Chaetogaster is a genus belonging to the segmented worms (Annelida). It is classified in the family Naididae (subfamily Naidinae) in the order Oligochaeta. These are ca. 2–25 mm long transparent worms that are very common in fresh water and often form chains of individuals through asexual multiplication.

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Chaetogaster diaphanus (Gruithuisen, 1828) is a freshwater oligochaete worm that is common in the Great Lakes. It is naidid worm without dorsal chaetae, with a highly modified and enlarged pharynx, a terminal mouth, and a reduced prostomium.

Many oligochaete worms begin life as eggs deposited in a cocoon. Worms hatch between eight days and 10 weeks after deposition and superficially resemble adults except being smaller in size. All oligochaete species reproduce sexually, but some, especially those in Subfamily Naidinae, also reproduce asexually by transverse division or budding.

May 26, 1996 · Chaetogaster diaphanus (Gruithuisen) Recognition. All dorsal chaetae are normally absent only in this genus and sometimes in the very different Ophidonais serpentina. The shape of Chaetogaster is distinctive with large mouth and pharynx and reduced prostomium.

A Naidid Worm — Chaetogaster limnaei. Montana Field Guide. Montana Natural Heritage Program. Retrieved on January 19, 2025, from https://FieldGuide.mt.gov/speciesDetail.aspx?elcode=IAOLI44020. Montana Field Guide contains a wealth of information about Montana's diverse species.

It is interesting to watch these worms working their way rapidly through close-set weeds. The anterior bundles of setae can be thrust forward, and expanded like a fan, and are used like claws, to drag the rest of the body forward. (ref. ID; 1928)

Chaetogaster is a genus belonging to the segmented worms (Annelida). It is classified in the family Naididae (subfamily Naidinae) in the order Oligochaeta. These are ca. 2–25 mm long transparent worms that are very common in fresh water and often form chains of individuals through asexual multiplication.

Taxonomic confusion has been caused by differences in what have been considered 2 subspecies of this worm: Chaetogaster limnaei limnaei is an ectosymbiont and is present inside the mantle cavity of the snail, whereas Chaetogaster limnaei vaghini is parasitic and lives in the kidney of the snail.

Macro photography of sludge worms (phylum Annelida, order Oligochaeta, family Tubificidae)