The type specimen was collected in Santa Luzia do Itanhi [pt], Mata do Crasto, Brazil, on the bark of a tree, in March 2012.

[2] The thallus of Astrothelium globosum is corticate, consisting of closely appressed, nearly spherical warts measuring 0.3–0.9 mm in diameter.

Ascomata are pyriform, measuring 0.2–0.4 mm in diameter, and usually appear in groups of 2–5, immersed in the bark and visible from above by black ostioles between the thallus warts.

The hamathecium is not inspersed, and ascospores are 8 per ascus, hyaline, 3-septate, long ellipsoid, 35–40 by 11–13 μm, with diamond-shaped lumina and surrounded by a gelatinous sheath.

[2] This species is distinguished by a unique thallus consisting of almost spherical warts, an unusual three-dimensional feature for a crustose lichen.