Onyx

Onyx	Contents	Rev: 08/22/2026
	Classification	Biology and Ecology
	Morphology and Anatomy	Life Cycle
Return to Onyx Menu		Ecosystem Functions and Services
	Distribution	Management
Return to Desmodoridae Menu	Feeding	References
	Go to Nemaplex Main Menu	Go to Dictionary of Terminology

Classification:

Chromadorea
Chromadoria
Desmodorida: Desmodorina
Desmodoroidea
Desmodoridae: Spiriniinae
: Onyx Cobb, 1891
Type species of the genus: Onyx perfectus Cobb, 1891

Synonyms:

Oistolaimus Ditlevsen, 1921

Morphology and Anatomy:

Cuticle with transverse striations but amphids not surrounded by cuticle striations.
Six shortyouter labial setae and four cephalic setae in a single circle
Amphidial fovea a single open loop
Buccal cavity with a long spear-like dorsal tooth.
Posterior pharyngeal bulb without thickened cuticular lining.

Females:

Didelphic-amphidelphic

Ref: Tchesunov, 2013; Huang and Guo, 2022

Males:

Monorchic
Pre cloacal supplementary organs as cuticularized S-shaped tubes.

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

Feeding:

Food Sources and Feeding strategies for the genus Onyx

Probably epistrate feeders

Life Cycle:

For Ecophysiological Parameters for this genus, click

Ecosystem Functions and Services:

Huang, Y. and Guo, Y. 2022. Free-living Marine Nematodes from the East China Sea. Springer, Singapore and Science Press, Beijing.

Tchesunov. A.V. 2013. 7.13 Order Desmodorida de Coninck, 1965 In Schmidt-Rheas and de Gruyter, W. Handbook of Zoology.Gastrocticha, Cycloneuralia, Gnatifera. Volume 2: Nematoda

Onyx

Contents

Classification:

Back to Top

Morphology and Anatomy:

Back to Top

Distribution:

Back to Top

Feeding:

Back to Top

Biology and Ecology:

Back to Top

Life Cycle:

Back to Top

Ecosystem Functions and Services:

Back to Top

Management:

Back to Top

References:

Back to Top

Revised by Howard Ferris: August 22, 2026.