As in Fula, the Basenji imported from Africa by Veronica Tudor Williams. The colour first showed, I believe, in her descendents. No melon pips, no tan on the face, just where your girl has it, behind the ears and on the legs. If you email me privately, I will send you a picture of one of mine. It is uncommon but the mutation does occur. Your girl is almost certainly a fula-black and you will be able to trace her backwards on the pedigree on-line data base once we have her in it.
Go to the pedigree on-line website anyway (see signature block) and you can trace up and down from Fula.
What is your girl's name ? Registered, I mean. It could be she is already in the database.