Updated systematics of Trichaptum s.l. (Hymenochaetales, Basidiomycota)

Trichaptum sensu lato is a widespread wood-decay fungal group important for the transfer of energy and recycling of nutrients in forest ecosystems. The taxonomy of Trichaptum s.l. was previously mostly based on morphology, and phylogenetic relationships among taxa of Trichaptum s.l. are poorly known. The systematics of Trichaptum s.l. was revised using morphology, and molecular study which analysed the combined datasets of ITS+nLSU+mt-SSU+nuc-SSU+TEF1 from 256 samples. Maximum Likelihood (ML) and Bayesian Inference (BI) were employed to perform phylogenetic analyses of these datasets. The traditional Trichaptum s.l. is polyphyletic. Two main clades, distantly related, are recognized and two new families, Hirschioporaceae and Trichaptaceae, are proposed to represent these two clades. All analyzed samples formed seven independent clades representing seven genera, among them five newly proposed. 38 independent lineages are nested in the seven genera, and 10 of them are described as new species. In addition, a total of 49 taxa are identified by phylogenetic analyses and morphological examination of 625 specimens from 19 countries, and 28 new combinations are proposed. To support our results, divergence time estimation and historical biogeography of Trichaptum s.l. are analyzed. Photos and illustrations for ten new species are presented, and a full description for each new species is given. This study recognizes 49 taxa in seven genera belonging to Hymenochaetales and provides a modern global treatment of Trichaptum s.l. Keys to families and genera are provided, and identification keys to accepted species worldwide are given.

Automated summary

This study revises the systematic classification of Trichaptum s.l. using morphology and molecular research, finding that the traditional Trichaptum s.l. is not monophyletic. Two main clades, distantly related, are recognized and two new families, Hirschioporaceae and Trichaptaceae, are proposed. The study also identifies 49 taxa through genetic analysis and morphological examination of 625 specimens, proposing 28 new combinations.