Parallel evolution of lichen growth forms in the family Roccellaceae (Arthoniales, Ascomycota)

The phylogenetic relationships within the family Roccellaceae (lichen fungi) were investigated. Seventy‐two nucleotide sequences of the nuclear large subunit ribosomal RNA gene (LSU) and the second largest RNA polymerase subunit (RPB2) were newly obtained from 48 taxa. The family Roccellaceae was highly supported as monophyletic. The fruticose growth habit has evolved or been lost multiple times in the family and several times even within genera. In Roccellina with 31 species it has evolved three times and in Pentagenella with three species it has been lost once. The genera Roccella and Roccellina were found paraphyletic as two Roccella species nested with Roccellina. The non‐fruticose genus Roccellina was emended to include these two fruticose species as well as the monotypic, fruticose genus Roccellaria. As a result of the phylogenetic analyses six new nomenclatural combinations were made: Pentagenella corallina (Follm. and Peine) Tehler, Pentagenella ligulata (Peine and Follm.) Tehler, Roccellina cumingiana (Gay) Tehler, Roccellina hypomecha (Ach.) Tehler, Roccellina mollis (Hampe) Tehler, Roccellina portentosa (Mont. ex Gay) Tehler. Roccella is mainly distributed on the northern hemisphere while Roccellina is mainly distributed on the southern hemisphere. The Roccella species present on the Galapagos Islands are related to those in California and the northern hemisphere not, as was generally believed, to those in Chile and the southern hemisphere. The present data set may indicate that Bayesian analysis can give misleading topologies and overestimated posterior support values when insufficiently sampled taxa are included in an otherwise well sampled data set. © The Willi Hennig Society 2007.