Hello Detlef, As you have pointed out, after enlarging the photos and comparing these two pieces closely I have to agree that Richard is correct in his assessment that this is a Tuareg knife. There are differences in that the blade on my example has a sharpened false edge and the guard itself is much heaver than the one on Richards example, but the overall styling of these two knives are the same. This holds for the scabbard as well though now I will have to make a much more elaborate toe piece than I had originally thought would be necessary.
Thank you all for your interest, comments and especially for identifying who, where and when this piece was made. As the piece shown in Richards photo is the only other example I have seen I would still appreciate if anyone else could furnish photos of other examples of this particular style of knife.
Best,
Robert