Gonotichia
Gonotichia is a small genus of cyanolichens in the family Lichinellaceae. The genus was established in 2024 as part of a major reorganisation of cyanolichen classification based on DNA studies, and contains just two species that form tiny, dark crusts on sun-exposed rocks. These lichens are characterised by their distinctive reproductive structures that develop as swellings within the lichen body rather than as separate disc-like structures on the surface.
Taxonomy
The genus was circumscribed by Matthias Schultz and María Prieto as part of a class-wide phylogenetic revision that reorganised Lichinomycetes into four families. Within this scheme, Gonotichia forms a distinct clade in Lichinellaceae, which the authors diagnose chiefly by thallinocarpous ascomata and a Lichinella-type ascus. The type species is Gonotichia octosporella, a taxon that was originally described as Gonohymenia octosporella by Georg Lettau in 1942. A second species, G. depauperata, was also included in the original treatment.
Description
Species of Gonotichia are minute, rock-dwelling cyanolichens. The thallus is crustose, forming thin, dark, irregular patches on the substrate rather than a leafy or shrubby form. The sexual reproductive structures are, i.e. the ascomata develop within swellings of the thallus instead of as open, disc-like apothecia on the surface. Asci conform to the Lichinella-type used to characterise Lichinellaceae; in the type species they bear eight ascospores.
Gonotichia species occur on sun-exposed mineral substrates, especially siliceous rock, in open sites. Their very small, dark crusts are typical of many Lichinellaceae, which are scattered but widespread in suitable dry, well-lit habitats.
Species
The following species are accepted in the 2024 treatment:Gonotichia depauperata