A new genus of lichenized fungi of the family Porinaceae is described, known from Costa Rica and Brazil. Flabelloporina Sobreira, M. Cáceres & Lücking is a thus far monospecific genus with an isolated position of its only species in the family, morphologically different from all other genera in Porinaceae. The genus is characterized by the production of numerous, flabelliform squamules on the surface of the thallus, together with black perithecia and transversally septate ascospores (with three septa in the only species). The new combination Flabelloporina squamulifera (Breuss, Lücking & Navarro) Sobreira, M. Cáceres & Lücking is proposed, based on Porina squamulifera Breuss, Lücking & Navarro, and the species is for the first time reported from Brazil.