Choanolaimus

Choanolaimus	Contents	Rev: 02/22/2026
	Classification	Biology and Ecology
	Morphology and Anatomy	Life Cycle
Return to Choanolaimus Menu		Ecosystem Functions and Services
	Distribution	Management
Return to Selachinematidae Menu	Feeding	References
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Classification:

Chromadorea
Chromadoria
Chromadorida
Selachinematidae: Choniolaiminae
Choanolaimus de Man, 1880

Type species of the genus: Choanolaimus psammophilus de Man, 1880

Synonyms:

Note: genera designated as family Choanolaimidae are trnsferred to Selachinematidae

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Morphology and Anatomy:

Nematodes around 2 mm long with a thick cuticle that is strongly striated and a rather thick body, around 80 um..
The coloration of the nematode is described as clear and transparent in the esophageal region and milky in the intestine and tail region.
Head region flattened, six lips with two circles of labial papillae; all anterior sensilla are papilloid
Cuticle punctated, laterally differentiated with larger more widely separated dots
Amphideal fovea coiled in two or three turns
Radially symmetrical stoma consists of two compartments: an anterior broad, cup-shaped chamber and a posterior narrow, cylindroid chamber. The anterior chamber is reinforced by six radial cuticularized rhabdions that may that are posteriorly bicuspid.
Pharynx cylindrical, muscular
Tail very short, rounded conical or semicircular

Ref: Palomo, 1983; Tchesunov, 2013

Choanolaimus

Females:

Body size range for the species of this genus in the database - Click:

Males:

Diorchic, with outstretched anterior testis and reflexed posterior testis.
Strong spicules and a gubernaculum. No caudal alae
Precloacal supplements (7) are papilloid and pierced by fine pores

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Distribution:

Freshwater, brackish water and marine habitats, and sand dunes.

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Feeding:

Food Sources and Feeding strategies for the genus Choanolaimus

Remains of enchytreids were observed in the intestine of C. psammophilus (Palomo, 1983). Nematode spicules and stylets have also been observed in the intestine.

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Biology and Ecology:

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Life Cycle:

For Ecophysiological Parameters for this genus, click

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Ecosystem Functions and Services:

Predator.

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Management:

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References:

Palomo, A. 1983. Primera cita en Espana y redescripcion de Choanolaimus psammophilus de Man, 1880 (Nematoda: Choanolaimidae). Nematologia Mediterranea 11:79-85.

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