Astrothelium disjunctum is a species of corticolous (bark-dwelling), crustose lichen in the family Trypetheliaceae.

[1] Found in Brazil, it was formally described as a new species in 2016 by lichenologists André Aptroot and Marcela Cáceres.

The lichen has a smooth and somewhat shiny, pale yellowish-grey thallus that has a black prothallus line (about 0.3 mm wide) and covers areas of up to 5 cm (2 in) in diameter.

The ascomata are roughly spherical (globose) and typically occur in groups of 5 to 25, usually immersed in the bark tissue as pseudostromata.

[2] The characteristic that largely distinguishes it from other members of Astrothelium are its smooth to coarsely uneven thallus.