A new species of Marsupella sect. Ustulatae Müll. Frib. ex R.M. Schust. is described following an integrated morphological and molecular-phylogenetic study which examined the recently found dioicous plants growing epilithically on acidic substrates in several mountain ranges of Portugal between Peneda-Gerês in the north and Serra da Monchique in the extreme south. Employed molecular markers (plastid trnF-trnT region and nuclear ribosomal ITS) confirmed the distinctness of the lineage from other currently recognized species in the section, and furthermore, previously neglected diversity within M. sprucei (Limpr.) Bernet was signaled. Although not yet confirmed outside Portugal, the newly reported species is probably not rare in the region and has likely been overlooked as M. funckii (F. Weber & D. Mohr) Dumort. or M. profunda Lindb. in the past.
Keywords: European liverwort endemic; ITS; Marsupella; Portugal; integrative taxonomy; trnF–trnT.