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Thesis Details
TitleUnexpected microfungal diversity : woody decay Lasiosphaeriaceae, Chaetosphaeriaceae and Helminthosphaeriaceae of New Zealand
AuthorAtkinson, Toni June
InstitutionUniversity of Otago
AbstractNew Zealandís lignicolous pyrenomycete flora has been little studied. The cosmopolitan Lasiosphaeriaceae, largest and least studied family in the Sordariales, has long been noted for its morphological diversity and the artificiality of its grouping. This first systematic study of lignicolous Lasiosphaeriaceae in New Zealand uses morphology and phylogenetics to elucidate relationships within the New Zealand mycota and facilitate comparisons with relatives worldwide. Collection areas spanned New Zealandís 13 degrees of latitude and included a range of native forest types. The novel application of recently-available molecular biology techniques allowed sequencing from single pyrenomycete fruitbodies. Two new genera and 15 new species or species complexes are proposed in total. A new genus is proposed within the Lasiosphaeriaceae to accommodate an interesting new collection. Seven new species are described in the known genera Lasiosphacria and Lasiosphaeris and the polyphyly of certain Lasiosphacria taxa is discussed. Five new taxa are described within the Chaetosphaeriaceae, including a pair with surprisingly unique morphology. All are currently placed within Chaetosphaeria, but comprise part of a recently recognised long-spored clade that is sister to that which includes the type genus. Within the Helminthosphaeriaceae one new genus is proposed to accommodate an unusual new collection; and a new species described within Hilberina, but its transference to a new genus predicted as knowledge of this recent family grows. Phylogenetic results support the separation of the Chaetosphaeriaceae and Helminthosphaeriaceae from the Lasiosphaeriaceae where many of these taxa were previously. The traditional morphological character of ascospore shape is shown to have little use in the delimitation of genera. More recently emphasised characters such as peridial wall structure may have more value, however the fruitbody wall of some New Zealand taxa could not be more different from their phylogenetic relatives. New Zealand taxa are noted for their frequently unprecedented morphology and/or unique genetics in comparison with other known taxa, which are predominantly from the northern hemisphere. The high levels of morphological and genetic divergence among New Zealand taxa appear to reflect extensive microfungal endemism on these relatively isolated islands; but surveys of diversity in other parts of Gondwana are desperately needed. A Key to New Zealand taxa within the Lasiosphaeriaceae, Helminthosphaeriaceae and long-spored Chaetosphaeriaceae is provided.
Thesis E-Thesis currently not available.