[in French with Esperanto and English abstracts] Description of the new species Corticifraga ramalinae P. Pinault, Ertz et Cl. Roux sp. nov., close to C. peltigerae, from which it differs by its parasitism on the thallus (rarely the apothecia) of Ramalina fraxinea where it does not induce galls but which its discolors, by its spores (0)3 – septate, a little longer and less wide, mostly 17,5 – 25,5 × 4 – 5 μm, and by its distinct phylogenetic position (its sequence) (sister species of C. fuckelii). Identification key for the Corticifraga species in the world. Comparison with related or analogous Corticifraga species.