Neotropical mountain forests are characterized by having hyperdiverse and unusual fungi inhabiting lichens. The great majority of these lichenicolous fungi (i.e., detectable by light microscopy) remain undescribed and their phylogenetic relationships are mostly unknown. This study focuses on lichenicolous fungi inhabiting the genus Lobariella (Peltigerales), one of the most important lichen hosts in the Andean cloud forests. Based on molecular and morphological data, three new genera are introduced: Lawreyella gen. nov. (Cordieritidaceae, for Unguiculariopsis lobariella), Neobaryopsis gen. nov. (Cordycipitaceae), and Pseudodidymocyrtis gen. nov. (Didymosphaeriaceae). Nine additional new species are described (Abrothallus subhalei sp. nov., Atronectria lobariellae sp. nov., Corticifraga microspora sp. nov., Epithamnolia rugosopycnidiata sp. nov., Lichenotubeufia cryptica sp. nov., Neobaryopsis andensis sp. nov., Pseudodidymocyrtis lobariellae sp. nov., Rhagadostomella hypolobariella sp. nov., and Xylaria lichenicola sp. nov.). Phylogenetic placements of 13 lichenicolous species are reported here for Abrothallus, Arthonia, Globonectria, Lawreyella, Monodictys, Neobaryopsis, Pseudodidymocyrtis, Sclerococcum, Trichonectria and Xylaria. The name Sclerococcum ricasoliae comb. nov. is reestablished for the neotropical populations formerly named S. lobariellum (Sclerococcales). A key to sexual and asexual states of 40 species of lobariellicolous ascomycetous fungi is provided. Teleomorph-anamorph connections were established for several species using molecular methods and/or visual observations in nature. Additionally, we found that the anamorphic species Cornutispora ophiurospora inhabiting Lobariella was often accompanied by ascomata of Spirographa. Results of phylogenetic analyses, including newly generated sequences of several Cornutispora and Spirographa species inhabiting various host lichens, support the conclusion that Cornutispora is a synonym of Spirographa. Our Maximum Likelihood inference based on multiple loci show that all studied Spirographa (including Cornutispora) belong to a new lineage within Ostropales. Based on these highly supported phylogenetic placements and the distinct character states of their conidiomata, in comparison with other Lecanoromycetes, a new family is proposed – Spirographaceae fam. nov. This new lineage includes broadly distributed mycoparasites, inhabiting various lichen and fungal hosts, and representing an early diversification event preceding the lichen-forming clade of Fissurinaceae, Gomphillaceae and Graphidaceae. Two lichenicolous species, Asteroglobulus giselae and Pleoscutula arsenii, were found to be nested within the Spirographa clade, and their teleomorph-anamorph connections were confirmed based on genotypic and phenotypic data. This phylogenetic result is corroborated by their highly similar ascomata anatomy. Together these results strongly indicate that both species are congeneric with Spirographa. As a result, four new species (S. aggregata sp. nov., S. galligena sp. nov., S. maroneae sp. nov., and S. parmotrematis sp. nov.) and 15 new combinations are proposed (Spirographa ascaridiella comb. nov., S. arsenii comb. nov., S. ciliata comb. nov., S. giselae comb. nov., S. herteliana comb. nov., S. hypotrachynae comb. nov., S. intermedia comb. nov., S. lichenicola comb. nov., S. limaciformis comb. nov., S. ophiurospora comb. nov., S. pittii comb. nov., S. pyramidalis comb. nov., S. triangularis comb. nov., S. tricupulata comb. nov., and S. vermiformis comb. nov.). Species of the genus Spirographa, as outlined here, are strongly host-specific, mainly at the generic level of their host. Some host genera can harbour more than one Spirographa species.
Closely related lichen-forming fungal species circumscribed using phenotypic traits (morphospecies) do not always align well with phylogenetic inferences based on molecular data. Using multilocus data obtained from a worldwide sampling, we inferred phylogenetic relationships among five currently accepted morphospecies of Peltigera section Peltidea (P. aphthosa group). Monophyletic circumscription of all currently recognized morphospecies (P. britannica, P. chionophila, P. frippii and P. malacea) except P. aphthosa, which contained P. britannica, was confirmed with high bootstrap support. Following their re-delimitation using bGMYC and Structurama, BPP validated 14 putative species including nine previously unrecognized potential species (five within P. malacea, five within P. aphthosa, and two within P. britannica). Because none of the undescribed potential species are corroborated morphologically, chemically, geographically or ecologically, we concluded that these monophyletic entities represent intraspecific phylogenetic structure, and, therefore, should not be recognized as new species. Cyanobionts associated with Peltidea mycobionts (51 individuals) represented 22 unique rbcLX haplotypes from five phylogroups in Clade II subclades 2 and 3. With rare exceptions, Nostoc taxa involved in trimembered and bimembered associations are phylogenetically closely related (subclade 2) or identical, suggesting a mostly shared cyanobiont pool with infrequent switches. Based on a broad geographical sampling, we confirm a high specificity of Nostoc subclade 2 with their mycobionts, including a mutualistically exclusive association between phylogroup III and specific lineages of P. malacea.