ARTHROPOD CHARACTERISTICS

A Fuller and More Formal List

Quoted from An Introduction to the Study of Insects, Fifth Edition, by Donald J.Borror, Dwight M. De Long, and Charles A. Triplehorn, Saunders College Publishing:

• The body segmented, the segments usually grouped in two or three rather distinct regions.
  
  
• Paired segmented appendages (from which the phylum gets its name).
  
  
• Bilateral symmetry.
  
  
• A chitinous exoskeleton, which is periodically shed and renewed as the animal grows.
  
  
• A tubular alimentary canal, with mouth and anus.
  
  
• The circulatory system an open one, the only blood vessel usually being a tubular structure dorsal to the alimentary canal with lateral openings in the abdominal region.
  
  
• The body cavity a blood cavity or hemocoele, the coelom reduced.
  
  
• The nervous system consisting of an anterior ganglion or brain located above the alimentary canal, a pair of connectives extending ventrally from the brain around the alimentary canal, and paired ganglionated nerve cords located below the alimentary canal.
  
  
• The skeletal muscles striated (except in the Onychophora).
  
  
• Excretion usually by means of tubes (the Malphigian tubules) that empty into the alimentary canal, the excreted materials passing to the outside by way of the anus.
  
  
• Respiration by means of gills, or tracheae and spiracles.
  
  
• No cilia or nephridia (except in the Onychophora).
  
  
• The sexes nearly always separate.

Not all of these characteristics are unique to arthropods, but the combination makes an arthropod, and all must be present (except as noted).

To learn more about arthropods after traveling through our virtual arthropod zoo, check out more Sonoran Arthropod Studies Institute Web Pages!

 

Start of Zoo | More Arthropod Pages (outside zoo)

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