Diverse Communities of Endemic and Cosmopolitan Lineages at Local Sites in the Lecanora polytropa Aggregate (Ascomycota)

Abstract

Recent work has suggested exceptional species-level diversity in the lichen-forming Lecanora polytropa complex (Lecanoraceae, Ascomycota). However, biogeographic patterns and the spatial structuring of this diversity remains poorly known. To investigate diversity across multiple spatial scales, we sampled members of this species complex from two distinct regions—the Pacific Coast Ranges in southern Alaska, USA, and montane habitats in Spain. We also included sequence data from several species within this complex that were recently described from populations in France. Using the standard DNA barcoding marker and a sequence-based species delimitation approach (ASAP), we inferred a total of 123 candidate species (SHs) within the Lecanora polytropa complex, 32 of which were sampled for the first time here. Of 123 SHs, 21 had documented intercontinental distributions, while the vast majority were found at much smaller spatial scales. From our samples collected from Alaska, USA, and Spain, representing 36 SHs, we found high genetic diversity occurring within each sampled site, but limited overlap among all sites. Mountain ranges in both regions had high proportions of endemic lineages, with the highest diversity and endemism occurring in mountain ranges in Spain. Our sequence data generally support the recent taxonomic proposals, and an integrative taxonomy may help partly resolve the taxonomic conundrums within this hyper-diverse lineage.