Phylogeny,taxonomy and diversification events in the Caliciaceae

Although the high degree of non-monophyly and parallel evolution has long been acknowledged within the mazaediate Caliciaceae(Lecanoromycetes,Ascomycota),a natural re-classification of the group has not yet been accomplished.Here we constructed a multigene phylogeny of the Caliciaceae-Physciaceae clade in order to resolve the detailed relationships within the group,to propose a revised classification,and to perform a dating study.The few characters present in the available fossil and the complex character evolution of the group affects the interpretation of morphological traits and thus influences the assignment of the fossil to specific nodes in the phylogeny,when divergence time analyses are carried out.Alternative fossil assignments resulted in very different time estimates and the comparison with the analysis based on a secondary calibration demonstrates that the most likely placement of the fossil is close to a terminal node rather than a basal placement in the Calicium clade.Our dating analysis show two successive events giving rise to main clades of mazaediate taxa within the Caliciaceae,in the Upper-Lower Cretaceous boundary and in the Paleocene.As a result of this study,Cyphelium is synonymized with Calicium,Acolium is resurrected,and the new genera Allocalicium and Pseudothelomma are described.Twelve new combinations are proposed:Acolium karelicum,Acolium marcianum,Allocalicium adaequatum,Calicium carolinianum,Calicium lecideinum,Calicium lucidum,Calicium notarisii,Calicium pinicola,Calicium trachyliodes,Pseudothelomma occidentale,Pseudothelomma ocellatum and Thelomma brunneum.A key for the mazaedium-producing Caliciaceae is included.