Vegetative hyphae: brown, torulose, branched and anastomosed, 4-6 µm in diam., forming a superficial reticulum on the host thallus, BCr-; Pseudothecia: black, sessile, globose to subglobose, 25-35(-40) µm in diam.; wall: upper and lower part brown, composed by 1-2 cell layers, mostly 5-10 µm thick, hyphae 3-4 µm wide and 4-5 µm long; hamathecium: without paraphysoids and periphyses; asci: bitunicate, fissitunicate, broadly saccate, sessile, 16-20 x 8-9 µm, 8-spored; epiplasma: in young asci I+ orange (dextrinoid reaction), with an ocular chamber; ascospores: brown, 1-septate, cells of equal size, not or slightly constricted at the septa, ellipsoid, (6.5-)7.5-8(-8.5); Pycnidia: not observed.; Host: on the thallus and apothecia of Teloschistes chrysophthalmus; World and Sonoran distribution: known from Baja California Sur.; Notes: This Sphaerellothecium species has the smallest pseudothecia and ascospores within the genus.