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

The lichen has a smooth and somewhat shiny, olive-green to olive-brown thallus that lacks a prothallus and covers areas of up to 5 cm (2 in) in diameter.

The ascomata are more or less spherical (globose), measuring 0.8–1.2 mm in diameter, and typically occur in groups of 3 to 15, usually immersed in pseudostromata.

The species epithet curvisporum refers to the curved ascospores (measuring 115–135 by 29–36 μm), which have five septa that divide the spore into distinct compartments.

[2] The characteristics that distinguish A. curvisporum from other members of Astrothelium include its grouped ascomata and its curved ascospores.