ENT 317

Six Common Characteristics of Arthropods:

There are six fairly common characteristics of arthropods that will allow you to differentiate members of the phylum from other members in the invertebrate world.

All arthropods share these characteristics:

  1. Exoskeleton. An exoskeleton is the supporting structure on the outside of the body of an arthropod. The exoskeleton of an arthropod is a chemically complex layer. It is made up of chains of a polysaccharide called chitin. Chitin itself is a very resistant substance. The exoskeleton functions in several ways. It's a site for the attachment of muscles. It also regulates materials such as water and oxygen as they move in and out of the organism. The exoskeleton obviously is a physical barrier to injury from external sources. It also is a barrier to potential entry of insect pathogens.
  2. Segmented bodies.
  3. Jointed appendages such as mouthparts and antennae.
  4. Bilateral symmetry. A line or a cut made from head to tip of abdomen would be equal as viewed externally.
  5. Dorsal blood vessel.
  6. Ventral nerve cord.