Forgive the unconscionable pun within the title of this Category! Not. If a scientific term, description, or statement fascinates you, and you want to know more, just Google/ Bing it. Arthropods are a Genus of invertebrates with a hard external skeleton, a segmented body, and jointed attachments called appendages. Insects, one group of Arthropods, with six legs, are the most diverse group of animals, comprising 50% of animal life on Earth – Google it. In addition. eight legged arachnids (spiders, mites, scorpions), and four or eight legged crustaceans (crabs, lobsters, crayfish, shrimp, krill and barnacles) are the other two major groups of Arthropods.