Which crustacean is the largest living arthropod by leg span?

The Japanese spider crab is the largest living arthropod by leg span, with an exceptional span of about 5.5 metres from claw tip to claw tip. Its body is much smaller than that measurement, but its extremely long legs make the species unmistakable.

This crab lives in deep waters around Japan, commonly from roughly 50 to 600 metres, although its range and depth vary with life stage. It uses its claws to handle food and may consume dead animals, mollusks, and other seafloor organisms. Its orange body and white-spotted legs provide a distinctive appearance.

The Japanese spider crab belongs to the arthropods, the enormous animal group that includes insects, spiders, and other crustaceans. It is not the same animal as the coconut crab, which is the largest terrestrial arthropod by mass. King crabs can also become large, but the Japanese spider crab holds the familiar record for greatest leg span among living arthropods.