The gap described above is not a small one, and it is worth stating what follows from it.
An astrological chorography that stops at the Sahara has nothing to say about the divinatory and cosmological systems of the rest of the continent, and those systems are neither absent nor derivative. Ifa divination among the Yoruba, geomantic practice across West and North Africa, and the many regional traditions this atlas covers under their own entries developed on their own terms. Some of them share material with the Mediterranean world through long standing trade and through Islam, and geomancy in particular has a documented history of movement between North Africa, the Islamic world and Latin Europe. None of them is a branch of Ptolemy's system.
So this entry is deliberately narrow. It records what classical astrological chorography said about the part of Africa it knew, which is a small and specific claim, and it does not extend that claim over a continent. The African traditions the atlas holds are described where they belong, under their own names and their own sources, rather than fitted to a Mediterranean quartering that was never built to hold them.
The alternative, filling the gap with a modern assignment, would produce a table that looks complete and is not. Naming the limit is the more useful record, and it is the one this entry keeps.
Sources Ifa Divination: Communication between Gods and Men in West AfricaWilliam Bascom with Recherches sur une technique divinatoire: la geomancie dans l'Occident medievalTherese Charmasson