Phylogenetic analysis of some foliicolous lichens collected in Hainan Province, China, revealed a new lineage morphologically similar to Porina but phylogenetically related to Strigulaceae (Dothideomycetes), differing from the latter in ascus type. The monospecific genus Tenuitholiascus gen. nov. is introduced for the single species, T. porinoides sp. nov., which is placed in the new, monogeneric family Tenuitholiascaceae, sister to Strigulaceae in Strigulales. The new taxon closely resembles the genus Porina in external morphology and ascospore type, as well as the thin-walled asci and unbranched paraphyses. Yet, it is entirely unrelated to the latter, which belongs in class Lecanoromycetes in the order Gyalectales.

We employed a molecular phylogenetic approach using five markers (ITS, nuSSU, nuLSU, TEF1-α, and RPB2) to assess potential cryptic speciation in foliicolous members of Strigula s.lat. (Strigulaceae), including the recently segregated genera Phylloporis, Puiggariella, Raciborskiella, Racoplaca, and Serusiauxiella, from tropical areas in Asia, with selected materials from the Neotropics as reference. On the basis of combined molecular and phenotypic datasets, two new species of Racoplaca and 10 new species of Strigula s.str. are described: Racoplaca macrospora sp. nov., R. maculatoides sp. nov., Strigula guangdongensis sp. nov., S. intermedia sp. nov., S. laevis sp. nov., S. microcarpa sp. nov., S. pseudoantillarum sp. nov., S. pseudosubtilissima sp. nov., S. pycnoradians sp. nov., S. sinoconcreta sp. nov., S. stenoloba sp. nov., and S. subtilissimoides sp. nov. In addition, we propose the new combination Phylloporis palmae comb. nov. (≡ =Manaustrum palmae) and we validate the earlier combination Racoplaca melanobapha comb. nov. (≡ Verrucaria melanobapha; Strigula melanobapha). Our data clearly indicate a considerable degree of cryptic diversification in foliicolous representatives of Strigula s.lat., particularly in the presumably widespread taxa Strigula antillarum, S. concreta, S. nitidula, and S. smaragdula. Given that these phylogenetic revisions are thus far limited to few regions, we predict that our findings only represent the proverbial tip of the iceberg in this group of lichenized fungi.

The lichenized fungal genus Astrothelium is an important element of crustose lichen communities in tropical to subtropical forests. Morphological and molecular phylogenetic approaches to investigate species diversity of Astrothelium (Trypetheliaceae) from Southern China were carried out in this study. Bayesian and maximum-likelihood (ML) analyses were generated based on the combined data set of internal transcribed spacer (ITS), partial regions of the nuclear ribosomal large subunit (LSU), and the largest subunit of RNA polymerase II gene sequences (RPB1). The morphological comparison with the known Astrothelium taxa and molecular phylogeny support five new species: Astrothelium jiangxiense sp. nov., A. luminothallinum sp. nov., A. pseudocrassum sp. nov., A. subeustominspersum sp. nov., and A. subrufescens sp. nov. All these species are described and illustrated in detail.