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 Ceriporia and Meripilus 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 Ceriporia and other related genera in Irpicaceae and Meripilus in Meripilaceae were carried out.

Ceriporia 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. Meripilus is similar to Ceriporia, 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, TEF 1, RPB 1, and RPB 2, as well as two combined datasets: ITS + nLSU + TEF 1 + RPB 1 + nSSU for Ceriporia and ITS + nLSU + TEF 1 + RPB 2 + nSSU for Meripilus.

Three new species of Ceriporia, one new species of Meruliopsis, and six new species of Meripilus are described and illustrated. Moreover, the evolutionary times of the Polyporales, including Irpicaceae and Meripilaceae, were revealed based on the conserved regions of three-loci DNA sequences (ITS + nLSU + TEF 1). Irpicaceae and Meripilaceae 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 Ceriporia 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 Meripilus also occurred during the late Cretaceous, with a mean crown age of 81.38 Myr [95 % HPD: 61.89–105.78 Myr].