Cryptic species diversity in polypores : the Skeletocutis nivea species complex

We propose a taxonomic revision of the two closely related white-rot polypore species, Skeletocutis nivea (Jungh.) Jean Keller and S. ochroalba Niemela (Incrustoporiaceae, Basidiomycota), based on phylogenetic analyses of nuclear ribosomal internal transcribed spacer (ITS) and translation elongation factor EF-1 alpha sequences. We show that prevailing morphological species concepts of S. nivea and S. ochroalba are non-monophyletic and we delineate new species boundaries based on phylogenetic inference. We recognise eleven species within the prevailing species concept of S. nivea (S. calida sp. nov., S. coprosmae comb. nov., S. futilis sp. nov., S. impervia sp. nov., S. ipuletii sp. nov., S. lepida sp. nov., S. nemonzlis sp. nov., S. nivea sensu typi, S. semipileata comb. nov., S. unguina sp. nov. and S. yuchengii sp. nov.) and assign new sequenced epitypes for S. nivea and S. semipileata. The traditional concept of S. ochroalba comprises two independent lineages embedded within the S. nivea species complex. The Eurasian conifer-dwelling species S. cummata sp. nov. is recognised as separate from the North American S. ochroalba sensu stricto. Despite comprehensive microscopic examination, the majority of the recognised species are left without stable diagnostic character combinations that would enable species identification based solely on morphology and ecology.Peer reviewe