Was just about to edit my post with that. Forgot it had been spotted. That leaves only Zenobia, Dido and Nandi (Nandi has pretty much a 0% chance in my opinion) for female African rulers that I know of (excluding existing civs). Do we know of any others? My African history is not up to snuff.
[Edit]: Found some:
Yaa Asantewaa (Ashanti)
Taytu Batel (Ethiopia)
Amina (Zaria)
Amina seems unlikely because she's a folk hero that may or may not have even existed. Very little is known about her outside the realm of mythos. We aren't even completely sure when she reigned (that worked for Hiawatha and Dido previously, though).