A taxonomic and phylogenetic revision of Penicillium section Aspergilloides

Species belonging to Penicillium section Aspergilloides have a world-wide distribution with P. glabrum, P. spinulosum and P. thomii the most well-known species of this section. These species occur commonly and can be isolated from many substrates including soil, food, bark and indoor environments. The taxonomy of these species has been investigated several times using various techniques, but species delimitation remains difficult. In the present study, 349 strains belonging to section Aspergilloides were subjected to multilocus molecular phylogenetic analyses using partial β-tubulin (BenA), calmodulin (CaM) and RNA polymerase II second largest subunit (RPB2) sequences. Section Aspergilloides is subdivided into 12 clades and 51 species. Twenty-five species are described here as new and P. yezoense, a species originally described without a Latin diagnosis, is validated. Species belonging to section Aspergilloides are phenotypically similar and most have monoverticillate conidiophores and grow moderately or quickly on agar media. The most important characters to distinguish these species were colony sizes on agar media, growth at 30 °C, ornamentation and shape of conidia, sclerotium production and stipe roughness.