Revision of Trimmatothele (Verrucariaceae), and description of Oevstedalia for Trimmatothelopsis antarctica, a new lichen genus with true ascoconidia

Abstract

The type species of Trimmatothele is shown to differ from Verrucaria only by the multispored asci. Trimmatothele is consequently regarded as a younger synonym of Verrucaria, and the new combination Verrucaria perquisita proposed. The species is just known from Europe, where it is very rare on calcareous rocks and has a boreo-alpine distribution. Trimmatothelopsis antarctica is a very distinct lichen, not related with Verrucaria, and the new genus Oevstedalia is described to accommodate it. Oevstedalia is characterized by relatively pale perithecia with a hyphal wall, abundant pseudoparaphyses, sparse, thin, basally branched and anastomosed interascal filaments, an I− and K/I− centre, and very large, subcylindrical, entirely thin-walled, K/I+ blue asci containing in the living state 8 conidial balls filled with numerous ascoconidia. Oevstedalia might be related to the Epigloeaceae (family inc. sedis) and represents the first example of a lichenized ascomycete forming true ascoconidia. O. antarctica appears to be endemic in Antarctica, where it seems to be widespread and relatively common. No material is available for Trimmatothele umbellulariae and Lesdainea maritima, and no final conclusion can be given for the taxonomic status of these two species.