The Chortís Highlands of Mesoamerica exhibit a high degree of in situ evolutionary diversification, exemplified by numerous endemic radiations of stream-dwelling treefrogs (Anura: Hylidae: Atlantihyla, Duellmanohyla, and Ptychohyla), which have been a source of ongoing taxonomic uncertainty. Recent evidence suggests that one species, Atlantihyla spinipollex, may conceal an unrecognized sister species found in Refugio de Vida Silvestre Texiguat. We applied an iterative integrative taxonomic framework to assess this population within the context of Chortís Highlands populations of Atlantihyla spinipollex sensu stricto, Duellmanohyla salvadorensis, D .  salvavida, D .  soralia, and Ptychohyla hypomykter, using both a single locus (mtDNA: 16S) and multilocus (mtDNA: 12S, 16S; nDNA: POMC, RAG-1, Rhodopsin) datasets accompanied by distance- and tree-based species delimitation methods to inform our taxonomy. Samples of A .  spinipollex sensu lato formed two deeply divergent monophyletic lineages, suggesting that populations from the central and eastern Cordillera Nombre de Dios are conspecific, while the population from Refugio de Vida Silvestre Texiguat represents a previously undescribed species. We analyzed morphological and bioacoustic variation within and between the two lineages of A .  spinipollex sensu lato and found support for recognition of two distinct taxa. We restricted the name A .  spinipollex to populations in the central and eastern Cordillera Nombre de Dios, and formally describe the Texiguat population as a new species. We recommend the new species be considered Critically Endangered due to ongoing habitat loss within what remains of its highly restricted natural distribution. This new species joins 26 other endemic species of amphibians and reptiles at Texiguat

Atlantihyla melissa sp. nov., Atlantihyla spinipollex, Chortís Block Highlands, Cordillera Nombre de Dios, Ptychohyla hypomykter, Refugio de Vida Silvestre Texiguat