Filenchus cylindricollis
 (Thorne & Malek, 1968) Siddiqi, 1986
Syn: Tylenchus cylindricollis

Body tapering slightly anteriorly to a broad, rounded lip region; posteriorly it ends in an elongate, uniformly tapering tail with an abrubt minute, conoid or rounded terminus.  Striaeabout 2.5u apart. Lateral fields with refractive crenate borders and two obscure incisures between them.  Spear 10u long, strong with large knobs, its muscles extending forward into lip region and attached to cephalic cuticle. Deirids difficult to see, about opposite excretory pore.  Intestine with large, refractive granules obscuring details of gonads.  Posterior uterine branchless than half as long as body width.  Vulva-anus distanceslightly longer than tail.
Male similar to female with well developed bursa and arcuate, cephalated spicula. Gubernaculum thin, trough-like.

Tylenchus cylindricollis is distinctive because of the broad head, spear muscles attached to cephalic cuticle, wide lateral fields with refractive borders and uniformly tapering tail ending in an abrupt conoid or rounded terminus.

Habitat:  Native sod from summit of Medicine Butte, Parker and Hammer, South Dakota; Stanley and Devils Lake, North Dakota; Sidney, Powder River and Montana Route 12; North Dakota state line, Montana.