Molecular data support the Laboulbeniales as a separate class of Ascomycota, Laboulbeniomycetes

The Laboulbeniales have had a clouded taxonomic history, Initially interpre ted as abnormal cuticular outgrowths of arthropods, they have since been co nsidered to be acanthocephalans, basidiomycetes, and zygomycetes as well as ascomycetes. Phylogenetic analysis or partial sequences of SSU rDNA with s pecies of Chytridomycota as outgroup taxa, and including trichomycete and e ntomophthoralean Zygomycota, provides evidence of the placement of a laboul beniales-Pyxidiophora clade among the Ascomycota. Support for parsimony ana lyses came from maximum likelihood ratio tests applied to trees with ten di fferent topological constraints. The placement among Ascomycota, excluded f rom Sordariomycetes, is well supported, and indicative of a distinct lineag e, class Laboulbeniomycetes. At this time. however, we are unable to disco er close relatives of the clade among other filamentous ascomycetes.