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Which annelids live in freshwater habitats?
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annelid
The structure of polychaetes. (Left) Free-moving polychaetes. (A) Neanthes, (B) Nereis. (Right) Tube-dwelling (sedentary) polychaetes. (C) Amphitrite, (D) Sabella.
Annelids are found in a variety of environments, including freshwater habitats. While the majority of polychaetes are marine, certain species and groups within the other two classes of annelids are adapted to life in fresh water:
- Oligochaetes: While many oligochaetes are terrestrial (such as earthworms), certain small species are found in fresh water. The order Haplotaxida is noted as being composed chiefly of aquatic worms, including genera such as Nais and Tubifex (sludge worms).12
- Leeches (Hirudinea): Most leeches inhabit freshwater or humid environments. They are primarily found in fresh water, though some terrestrial and marine forms exist. Examples of freshwater leeches include those in the orders Rhynchobdellida (such as Glossisphonia) and Arhynchobdellida (such as Hirudo and Erpobdella). Additionally, the order Branchiobdellida consists of species that are parasitic or commensal on freshwater crayfish.12
- Polychaetes: Although primarily marine, some polychaetes inhabit freshwater environments. For example, the feather duster (Manayunkia speciosa) is known to inhabit the Great Lakes and various rivers in the United States.1