by the erosive base and filled with moderate to fine, uniform and blocky sand-grain size sediments that are of good reservoir quality. Mud-rich sediments, which are of excellent sealing rock potential, capped this sand formation. Moreover, tidal channels are typified by the erosive base and filled with fining-upwards sand sequences with tops covered by muddy sediments. Finally, the regressive barrier sands are filled by coarsening-upwards sediments with basal organic-rich deposits that are likely to be good quality source rock. The oil potential of these sites is of interest to the oil company and the reconstructed palaeoenvironments will be useful for deepwater exploration and exploitation, and probably remove or minimize the risks that are commonly involved in this task.Item Permo-Triassic palynology and palaeobotany of Zambia: a review(2016-03) Barbolini, Natasha; Bamford, Marion K.; Tolan, StephenPermian and Triassic deposits in Zambia have been sporadically researched since the beginning of the 20th century, but there have not been many detailed works on the palaeobotany and palynology of these Karoo-aged rocks. Studies that have been published, suffered from a lack of inter-basinal correlation, which was also hampered by differing stratigraphic subdivisions. We review previous records of palynomorphs, megafloral remains and fossil wood in Zambian Permo-Triassic deposits, present a synthesis of micro- and macrofossil occurrences throughout the country, and propose a standardised subdivision for the Luangwa Valley. This will aid in future correlations between different Karoo basins and act as a framework for future palaeobotanical research in both Zambia and Gondwana.Item The macrovertebrate fossil assemblage from the Name Chamber, Sterkfontein: taxonomy, taphonomy and implications for site formation processes(2015-11-27) Val, Aurore; Stratford, Dominic JThe Name Chamber contains some of the deepest fossiliferous deposits in the Sterkfontein Caves, at ~20 metres below the surface deposits of Members 4 and 5. Recent excavations complemented by detailed studies of the geological context, as well as of the microfaunal and lithic (i.e. Oldowan artefacts) assemblages, have shed some light on the complex history of sediment accumulation in that part of the Sterkfontein karstic system. The Name Chamber has a long and intricate history of deposition that is of particular value for understanding the redistribution of Oldowan-bearing sediments from Member 5 into the deep chamber below. Recognizing sediment movement and sources through multidisciplinary investigations is of key importance to reconstructing primary lithic assemblages and ultimately the behavioural proxies associated with them. Here, we present the results of a taxonomic and taphonomic analysis of the macrofaunal assemblage recovered during excavations of the decalcified sediments of the Western Talus in the Name Chamber. The taxonomic composition of the faunal spectrum is similar to that of Member 5 East Oldowan, with an overrepresentation of medium-sized bovids and the occurrence of taxa associated with grasslands. The taphonomic features of the fossil remains are characteristic of a mixed assemblage with indications of contributions by carnivores, slope wash and gravity collecting bones from the catchment surface (including carnivore-gnawed and butchery-marked specimens). The results independently corroborate lithic and microfaunal analyses and support the hypothesis of multiple origins for the sediments of the Name Chamber, with a main contribution from Member 5 East Oldowan (notably illustrated in the Name Chamber assemblage by the identification of several cut-marked remains and a bone tool), shortly after it accumulated at about 2.18 Ma. There is also indication of a minor contribution from Member 4 but no evidence for a noticeable contribution from Post-Member 6 (L/63 Infill).