Octonchus		Contents		Rev 06/16/2026
		Classification		Hosts
		Morphology and Anatomy		Life Cycle
Return to Octonchus Menu		Economic Importance		Damage
		Distribution		Management
Return to Oncholaimdae Menu		Feeding		References
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Classification:

Enoplea

     Enoplia

        Enoplida

          Oncholaimina

              Oncholaimoidea

                    Oncholaimidae

     Octonchinae

Octonchus Clark, 1961

Type species of the genus: Octonchus marinus (Schulz, 1932) Clark, 1961

Synonyms:

Polydontus marinus Schulz, 1932

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Morphology and Anatomy:

Notes (from Pastor De Ward et al, 2015): The genus was erected based on a juvenile specimen of Polydontus marinus Schulz, 1932. The original description was of a buccal cavity with one large tooth and eight small teeth (nine distinct teeth) (Sachulz, 1932). Kreis (1934), incorrectly re-described Polydontus as having eight teeth. Clark, 1961 found that the genus name Polydontus was already in use for a mollusc and changed the name to Octonchus based on the eight teeth in the redescription by Kreis (1934).

• Stoma with 8 teeth; distinct in the family Oncholaimidae in having more than three teeth, a character which also occurs in the monotypic genera Paroctonchus and Patagonema of the subfamily Octonchinae.
• Number and arrangement of teeth in the buccal cavity in Paroctonchus: three large teeth with the left ventrosublateral one the largest plus about 27 small teeth distributed on the wall. By contrast, Octonchus has one large tooth plus eight small teeth, while Patagonema has three large teeth with the right ventrosublateral one the largest plus 12 small teeth on three mandibular ridges.
• Posterior end of buccal cavity surrounded by a pharyngeal collar.
• Amphidial fovea pocket-like with transverse slit-like aperture in middle portion of buccal cavity.
• Tail conical-cylindrical, short
• Marine nematodes

Male:

Female:

Ref: Smol et al., 2014

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Distribution:

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Economic Importance:

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Feeding:

Food Sources and Feeding strategies for the genus Octonchus

     Omnivores?

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Life Cycle:

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Damage:

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Management:

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References:

Clark, W.C. 1961. A revised classification of the order Enoplida (Nematoda). New Zealand Journal of Science 4:123-150.

Kreis, H. 1934. Oncholaiminae Filipjev 1916. Eine monographische Studie. Capita Zoologicus 4:1-271.

Pastor De Ward, C.T., Lo Russo, V., Villares, G. 2015. Patagonema iubatum gen. nov. and sp. nov. (Nematoda,Oncholaimidae, Octonchinae) from Patagonia sandy beach (Argentina). Journal of the Marine Biological Association of the United Kingdom. 95:101-109. doi:10.1017/S0025315414000708

Schulz, E. 1932. Beitrage zur Kenntnis mariner nematoden aus der Kieler Bucht. Zoologische Jahrbucher (Systematik) 62:331-430.

Smol, N., Muthumbi, A., Sharma, J. 2014. Order Enoplida, 7.3. In Schmidt-Rhaesa, A. (ed) Handbook of Zoology. De Gruyter, Berlin

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Copyright 1999 by Howard Ferris.
Revised: June 16, 2026.