Kingdom - Animalia

Phylum - Annelida: segmented worms

 

Annelids have:

  • bilateral symmetry.
  • segmentation.
  • three body regions - a prosomium, a trunk and a pygidium.
  • chaetae/setae - bristles made of chitin.
  • no true respiratory organs.
  • a closed circulatory system.
  • a nervous system.
 

In Illinois there are four groups:


Hirudinea
leeches

  • 32 species
  • caudal attachment sucker
  • no chaetae
  • reduced body cavity
  • have a clitellum - thick ring near head that stores eggs.

 leech.png

 

 

 

Oligochaeta
"earthworms"

  • 43 terrestrial species
  • 83 aquatic species
  • have few chaetae (bristles).
  • have a clitellum - thick ring near head that stores eggs.
  • have a large coelom (body cavity) that acts as a hydroskeleton.

 aquaticworm.png

sludgeworms.png

Branchiobdellae
crayfish worms

  • 9 species
  • similar to leeches
  • found as exoparasites on crayfish
  • have a clitellum - thick ring near head that stores eggs.

 

 

 

 

 

 

 

 

Aphanoneura
suction-feeding worms

  • 3 species
  • do not have a clitellum - thick ring near head that stores eggs.