Volume 50 April 2016

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    Complete volume 50
    (Evolutionary Studies Institute, 2016-04)
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    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.
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    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.
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    Palynostratigraphy, palynofacies and thermal maturation of the Nsukka Formation from an excavation site in Okigwe, Southeastern Nigeria
    (2016-03) Durugbo, Ernest Uzodimmaa
    There 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.
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    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.