Hi Tim,
You always keep bringing in fascinating new entries from Africa, and it's great to learn more on the ever widening scope of weapons revealed from the cultures there thanks to you!
The fighting sticks are most interesting and I honestly know little about them aside from seeing something on them while researching the Sudanese 'haladie' some time ago. It is most interesting to see weapons of similar concept and presumably similar use coming from such vastly distant regions. The 'nulla nulla' you note from Australia, the 'haladie' which Stone notes in from Syria as well as found in the Sudan, and of course the buffalo horn 'madu' of India. While such vast distances suggest convergent evolution, it is tempting to consider early connections via trade in certain cases...although the Australian connection seems pretty remote
and probably unlikely of course.
Best regards,
Jim