Gilbertaria, a first crustose genus in the Sphaerophoraceae (Lecanoromycetes, Ascomycota) for Catillaria contristans, Toninia squalescens and related species

Lecideoid lichen-forming fungi are a large, heterogeneous group that includes many species described during the nineteenth century that are of unclear taxonomic status. We revise such a group, the species of which have previously been treated under the much-misunderstood names Catillaria contristans or Toninia squalescens, and use a seven-locus phylogeny to determine its phylogenetic position. We found strong support for a previously unrecognized monophyletic lineage within the Sphaerophoraceae, comprising five phylogenetic species, and describe the new genus Gilbertaria to accommodate them. The new genus is characterized by a crustose growth form, 1-septate ascospores, thick ((1.5-)2-3(-4) mu m wide) paraphyses and asci of the Biatora-type. We revise the nomenclature and give new delimitations and descriptions of the Northern Hemisphere species Gilbertaria contristans comb. nov., G. holomeloides comb. nov., G. squalescens comb. nov. and describe the new species G. astrapeana from the Falkland Islands.

Automated summary

This study revises a group of Lecideoid lichen-forming fungi and identifies a previously unrecognized monophyletic lineage, which is described as a new genus Gilbertaria. The new genus has distinct characteristics and the nomenclature of Northern Hemisphere species is revised and described.