NICE AFRICAN DAGGER ...but what is it????

[katana]

Hi,
acquired this nice, possibly early 20th C, African dagger. Got it cheap as the blade was stuck in the scabbard. Gallons of oil, patience, and 'gentle' brute force finally freed the blade (rust on the blade). Overall very well made and sturdy (the brute force used proved that ) Blade is forged, tempered and relatively thin. The handle has a woven covering with a guard and a 'ring' pommel. The sheath is leather, well made and finely stitched. The leather is woven with reed type material.....which seems to imitate snake/reptile skin. There is a leather 'button' decoration fixed near the scabbard's throat and a 'mushroom' detail (leather covered and stitched) on the scabbard end.
I am very happy with it....it feels 'good' in the hand ...but cannot find a similar dagger to find out it's possible origins.

OAL 13" (approx. 32 cms)
Blade 7" (approx. 15.5cms)

So please if anyone has any ideas or comments I would be grateful.

Thanks
David