Helicotylenchus leiocephalus
Sher, 1966
(Thorne and Malek, 1968 description)
L = 0.8 mm;  a = 31; b = 6.2; c = 0; V = 60
Body assuming a complete spiral when relaxed. Lip region conoid, without annules. Spear 26u-28u long with strong, slightly cupped knobs, its muscles attached to a sclerotized extension of the cephalic armature.  Dorsal gland outlet about 1/3 spear length behind knobs. Excretory pore about opposite anterior end of esophagus.  Hemizonid anterior and adjacent to pore, occupying about 3 annules.  Ovaries outstretched, an offset spermagonium usually visible.  Tails bluntly rounded, 8 ventral annules on specimens from a Cottonwood, South Dakota,  collection while on those from near Presho they bore from 12-15. A few specimens were almost devoid of striae from opposite middle of spear through lip region.

Habitat:  Native grass in vicinities of Oelrichs, Dixon, Dupree and Herrick South Dakota; winter wheat, Opal, South Dakota; and Bromus sp., Wahpeton, North Dakota