Different diversification histories in tropical and temperate lineages in the ascomycete subfamily Protoparmelioideae (Parmeliaceae)

Abstract

Background: Environment and geographic processes affect species’ distributions as well as evolutionary processes, such as clade diversification. Estimating the time of origin and diversification of organisms helps us understand how climate fluctuations in the past might have influenced the diversification and present distribution of species. Complementing divergence dating with character evolution could indicate how key innovations have facilitated the diversification of species.Methods: We estimated the divergence times within the newly recognised subfamily Protoparmelioideae (Ascomycota) using a multilocus dataset to assess the temporal context of diversification events. We reconstructed ancestral habitats and substrate using a species tree generated in *Beast.Results: We found that the diversification in Protoparmelioideae occurred during the Miocene and that the diversification events in the tropical cladeMaroninapredate those of the extratropicalProtoparmelia. Character reconstructions suggest that the ancestor of Protoparmelioideae was most probably a rock-dwelling lichen inhabiting temperate environments.Conclusions: Major diversification within the subtropical/tropical genusMaroninaoccurred between the Paleocene and Miocene whereas the diversifications within the montane, arctic/temperate genusProtoparmeliaoccurred much more recently, i.e. in the Miocene.