Description: Thallus inapparent, not lichenized, with hyaline vegetative hyphae immersed in the thallus of Acarospora-species, causing discolourations on the areoles of the host. Apothecia arthonioid, round, usually single, developing superficially, 0.1-0.3 mm across, with a black, convex disc, without a distinct margin. Proper exciple poorly developed; epithecium brown to reddish brown, 10-20 µm high, K+ olive green or brown-black; hymenium colourless to pale brown, 40-55 µm high, I+ red, K/I+ blue; paraphysoids 2.5-3.5 µm thick, the apical cells to 4-5 µm wide; hypothecium dark reddish brown, K+ brown-black, with pigments in intercellular spaces. Asci 8-spored, broadly clavate, semi-fissitunicate, with a large apical dome, a distinct ocular chamber, and a K/I+ blue ring-structure in tholus, Arthonia-type. Ascospores 1-septate, hyaline, constricted at septa, ellipsoid, (9-)10-14 x (4-)5-6 µm, with a perispore reacting I-. Photobiont absent. Spot tests: K-, C-, KC-, P-. Chemistry: without lichen substances.
Note: a lichenicolous fungus growing on the thalli of Acarospora-species; described from Turkey and also known from Spain; to be looked for in Italy.