Family Heteroscorpionidae Kraepelin, 1905 (6 spp.) (scorpions of Madagascar) Geographical distribution Scorpions are found on all continents except Antarctica. The diversity of scorpions is greatest in subtropical areas; it decreases toward the poles and equator, though scorpions are found in the tropics. Scorpions did not occur naturally in Great Britain but were accidentally introduced by humans, and have now established a population. New Zealand, and some of the islands in Oceania, have in the past had small populations of introduced scorpions, but they were exterminated. Five colonies of Euscorpius flavicaudis have established themselves since the late 19th century in Sheerness in England at 51°N, while Paruroctonus boreus lives as far north as Red Deer, Alberta, at 52°N. A few species are on the IUCN Red List; Lychas braueri is classed as critically endangered (2014), Isometrus deharvengi as endangered (2016) and Chiromachus ochropus as vulnerable (2014). Scorpions are xerocoles, meaning they primarily live in deserts, but they can be found in virtually every terrestrial habitat including high-elevation mountains, caves, and intertidal zones. They are largely absent from boreal ecosystems such as the tundra, high-altitude taiga, and mountain tops. The highest altitude reached by a scorpion is in the Andes, for Orobothriurus crassimanus. As regards microhabitats, scorpions may be ground-dwelling, tree-loving, rock-loving or sand-loving. Some species, such as Vaejovis janssi, are versatile and are found in all habitats on Socorro Island, Baja California, while others such as Euscorpius carpathicus, endemic to the littoral zone of rivers in Romania, occupy specialized niches. Morphology Scorpions range in size from the Typhlochactas mitchelli of Typhlochactidae, to the Heterometrus swammerdami of Scorpionidae. The body of a scorpion is divided into two parts or tagmata: the cephalothorax or prosoma, and the abdomen or opisthosoma. The opisthosoma is subdivided into a broad anterior portion, the mesosoma or pre-abdomen, and a narrow tail-like posterior, the metasoma or post-abdomen. External differences between the sexes are not obvious in most species. In some, the metasoma is more elongated in males than females. Cephalothorax The cephalothorax comprises the carapace, eyes, chelicerae (mouth parts), pedipalps (which have chelae, commonly called claws or pincers) and four pairs of walking legs. Scorpions have two eyes on the top of the cephalothorax, and usually two to five pairs of eyes along the front corners of the cephalothorax. While unable to form sharp images, their central eyes are amongst the most light sensitive in the animal kingdom,