Dissertation Research: Phylogenetic Studies in the Lasiosphaeriaceae (Fungi, Ascomycetes, Sordariales)

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The family Lasiosphaeriaceae is one of the largest and least studied families in a group of fungi known as pyrenomycetes. It contains several ecologically and economically important genera, which occur throughout temperate and tropical regions and produce minute, dark-colored, flask-shaped fruiting structures on wood and dung. Numerous genera have been transferred into this family without critically assessing their evolutionary relationships. This study will (1) provide a monophyletic circumscription of the Lasiosphaeriaceae and test hypotheses about morphological characters currently used in ascomycete systematics; (2) provide a taxonomic revision of Lasiosphaeria, one of the largest and most complex genera in the family. Lasiosphaeria; (3) focus on the L. hirsuta and L. ovina species complexes, establishing species boundaries. This study will serve as a model system for future studies in ascomycete systematics by using a multi-gene approach, incorporating both protein-coding and ribosomal genes, along with morphological characters for determining phylogenetic relationships at the specific, generic and familial levels. The Lasiosphaeriaceae and its type genus Lasiosphaeria are of particular systematic interest for several reasons. Phylogenetic analyses of DNA sequences that included single representatives of four of the ten families of Sordariales suggested that the order is not monophyletic. A detailed assessment of the evolutionary relationships among these families is needed to address this issue, but a meaningful sampling strategy requires revision of key genera like Lasiosphaeria. The Lasiosphaeriaceae either contains, or is closely related to, the family containing Neurospora and Sordaria. Representatives of the Sordariaceae will be included in our analyses to evaluate these generic and familial relationships. Ascospore morphology has been used extensively throughout the filamentous ascomycetes for distinguishing families and genera even though this one-character taxonomy has never been rigorously tested. This study will be the first to objectively test the evolutionary potential of this character system. Although many Lasiosphaeriaceae are encountered throughout temperate and tropical areas, identification guides are not available. With the aid of digital image capturing systems, this study will produce detailed hardcopy and web-based identification guides for taxa in the Lasiosphaeriaceae.