Arthropod Characteristics

Arthropods are characterized by the following:

   A.  Segmented body plan (metamerization), without internal separation of segments. In many arthropods groups, segments have become specialized into distinct body regions (tagmosis).

   B.  An outer exoskeleton of chitin, usually also hardened with the protein sclerotin (sclerotized) or with calcium carbonate.

   C.  Jointed appendages that have been modified for varied uses including legs, jaws, sucking tubes, gills, egg depositors, antennae, etc.

   D.  An open circulatory system with a hemocoel.

   E.  Dorsal brain and a ventral nerve cord.