This genus is known in the fossil record from the Silurian to the Quaternary (from about 418.7 to 0.0 million years ago). Fossils of species within this genus have been found in Europe, United States, South America, Egypt, Iran, Iraq, India, Japan and Australia.
The monomerous, crustose thalli are composed of a single system of filaments which grow close to the underlying surface. Lithophyllum reproduces by means of conceptacles. The epithallus is periodically shed to avoid organisms growing on top of the alga.
The valid species currently considered to belong to this genus are: