Multilocus phylogeny of Acrospermaceae: New epibiotic species and placement of , and anamorphs.

is a poorly known genus of epibiotic and saprophytic species with a subcosmopolitan distribution. Here, we investigate the intriguing relationship between and its host plants in the fern family Polypodiaceae, where it occurs upon approximately 45 neotropical species. We conducted phylogenetic analyses using an eight-marker comprehensive ascomycete data set comprising 719 species representing all major lineages along with 23 new specimens sampled from ferns. We ask whether fern-dwelling are monophyletic, whether epibiotic have evolved independently from saprophytic ancestors, and identify anamorphic phases by incorporating sequences for all suspected taxa. Our results corroborate the placement of Acrospermales within the Dothideomycetes with strong support. However, the order remains incertae sedis due to weak support along the branches subtending the clade that includes the Acrospermales plus Dyfrolomycetales. Our results show a strong phylogenetic pattern in lifestyles but do not clearly identify an ancestral life history state. The first divergence in Acrospermaceae splits fungicolous taxa from taxa that inhabit plants; saprophytes and anamorphic phases found on angiosperms occur in both clades. Fungicolous species are monophyletic, whereas species with an epibiotic or necrotic life history upon plants are nonmonophyletic due to the position of the saprophyte . Previously, all collected from ferns were identified as . Our results indicate that this is not monophyletic due to the inclusion of . Two species are described herein as , sp. nov., and , sp. nov. We find no instances of co-cladogenesis; however, our ability to detect this is limited by the lack of resolution in the clade. Rather, we see that that the distribution of epibiotic is explained by the overlap between the ecological niche of the species and its host.