Largest arachnid (current)

The largest present-day arachnid on record is a specimen of the giant forest scorpion Heterometrus swammerdami that was found during World War II in the village of Krishnarajapuram, India, and measured 29.2 cm (11.49 in) in overall length from the tips of its pedipalps or "pincers" to the end of its sting. This species is from southern India, and males frequently attain a length of more than 18 cm (7 in).

Despite its great size, this scorpion species is not considered dangerous to humans, because its venom is not particularly potent. It is likely that this is because it uses its powerful pincers to hold and crush its prey, rather than killing it with venom from its sting as smaller, more deadly scorpions do, so is venom has not evolved into so potent a substance.

The largest species of arachnid ever is Brontoscorpio anglicus, a species of giant prehistoric scorpion that existed in what is now Worcestershire, central England, UK, during the Upper Silurian Period, approximately 425 million years ago. It is presently represented only by a single incomplete free finger from a right-hand pedipalp (pincer), but based upon the latter's dimensions, palaeontologists have estimated that the complete creature would have measured at least 90 cm in total length.