There are currently 4 described species of Hapalochlaena. Three are common, H. lunulata from Indonesia, the Philippines and surrounding areas, H. maculozsa from southern Australia and H. fasciata from southeastern Australia. There are clearly several other undescribed species. We will be describing on from northern Queensland, Norman lists 4 other species in his book "Cephalopods: a World Guide", and there are probably at least a couple more species that have been seen further north.
Roy