Monophyly of the gomphoid-phalloid clade was confirmed based on multigene
phylogenetic analyses. Four major subclades (Hysterangiales, Geastrales, Gomphales
and Phallales) were also demonstrated to be monophyletic. The interrelationships
among the subclades were, however, not resolved, and alternative topologies could not
be rejected statistically. Nonetheless, most analyses showed that the Hysterangiales
and Phallales do not form a monophyletic group, which is in contrast to traditional
taxonomy. The higher-level phylogeny of the gomphoid-phalloid fungi tends to
suggest that the Gomphales form a sister group with either the Hysterangiales or
Phallales. Unweighted parsimony character state reconstruction favors the independent
gain of the ballistosporic mechanism in the Gomphales, but the alternative scenario of
multiple losses of ballistospory could not be rejected statistically under likelihood based
reconstructions. This latter hypothesis is consistent with the widely accepted
hypothesis that the loss of ballistospory is irreversible. The transformation of fruiting
body forms from nongastroid to gastroid was apparent in the lineage leading to
Gautieria (Gomphales), but the tree topology and character state reconstructions
supported that truffle-like taxa of the Phallales are ancestral to stinkhorns, which
possess more complex, epigeous fruiting bodies. Importantly all taxa within the
Phallales are statismosporic and thus the derived stinkhorn morphology does not
require an independent gain of ballistospory.
Biogeographical analyses of the Hysterangiales strongly suggest that the
ectomycorrhizal lineages within the Hysterangiales originated in the East Gondwana.
The synonymous substitution rate indicated a Paleozoic origin of the Hysterangiales
although a possibility of a Cretaceous origin could not be discarded. Because modern
ectomycorrhizal plants were absent during the Paleozoic era, a potential existence of
the Hysterangiales during this time must be explained either by novel ectomycorrhizal
association of the Hysterangiales with unknown plant lineages, or multiple,
independent gains of ectomycorrhizal habit. The Paleozoic origin of the
Hysterangiales also indicates that mycophagous animals may not be the most
important factor for range expansions of the Hysterangiales.
Taxonomic revisions are made for the gomphoid-phalloid fungi. One subclass
(Phallomycetidae), two orders (Hysterangiales and Geastrales), four families
(Gallaceaceae, Phallogastraceae, Trappeaceae and Sclerogastraceae), 7 genera
(Austrohysterangium, Cribbangium, Rodwayomyces, Beeveromyces, Cazomyces,
Insulomyces and Viridigautieria) and 22 new combinations are proposed. / Graduation date: 2006
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/28641 |
| Date | 26 October 2005 |
| Creators | Hosaka, Kentaro |
| Contributors | Spatafora, Joseph W. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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