Genus Helicotylenchus

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ORDER RHABDITIDA
INFRAORDER TYLENCHOMORPHA
            Family Hoplolaimidae
                        Genus Helicotylenchus

 "Small to medium-sized (0.4-1.2 mm). Females spirally coiled or rarely C-shaped. Lateral field with four lines. Cephalic region continuous or rarely offset, no longitudinal striae on head annules. Cephalic framework moderately developed, lateral ribs refractive. Stylet robust, average-sized, both parts of approximately equal length. Dorsal gland orifice usually one-third of stylet length posterior to knobs. Pharyngeal glands overlapping intestine laterally and verntrally, the longest overlap on ventral or lateral side of body, glands separate. Female reproductive system usually paired, branches opposite outstretched, sometimes posterior branches less developed to a varaible degree. Epiptygma single or double. Tail 1-2 body diameters long, typically more curved dorsally, with or without terminal ventral process, sometimes rounded. Phasmids small, at level of anus. Bursa surrounding tail terminus." Bert and Borgonie, 2006

Genus Helicotylenchus  Steiner, 1945
 syn.: Rotylenchoides Whitehead, 1958 
   Zimmermannia  Shamsi, 1973
Hoplolaiminae. 
“Female: Body vermiform, spiral to straight. Labial region continuous to slightly offset, rounded or anteriorly flattened, generally annulated but never longitudinally striated; anterior lip annulus generally not divided into sectors, with elongate amphid spertures (SEM). Rarely faint or marked lip sectors are present. Lateral field with four lines. Phasmids small, near anus; cephalids and caudalid present. Tail 1 to 2 1/2 body diameters long, typically more curved dorsally, with or without a terminal ventral process, sometimes rounded. Stylet and labial framework average-sized. DGO from 6 to 16 um from stylet base. Median bulb rounded with average-sized valve. Glands overlap intestine dorsally and ventrally, all three glands of about the same length. Two genital branches, the posterior one sometimes degenerated or reduced to a PUS. Epiptygma present, inconspicuous. Male: Slight secondary sexual dimorphism seen in smaller anterior end. Caudal alae enveloping tail end.” From Powers and Mullin website http://nematode.unl.edu/

           
References:

Bert, W.and G. Borgonie. Order Rhabditida: Suborder Tylenchina.  2006.  In: Eyualem Abebe, Traunspurger W., and Andrassy I. (eds) Freshwater Nematodes: Ecology and Taxonomy. CABI Publishing, Cambridge, MA, pp. 680

Powers T. and P. Mullin. Plant and Insect Parasitic Nematodes. University of Nebraska Nematology Website. http://nematode.unl.edu/