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Mycobonia and Pseudofavolus (Polyporales, Basidiomycota) are polyporoid genera with tropical and subtropical distribution. Both genera are morphologically similar in presenting flabelliform to conchate subsessile basidiomata, with a dimitic hyphal system, consisting of clamped generative hyphae and skeleto-binding hyphae that produce large basidiospores with smooth, thin walls. However, while Pseudofavolus species present a poroid hymenophore, in Mycobonia it is stereoid with hyphal pegs that resemble thin teeth. Mycobonia and Pseudofavolus have a controversial taxonomy, and the phylogenetic relationships between their species have yet to be assessed. For this reason, we performed molecular phylogenetic analyses on specimens of Mycobonia and Pseudofavolus from both the Neotropics and Asia, using internal transcribed spacers (ITS), the large subunit of nuclear rDNA (nc LSU rDNA), and also the genes encoding the second largest subunit of RNA polymerase II (RPB2). Furthermore, in order to develop an evolutionary analysis of the hymenophore configuration, we performed stochastic character mapping of ancestral states for the hymenophore type presented in Polyporus s.l. Our study revealed that Pseudofavolus is an artificial group and its species actually nest in a clade within Mycobonia. Therefore, in order to establish a monophyletic group, based upon priority of publication, we re-circunscribed Mycobonia to encompass both stereoid and poroid hymenophore species. Two new combinations are presented from the Neotropics: Mycobonia cucullata and M. miquelii. A new species from tropical Asia, M. yuchengii, is also described. We presente a summary of stochastic mapping of ancestral states estimates of hymenophore type in Polyporus s.l. The ancestral state for Mycobonia clade is estimated to have angular pores. |
