Looking again, and realising that it is only 16 inches long. It seems to be more of a dagger. When it you think of a dagger you tend to think of a metal knife to cut and penetrate flesh and muscle but I think a wood dagger is more about blunt force trauma to the face, head and upper torso. I can see similar decorations on Solomon and Amazon weapons but I just have a feeling that this is Amazon. Reference is make to daggers here---
http://digitalcommons.unl.edu/cgi/vi...t=anthrotheses
Perhaps it is Guyanese?