the old 2nd edition Chult had a great spin on goblins.
Dragon Magazine 189 also had great stuff on african adventures
and of course you can have a lot of fun using the adventures of john manville for that european perspective of the dark continent.
here's a link for mythical beasties in ethiopia
http://www.theoi.com/Thaumasios/TheresAithiopikoi.html
I do agree with the varana - very neat concept that we can thank the lion king for.
Cat races are fun, but kinda overdone. Still love wemics and litorians though.
Spirit folk would be fun. Bamboo could be turned to jungle, river do not need a change and could be used to cover waterfalls (considered a very dangerous area), in fact their is this legend called the mamba mumbo. Sea spirit folk would not be nearly as common. If you could make a version that was lightning you could have serious fun. Many african cultures associate lightning as revenge of the gods. In fact in some areas, you can pay to have lightning quite literally strike somebody down.
How about a kong like race located in the depths of the kongo? Smaller but still big...perhaps based on the goliath.
remember much of african "supernatural" is based on people being booted out of your tribe. A couple of prestige classes showing the evolution of these outsiders to monsters might be fun.
also cannibal stories are common. whether you decide to make a sentient eating race or another tribe is up to you.
If you go savage species, a race that would be a blast today is the flying jackel. They have wings and are pretty much a jackel in form, but have hands on their forepaws. They are also tricksters. They shouldn't be too high an ecl and most tricksters type races translate better then more physical types.