With no close relatives in its subfamily, this species is quite literally one-of-a-kind. Its closest relatives are the three species of the Hoplophryninae subfamily of the narrow-mouthed frogs, which are commonly referred to as the banana frogs and Amani forest frog of Tanzania, Africa. These were geographically isolated from the black microhylid frog by continental drift over the last 140 million years. Unusually, this species of narrow-mouthed frog does not favour communication by sound, and the male does not possess a vocal sac. Much work needs to be done to reveal the ecology of this species as it has seldom been studied since its rediscovery in 1997.