First insights into genetic diversity and relationships of European taxa of Solenopsora (Catillariaceae, Ascomycota) with implications for their delimitation

Abstract

The lichen genus Solenopsora occurs predominantly in temperate and subtropical regions of the world, and the centre of diversity and distribution is in the Mediterranean, Macaronesian, and Madrean floristic regions. Taxonomic treatment of several taxa has varied over time and the concepts lack clarity. Focusing on multilocus sequence data, morphology, anatomy, chemistry, and ecological preferences, the present study investigates European Solenopsora taxa to obtain the first insights into their genetic variation and relationships. Our results show discrepancy between the number of currently recognized taxa in Europe and the number of genetic entities identified. We recognize eight species in the genus in Europe: Solenopsora candicans, Solenopsora cesatii (including Solenopsora carpatica), Solenopsora grisea, Solenopsora holophaea, Solenopsora liparina, Solenopsora marina, Solenopsora olivacea, and Solenopsora vulturiensis. We gathered evidence to recognize S.liparina, an edaphic vicariant of S.candicans confined to ultramafic rocks, as a separate species. We disclosed a previously unknown sister relationship between S.grisea and S.vulturiensis. Taxonomic synopses, geographical distribution, and an identification key for the treated taxa are provided. Phylogenetic analyses revealed two major lineages among the European Solenopsora spp., differentiated by thallus organization, the presence/absence of rhizines on lower side of the thallus, secondary chemistry, and anatomy of upper cortex. The generic circumscription and phylogenetic position, however, appear problematic and additional studies with increased sampling including related genera are needed.