Keratosphaera H.B.P. Upadhyay, Publicações Inst. Micol. Recife 402: 5 (1964).
Index Fungorum number: IF 2561; Facesoffungi number: FoF 12249, 6 morphological species (Species Fungorum 2022), no molecular data available.
Hyperparasitic, foliicolous on lichens, on Mazosia phyllosema (Nyl) A. Zahlbra, on living leaves. Colonies occurring on thallus of Mazosia, superficial, irregularly, scattered as black dots, lacking superficial mycelium. Sexual morph: Ascomata erumpent to superficial, solitary, scattered, globose, brown to black, with black setae, unbranched, tapering towards the apex, base wider. Asci 6–8-spored, bitunicate, ellipsoid to obclavate, subsessile, with paraphyses. Ascospores 1–2-seriate, oblique, clavulate, obtuse, 2–3-septate, hyaline, smooth-walled. Asexual morph: Unknown (adapted from Boonmee et al. 2017).
Type species: Keratosphaera batistae H.B.P. Upadhyay
Notes: Keratosphaera is characterised by erumpent to superficial, solitary ascomata, ellipsoid to obclavate, subsessile asci and oblique, clavulate, obtuse, 2–3-septate, hyaline ascospores. The type specimens of K. batistae is lost. Boonmee et al. (2017) provided an updated description and illustration based on the protologue of Upadhyay (1964). Hyde et al. (2013) accepted Keratosphaera in Pseudoperisporiaceae. Wijayawardene et al. (2017, 2020) listed Keratosphaera in Dothideomycetes genera incertae sedis. Detailed morphology of Keratosphaera is unclear. Keratosphaera lacks sequence data. Fresh collections with DNA sequence data are needed to confirm the taxonomic placement of the genus.