Taxonomic revision of fleshy species of Hydnellum, Neosarcodon, and Sarcodon (Thelephorales) from Australasia.

Abstract

Stipitate Thelephorales are basidiomycetous, mostly hydnoid, ectomycorrhizal fungi. Some species have declined considerably, and some are threat-listed as vulnerable or endangered. These ecological concerns require a well-resolved taxonomy to understand diversity in this group of fungi and facilitate conservation. However, phylogenetic studies have mostly neglected Southern Hemisphere representatives. This study examines the fleshy species of stipitate Thelephorales from native forests in Australia and New Zealand, using morphological analyses and phylogenetic analyses of nuc rDNA internal transcribed spacer region ITS1-5.8S-ITS2 (ITS barcode) and D1-D2 domains at the 5' end of nuc 28S rDNA (28S) sequences amplified from DNA isolated from fungarium collections and environmental DNA (eDNA) sequences from the Australian Microbiome initiative. Five new species, Sarcodon austrofibulatus, Hydnellum gatesiae, H. nothofagacearum, H. pseudoioeides, and H. variisporum, are described, Sarcodon carbonarius is transferred to Neosarcodon, and a key is provided for the six named species in the region. Boletopsis and Neosarcodon are reported from Australia for the first time based on detections from eDNA in soil samples taken from native forests. The Australasian species of Hydnellum occupy a highly derived position with the phylogeny of the genus, the members of which are otherwise all from the Northern Hemisphere, suggestive of a long-distance dispersal origin for the Australasian species.