A molecular phylogeny and a new classification of parmelioid lichens containing Xanthoparmelia-type lichenan (Ascomycota: Lecanorales)

Generic concepts in the parmelioid lichens have been discussed intensively over the past three decades without reaching a broad consensus. We have now employed molecular data from three genes to provide a basis for a revised generic concept of the parmelioid lichens containing Xanthoparmelia-type lichenan. The phylogeny of the parmelioid lichens containing Xanthoparmelia-type lichenan was reconstructed using a combined Bayesian analysis of nuclear ITS, LSU rDNA and mitochondrial SSU rDNA sequences, and a maximum parsimony analysis was also made for comparison. 179 new partial sequences of 58 taxa were generated and 12 sequences were downloaded from GenBank. Our results indicate that the lichens containing Xanthoparmelia-type lichenan form a monophyletic group. However, the segregates proposed earlier do not form distinct clades within the group. Alternative hypotheses of monophyletic Karoowia and Neofuscelia that are not nested within Xanthoparmelia were rejected with our dataset; Karoowia is polyphyletic, and Neofuscelia is reduced to synonymy under Xanthoparmelia. Xanthomaculina convoluta also belongs to Xanthoparmelia. Since we were unable to sequence the umbilicate type species of Xanthomaculina, we refrain from synonymizing that genus with Xanthoparmelia here. The synonymy of Chondropsis and Paraparmelia under Xanthoparmelia already proposed is supported. The revised and enlarged genus Xanthoparmelia includes species that have cell walls with Xanthoparmelia-type lichenan, a palisade plectenchyma with a pored epicortex, lack pseudocyphellae, with usually simple rhizines, generally bifusiform conidia, and medullary chemical diversity. Ten new names are proposed, and 129 new combinations are made into Xanthoparmelia.