Annelids - Segmented Worms

General Information

  • Latin: Annulus = Little Ring
  • Also known as ringed worms or segmented worms
  • Includes earthworms, leeches, marine worms
  • Approximately 15,000 + species, ranging in size from microscopic (less than 1mm) to the Australian giant Gippsland earthworm (3m long)
  • 2/3 of annelids are marine species

Distribution

  • Found worldwide

Habitat

  • Live in a diversity of freshwater, brackish, marine, and terrestrial habitats
  • From the deepest marine sediments to soils in your backyard

Distinguishing Features

  • The Annelids are coelomate and triploblastic.
  • Bilaterally symmetrical
  • They exhibit organ system level organization. (when two or more organs work together for a specific function).
  • Their body is segmented.
  • Do have parapodia for locomotion
  • Invertebrate
  • Long cylindrical shaped bodies made up of many similar segments
  • Has Chaetae (setae) (bristles for anchorage, movement and sometimes defence)
  • No hard skeleton exoskeleton (unlike Arthropoda)
  • No antennae, no appendages (legs)
  • No obvious head end

Annelids are divided into 3 groups (2 of which are terrestrial)

  1. Class: Clitellata (having a Clitellum)
    • Subclass:     Hirudinidea       - Leeches
    • Subclass:     Oligochaeta      - Worms
  2. Class: Polychaeta (pol-ee-keets)  - Marine worms
    • Subclass:     Echiura             - Spoon Worms
    • Subclass:     Errantia             - Free Swimming Worms
    • Subclass:     Sedentaria        - Sedentary Worms   
  3. Order: Sipuncula                          - Peanut worms

 

VICTORIAN SPECIES

Subclass: Hirudinea - Leeches

Glossiphonia sp. _ Freshwater Leech 

Sweetwater Creek, Frankston. Photo by Paul Sorensen

 

Subclass: Oligochaeta _ Worms

Eisenia sp. _ Freshwater Red Worm                                                                                Oligochaeta sp. _ Freshwater Worm

         

Sweetwater Creek, Franskton_Photo by Paul Sorensen                                                  Sweetwater Creek, Frankston_Photo by Paul Sorensen

 

Subclass: Echiura - Spoon Worms

Ikeda taenioides_Sand Worm

Frankston Pier_Photo by Paul Sorensen

 

Subclass: Errantia - Free Swimming Worms

Eunicidae sp._Eunicidae

Blairgowrie Pier_Photo by Paul Sorensen

 

Aphrodita australis_Southern Sea Mouse

Blairgowrie Pier_Photo by Paul Sorensen

 

Glycera sp._Annelid                                                                                                    Hesionidae sp._Ragworm

    

Deakin University_Photo by Paul Sorensen                                                                Blairgowrie Pier_Photo by Paul Sorensen

 

Subclass: Errantia - Free Swimming Worms

Sabella spallanzanii_Fan Worm

Blairgowrie Pier_Photo by Paul Sorensen

 

Order: Sipuncula - Peanut Worms

Phascolosoma noduliferum_Peanut Worm

Deakin University_Photo by Paul Sorensen

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