Chaetosphaerellaceae Huhndorf, A.N. Mill. & F.A. Fernández, Mycol. Res. 108(12): 1387 (2004)

Index Fungorum number: IF82145; Facesoffungi number: FoF01114; 6 species.

Saprobic on woody substrates in terrestrial habitats. Sexual morph: Ascomata perithecial, dark brown to black, scattered to densely gregarious, superficial, sitting in a subiculum or subiculum absent, pyriform, obpyriform or ovoid, turbinate, coriaceous, tuberculate or smooth, with or without, brown, branched or unbranched setae, papillate or papilla lacking, collabent or not collapsing, ostiolate. Subiculum abundant or sparse, sometimes lacking, brown to dark brown, consisting of septate, branched or unbranched with spiny hyphae. Peridium with Munk pores, an outer layer composed of dark brown to brown cells of textura angularis; inner layer composed of hyaline cells of textura prismatica. Paraphyses inflated, often present only in young ascomata. Asci 8-spored, unitunicate, clavate, long or short pedicellate, apical ring distinct, indistinct or absent, evanescent. Ascospores 1–3-seriate or overlapping, with brown or brown median cells and hyaline end cells, oblong cylindrical, ellipsoid or fusiform, 1–3-septate. Asexual morph: Conidiophores macronematous, mononematous, erect, straight, solitary or divaricate with 2–4 metulae, brown, septate, branched, percurrent, with a terminal, ampulla. Conidiogenous cells holoblastic or enteroblastic, integrated, terminal. Conidia hyaline to dark brown, oval or elliptical, solitary or catenate (adapted from Maharachchikumbura et al. 2016b).

Type genus – Chaetosphaerella E. Müll. & C. Booth.

Notes – Chaetosphaerellaceae, typified by Chaetosphaerella (Müller & Booth 1972), was introduced by Huhndorf et al. (2004a) for fungi with superficial, ostiolate ascomata sitting on a subiculum, clavate or cylindrical asci, with pigmented ellipsoid ascospores, and enteroblastic or holoblastic conidiogenesis. In a taxonomic re-evaluation of Chaetosphaeria species, Réblová (1999a, b, c, d) accepted Chaetosphaerella phaeostroma and C. fusca in the genus and placed them in the Helminthosphaeriaceae based on peridium anatomy, setae, ascal anatomy, absence of Quellkörper and conidiogenesis. Chaetosphaerella fusispora Sivanesan was excluded from the genus and transferred to Crassochaeta based on differences in the ascus, hamathecium and ascospore anatomy by Réblová (1999b). Chaetosphaerella is associated with asexual morphs formerly referred to Oedemium and Veramycina. Réblová (1999a) discussed relationships of Chaetosphaerella with Nitschkiaceae based on the peridium. A phylogeny based on LSU rDNA sequence data showed that Chaetosphaerella and Crassochaeta clustered in the same clade, for which Chaetosphaerellaceae was described (Huhndorf et al. 2004a). Mugambi & Huhndorf (2010) referred Spinulosphaeria to Sordariomycetes genera incertae sedis, based on morphology and analysis of LSU sequence data of S. nuda. In a combined LSU, SSU, tef1 and rpb2 dataset, S. nuda formed a sister group to Chaetosphaerella species with high support in Chaetosphaerellaceae (Mugambi & Huhndorf 2010, Maharachchikumbura et al. 2015, 2016b). Réblová et al. (2016b) proposed Chaetosphaerella as a correct name for the genus and recommended Chaetosphaerella for protection over Oedemium and Veramycina.