Demonema		Contents		Rev: 02/22/2026
		Classification		Biology and Ecology
		Morphology and Anatomy		Life Cycle
Return to Demonema Menu				Ecosystem Functions and Services
		Distribution		Management
Return to Selachinematidae Menu		Feeding		References
		Go to Nemaplex Main Menu		Go to Dictionary of Terminology

Classification:

Chromadorea

  Chromadoria

   Chromadorida

    Selachinematidae

Selachonematinae

       Demonema Cobb, 1894

Type species of the genus: Demonema rapax Cobb, 1894

    Synonyms:
     

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Morphology and Anatomy:

• All the anterior sensilla papilloid.
• Three mandibles: two large equal lateroventral mandibles distally knobbed and consisting of two parts, whereas the dorsal mandible is vestigial.
•  Pharynx cylindrical.
• Tail consists of anterior conical and posterior long and cylindrical.
• Amphidial fovea multispiral.

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Distribution:

Predatory marine nematodes.

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Feeding:

Food Sources and Feeding strategies for the genus Demonema

Considered voracious predators

For feeding, the mandibles are operated by a powerful complex of pharyngeal muscles. The anterior broadening of the pharynx contains not only normal radial muscular fibres, but also oblique fibres attached to the mandibular arm and apodemes. A muscular envelope surrounds the anterior widening of the pharynx. It consists of longitudinal muscles which originate on the inner side of the somatic cuticle surrounding the mouth and insert on the basal lamina of the pharynx behind its anterior widening.

The longitudinal extra-pharyngeal muscles act to protrude the anterior end of the pharynx and mandibles and to open the mouth and protrude the mandibles in order to capture and then ingest a prey nematode (Tchesunov and Okhlopkov, 2006).

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Biology and Ecology:

Free-living predator nematdes feeding on nematode prey

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Life Cycle:

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Ecosystem Functions and Services:

Predator.

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Management:

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References:

Tchesunov, A.V. 2013. 7.12 Order Chromadorida Chitwood, 1933. In Schmidt-Rheas and de Gruyter, W. Handbook of Zoology.Gastrocticha, Cycloneuralia, Gnatifera. Volume 2: Nematoda

Tchesunov, A.V. and Okhlopkov, J.R. 2006. On some selachinematid nematodes (Chromadorida: Selachinematidae) deposited in the collection of the Smithsonian National Museum of Natural History. Nematology 8:21-24.

Copyright 1999 by Howard Ferris.
Revised: February 22, 2026.