VPA 221: Veterinary Entomology and Acarology (1+1)

MORPHOLOGY- ARTHROPODS

• Arthropods are metamerically-segmented
• The segments of arthropods are associated in groups, the anterior segments form the head, the middle ones -the thorax and the posterior ones- the abdomen
• Appendages on the body are paired
• Head
  • Paired antenna and paired appendages modified for feeding
• Thorax
  • Walking legs
  • 3 Jointed legs-each limb is made up of pieces called Podomeres
• Peculiar internal anatomy
  • General body cavity is not a coelom, it’s a space filled with blood called haemocoel
• Tagmata
  • The tendency to form tagma/regions is unique to arthropods e.g. cephalisation
  • The process of modification of foremost segments to form head is called cephalisation
  • Other segments of body are fused to form definite regions of the body