Multi-locus phylogeny of Bryoria reveals recent diversification and unexpected diversity in section Divaricatae

<b>Abstract</b><br/><p>We used information on six gene regions - three nuclear protein-coding markers (Mcm7, GAPDH and Tsr1), two nuclear ribosomal markers (ITS rDNA and IGS rDNA), and a partial mitochondrial small subunit (mtSSU rDNA) - to examine infrageneric relationships in the genus <em>Bryoria </em>(Parmeliaceae, Lecanoromycetes) and to assess species delimitation in <em>Bryoria bicolor</em>/<em>B. tenuis</em> group in section Divaricatae. Our phylogenetic analyses based on the combined data set of six gene loci support the monophyly of sections Americanae, Divaricatae and Implexae, while section Bryoria is polyphyletic and groups in two clades. Species from Bryoria clade 1 are placed in an emended section Americanae. Our study reveals that section Divaricatae is young (c. 5 My) and undergoing diversification especially in South East Asia and western North America. Separate phylogenetic analyses of section Divaricatae using ITS produced a topology congruent with the current species concept. However, the remaining gene regions produced poorly resolved phylogenetic trees and the different species delmitation methods also gnerated highly inconsistent resluts, congruent with other studies that highlight the difficulty of species delmitation in groups with recent and rapid radiation. Based on our results we describe the new species <em>B. ahtiana </em>sp. nov., characterized by its bicolorous, caespitose, widely divergent thallus, conspicuously thickening main stems, well developed secondary branches, and rather sparse third-order branchlets. Another new lineage, here referred to as <em>B. tenuis</em> s. lat., is restricted to western North America and may represent a new species recently diverged from <em>B. tenuis </em>s. str., though further work is needed.</p>