12,000-year-old Göbeklitepe burials explain scattered bones

Estimating "common" is quite difficult, but given that there are pre-colonial aboriginal australian burial sites, we can estimate that it either can be traced to Africa or is sufficiently common to not be surprising. There is even evidence (not proof) of neanderthal burial rituals, fwiw.

The phrase is "jump the gun" or "jumped the gun" as in a fault start in a race started with a gun.

I always thought that 'ceremonial room' looked more like a sauna than a sacrificial pit. It reminded me of the Roman ruins at Bath more than anything else.

The point of naming it a "skull cult" is really just pointing out people found human remains to be important—something largely true today too, and hardly more romantic than our own understanding of burial.