Hyloxalus mystax is a species of frog in the family Dendrobatidae. It is endemic to Ecuador where it is only known from its type locality on the Cordillera del Cóndor at asl. It is a little known species not observed since 1972. Description Males measure and females in snout–vent length. They have scattered dark spots on the abdomen. Males have pronounced black stippling on the throat. The male call is a rapid series of chirps. Habitat and conservation The species' natural habitats are cool montane cloud forests. It was fairly common when the type series was collected in 1972; it has not been observed afterwards (there has not been sufficient search effort either). Threats to this species are unknown. References mystax Amphibians of Ecuador Endemic fauna of Ecuador Amphibians described in 1988 Taxonomy articles created by Polbot