Abstract
Five new species belonging to Hermatomyces (Hermatomycetaceae, Pleosporales) are described based on morphological investigations of specimens collected on rotten twigs and stems of various plants in Panama as well as phylogenetic analyses of sequence data of nuclear ribosomal and protein coding genes (EF1-α, RPB2, β-TUB). The new species are described as: Hermatomyces bifurcatus, H. constrictus, H. megasporus, H. sphaericoides, and H. verrucosus spp. nov. Previously described species such as H. sphaericus and H. tucumanensis were identified among the studied specimens. The new combination, H. reticulatus, is made for Subicularium reticulatum based on examination of the holotype and fresh collections. Hermatomyces subiculosus, originally described from Thailand, is reduced to synonymy with H. reticulatus; H. tectonae is synonymized under H. sphaericus based on morphological and molecular evidence; and H. chiangmaiensis and H. thailandicus are considered later synonyms of H. krabiensis and H. indicus, respectively. The type material of Scyphostroma mirum was found to be conspecific with H. tucumanensis and, therefore, the generic name Hermatomyces should be conserved or protected against the older name Scyphostroma and the binomial H. tucumanensis against S. mirum. Sixteen species of Hermatomyces are recognized, their distinctive characteristics are highlighted in line drawings and a key is provided for their identification. The peculiar morphology and consistent phylogeny of new and previously known Hermatomyces species supports the recognition of the recently introduced monotypic family Hermatomycetaceae as a well delimited monophyletic taxon within the order Pleosporales.