We describe a new species of marsupial frog, genus Gastrotheca, using morphological characters and molecular data as lines of evidence. The new species was discovered in the páramo and the ecotone between páramo and humid montane forest of Cordillera de Colán, at elevations between 3136 and 3179 m a.s.l., in northeastern Peru. The new species is distinguished from all its congeners by the combination of the following characters: Coarsely granular skin on dorsum, a green dorsal coloration without pattern, finger I shorter than finger II, turquoise iris, and a venter without blotches, flecks or dots. Furthermore, we include a detailed osteological description of the new Gastrotheca species based on Micro-CT scanning. Based on our phylogenetic analyses, the new species belongs to the Gastrotheca marsupiata species group, is sister to G. oresbios and closely related to G. psychrophila, G. spectabilis, G. stictopleura and one undescribed species. Additionally, we test for the presence of the fungal pathogen Batrachochytrium dendrobatidis (Bd). No Bd infection was detected for G. gemma sp. nov. specimens but Bd prevalence was detected among syntopic frogs.