Rupestriomyces and Spissiomyces, two new genera of rock-inhabiting fungi from China.

Bare rocks in arid and semi-arid climates may harbor a bewildering biodiversity of fungi that are overlooked in China. During a survey of rock-inhibiting fungi in China, more than 1000 were isolated and 14 belonging to Dothideomycetes (Ascomycota) were selected for detailed study. Phylogenetic trees based on combined sequence datasets of mt 16S rDNA, partial nuc rDNA 18S and 28S indicated that these strains clustered in two distinct, well supported and previously unknown lineages within the class Dothideomycetes. Therefore two new genera were established corresponding to those two clades. Spissiomyces gen. nov. is characterized by thick-walled, yellowish brown hyphae and globose or subglobose conidia, if present. Rupestriomyces gen. nov. is characterized by globose, barrel-shaped, ampulliform or ovoidal conidia formed from acropetal, catenate hyphae. Further phylogenetic analyses using combined sequence datasets of the rDNA internal transcribed spacer (ITS) region and 16S rDNA, part of genes of RPB2, TUB2, nuc rDNA 18S and 28S revealed that those strains represented five new species (i.e. Spissiomyces aggregatus, S. ramosus, Rupestriomyces sinensis, R. ampulliformis, R. torulosus). They were described, illustrated and compared with similar taxa based on morphological characteristics and phylogenetic relationships. The results of this paper provides insight into the richness and diversity of rock-inhibiting fungi in nature.