Phylogenetic relationships of the marine gasteromycete Nia vibrissa

Abstract

Phylogenetic relationships of the marine gasteromycete, Nia vibrissa, were investigated using four ribosomal DNA (rDNA) regions. Independent analyses of mitochondrial small-subunit (mt-ssu) rDNA, mitochondrial large subunit (mt-lsu) rDNA, nuclear small-subunit (nuc-ssu) rDNA, and nuclear large subunit (nuc-lsu) rDNA all suggest that Nia vibrissa is in the euagarics clade. The mt-lsu, nuc-ssu, and nuc-lsu datasets suggest that Nia vibrissa is closely related to the cyphelloid fungus, Henningsomyces Candidus, but in all three datasets the monophyly of the Nia-Henningsomyces group is weakly supported. Analyses of mt-ssu rDNA suggest that the sister group of Nia vibrissa is Schizophyllum commune, but again the relationship is weakly supported. A combined analysis of all four rDNA regions strongly supports the sister group relationship of Nia vibrissa and Henningsomyces candidus. Schizopkyllum commune and Fistulina hepatica form a strongly supported clade that is weakly supported as the sister group of the Nia-Henningsomyces clade. Schizopkyllum commune and Fistulina hepatica both resemble cyphelloid fungi in some aspects of their hymenophore morphology, and it is plausible that they could be closely related to Henningsomyces candidus. Eighteen genera of terrestrial gasteromycetes were included in the analyses, but none are closely related to Nia vibrissa, which therefore represents an independent origin of the gasteroid habit in the homobasidiomycetes.