Towards a natural classification of Annulatascaceae-like taxa: introducing Atractosporales ord. nov. and six new families

Abstract

Species with relatively small, membraneous, black ascomata, with or without long necks, unitunicate, cylindrical asci with apical rings and fusiform, hyaline ascospores with or without mucilaginous sheaths are common in freshwater habitats in tropical and temperate regions. Many of these taxa have originally been recorded as Annulatascaceae-like taxa. Twenty genera have been included in the family Annulatascaceae, mostly based on morphological characters, while molecular work and phylogenetic analyses are lacking for many genera. In this study, nine new Annulatascaceae-like taxa collected from Thailand were morphologically examined. Pure cultures obtained from single ascospores were used in molecular studies. The nine new strains and several other strains of Annulatascaceae-like Sordariomycetes species were used to establish phylogenetic and evolution relationships among the taxa, based on combined LSU, SSU, ITS and RPB2 sequence data. Phylogenetic analyses provide evidence to introduce one new order and six new families, to accommodate taxa excluded from Annulatascaceae sensu stricto. A new order Atractosporales is established based on the molecular study, including three new introduced families Conlariaceae, Pseudoproboscisporaceae and Atractosporaceae. Conlariaceae is introduced for the genus Conlarium which comprises two species, Conlarium duplumascosporun and a new Hyphomycetous asexual morph taxon Conlarium aquaticum which has subglobose or irregular, brown, clathrate, muriform conidia. Pseudoproboscisporaceae includes Pseudoproboscispora and Diluviicola, while Atractosporaceae includes the genera Rubellisphaeria and Atractospora. Barbatosphaeria, Xylomelasma and Ceratostomella form a distinct stable lineage which is introduced as a new family Barbatosphaeriaceae in Diaporthomycetidae families incertae sedis. A new family Lentomitellaceae is introduced in Diaporthomycetidae families incertae sedis, to accommodate the genus Lentomitella. Woswasiaceae is introduced to accommodate Woswasia, Xylochrysis and Cyanoannulus in Diaporthomycetidae families incertae sedis. Three new species of Fluminicola viz. F. saprophytica, F. thailandensis and F. aquatica are introduced. A new sexual morph, Dictyosporella thailandensis, is reported and Dictyosporella is excluded from Annulatascaceae and placed in Diaporthomycetidae genera incertae sedis. The first sexual morph of Sporidesmium, S. thailandense is also described. The new species Atractospora thailandensis, Diluviicola aquatica and Pseudoproboscispora thailandensis are also introduced. Platytrachelon is added to Papulosaceae based on phylogenetic analysis and morphological characters. Aquaticola, Fusoidispora and Pseudoannulatascus are excluded from Annulatascaceae and placed in Diaporthomycetidae genera incertae sedis. Mirannulata is accommodated in Sordariomycetes, genera incertae sedis.