Kubur has already given you all the correct info. I can only add that a knife with a similar hilt is the first item shown in "Panga Na Visu", where Zirngibl identifies it as Mandingo based on the leatherwork and states that these are encountered from Senegal all the way to Burkina Faso and the Ivory Coast.
A member of this forum, WoDiMi, who has an excellent site with pretty much any African weapon you can imagine, shows a few of these and also identifies them as Mandingo:
http://www.africanarms.com/gallery?7...dagger-37-5-cm
http://www.africanarms.com/gallery?0...agger-36-42-cm
http://www.africanarms.com/gallery?4...-39-7-cm-54-cm
http://www.africanarms.com/gallery?m...dagger-53-7-cm
Really nice dagger, congratulations!