What are arthropods know for?

Arthropods are characterized by segmented bodies, an exoskeleton made from chitin, and joint appendages. They are known for their near universal domain on planet earth, being at least half of all living animals by count (by some estimates up to ninety percent), and the heaviest by biomass. They also have more species than any other animal phylum, and a notoriously daunting task to completely classify since estimates are that millions of species have yet to be described, particularly in Insecta.