Morphological characteristics and phylogenetic analyses revealed Ossicaulis gansuensis sp. nov. (Lyophyllaceae, Basidiomycota) from Northwest China

Abstract

A new species, Ossicaulis, O. gansuensis, collected from the Qilian Mountains Natural Protection Station in Gansu Province, China, is described and illustrated. Its taxonomic position is established through morphological observations and phylogenetic analyses of multi-gene sequences (ITS+LSU+tef1-α+rpb2). Morphologically and ecologically, the new species is distinguished from other members of the genus by its white basidiomata, irregular pileus margins, larger basidia and basidiospores, and unique subcoprophilous and pine-cone-associated habitats. Molecular phylogenetic results show that O. gansuensis is nested within the monophyletic clade of Ossicaulis with high support (100/100/1), while also verifying the monophyly of related genera and the polyphyly of the traditional Lyophyllum sensu lato and Calocybe. In terms of evolutionary ecology, the shift from typical wood-decaying to pine-cone epiphytic and subcoprophilous habitats reflects an ecological niche compression and highly specialized survival strategy to avoid competition in the extreme cold and arid environment of the Qilian Mountains. This study not only fills the lineage and geographic distribution gaps in Ossicaulis in Asian cold-arid regions and Northwest China but also suggests that the Qilian Mountains and surrounding areas may serve as a significant center of fungal biodiversity.