Multilocus Molecular Phylogeny of the Umbilicaria aprina Group (Umbilicariaceae, Lichenized Ascomycota) Supports Species Level and Neo-Endemic Status of Umbilicaria krascheninnikovii.

The Northeast Asian endemic species of lichen-forming fungus Umbilicaria krascheninnikovii is herein discussed in the global context of biogeography and phylogeny of the U. aprina group. The name U. krascheninnikovii has been erroneously used by lichenologists for Umbilicaria spp. from high latitudes or altitudes worldwide, as there are omphalodisc apothecia and rough "crystals" of a necral layer on the upper surface. To test the monophyly and phylogenetic relationships within the U. aprina group, four independent DNA regions (nrITS/5.8S, RPB2, mtLSU, and mtSSU) were used for six rare species, including a dozen specimens of U. krascheninnikovii from its locus classicus in Kamchatka. The study is based on the phylograms obtained using maximum likelihood and a Bayesian phylogenetic inference framework. As a result of phylogenetic and biogeographic analyses, it was shown that U. krascheninnikovii is a neo-endemic of the areas of modern volcanism in Kamchatka, Japan, as well as in the Kurile Islands, where this species was recorded for the first time. The morphology of U. krascheninnikovii is herein described and illustrated. Increasing the role of the sexual process and reducing asexual thalloconidiogenesis are shown to be apomorphic traits in the U. aprina group. The combination of sexual and asexual reproduction provides adaptive advantages in changing environmental conditions.

Convergent evolution of a symbiotic duet: the case of the lichen genus Polychidium (Peltigerales, Ascomycota).

PREMISE OF THE STUDY: Thallus architecture has long been a powerful guide for classifying lichens and has often trumped photobiont association and ascomatal type, but the reliability of these characters to predict phylogenetic affinity has seldom been tested. The cyanolichen genus Polychidium unites species that have strikingly similar gross morphology but consort with different photobiont genera. If Polychidium were found to be monophyletic, photobiont switching among closely related species would be suggested. If, however, species were found to arise in different lineages, a convergent body plan and ascomatal type evolution would be inferred. METHODS: We tested the monophyly of Polychidium with a multilocus phylogeny based on nuclear and mitochondrial sequence data from all known Peltigeralean families and reconstructed ancestral states for specific thallus architecture and ascomatal ontogeny types relative to Polychidium and other clades. KEY RESULTS: We found that Polychidium consists of two species groups that arose independently in different suborders within the Peltigerales, associated with Nostoc and Scytonema photobionts, respectively. We infer from ancestral character state reconstruction that dendroid thallus architecture evolved independently in these two lineages. CONCLUSIONS: The independent development of similar dendroid thallus architecture in different fungal suborders with different photobionts represents a clear and previously overlooked example of convergent evolution in lichens. Our results also suggest a pattern of character state conservation, loss, and reversion in ascomatal ontogeny types, hitherto considered conserved traits useful for higher level ascomycete systematics.