Résumé
The Strunian regional substage corresponding to the uppermost Famennian of Belgium and northern France (Avesnois area) is marked by the occurrence of trilobites after an almost complete absence that began at the top of the Frasnian. The Strunian phacopid trilobites represented by Omegops, i.e., O. accipitrinus and O. maretiolensis, are recorded and illustrated from two Belgian sections (Spontin and Chansin) situated in the central part of the Dinant Synclinorium. These belong to the youngest known phacopids and they rank among the victims of the Hangenberg Crisis that took place near the Devonian–Carboniferous boundary. The phacopid fauna formed a trilobite association inhabiting a shallow shelf together with diverse brachiopod but also coral, crinoid, mollusc communities. These Belgian trilobites are compared with Omegops bergicus encountered in the northern France (Avesnois area).