Helicotylenchus oleae n. sp. and H. neopaxilli n. sp. (Hoplolaimidae), Two New Spiral Nematodes Parasitic on Olive Trees in Italy.

Helicotylenchus oleae n. sp. and H. neopaxilli n. sp., from olive roots and soil in Italy, are described and illustrated. Helicotylenchus oleae can be distinguished from the related species H. canadensis and H. tunisiensis especially by the smaller styler, its distinctive tail shape, and a tail longer than one anal body width. Helicotylenchus neopaxilli differs from the close species H. paxilli by having a conical, anteriorly truncated labial region, shorter stylet, and phasmids always anterior to level of anus. Also illustrated and discussed are histopathological changes within feeder roots of olive caused by the feeding activity of the semi-endoparasitic H. oleae.