Eurotiomycetes is a large class of ascomycetes with cleistothecial ascocarps within the subphylum Pezizomycotina, currently containing around 3810 species according to the Catalogue of Life. It is the third largest lichenized class, with more than 1200 lichen species that are mostly bitunicate in the formation of asci. It contains most of the fungi previously known morphologically as "Plectomycetes".

Systematics and phylogeny

Internal relationships

The class Eurotiomycetes was circumscribed in 1997 by Swedish mycologists Ove Erik Eriksson and Katarina Winka. At that time it only contained the order Eurotiales, which together with the next order added, Onygenales, form a monophyletic group comprising most of the fungi in "Plectomycetes", a group no longer in use that unified fungi under exclusively morphological characteristics. As more orders were added to Eurotiomycetes, the first two along with Arachnomycetales became constrained to the first subclass, Eurotiomycetidae. In 2001, the second subclass, Chaetothyriomycetidae, was erected to accommodate Chaetothyriales and its sister group Verrucariales, as well as Pyrenulales since 2004. These two remain as the major subclasses of Eurotiomycetes. The remaining subclasses were created through more phylogenetic analyses to accommodate outlying taxa or newly discovered groups: Mycocaliciomycetidae in 2007, Coryneliomycetidae and Sclerococcomycetidae in 2016, and lastly Cryptocaliciomycetidae in 2021. The following cladogram shows the relationships between all Eurotiomycetes orders and monotypic subclasses as of 2021:

External relationships

The class Eurotiomycetes forms a clade with Lecanoromycetes, the largest lichenized class of fungi.

Taxonomy

As of 2022, the taxonomy of Eurotiomycetes recognizes 5 subclasses, 10 orders, 34 families and 289 valid genera. The families are listed here followed by the number of genera. Only one genus, Neocladophialophora, remains incertae sedis within the class.

Nomenclature

The scientific classification for this particular class is particularly tricky, with one particular species having both the anamorph (asexual form), and teleomorph (sexual form) names used in reference to them.

Morphology

Many members (Eurotiales, Onygenales) produce an enclosed structure cleistothecium within which they produce their spores.