A new approach to the phylogeny of Euascomycetes with a cladistic outline of Arthoniales focussing on Roccellaceae

A phylogenetic working hypothesis of euascomycete relationships is presented. Paraphysoidal ascolocular fungi are monophyletic and ascohymenial fungi are paraphyletic as paraphyses are considered plesiomorphic and paraphysoids apomorphic within euascomycete fungi. As a result it is not necessary to postulate parallel evolution of the bitunicate ascus, and furthermore presence of paraphyses in the prototunicate caliciaceous fungi is no longer in conflict with paraphyses in ascohymenial fungi. A cladistic outline of the order Arthoniales with special focus on the Roccellaceae including 20 taxa and 92 characters is presented. The type species of all genera considered are used as terminal taxa. It is suggested that the type species of Arthothelium should be excluded from the order Arthoniales. The Arthoniaceae are paraphyletic as Arthonia radiata and Arthothelium spectabile form a grade pair. The family Roccellaceae is monophyletic and corroborated in its traditional sense, but some rearrangements within the family are made. Opegrapha vulgata and Lecanactis abietina form a pair, but the family Opegraphaceae is paraphyletic if the pair Chiodecton sphaerale and Schismatomma pericleum are included. The originally described ascoma of the species Darbishirella gracillima, Ingaderia pulcherrima, and Reinkella fragillima are found to be lichenicolous fungi. The mycobiont ascomata of Darbishirella gracillima produce 3- not 2-septate spores. No ascomata of the mycobionts of the two latter species have as yet been found. Key words: Euascomycetes, Arthoniales, Roccellaceae, phylogeny, cladistics, lichenicolous.