Opisthothylax is a monotypic frog genus in the family Hyperoliidae. The sole species is Opisthothylax immaculatus, also known as the gray-eyed frog . It is found in southern Nigeria, Cameroon, Equatorial Guinea, Gabon, western Republic of Congo, and southwestern Democratic Republic of the Congo. It might also be present in the Cabinda Enclave of Angola and in the Central African Republic.

...