Arachnids are a class of joint-legged invertebrate animals (arthropods), in the subphylum Chelicerata. All arachnids have eightlegs, although the front pair of legs in some species has converted to a sensory function, while in other species, different appendages can grow large enough to take on the appearance of extra pairs of legs. Spiders are the largest order in the class. Almost all extant arachnids are terrestrial, living mainly on land. However, some inhabit freshwater environments and, with the exception of the pelagic zone, marine environments as well. They comprise over 100,000 named species, including spiders, scorpions, harvestmen, ticks, mites, and solifuges.
Pages in category "Arachnids"
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