Phylum Annelida

Phylum Annelida

By chuck - Posted on 31 July 2010

Phylum/Division Information:: 

The Phylum Annelida - the true-segmented worms, comprises over 25,000 species worldwide.

Freshwater leeches, a subclass of Clitellata, are important components of benthic communities in nearly every freshwater ecosystem; many species also occur in terrestrial and semi-terrestrial habitats, although only one semi-terrestrial leech occurs in North America. Leeches are widely distributed throughout the world, and some groups are found in great abundance.

Oligochaetes, a subclass of Clitellata, represents the most diverse and widely distributed group of annelids in North America. Globally, we currently recognize over 7,000 species of freshwater, marine, groundwater, and terrestrial oligochaetes.

Polychaeta (bristle worms, sand worms, tube worms, suction-feeding worms) are a primarily marine group with several freshwater species.

Mark J. Wetzel, 2015.

Common Name: 
Segmented Worms
Phylum or Division: 


Eucarya > Animalia >

Classes of Phylum Annelida

Class Common Name Photo Example Where?
Clitellata Earthworms, aquatic oligochaete worms, crayfish worms, and leeches (NA) Here


Klemm, D.J., W.E. Moser, and M.J. Wetzel. 2015. Classification and checklist of the leeches (Phylum Annelida: Class Clitellata: Subclass Hirudinida) occurring in North America north of Mexico. World Wide Web URL:

Wetzel, M. J., R. D. Kathman, S. V. Fend, and K. A. Coates. 2015. Classification and Checklist of the Freshwater oligochaetes occurring in North America North of Mexico. World Wide Web URL:

Wetzel, M. J., and P. Morgan. 2007. The Aquatic Oligochaeta (Annelida, Clitellata) of the Great Smoky Mountains National Park, North Carolina and Tennessee, USA:

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