[2] A few very large genera (Ananteris, Centruroides, Compsobuthus, or Tityus) are known, but a high number of species-poor or monotypic ones also exist.

[2] Around 20 species of medically important (meaning potentially lethal to humans) scorpions are known, and all but one of these (Hemiscorpius lepturus) are members of the Buthidae.

The largest members are found among Androctonus (fattail scorpions), Apistobuthus, Centruroides, and Parabuthus; and can reach 12 cm (about 5 in).

[2] Scorpions from the genera Androctonus, Centruroides, Hottentotta,[Note 1] Leiurus, Parabuthus, and Tityus are notorious for their strong venom.

[7] Other toxins have been found to bind K+ leak channels to prevent the flow of potassium ions, disallowing the hyperpolarized nerve membrane from depolarizing and returning to its resting state.