Horseshoe crabs are really relatives of spiders, scorpions — ScienceDaily
Blue-blooded and armored with 10 spindly legs, horseshoe crabs have perhaps always seemed a bit out of place. First thought to be closely related to crabs, lobsters and other crustaceans, in 1881 evolutionary biologist E. Ray Lankester placed them solidly in a group more similar to spiders and scorpions. Horseshoe crabs have since been thought…