Helicotylenchus

Helicotylenchus	Contents	Rev 10/21/08
Spiral nematodes	Classification	Hosts
	Morphology and Anatomy	Life Cycle
Return to Helicotylenchus Menu	Economic Importance	Damage
	Distribution	Management
Return to Hoplolaimidae Menu	Feeding	References
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Classification:

      Tylenchida
       Tylenchina
        Tylenchoidea
         Hoplolaimidae
          Hoplolaiminae
           Helicotylenchus (Steiner, 1945)

    Synonyms:

           Rotylenchoides (Whitehead, 1958)
           Zimmermannia (Shamsi, 1973)

Morphology and Anatomy:

photo by Howard Ferris

Female: Body vermiform, spiral (when relaxed) to straight.

Labial region continuous to slightly offset, rounded or anteriorly flattened, generally annulated, but never longitudinally striated; anterior lip annule generally not divided into sectors, with elongate amphid apertures (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 2.5 body diameters long, typically more curved dorsally, with or without a terminal ventral process, sometimes rounded.

Stylet and labial framework average sized.

Dorsal esophageal gland opening (DEGO) from 6 to 16 µm 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 post-uterine sac. Epiptygma present, but folded inwards into the vagina. Vulval flaps present, inconspicuous.

Photograph from Ana Child, NREL, Colorado State University

Male: Slight secondary sexual dimorphism seen in smaller anterior end.

Caudal alae enveloping tail end.

Fortuner, et al.(1987), and H. Ferris.