The phylogeny of the family Pannariaceae (Lecanorales, lichenized Ascomycota) was investigated using ITS15.8SITS2 nuclear ribosomal DNA sequences representing 21 species. Phylogenetic estimations were performed using parsimony and a Bayesian Markov chain Monte Carlo (MCMC) tree sampling procedure. Several phylogenetic null hypotheses were tested, also using MCMC. The results indicate that Pannariaceae, as currently treated, is polyphyletic and that Degelia sect. Amphiloma, Fuscopannaria subg. Micropannaria, and Moelleropsis s.str. do not belong in the family. The inclusion of Parmeliella in the Pannariaceae could not be rejected, although it falls outside the family in the optimal trees. Psoroma, Santessoniella, Protopannaria, Fuscopannaria subg. Fuscopannaria, Moelleropsis s.str., and Pannaria unequivocally belong to the family. The Pannaria sphinctrina group belongs in Pannaria despite its green-algal photobiont. Protopannaria pezizoides is not, as sometimes treated, a Pannaria, although a relationship with Psoroma could not be ruled out. In the optimal trees, Moelleropsis s.str. is nested inside Fuscopannaria subg. Fuscopannaria and Santessoniella inside Psoroma, but null hypotheses of their independence from these genera could not be rejected. Pannaria cannot be divided into two monophyletic subgenera, Pannaria and Chryopannaria. The photobiont has changed twice or three times and the ascus apex and hymenial amyloidity twice within the Pannariaceae.Key words: lichens, Pannariaceae, ITS, ribosomal DNA, phylogeny, MCMC.
On Optimal Trees for Irregular Gather and Scatter Collectives
