Fossil and living corallinaceans related to the mediterranean endemic species Lithophyllum racemus (Lamarck) Foslie

New observations on asexual and sexual thalli of the Mediterranean species Lithophyllum racemus and description of its variability in a Tyrrhenian population have led to reinterpretation of the features of some fossil and living taxa. The external appearance and the reproductive and vegetative anatomy of the fossil species Lithophyllum viennotii corresponds to tetrasporangial plants of L. racemus. The fossil species Lithophyllum microsporum, whose holotype is redescribed here, represents a sexual stage of L. racemus, probably the carpogonial/carposporangial plants. Consequently, the stratigraphical distribution of L. racemus is widened back to the Aquitanian, and the species can thus be considered a Mediterranean paleoendemic. No character was found supporting the distinction of Lithophyllum duckeri from L. racemus, therefore this species is also considered conspecific with L. racemus.