Curviclavula, a new genus of anamorphic Helotiales (Leotiomycetes) isolated from air

Abstract

A new genus Curviclavula, with C. anemophila as the type species, is established to accommodate a hyphomycetous anamorph isolated from a culturable air sample collected outdoors in New Mexico, USA. The fungus is morphologically distinct in having 1–5 times dichotomously branched conidiophores and integrated, terminal or intercalary, indeterminate, irregularly sympodial conidiogenous cells with 1–2 flattened, inconspicuous, non-protuberant, and neither thickened nor darkened conidiogenous loci. The conidia are variable in shape, occasionally didymosporous or phragmosporous, but usually minutely cheiroid at first and composed of a subcylindrical to obconical, often inflated, straight or curved basal cell that bears a subglobose lateral cell and a short row of 2–4 cells. The apical cell of the developing conidium curves and fuses with the lateral and adjacent cells once in contact to eventually forming a tightly appressed, subglobose to broadly clavate conidium. Conidial secession is schizolytic, but the conidial basal cells often show minute marginal frills and darkened hila. Phylogenetic analyses using DNA sequences from the nuclear ribosomal large subunit and internal transcribed spacer region also supported Curviclavula as distinct and placed it within the Helotiales (Leotiomycetes, Ascomycota) with strong affinity to the family Hyaloscyphaceae.