Cystiphylloides marennense n. sp., C. minimum (Wedekind, 1922), Atelophyllum emsti (Wedekind, 1922), Thamnophyllum godefroidi n. sp., Spinophyllum longiseptatum (Lütte, 1984) and Iowaphyllum sp. have been mainly collected on the south side of the Dinant Synclinorium, close to the boundary between the Lower and the Middle Givetian. Indeed, this material comes mostly from the lower part of the Mont d’Haurs Formation which is characterized by a high biodiversity. The genus Atelophyllum Wedekind, 1925 has been preferred to Mesophyllum Schlüter, 1889 and Lekanophyllum Wedekind, 1924 as the holotype of its type species Atelophyllum emsti has been figured in both transverse and longitudinal sections. A colony of Iowaphyllum is observed for the first time in the Givetian of Belgium. As a whole, the fauna of the Mont d’Haurs Formation is widely distributed in various areas of the Old World Realm (Europe, Asia and Australia). However, it shows strong affinities with the neighbouring countries of Belgium and especially with the Givetian rugose corals of the Eifel Hills, the Bergisches Land and the Sauerland in Germany.