Barry, I do not think the hollow at the distal end is due to the pith under the hard wood of palm timber. You can see from these new pictures rather bright as the flash was on, that the hollow is within the hard wood being virtually a continuation of the main solid club. There must be some other reason for this feature? Also the strange pointy tip on the convex side. Interesting similaities between the Kayabi club and the Ikpeng club. Both made of palm wood, though they are different palm timbers. The Kayabi is a lighter brown timber and although a larger club at 1.433kg. The Ikpeng club smaller, of a dark brown to black timber is 1.628kg. Like combatants in other parts of the world. Conflicts are fought with very similar weapons of differing styles.
Interesting extract about conflict and contact.
https://www.jstor.org/stable/2020374...n_tab_contents
The black and white aerial photo of Kayabi village was taken 1958.