A preliminary phylogeny of the Lecanora saligna-group, with notes on species delimitation

Abstract

AbstractLecanora s. lat. is a genus of crustose, rarely placodioid lichens comprising c. 1000 recognized species and subdivided into several morphology-based groups. Some of these groups have been supported in phylogenetic analyses and segregated as new genera. One of the remaining groups that has not been previously studied by molecular methods in much detail, the L. saligna-group, includes corticolous and lignicolous crustose lichens, usually containing isousnic or usnic acid (or both) as major secondary metabolites. As part of our ongoing project ‘Lecanomics’, a phylogenetic analysis based on two loci was conducted and found the L. saligna-group to be divided into two main clades and several well-supported minor clades. The L. varia clade, chosen as one of the outgroups, emerged within the L. saligna-group. The majority of the clades are characterized by phenotypic differences. However, several well-supported clades share similarities with their sister groups, suggesting that species circumscriptions based solely on phenotypic characters may be too conservative to characterize the true species diversity present within the group. Also, there is evidence for some geographical separation of lineages; for example, most North American individuals, previously known as Lecanora saligna and L. albellula, form two clades separate from their European namesakes and are here preliminarily called ‘Lecanora sp. B’, ‘Lecanora sp. C’ and ‘Lecanora sp. D’. However, L. saligna and L. albellula also appear to occur in North America, and some specimens from the Caucasus and Iran cluster within the North American clades. Lecanora anopta and L. subravida are reported for the first time from Iran.