A new semiarboreal species of the Rhinella festae group is described from montane forests of the Cordillera Azul National Park between 1245 and 1280 m a.s.l. in the Cordillera Oriental, San Martín region, northern Peru. The new species is morphologically and genetically compared with members of the Rhinella acrolopha group (former genus Rhamphophryne) and members of the R. festae group. The new species is characterized by its large size (female SVL 47.1-58.3 mm, n = 4), eight presacral vertebrae, fusion of the sacrum and coccyx, long protuberant snout, snout directed slightly anteroventral in lateral view, cranial crests moderately developed, absence of occipital crest, presence of tympanic membrane, dorsolateral rows of small conical tubercles extending from parotoid gland to groin, hands and feet with long digits, fingers basally webbed and toes moderately webbed. Phylogenetically it is a member of the R. festae group which is most closely related to R. chavin and R. yanachaga from Peru. Morphologically the new species shares similarities with R. tenrec and R. truebae, members of the R. acrolopha group from Colombia.
Keywords: Amphibia; Rhinella acrolopha group; Rhinella lilyrodriguezae new species; phylogeny.