Morphological evaluation of Trichodina heterodentata Duncan, 1977 (Ciliophora: Peritricha) from tadpoles and fish

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Date
2013-01
Authors
Groenewald, Hanlie
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University of the Free State
Abstract
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.
Afrikaans: Mobiliene siliofore vorm deel van die familie Trichodinidae Claus, 1874 en is van die mees algemene en wyd verspreide vissimbionte. Die meeste van die 260 trigodinas wat vanaf visse beskryf is, word uitsluitlik met visse geassosieer. Sommiges word ook geassosieer met salamanders, skaaldiere of holtediere soos in die geval van Trichodina pediculus Ehrenberg, 1831 wat op visse sowel as hidras voorkom. Jong en volwasse verteenwoordigers van Anura word ook deur verskeie trigodinas as gashere gebruik. Endotrigodinas soos T. xenopodos Fantham, 1924 besmet die blaas van volwasse paddas tydens ampleksus en voed op die dooie selle binne die gasheer se blaas. Ektotrigodinas word wêreldwyd op die vel en / of kieue van verskeie paddavisse aangetref. Paddavistrigodinas is gewoonlik nie gasheerspesifiek nie en word ook op visse aangetref wat in die selfde waterbronne as die besmette paddavisse voorkom. Paddavisse word dus as fakultatiewe gashere vir trigodinas beskou. Slegs ‘n paar studies het voorheen op die versameling en / of bestudering van paddavistrigodinas in suider Afrika gekonsentreer. Die doelwit van die huidige studie was om vas te stel of paddavistrigodinas in suider Afrika vistrigodinas is wat slegs tydelik deur paddavisse gehuisves word, of ‘n ander spesie is wat nie op visse voorkom nie. Kruis-besmettingseksperimente het aangedui dat trigodinas wat natuurlik op paddavisse voorkom, ‘n lewensvatbare bevolking op visse kon vorm wat nie natuurlik besmet was nie. Hierdie bevinding dui aan dat die paddavistrigodinas moontlik onder natuurlike toestande op die visse kan voorkom. Trigodinas wat vanaf verskeie vis en paddavis spesies in Suid-Afrika en Botswana oor die laaste 30 jaar versamel is, is bestudeer. Morfologiese ondersoeke van hierdie trigodinas is uitgevoer deur van drie bekende metodes, soos voorgestel deur Lom (1958), Gong et al. (2005) en Van As en Basson (1992), gebruik te maak. Deur hierdie metodes te gebruik, is daar vasgestel dat die paddavistrigodinas T. heterodentata Duncan, 1977 verteenwoordig. Trichodina heterodentata is wêreldwyd verspreid en het vermoedelik ‘n affiniteit vir lede van die Cichlidae as visgashere, hoewel dit voorkom of hierdie trigodinas ook wyd verspreid op verskeie paddavisse voorkom wanneer albei gasheer groepe in dieselfde waterbron beskikbaar is.
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Dissertation (M.Sc. (Zoology and Entomology))--University of the Free State, 2013, Trichodina heterodentata, Tadpoles, Fishes, Southern Africa, Cross-transmission experiments, Morphological analysis, Xenopus, Xenopus laevis -- Parasites
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