Taxonomy and Phylogeny of Cystolepiota (Agaricaceae, Agaricales): New Species, New Combinations and Notes on the C. seminuda Complex

Species of Cystolepiota are known as diminutive lepiotaceous fungi with a worldwide distribution. Previous studies revealed that Cystolepiota is not monophyletic and preliminary DNA sequence data from recent collections suggested that several new species exist. Based on multi-locus DNA sequence data (the nuc rDNA internal transcribed spacer region ITS1-5.8S-ITS2, ITS; the D1-D2 domains of nuc 28S rDNA, LSU; the most variable region of the second-largest subunit of RNA polymerase II, rpb2 and a portion of the translation-elongation factor 1-a. tef1), C. sect. Pulverolepiota forms a distinct clade separating from Cystolepiota. Therefore, the genus Pulverolepiota was resurrected and two combinations, P. oliveirae and P. petasiformis were proposed. With the integration of morphological characteristics, multi-locus phylogeny, and information on geography and habitat, two new species, viz. C. pseudoseminuda and C. pyramidosquamulosa, are described and C. seminuda was revealed to be a species complex containing at least three species, viz. C. seminuda, C. pseudoseminuda, and Melanophyllum eryei. In addition, C. seminuda was re-circumscribed and neo-typified based on recent collections.

Automated summary

By combining multi-locus DNA sequence data and morphological characteristics, new species within the Cystolepiota genus have been identified, leading to the resurrection of the Pulverolepiota genus. It was also discovered that C. seminuda is a species complex, consisting of at least three species. The study provides a comprehensive understanding of the phylogeny and taxonomy within this group of fungi.