Ctenophryne is a genus of microhylid frogs. They occur in southern Central America (Costa Rica, Panama) and South America. Their common names are egg frogs and Nelson frogs, the latter applying to species in the formerly recognized Nelsonophryne.
As of 2017, Ctenophryne includes two other genera, Nelsonophryne and Melanophryne, in synonymy. The latter might represent valid genera, but molecular analyses could not resolve their relationships in a robust way. Placing Nelsonophryne and Melanophryne in the synonymy of Ctenophryne is an interim measure that avoids paraphyly, until new data might resolve the relationships. When Ctenophryne is defined this way, it is a monophyletic group that is the sister group to allother gastrophrynines.
Ctenophryne range from relatively small Ctenophryne barbatula (female size 26mm27mm in snout–vent length) to moderately large Ctenophryne aterrima (female size to 67mm). The current definition of the genus is essentially based on molecular phylogenetics rather than morphology.
There are six species: