In southern Africa, 20 species of Parabuthus are distributed throughout the sub region, predominantly diverse in the arid and semi-arid regions.
These large scorpions are the most venomous scorpions in southern Africa. Lengths range from 70mm to 180mm. Their distribution is influenced by rainfall, generally occurring in areas receiving less than 600mm of annual rainfall. Most species inhabit sandy regions.
All members of this genus except P. distridor have rough areas on the upper surface of the first tail segment. In many species the second tail segment is also characterised by a second rough area on its upper surface. These scorpions scrape their sting on these rough areas, thus producing a ‘chick-chick’ sound. Their tails are extremely thick, strong with keels. Their pincers are smooth and weak. Many species are able to produce large amounts of venom from their large venom glands. No Parabuthus sp. has a subaculeur tubercle.
All species of Parabuthus are adapted for burrowing. Although most species of Parabuthus construct burrows in the open ground, Other species such as P. muelleri, P. planicauda, P. transvaalicus and P. villosus construct burrows under stones or rocks. Parabuthus use the ridges on the fifth tail segment to loosen substrate, before dragging away the substrate using the first two pairs of leg. Their burrows are very different in that of Opistophthalmus sp. As Parabuthus sp. burrow, they just shovel the substrate behind them. Their burrows look like they have been filed in. Opistophthalmus sp. carry the substrate out of the burrow. Gravid females often excavate deep burrows in which to give birth.
Many species show a narrow habitat tolerance. Several species are adapted to living in the sand dunes systems of the Namib and Kalahari deserts. These specialized adaptations assist in locomotion and burrowing in soft sand. P. kalaharicus for example can be found in shallow burrows at the base of vegetation or under rocks in sandy and gritty areas between the sand dunes of the Kalahari Sand System. These sand dune living scorpions are unable to burrow into hard substrate. This intolerance to hard substrate restricts their distribution accordingly. At the other end of the scale P. planicauda and P. villosus are adapted for rocky habitats. This is evident in their flattened appearance and elongated appendages.
Although scorpions are nocturnal except P. villosus that may be found active during the day. In the Northern Cape of South Africa, and Namibia, P. villosus is a large hairy scorpion that is active in the morning and late afternoon. P. villosus is the largest member of the Buthidae in the world.
These aggressive predators are often the dominant scorpion species where they occur. Other scorpion species often avoid the more aggressive species by being active at different time, or by restricting their activities to vegetative areas. Although many other species of Parabuthus sit and wait under vegetation for prey items to wander past, several species actively hunt. One such active hunter is P. granulatus that is southern Africa’s most venomous scorpion.
In southern Africa, 3 species have been directly implicated in human fatalities. P. granulatus, P. transvaalicus and P. mossambicensis. A few Parabuthus sp. have been known to spray venom, but none more so than P. transvaalicus. The venom vesicle is wider than the past segment of the tail. Only when irritated will this scorpion spray venom. Due to the distribution of this genus in arid and semi-arid areas, human envenomations are reduced. It should be noted that all Parabuthus species have the potential to inflict serious symptoms. It must be noted that many human fatalities occur in rural areas where little or no medical attention is administered.