Using a temporal phylogenetic method to harmonize family- and genus-level classification in the largest clade of lichen-forming fungi Pradeep K. Divakar 1 • Ana Crespo 1 • Ekaphan Kraichak 2 • Steven D. Leavitt 3 • Garima Singh 4 • Imke Schmitt 4 • H. Thorsten Lumbsch 5 Received: 14 January 2017 / Accepted: 7 April 2017 / Published online: 11 April 2017 Ó School of Science 2017 Abstract Although classification at supra-specific ranks is inherently arbitrary, comparable taxonomic ranks within clades can facilitate more consistent classifications and objective comparisons among taxa. Different circumscrip- tions of the hyper-diverse lichen-forming fungal family Parmeliaceae and widely different generic circumscriptions among authors have been proposed. For this study, we use a recently developed temporal approach that uses time- calibrated chronograms to identify temporal bands for specific ranks in Parmeliaceae and allied groups with the overarching goal of establishing a consistent, stable classi- fication. A data set of 330 species, representing 73 genera in the family and 52 species of related families was used to address the circumscription of Parmeliaceae and its genera following the proposed temporal approach. Based on the results of this study, we propose a revised, temporal-based classification for Parmeliaceae, including all clades that share a common ancestor 102.13–112.88 Ma for families and a time window of 29.45–32.55 Ma for genera. Forty- five of the currently accepted genera in Parmeliaceae were supported in their current circumscription. Two subfamilies are accepted within Parmeliaceae: Protoparmelioideae Divakar et al. subfam. nov., including Protoparmelia and the resurrected genus Maronina, and Parmelioideae, including the bulk of genera in the family. The new genus Austromelanelixia Divakar et al. is proposed to accom- modate a clade of southern Hemisphere species previously included in Melanelixia. Eumitria and tentatively Dolic- housnea are resurrected as genera separate from Usnea. The following genera are reduced to synonymy: Alloce- traria, Cetrariella, Usnocetraria, and Vulpicida with Ce- traria; Arctocetraria, Cetreliopsis, Flavocetraria, Kaernefeltia, Masonhalea, Tuckermanella, and Tucker- mannopsis with Nephromopsis; and the lichenicolous genera Nesolechia and Raesaenenia with the lichen-form- ing genera Punctelia and Protousnea, respectively. A total of 47 new combinations and three new names at the species level are proposed. Keywords Ascomycota Á Gypsoplacaceae Á Lecanorales Á Lichenized fungi Á Parmeliaceae Á Phylogeny Á Protoparmelia Á Taxonomy Á Taxonomic ranks Introduction Classification of organisms predates evolutionary thinking. Linnaeus, who systematically used a ranked classification (Linnaeus 1767), understood a ‘‘natural system’’ as reflecting a divine plan and not evolutionary relationships. Today it is generally accepted that organisms continuously Electronic supplementary material The online version of this article (doi:10.1007/s13225-017-0379-z) contains supplementary material, which is available to authorized users. & Ekaphan Kraichak ekaphan.k@ku.th 1 Departamento de Biologı ´a Vegetal II, Facultad de Farmacia, Universidad Complutense de Madrid, 28040 Madrid, Spain 2 Department of Botany, Faculty of Science, Kasetsart University, Bangkok, Thailand 3 Department of Biology and M.L. Bean Life Science Museum, Brigham Young University, 4102 Life Science Building, Provo, UT 84602, USA 4 Department of Biological Sciences, Institute of Ecology, Evolution and Diversity, Goethe Universita ¨t and Senckenberg Biodiversity and Climate Research Centre (BiK-F), Frankfurt am Main, Germany 5 Science & Education, The Field Museum, Chicago, IL, USA 123 Fungal Diversity (2017) 84:101–117 DOI 10.1007/s13225-017-0379-z