The new species Lecanora bicinctoidea, its position and considerations about phenotypic evolution in the Lecanora rupicola group.

A phylogenetic analysis of the Lecanora rupicola group based on combined nITS rDNA and β-tubulin sequences and a combined dataset of ITS, βtubulin and partial sequences of polyketide synthase genes reveals a previously unrecognized species, which here is introduced under the name Lecanora bicinctoidea. The new species is a sister group of the L. swartzii complex (including L. swartzii and L. lojkaeana), which is characterized by eucorticate ascomata, and a morphological diversity that includes also a dwarf-fruticose lineage. The preferential occurrence on vertical to overhanging siliceous rocks corresponds more closely to L. swartzii. A detailed investigation of phenotypic characters reveals that the new species differs from the superficially similar morphospecies L. bicincta in several ways, such as a thallus of comparatively small areoles and broadly sessile ascomata and the development of an anaphithecial cortex devoid of algal remnants (i.e. an eucortex). L. bicinctoidea contains methyl 3α-hydroxy-4-O-demethylbarbatate, a chemical compound not known from other members of the L. rupicola group. We also discuss the importance of eucortex formation as one of several factors that are involved in the evolution of substrate-detached thallus structures. [ABSTRACT FROM AUTHOR]