Tylenchorhynchus

Contents

Rev 07/22/2008

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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.

Females:

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

Males:

• Monorchic.
• Have caudal alae which are rarely lobed. 
• Spicules with well-developed velum. 
• Arcuate tail enveloped by bursa.  

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.

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.

Diagram from Urs Wyss, Nemapix.