Abstract
The Lichinales are a group of lichenized ascomycetes that almost exclusively possess
cyanobacteria as their primary photobiont and are hitherto separated from the Lecanorales,
the major group of lichenized ascomycetes, by thallus structure, ascoma ontogeny,
ascus structure and ascus function. The relationship of the two families Peltulaceae
and Lichinaceae, both placed within the Lichinales, with the Heppiaceae, placed within
the Lecanorales, was investigated, as well as a possible sister group relationship
of the Lichinales to the Lecanorales. Phylogenetic analyses included non-molecular
data as well as 18S rDNA sequence data. The monophyly of the Lichinales including
the family Heppiaceae and a sister group relationship of Lichinales and Lecanorales,
based on the shared presence of lecanoralean asci, are proposed in a morphological
hypothesis. Parsimony and distance analyses of 18S rDNA sequence data strongly support
the monophyly of the Lichinales, including all three families. Therefore, the presence
of rostrate, lecanoralean asci in Peltula and part of the Lichinaceae suggests that this ascus type is an autapomorphy of the
monophyletic Lichinales. Furthermore, the occurrence of prototunicate asci in the
Heppiaceae and most of the Lichinaceae is autapomorphic and was gained independently
by reduction of the rostrate ascus. The 18S rDNA analysis did not reject the non-molecular
hypothesis of a sister group relationship of the Lichinales and the Lecanorales as
based on ascus characters. The alternative placement of the Lichinales as the sister
group of all inoperculate euascomycetes excluding the Sordariomycetes and most of
the Leotiales in the gene tree received unsufficient bootstrap support and no support
from any non-molecular data and consequently was rejected.
Key words
Lichenized ascomycetes - Lichinales - Lecanorales - phylogeny - ascus and ascoma evolution
- SSU rDNA
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schultz@rhrk.uni-kl.de
Section Editor: M. Jahns
