Family Oncholaimidae

Revised 05/10/22







Oncholaimidae Filipjev, 1916

Free-living marine nematodes. Several species reported from coastal mangrove swamps.

  • Lips usually fused..
  • Large cylindrical buccal cavity, usually with 3 immovable teeth of unequal size  surounded in the psoterior region by esophageal tissue
  • Esophageal glamds open through the teeth.
  • Amphidial fovea pocket-shaped, posterior to buccal cavity.
  • Esophagus muscular throughout length, esophageal gland openings just posterior to buccal cavity.
  • Males mainly diorchic, spicules varied in shape and size; gubernavulum present or absent.
  • Females didelphic amphidelphiuc or monodelphic prodelphic; ovaries reflexed.

Ref: Smol et al 2013

The Oncholaimidae has  more than 300 species and is one of the larges families of the Class Enoplida. The species are widespread in the seas and oceans of the world,  especially in intertidal regions and the upper part of the sublittoral regions.  They also occur in freshwater lakes, rivers and even underground waters.

The Oncholaimidae can be represented as seven subfamilies (Adoncholaiminae, Krampiinae, Octonchinae, Oncholaimellinae, Oncholaiminae, Pelagonematinae and Pontonematinae), differentiated by features such as the number and length of teeth, the position of the largest tooth, the structure of the female reproductive system, and the presence and development of the demanian system (Smol & Coomans, 2006).

Oncholaomidae - anterior 

Ref:  Neres, et al., 2014.


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Neres, P.F., Da Silva, M.C., Mirands-Jr, G.V., Fonseca-Genevois, V., Esteves, A.M. 2014. Five new species of Oncholaimellus (Oncholaimidae: Nematoda) from north-east Brazil, with an emended diagnosis and an updated key to the genus . J. Marine Biol, Assoc. UK 94:703-727.

Smol N. and Coomans A. 2006. Order Enoplida. In Eyualem-Abebe Traunspurger W. and Andra´ssy I. (eds) Freshwater nematodes: ecology and taxonomy. Wallingford, UK: CABI Publishing, pp. 225–292.

Smol, N., Muthumbi, A., Sharma, J. 2013. Order Enoplida, 7.3. Handbook of Zoology,


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