Astrothelium amylosporum is a species of corticolous (bark-dwelling) lichen in the family Trypetheliaceae. Found in Bolivia, it was formally described as a new species in 2016 by lichenologists Adam Flakus and André Aptroot. The type specimen was collected near Florida village in Noel Kempff Mercado National Park (Santa Cruz Department); there, at an altitude of 220m (720feet), it was found growing on bark in a Beni savanna with trees. It is somewhat similar to Astrothelium subdisjunctum, but differs from that species in its eight-spored asci and amyloid ascospores. The species epithet amylosporum refers to this latter characteristic.