Characteristic Features of Phylum Arthropoda

1. Well-developed muscular system along with striated muscles attached to the exoskeleton, and visceral organs having smooth muscles.
2. Segments take jointed appendages.
3. Coelom present but extremely reduced and obliterated in the adult. The main body cavity is haemocoel, a characteristic space among organs and tissues, filled with blood.,
4. Nonexistence of cilia.
5. Exoskeleton contains a tough cuticle made up of chitin, protein and lipid, sometimes strengthened with calcium carbonate. The cuticle, secreted by the underlying epidermis, is shed periodically to allow growth of body.
6. Circulatory system that is open type.
7. Body bilaterally symmetrical and metamerically segmented; segments show a tendency to combine or fuse together to form functional units called tagmata, such as cephalothorax and abdomen, head and trunk, or head, thorax and abdomen.
8. Mouth parts changed from appendages; well developed alimentary canal.
9. Respiratory organs are generally tracheae, booklungs or gills.
10. Sexes are separate; fertilization internal; development often involves metamorphosis.
11. Nervous system is of the annelidan plan.
12. Excretory organs Malpighian tubules, coxal glands, antennal glands or maxillary glands.