Preliminary classification of Leotiomycetes

Abstract

Leotiomycetes is regarded as the inoperculate class of discomycetes within the phylum Ascomycota. Taxa are mainly characterized by asci with a simple pore blueing in Melzer's reagent, although some taxa have lost this character. The monophyly of this class has been verified in several recent molecular studies. However, circumscription of the orders, families and generic level delimitation are still unsettled. This paper provides a modified backbone tree for the class Leotiomycetes based on phylogenetic analysis of combined ITS, LSU, SSU, TEF, and RPB2 loci. In the phylogenetic analysis, Leotiomycetes separates into 19 clades, which can be recognized as orders and order-level clades. Leotiomycetes include 53 families (Ascodichaenaceae, Amicodiscaceae fam. nov., Amorphothecaceae, Arachnopezizaceae, Ascocorticiaceae, Calloriaceae, Cenangiaceae, Chaetomellaceae, Chlorociboriaceae, Chlorospleniaceae fam. nov., Bryoglossaceae fam. nov., Cochlearomycetaceae, Cordieritidaceae, Cyttariaceae, Deltopyxidaceae fam. nov., Dermateaceae, Discinellaceae fam. nov., Drepanopezizaceae, Erysiphaceae, Gelatinodiscaceae, Godroniaceae, Hamatocanthoscyphaceae fam. nov., Helicogoniaceae, Helotiaceae, Hemiphacidiaceae, Heterosphaeriaceae, Hyaloscyphaceae, Hydrocinaceae fam. nov., Hyphodiscaceae fam. nov., Lachnaceae, Lahmiaceae, Lauriomycetaceae, Leotiaceae, Leptodontidiaceae, Lichinodiaceae, Loramycetaceae, Marthamycetaceae, Medeolariaceae, Mitrulaceae, Mollisiaceae, Neocrinulaceae, Neolauriomycetaceae, Pezizellaceae, Phacidiaceae, Ploettnerulaceae, Rhytismataceae, Rutstroemiaceae, Sclerotiniaceae, Solenopeziaceae fam. nov., Thelebolaceae, Triblidiaceae, Tympanidaceae and Vibrisseaceae) and 14 family-level clades (Alatospora-Miniancora clade, Aquapoterium-Unguicularia clade, Bulgariella clade, Coleophoma-Parafabraea clade, Colipila clade, Corticifraga-Calloriopsis clade, Epicladonia-Epithamnolia clade, Flagellospora clade, Gelatinomyces clade, Micraspis clade, Patellariopsis clade, Phialocephala urceolata clade, Peltigeromyces clade and Trizodia clade). We briefly discuss the phylogenetic placements of these families and family-level clades. We provide an outline of the genera and the families of Leotiomycetes and a table summarising sexual morph characters of all the families/family-level clades of Leotiomycetes. Nine new families are introduced and we provide descriptions and illustrations of 50 Leotiomycetes taxa including six new genera and 22 new species, from collections made in China, Italy, Thailand, Russia, UK and Uzbekistan. Small scale phylogenetic analyses using concatenated datasets of five loci (rDNA, TEF and RBP2) are provided, where the backbone tree is insufficient to confirm the phylogenetic placement of our collections. This paper contributes to a more comprehensive update and improved identification of Leotiomycetes based on available literature and our collections.