This is the only population of AUS that looks different from every other AUS although that is less than clear in the only known photo of the fish, above; they're almost black in real life. They were discovered by Radda, Puerzel and Huber 1 km west of Mayumba in stagnant water. Introduced into the hobby, they were around for a couple of years - I had them - but they were very very difficult to breed and are now (2011) extinct in the hobby. Somebody ought to go back and see if they're still there, they may be extinct in the wild, too now. You can tell Mayumba apart from other AUS as Mayumba have in white pectoral fins, they're orange in all other forms of AUS.
In 2012 AUS were collected mouth of the Kouilou, just north of Mayumba and Nyanga systems, in the South of Gabon, but neither one looks like the white finned Mayumba form.