Masters Degrees (Zoology and Entomology)
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Browsing Masters Degrees (Zoology and Entomology) by Author "Basson, L."
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Item Open Access Morphological evaluation of Trichodina heterodentata Duncan, 1977 (Ciliophora: Peritricha) from tadpoles and fish(University of the Free State, 2013-01) Groenewald, Hanlie; Basson, L.; Van As, J. G.English: Mobiline ciliophorans belonging to the family Trichodinidae Claus, 1874 are amongst the most common and widely distributed symbionts of fishes. Most of the 260 trichodinid species described from fishes are exclusively associated with fish hosts. A few are also associated with salamanders, crustaceans or coelenterates such as in the case of Trichodina pediculus Ehrenberg, 1831 that are hosted by fish or hydras. Juvenile and adult anurans also play host to some trichodinid species. Endotrichodinids such as T. xenopodos Fantham, 1924 infect the bladder of adult frogs during amplexus and feed on the debris within the bladder of the host. Ectotrichodinids are hosted on the skin and / or gills of various tadpole species worldwide. Tadpole trichodinids are typically not host specific and occur on fishes in the same water medium and are thus using tadpoles as facultative hosts. Only a few studies concentrated on the collection and / or identification of tadpole trichodinids in southern Africa.The objective of the present study was to determine if trichodinids hosted by tadpoles in southern Africa are fish trichodinids that are temporarily hosted by tadpoles or a different species that are not commonly found on fishes. Cross-transmission experiments indicated that trichodinids from naturally infested tadpoles could form a viable population on naturally uninfested fishes. This indicated that the tadpole trichodinids could be found on fishes in natural conditions. Trichodinids that were collected from various fish and tadpole species in South Africa and Botswana over the past 30 years, were examined. Morphological analysis of the examined trichodinids was undertaken by means of three known methods. These methods aided in describing all examined trichodinids as belonging to T. heterodentata Duncan, 1977. Trichodina heterodentata is globally distributed and has an apparent affinity for cichlids as fish hosts, but seems to be equally widely distributed on a variety of tadpole hosts, if both these hosts are available in the same water medium.Item Open Access Taxonomic review of the genus Histotylenchus Siddiqi, 1971 (Nematoda: Belonolaimidae) in South Africa(University of the Free State, 2011-11) Landman, Henda; Jansen van Rensburg, C.; Basson, L.; Marais, M.English: A diverse and abundant nematode fauna is known to exist in South Africa with plant parasitic nematodes being the most representative. Seven genera belonging to the family Belonolaimidae Whitehead, 1960 are known to occur in South Africa, including Histotylenchus Siddiqi, 1971, a small genus only found in Africa and India. Nematodes belonging to the family Belonolaimidae are obligatory, primarily migratory ectoparasites of roots. These nematodes are found in cultivated soils and natural veld and are usually seen as mild plant parasites. Histotylenchus is represented by three species from South Africa, namely Histotylenchus hedys Kleynhans, 1975, Histotylenchus histoides Siddiqi, 1971 and Histotylenchus mohalei Kleynhans, 1992. Diagnostic characters of Histotylenchus include a lip region confluent with body contour or offset, asymmetrical stylet conus with an angular lumen, a large metacorpus valve, genital tracts about equal, lateral fields with four lines usually areolated, spicules tapering distally with distinct vela and gubernaculum proximally recurved with titillae. The aim of this study was to review all existing literature concerning the genus Histotylenchus in Africa, and to examine and describe the species from this genus collected in South Africa, which are deposited in the National Collection of Nematodes, Biosystematics Programme, Agricultural Research Council, Plant Protection Research Institute, Pretoria, South Africa. Results showed that a total of 44% of the fixed material examined was not suitable for this morphological study as a result of the separation of the cuticle from the body. This phenomenon is reported from this genus for the first time. Histotylenchus hedys and Histotylenchus mohalei were re-described from material of the National Collection of Nematodes, while Histotylenchus histoides was re-described from type material of the Rothamsted Nematode Collection housed at the Food and Environment Research Agency (Fera), York, United Kingdom; and CABI Bioscience, Egham, United Kingdom. A new species, Histotylenchus niveus sp. n., was described from material collected in the Witsand Nature Reserve, Northern Cape, South Africa. Additionally, two species Histotylenchus sp. 1 and Histotylenchus sp. 2 were described during this study and could possibly be new to science. However, additional material needs to be collected to verify these results. The present study revealed that further research into the genus is necessary, especially since the current information is limited and incomplete.