Pseudosteineria

Pseudosteineria	Contents	Rev: 08/04/2025
	Classification	Biology and Ecology
	Morphology and Anatomy	Life Cycle
Return to Pseudosteineria Menu		Ecosystem Functions and Services
	Distribution	Management
Return to Xyalidae Menu	Feeding	References
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Classification:

Chromadorea
Chromadoria
Monhysterida: Monhysterina
Sphaerolaimoidea
Xyalidae
Pseudosteineria Wieser, 1956

Type species of the genus: Pseudosteineria anteferens Wieser, 1956

Synonyms:

Morphology and Anatomy:

Genus Pseudosteineria was established by Wieser (1956) as a subgenus of Theristus Bastian, 1865. De Coninck (1965) raised it to genus level.

With general characteristics of family Xyalidae, and:

Body spindle-shaped.
Cuticle distinctly annulated. Lateral differentiation may be present as lateral fields.
Anterior sensilla in two crowns (6 + 12) with the second crown composed of six anterior outer labial sensilla, four posterior cephalic sensilla, and two additional lateral sensilla.
Long cervical setae, arranged in six or eight groups about the level of the amphids, at some distance posteriorly to the cephalic capsule.
Other somatic setae can be short or very long, scarce or abundant, and irregularly distributed along the body.
Amphideal fovea circular, just before, just behind or at the level of subcephalic setae.
Buccal cavity conical.
Tail conico-cylindrical, consisting of proximal conical and slender cylindrical distal parts. Tail tip slightly inflated with long terminal setae

Females:

Monodelphic, ovary outstretched
Vulva at 60-70% of body length

Ref: Cidreira et al., 2020

Pseudosteineria longisetis Male anterior region
Drawings from Cidreira et al., 2020

Males:

Copulatory apparatus variable in shape
Spicules slender to broad, equal or unequal in length
Precloacal supplements 0-3

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

Distribution:

Free-living marine nematodes mostly in intertidal sediments.

Feeding:

Food Sources and Feeding strategies for the genus Pseudosteineria

Life Cycle:

For Ecophysiological Parameters for this genus, click

Ecosystem Functions and Services:

Bastian, H.C. (1865) Monograph of the Anguillulidae, or free nematoids, marine, land, and freshwater; with descriptions of 100 new species. The Transactions of the Linnean Society of London, 25 (2): 73-184. https://doi.org/10.1111/j.1096-3642.1865.tb00179.x

Cidreira, G., Venekey, V., De souza Alves, O.F., Kelmo, F. 2020. Description of Pseudosteineria longisetis sp. n. from northeastern Brazil with a review of the genus Pseudosteineria Wieser, 1956 (Nematoda: Xyalidae). Zootaxa 4763 (3): 354-370 doi.org/10.11646/zootaxa.4763.3.2

De Coninck, L.A. (1965) Classe des Nematodesâ€”SystÃ©matique des nematodes et sous-classe des Adenophorea. Traite de Zoologie, 4 (2): 586-681