Acanthohelicospora Boonmee & K.D. Hyde gen. nov.,Index Fungorum number: IF550572.

Etymology: From ‘acantho’ referring to the sexual morph having setae and ‘helicospora’ referring to the helicosporous conidia of the asexual morph.

Saprobicon dead wood.Sexual state:Ascomata superficial, solitary, scattered, globose to subglobose, black, ostiolate, surrounded with black setae that taper to an acute apex. Peridium composed of several layers, with outer layer of cells compressed and black, with inner layer comprising brown cells of textura angularis. Hamatheciumcomprising numerous,filiform, septate, branched, hyaline pseudoparaphyses. Asci 8-spored, bitunicate, cylindrical, pedicellate, with thick, rounded apex, lacking an ocular chamber. Ascospores overlapping fasciculate, long fusiform-cylindrical, straight to slightly curved, greater than 7-septate, not constricted at any septum, hyaline, smooth-walled. Asexual state:hyphomycetous, helicosporous, helicomyces-like.Conidiophores mononematous, erect, pale brown to brown, smooth-walled. Conidiogenous cells holoblastic, terminal or intercalary, dentate, smooth, with a thickened and truncate conidiogenous loci. Conidiahelicosporous, with wide filaments, coiled, curved, elongated, tapering to narrowly rounded ends, multiseptate, not constricted at septum, hyaline, guttulate, smooth-walled.

Type species: Acanthohelicospora pinicola Boonmee & K.D. Hyde

Notes: The genus Acanthohelicosporium has well-developed spectacular setae on the ascomata, cylindrical asci and oblong ascospores. The asexual state of Acanthohelicospora pinicola developed in culture and appears similar to Helicosporium, except that the conidiophores are micronematous and not setiferous as in the former (Ellis 1971; Seifert et al. 2011). Thus, the monotypicgenus Acanthohelicospora is typified by A. pinicola which differs from all hitherto described species of Acanthostigma and Acanthostigmina(Réblová and Barr 2000; Kodsueb et al. 2004; Promputtha and Miller 2010; Sánchez and Bianchinotti 2010; Sánchez et al. 2012). Acanthostigma scopulumPeck and Acanthohelicospora pinicola share some morphological features (Réblová and Barr 2000; Kodsueb et al. 2004; Promputtha and Miller 2010), however, they differ in the dimensions of the ascomata, asci and ascospores including the number of septa. Acanthohelicospora pinicola groups with an asexual species named Helicosporium guianenseLinder with high support (96% BS and 0.99 PP), in a sister group to Acanthostigma scopulum and Helicosporium aureum (Corda) Linderwith 83% BS support. Putatively named strains of Acanthostigma scopulum, A. aureum and A. guianensein GenBank are here renamed asAcanthohelicospora in the phylogenetic tree, but are not formally synomymised as these are not ex-type strains and their characters are unknown.