Richtersia

Richtersia	Contents	Rev: 08/15/2026
	Classification	Biology and Ecology
	Morphology and Anatomy	Life Cycle
Return to Richtersia Menu		Ecosystem Functions and Services
	Distribution	Management
Return to Richtersiidae Menu Return to Selachinematidae Menu	Feeding	References
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Classification:

Chromadorea
Chromadoria
Desmodorida
Desmodorina: Desmodoroidea
Richtersiidae
Richtersia Steiner, 1916

Type species of the genus: Richtersia collaris Steiner, 1916

Classification of Richtersia and Desmotersia in the Selachinematidae has been adopted by some authors, example Neira & Decraemer 2009. However, , Tchesunov (2013) considers that the lack of cuticular spines differ from those in the Selachonematidae

: Synonyms:

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Morphology and Anatomy:

Genus with characteristics of the family Richtersiidae, and:

Buccal cavity without teeth,
Extremely short (up to 300 um) and fusiform body
longitudinal rows of spines.
Distinctive short fusiform body.
Cuticle with small body annuli ornamented with longitudinal rows or fields of spines and setae.
Head usually set off from the body by a cuticular collar, in which lips and anterior setae are situated.
Four cephalic and six cervical setae present.
Buccal cavity without teeth.
Amphideal fovea, situated after cuticular collar.
Pharynx without posterior bulb.

.Richtersia argentinae (A) male head, amphid level; (B) male head, buccal cavity; (C) female tail; (D) male copulatory apparatus and tail.

Drawings from Pastor de Ward and Lo Russo, 2007

Females:

Didelphic, amphidelphic;
Ovaries in general antidromously reflexed.

Males:

Monarchic, testis outstretched,
Spicules equal or unequal
With or without gubernaculum.
Without actual supplements but precloacal thorn-like spines can be present (also postcloacal spines).

Ref: Pastor de Ward and Lo Russo, 2007

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

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Distribution:

Mostly found in fine to medium grain sand and sometimes inm muddu marine sediments/.

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Feeding:

Food Sources and Feeding strategies for the genus Richtersia

Microbial epistrate feeders.

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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:

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Management:

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References:

Kreis, H.A., 1929. Freilebende marine Nematoden von der Nordwestkuste Frankreichs (Trebuerden: Cotes du Nord). Capita Zool. 2, 1-98.

Neira, C., Decraemer, W. 2009. Richtersia levinae, a new genus and new species of free-living nematode from bathyal oxygen minimum zone sediments off Callao, Peru, with discussion on the classification of the genus Richtersia (Chromadorida: Selachinematidae). Organisms, Diversity and Evolution 9: 1.e1-1.e15

Pastor de Ward, C.T., Lo Russo, V. 2007. A review of the genus Richtersia (Nematoda: Selachinematidae): new species from Golfo San Jose and Golfo San Mateas, Chubut (Argentina). J. Mar. Biol. Ass. U.K. 87: 1153-1160

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

Richtersia

Copyright © 1999 by Howard Ferris. Revised: August 15, 2026.

Copyright © 1999 by Howard Ferris.
Revised: August 15, 2026.