Rev 09/14/2023

Stylet or Stunt nematodes Classification Hosts
Morphology and Anatomy Life Cycle
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Distribution Management
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           Tylenchorhynchus Cobb, 1913

      Bitylenchus (Filip'ev, 1934)
      Telotylenchus (Siddiqi, 1960)
      Quinisulcius (Siddiqi, 1971)
      Dolichorhynchus (Mulk and Jairajpuri, 1974)
      Trilineellus (Lewis and Golden, 1981)
      Divittus (Jairajpuri, 1984)
      Morasinema (Javed, 1984)
      Tessellus (Jairajpuri and Hunt, 1984) 
      Neodolichorhynchus (Jairajpuri and Hunt, 1984)

Note: several of these are consiidered valid taxa by various authors
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Morphology and Anatomy:




Female and male of Tylenchorhynchus. 

Photograph by Jon Eisenback, Nemapix.


General Characteristics

  •  Body medium-sized.  
  • Cephalic framework slight to heavily sclerotized. 
  • Phasmids prominent.  
  • Lateral field with two, three, four, or five lines, sometimes areolated.  Longitudinal ridges sometimes present on body.  
  • Tail conoid to subcylindroid, about three times as long as wide (c' = 2 to 4), sometimes with thicker cuticle in the distal portion.  
  • SEM face view typically with labial disc fused with first lip annule, and with lateral sectors regressed.  The remaining sub-median sectors give a distinctive quadrangular appearance to the face view.  Papillae often present on submedian sectors.  Head continuous to slightly offset. 
  • Stylet 15 to 30 µm long, thin to slender, has strong knobs, with cone about as long as shaft, sometimes needle-like.  
  • Esophageal glands bound by a membrane into a large basal bulb. Appear to butt into intestine. 
  • Deirids often absent.


  • Diovarial, amphidelphic, ovaries outstretched, vulva about 50%.
  • Tail round.


Note also Merlinius, Quinisulcius = (Tylenchorhynchus) etc.

 [Ref: Fortuner & Luc (1987), and H. Ferris.]


Drawings by Thorne and Malek, 1968; photographs by Peter Mullin (UNL), 2000.

Photograph by Howard Ferris
Tylenchorhynchus sp. from organic vegetable system, Salinas, California
Genus monographed by Allen in 1955 - 34 species, 22 new species, 12 old or already described.  In 1962, A.D. Baker listed 55 species.  Sher listed over 100 species (200 in family and subfamily).

Several related genera are differentiated on the following characters:

1. Number of lateral lines; 
2. Annulation of cuticle;
3. Shape of lip region and number of annules;
4. Length of spear;
5. Shape and length of female tail;
6. Position of hemizonid.

Body size range for the species of this genus in the database - Click:
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Widely distributed - almost any collection will usually contain from one to four species.

Over 100 species of stunt nematodes have been described.

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Economic Importance:

D-rated pest in California Nematode Pest Rating System.

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Generally true ectoparasites on epidermal cells and root hairs, but capable of endoparasitic feeding on some hosts.     

Feeding structure and function in Tylenchorhynchus.  Configuration of dorsal and subventral esophageal glands (right); dorsal esophageal gland opening and stylets (top left); metacorpus (bottom left.

Diagram from Urs Wyss, Nemapix.

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For an extensive host range list for this genus, click
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Life Cycle:

For Ecophysiological Parameters for this genus, click 
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Fortuner & Luc, Rev. Nematol. 10:183-202 (1987)

Geraert, E. 2011.  The Dolichodoridae of the World.  Academia Press, Gent 520p

H. Ferris.

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Copyright © 1999 by Howard Ferris.
Revised: September 14, 2023.