Global diversity and taxonomy of the Inonotus linteus complex (Hymenochaetales, Basidiomycota): Sanghuangporus gen. nov., Tropicoporus excentrodendri and T. guanacastensis gen. et spp. nov., and 17 new combinations

Abstract

Although Inonotus linteus complex is placed in the genus Inonotus, its perennial basidiocarps with a dimitic hyphal system, at least in the trama, distinguish the complex from other species in the genus, which have an annual habit and a monomitic hyphal system. The species number of Inonotus linteus complex has been increased in China and tropical America in recent publications. However, whether species in this complex belong to Inonotus has not specifically been addressed. To explore the phylogenetic placement of species of Inonotus linteus complex, we performed a comprehensive study using morphological and phylogenetic data based on global samples. nLSU (53 with 13 new) and ITS (70 with 18 new) datasets were used to produce the phylogenetic results. Taking into consideration the phylogenies inferred from the nLSU and ITS datasets, Inonotus is a polyphyletic genus comprising at least three clades. Clade A, the core Inonotus clade, contains the generic type, Inonotus hispidus, while Clades B and C comprise species from the Inonotus linteus complex. Morphological and phylogenetic evidence indicates that Clades B and C are new genera, and Sanghuangporus and Tropicoporus are introduced in this study. Ten species are transferred to Sanghuangporus and seven to Tropicoporus. Tropicoporus excentrodendri and T. guanacastensis spp. nov. are described, and their distinctive characters are discussed. Keys to the two new genera and the Inonotus sensu stricto, and to species of each new genus are provided.