Sarcogyne albothallina is a species of rock-dwelling, crustose lichen-forming fungus in the family Acarosporaceae. It was formally described as a new species in 2016 from specimens collected from the Missouri Breaks region of Montana. It is differentiated from others in Sarcogyne by its white, non-powdery thallus and by the presence of 4-O-methylhiascic acid, a combination of features that separates it from other species sharing a blackened upper spore-bearing surface (carbonized ).