Tripyla alaecaudata




Rev 04/24/2023

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Tripyla alaecaudata Cid del Prado, Ferris and Nadler, 2010

Note:  A recent classification removes the suborder Tripylina from the order Enoplida and places it, along with suborders Tobrilina and Diphtherophorina, in the order Triplonchida in subclass Dorylaimia (De Ley et al., 2006; De Ley & Blaxter, 2004).  That move does not seem to be generally accepted.

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Morphology and Anatomy:

Female. (A-I). A: Anterior region; B, C: Cardia; D: Posterior region lateral; E: Vagina and glands; F: Spermatheca; G: Rectum; H: Posterior gonad lateral view: I: Tail latero-ventral view; K: Entire body: Male. (J, L-N). J: Tail, latero-ventral view; L: Spinneret; M: Spicules and gubernaculum; N: Entire body.



drawings and photomicrographs by Ignacio Cid del Prado (Cid del Prado et al., 2010)


  • Body J-shaped upon fixation.

  • Cuticle behind the lip region with transverse striations, which are 1.0 um wide at the anterior end and 2.0 um wide in the vulval region.

  • Lip region symmetrical

  • Amphid apertures 18-28 um  from the anterior end.

  • No body pores observed.

  • Inner labial papillae very small; outer labial setae distinct, 5.0-6.0 um long or 18-27% of  lip region width, cephalic setae conical, thinner and smaller than outer labial setae, 2.0-3.0 um long and 3.0-5.0 um  behind outer labial setae.

  • Dorsal tooth wedge-shaped and tucked into an invagination in opposing stoma wall; two very small teeth, 1.0-6.0 um anterior to the dorsal tooth.

  • Cardia between pharynx and intestine.

  • Vulval lips protruding, 3.0-6.5 um in live specimens but less after dehydration. Lateral to the vagina there are two granule-containing glands with fine ducts opening into the vagina close to the vulva.

  • Spermatheca oval-shaped, 21-26 um long by 17-28 um wide.

  • Terminal portion of the tail is straight or curved ventrally.

  • Llateral caudal alae extending anteriorly from tail tip, 137-240 um on the right and 139-253 umon the left with a pair of papillae  at approximately the same distance posterior to the anus.

  • Spinneret short, terminal.


  • Body size similar to female.

  • No body pores observed.

  • At least fifteen ventral papillae were observed, approximately 68 um apart, with the first 73 um from the anterior end and the last 84 um anterior to the cloacal opening.

  • Spicules 9.6-13.0 um wide at the manubrium, end of the shaft being bifid. Gubernaculum straight. Spicules surrounded by a muscular pouch

  • Lateral caudal alae extending anteriorly from tail tip, 146-180 umon the right and 120-177 um on the left. Paired papillae in the caudal alae.

  • Spinneret short, terminal

Cid del Prado et al., 2010.

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


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 Type locality and habitat: Western hills of the Napa Valley, 0.75 km west of UC Oakville Experimental Vineyard, Oakville, California (N 38° 25.95’; W 122° 25.34’). Collected from moist soil in a grassy area (wild oats and native grasses).


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Nematodes of the family Tripylidae are generalist predators of small aquatic and soil organisms. Many authors have commented on the freshwater and
wet soil in which these nematodes are found, and on the nature of their prey based on observation of intestinal contents or from behavior. Among the recorded prey, as reviewed and collated by Small (1987), are nematodes, rotifers and protozoa (Cid del Prado et al., 2012).

Nematodes in the Tripylidae attach to soil particles or other substrate via adhesive material extruded from the caudal glands through the spinneret.  Thus anchored, the body moves quite reapidly in water films, sometimes thrashing vigorously.  This behavior has at least three possible purposes: 1. to make tactile contact with prey organisms, 2. to create currents that stir up the sediment and potential prey organisms settled therein, and 3. to anchor the nematode in currents of moving water.

Interestingly similar attachment and feeding behavior occurs in other nematode groups  that, based on most characters, appear to be only distantly related.  For example, the generalist predators of the Tripylidae are in the Class Enoplea, Subclass Enoplia, Order Enoplida, the specialist predators of other nematodes in the Mononchidae are in the Class Enoplea, Subclass Dorylaimia, Order Mononshida, while the bacterivorous Plectidae are in the Class Chromadorea, Subclass Chromadoria, Order Plectida, according to the phylogeny proposed by De Ley and Blaxter, (2002, 2004).

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Biology and Ecology:



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Life Cycle:

Ecophysiological Parameters:

For Ecophysiological Parameters for this species, click If species level data are not available, click for genus level parameters

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Ecosystem Functions and Services:

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Cid del Prado, I., H. Ferris and S.A. Nadler. 2010. Soil inhabiting nematodes of the genera Trischistoma, Tripylina and Tripyla from México and the USA with descriptions of new species. Journal of Nematode Morphology and Systematics 13-28-49.

De Ley, P., Decraemer, W. & Eyualem-Abebe. (2006).  Introduction: summary of present knowledge and research addressing the ecology and taxonomy of freshwater nematodes. In Eyualem-Abebe, Andrassy, I. & Traunspurger, W. (Eds). Freshwater Nematodes: Ecology and Taxonomy. Wallingford, UK, CABI Publishing, pp. 3-30.

Zullini, A. (2006).  Order Triplonchida. In Eyualem-Abebe, Andrassy, I. & Traunspurger, W. (Eds). Freshwater Nematodes: Ecology and Taxonomy. Wallingford, UK, CABI Publishing, pp. 293-323



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Copyright © 1999 by Howard Ferris.
Revised: April 24, 2023.