© 2018 Magnolia Press. Pleurothallis marioi was described in Phytotaxa as a new species on 2 June 2017 (Zambrano et al. 2017: 81). However, this name was invalid according to Article 40 of the International Code of Botanical Nomenclature (McNeill et al. 2012), because the protologue was ambiguous in specifying the holotype; whether it was the material in spirit, or a cultivated material that would be unsuitable as a holotype according to Article 40 of the ICN (McNeill et al. 2012). Since all other requirements of the Melbourne Code have been fulfilled, here we provide a new, unambiguous holotype assignment in order to validate this species name P. marioi Zambrano et al. (2017: 81).