Global phylogeny of the family Gomphillaceae (Ascomycota, Graphidales) sheds light on the origin, diversification and endemism in foliicolous lineages

Foliicolous lichens grow on living leaves of vascular plants. They are mostly found in tropical to subtropical or temperate rainforests. Many phenotype-based species are considered as pantropical or even sub-cosmopolitan, either attributed to old ages, having existed prior to continental breakups or long-distance dispersal. We built a much expanded, global phylogeny of Gomphillaceae, the most diverse group of leaf-dwelling lichenised fungi. Our sampling encompassed six major biodiversity hotspots: MIOI (Madagascar and the Indian Ocean Islands), the Caribbean, New Caledonia, the Colombian Chocó, Mesoamerica and the Atlantic coast of Brazil. It was based on multilocus sequence data (mtSSU rDNA, nuLSU rDNA and RPB1), including 2207 sequences of 1256 specimens. Species delimitation methods combined with a phenotype matrix identified 473 putative species. Amongst these, 104 are confirmed as described, 213 are classified as cryptic or near cryptic (hidden diversity), 100 represent new species to science (identified on the basis of phenotype) and 56 remain unidentified. Amongst the 104 species with a valid name, 40.5% are distributed across 2–5 continents (lichenogeographical regions) by applying the phenotype-based species concept. However, using the integrative approach to delineate species, this estimate is reduced to 9%. We estimate the global species richness of Gomphillaceae at 1,861–2,356 species. The timing of species-level divergences suggests that the current distribution of foliicolous lichens is shaped more by long-distance dispersal and rapid diversification than by vicariance. The origin of the family and major clades appears to be in the Neotropics, with subsequent numerous dispersal events. Our results support the separation of three major lineages, corresponding to the former families Asterothyriaceae, Gomphillaceae s.str. and Solorinellaceae, which should be recognised at the subfamily level.