Diastolaimus mexicanus		Contents		Rev 07/14/2026
		Classification		Biology and Ecology
		Morphology and Anatomy		Life Cycle
Return to Diastolaimus menu				Ecosystem Functions and Services
		Distribution		Management
Return to Chambersiellidae menu		Feeding		References
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Classification:

      Chromadorea
       Rhabditida
         Rhabditia
          Chambersiellidae

             Diastolaimus mexicanus  Cid del Prado Vera, 2012

Taxonomic note: Cermak et al. (2022) redescribed D. grossus and proposed D. mexicanus as a junior synonym of D. grossus. However, molecular analyses indcate that 28S rRNA gene sequences of D. mexicanus collected from the type and other locations were different from those of D. grossus (Cid del Prado Vera et al., 2023)

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Morphology and Anatomy:

Female:

• Body an open C-shape; cuticle very finely striated, Lateral field with three incisures.
• Head rounded, continuous with body contour; labial region with six triangle-shaped lips, each with a filamentous cirrus at the base, six setose, conoid outer labial sensilla,  and four papilliform cephalic sensilla near bases of outer labial setae
• Cephalic papillae shorter at the anterior part of the gymnostom. Oval amphid apertures level with the anterior of the stegostom,
• Cheilostom slightly sclerotized, gymnostom heavily sclerotized, stegostom funnel-shaped and enveloped by muscular pharyngeal tissue
•  Dorsal pharyngeal gland orifice in the posterior third of the stegostom.
• Pharyngeal corpus cylindrical without a median bulb, with prominent cuticular lining. Narrow isthmus; basal pharyngeal bulb oval, with strong transverse butterfly valve
•  Nerve ring in the anterior part of the isthmus. Excretory pore  posterior to the nerve ring. Deirids slightly posterior to excretory pore.
• Didelphic amphidelphic, ovaries opposed and reflexed with oocytes arranged in single file,
• Two small vulval glands present, one anterior and the other posterior to the vulval lips
•  Rectum is 1.3 times the anal body diameter with two associated small gland-like cells.
•  Phasmids at 40% of the tail length.
• Tail conoid, narrowing gradually and ending in a pair of sclerotized mucros.

Male:

• Seven pairs of genital latero-ventral precloacal and five pairs of postcloacal, papillae
• An aperture on the anterior lip of the cloaca in a ventral position, presumably for the secretion of the three glands,
• Spicules paired, symmetrically curved ventrally, with an elongate oval manubrium, which has an anterior extension;
• Gubernaculum conspicuous, sclerotized, its anterior part wide and reducing gradually to a thin tip.

Ref: Cid del Prado Vera (2012); Cid del Prado Vera at al (2023)

Reported median body size for this species (Length mm; width micrometers; weight micrograms) - Click:

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Distribution:

Described from moss in a temperate forest in Amecameca county. Mexico.

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Feeding:

Bacterial feeder.

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Biology and Ecology:

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Life Cycle:

Ecophysiological Parameters:

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Ecosystem Functions and Services:

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Management:

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References:

Cermak, V., Njezic, B.,  Foit, B.J., Kulich, P. Orsagova, H., Ruiz-Cuenca, A.N., Shokoohi, E. Abolafia, J. 2022. Redescription of Diastolaimus grossus (Truskova & Eroshenko, 1977) Andrassy, 1984 (Rhabditida, Chambersiellidae) from Europe and comments on its phylogenetic position. Journal of Helminthology 96e31:1 14.

Cid del Prado Vera, I. 2012. Two new species of nematodes (Cephalobida: Chambersiellidae) from moss from North and South America. Nematropica 42:108-114.

Cid del Prado-Vera, I., Ferris, H. Subbotin, S. A. 2023. A new species of the genus Diastolaimus and redescription of D. mexicanus Cid del Prado, 2012 (Rhabditida: Chambersiellidae) from Mexico. Nematropica 53:30-40.

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Copyright 1999 by Howard Ferris.
Revised: July 14, 2026 .