A global view of <i>Gyroporus</i>: molecular phylogenetics, diversity patterns, and new species

<p><i>Gyroporus</i> (Gyroporaceae, Boletales) is a highly diverse genus of poroid ectomycorrhizal mushrooms with a nearly worldwide distribution. Previous attempts to unravel the diversity within this genus proved difficult due to the presence of semicryptic species and ambiguous results from analysis of ribosomal RNA markers. In this study, we employ a combined morphotaxonomic and phylogenetic approach to delimit species and elucidate geographic and evolutionary patterns in <i>Gyroporus</i>. For phylogenetic analyses, the protein-coding genes <i>atp6</i> (mitochondrial adenosine triphosphate [ATP] synthase subunit 6) and <i>rpb2</i> (nuclear second largest subunit of RNA polymerase II) were selected based on their utility in studies of Boletales. We infer several distinct clades, most notably one corresponding to <i>G. castaneus</i> as a speciose Northern Hemisphere group, another unifying <i>G. cyanescens</i> and like entities, and a third group unifying <i>G. longicystidiatus</i> and a New World sister species. Also notable is the recovery of a sister relationship between the <i>cyanescens</i> and <i>longicystidiatus</i> clades. We formally describe five new species of <i>Gyroporus</i>, outline a number of provisional species, and briefly discuss distributional patterns. This study provides an important scaffold for future work on this well-known but poorly understood genus of fungi.</p>