A Portuguese plug bayonet, not mass produced
 

This might not be ethno in a tribal sense, but certainly not a mass produced thing. Dated end XVIII century.Two possibilities for the grip. Either the tapered section got worn or damaged from overuse, and it was repaired with harder whale bone, or the whole grip was originally made like that. The seller, a reputed person, showed me a Portuguese XVII century specimen, with the grip made in horn, but with the tapered section made with a horn tone different from the swell part. In the case, the swell was hollow core and the plug in part was solid, for higher resistance.
Blade floral decoration is still visible. It looks like there is a faded date or some number in one of the quillons, but is hard to tell.
fernando