Morphological and phylogenetic studies of two new neotropical species of Loweomyces (Polyporales, Basidiomycota)

The genus Loweomyces is characterized by resupinate to pileate, sessile to stipitate basidiomes, monomitic to dimitic hyphal system with presence of pseudoskeletal hyphae, thin-walled hymenial cystidia, and usually cyanophilous spore and hyphal walls. The genus has not been widely accepted and some authors placed Loweomyces species in Abortiporus, Tyromyces or Antrodiella. During a survey of polypores in southern Brazil, two unidentified species with similar features to Loweomyces spp. were found. Morphological and molecular studies were carried out in order to understand their morphological and evolutionary relationships and to confirm their phylogenetic placement and taxonomic identity. DNA sequences of the internal transcribed spacer and large subunit of ribosomal RNA gene were used for phylogenetic studies. Both studied species have similar morphological characteristics to other Loweomyces spp. and group close to L. fractipes phylogenetically; therefore, Loweomyces spissus and L. tomentosus are proposed as new species. Full descriptions, illustrations of microscopic features, and an identification key to the accepted species in the genus are presented.