The new genus Potyphyllum is erected with Cyathophyllum ananas Goldfuss, 1826 as type species, for which a neotype is selected here from the north side of the Namur Basin. It is a massive pseudocerioid rugose coral like Frechastraea Scrutton, 1968 with rather large corallites, spindle-shaped dilated septa as well as some horseshoe and inner dissepiments. In the Belgian Upper Frasnian, Potyphyllum ananas and P. veserense (Coen-Aubert, 1974) occur mainly in the Upper Palmatolepis rhenana conodont Zone. The latter two coral taxa, together with diverse species of Frechastraea and Phillipsastrea D’Orbigny, 1849, permit dating of the red marble lenses from the Petit-Mont Member which are developed at different levels of the Champ Broquet Formation, in the Dinant Synclinorium. In this lithostratigraphic unit are also incorporated the Neuville and Les Valisettes Members, formerly considered as two separate formations. At the present time, Potyphyllum is only known from Western and Eastern Europe.