Studies in phylogeny and divergence times of Irpicaceae and Meripilaceae (Polyporales, Basidiomycota), with an emphasis on Ceriporia and Meripilus including ten new species

Species in <i>Ceriporia</i> and <i>Meripilus</i> are important wood-decaying fungi causing white rot on both angiosperm and gymnosperm wood. Morphologically, the two genera share similar micromorphology: a monomitic hyphal system of cyanophilous generative hyphae bearing simple septa. Phylogenetic and morphological analyses of <i>Ceriporia</i> and other related genera in <i>Irpicaceae</i> and <i>Meripilus</i> in <i>Meripilaceae</i> were carried out. <i>Ceriporia</i> is characterized by mostly resupinate basidiomata with a white to brightly colored pore surface when fresh, usually without changing color when bruised, and cylindrical to allantoid basidiospores. <i>Meripilus</i> is similar to <i>Ceriporia</i>, but it has resupinate, effused-reflexed to pileate basidiomata, sometimes with an erubescent pore surface when bruised, and ellipsoid to globose basidiospores. Phylogenies of species in the two genera were reconstructed with multiple-loci DNA sequences, including ITS, nLSU, nSSU, TEF1, RPB1, and RPB2, as well as two combined datasets: ITS+nLSU+TEF1+RPB1+nSSU for <i>Ceriporia</i> and ITS+nLSU+TEF1+RPB2+nSSU for <i>Meripilus</i>. Three new species of <i>Ceriporia</i>, one new species of <i>Meruliopsis</i>, and six new species of <i>Meripilus</i> are described and illustrated. Moreover, the evolutionary times of the <i>Polyporales</i>, including <i>Irpicaceae</i> and <i>Meripilaceae</i>, were revealed based on the conserved regions of three-loci DNA sequences (ITS+nLSU+TEF1). <i>Irpicaceae</i> and <i>Meripilaceae</i> are estimated to have emerged at the junction of the early and late Cretaceous, with mean crown ages of 108.9 Myr and 97.23 Myr, respectively. Bayesian evolutionary analysis shows that the divergence of <i>Ceriporia</i> emerged with a mean crown age of 83.61 Myr [95% highest posterior density (HPD): 65.25-106.35 Myr], which occurred during the late Cretaceous; the initial diversification of <i>Meripilus</i> also occurred during the late Cretaceous, with a mean crown age of 81.38 Myr [95% HPD: 61.89-105.78 Myr].