Are crabs arrachnids

Answer 1

The class Arachnida includes animals with four pairs of legs. So mites, scorpions, false scorpions, harvestmen and vinegarones are all in the same class as Spiders. Crabs are Crustacea. The only link between them is that both classes are arthropods. Sea Spiders are in a separate class altogether.

Confusion and argument has raged over the position of Horseshoe Crabs. My understanding is that they are now generally accepted as arachnids

Answer 2

No, horseshoe crabs are not arachnids. They are very similar to arachnids in that they have eight legs, no backbone, and joint legs. However horseshoe crabs are from the class Merostomata not Arachnida.

Answer 3

No, despite the existence of both "crab spiders" (a kind of arachnid not a crab) and "spider crabs" (a type of crab not a spider), crabs are in subphyum Crustacea (crustaceans) whereas arachnids are in subphylum Chelicerata.