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Aim: Contemporary species' distributions are shaped by both geography and historical events, such as extinction, diversification in specific areas and long‐distance dispersals. In the most diverse family of lichen‐forming fungi, Parmeliaceae, the Hypogymnioid clade, is an example of an evolutionary lineage comprised of species occurring in temperate to subpolar regions in both hemispheres. Here, we elucidate the timing of diversification events and the impact of historical events on the species distribution in this lineage. Location: Worldwide. Taxon: Genera Arctoparmelia, Brodoa, Hypogymnia and Pseudevernia (Parmeliaceae). Methods: Our sampling focused on the most diverse genus of the clade, Hypogymnia, including c. 70% of the described species. We reconstructed phylogenetic relationships using a multi‐locus data set, estimated divergence times, and inferred ancestral distributions. Results: Our analyses suggest that the ancestor of the Hypogymnioid clade occurred in the Holarctic. In each of the four genera, all recovered as monophyletic here, diversification have occurred largely during the Miocene and Pliocene. A number of currently accepted species did not form monophyletic groups, especially in cases where specimens were collected from distinct geographic areas, with multiple, distinct clades corresponding to the geographic region of origin. Our results suggest that only a very few species in the Hypogymnioid clade have cosmopolitan distributions, all of which reproduces using vegetative propagules including both symbiotic partners. Main conclusions: While the diversification occurred predominantly in the Northern Hemisphere during the Miocene, a long‐distance dispersal event from the Northern to the Southern Hemisphere, resulted in diversification of a clade of species largely restricted to the Southern Hemisphere. Similar to other groups in this diverse family, our study highlights the need for re‐evaluation of species boundaries among members of the Hypogymnioid clade. [ABSTRACT FROM AUTHOR]

Disjunct intercontinental distributions have always fascinated biologists. With the increasing availability of molecular sequence data, there is a renewed interest in historical biogeography, especially in groups in which species boundaries have changed dramatically as a result, such as lichenized fungi. In the hyperdiverse family Parmeliaceae, Parmelina and Myelochroa have contrasting centres of distribution, with Myelochroa being most diverse in eastern Asia and Parmelina in Western Europe and the Mediterranean. We used multi-locus sequence data from 53 specimens to understand the impact of historical events on the current distribution patterns in these genera. We reconstructed phylogenetic relationships, estimated divergence times and inferred ancestral distributions. Our analyses suggested that the ancestor of the two genera occurred in the Old World and that these genera split during the Eocene. Diversification in both genera was estimated to have occurred during the Miocene, with the ancestor of Myelochroa probably occurring in Asia, whereas the ancestor of Parmelina probably occurred in the Turanian region and Europe or only Europe. The two Parmelina spp. occurring in the New World (P. coleae, P. yalungana) are not closely related and migrated independently from the Old World. [ABSTRACT FROM AUTHOR]