Chaetogaster (Annelida) Videos

Chaetogaster is a genus of freshwater worms that belongs to the annelid family, Naididae. Like other members of the class Oligochaeta, such as the common earthworm, this tiny naidid has sets of bristles, called setae or chaetae, located along the outside of its body. Chaetogaster species are predators, actively hunting and consuming smaller organisms. One species, Chaetogaster limnaei, is a parasite of snails and in the 1990s was also found to be parasitizing zebra mussels, an exotic invasive species that has been spreading throughout North American waterways.

Naididae is an ecologically diverse family of worms common in both running and standing waters. Many naidids are sediment dwellers but other species are found living among aquatic plants. The family includes detritivores, algivores, carnivores, and the parasitic species Chaetogaster limnaei. Sexual reproduction is rare in most species. Reproduction occurs predominantly by paratomy, asexual reproduction in which new organs are developed before the animal divides into two or more parts.

Currently, more than 830 species of annelids representing 27 families,12 orders, and five classes (Oligochaeta, Aphanoneura, Branchiobdellae, Acanthobdellae, and Hirudinea) are recognized as occurring in the U.S. and Canada; these include both native and introduced species.