Jebraeil Bahmani - Department of Plant Pathology, College of Agriculture and Natural Resources, Science and Research Branch, Islamic Azad University, Tehran, Iran.
Shapour Barooti - Department of Nematology, Plant Protection Research Institute, P. O. Box: ۱۴۵۴, Tehran ۱۹۳۹۵, Iran.
Reza Ghaderi - Department of Plant Protection, College of Agriculture, University of Shiraz, Iran.

During a survey on the identification of plant-parasitic nematodes associated with walnut in Sanandej region (Kurdistan province, western Iran), a population of Paratylenchus labiosus was collected and identified morphologically. Description, illustrations and morphometrics of the species are given and comparisons are made between it and some related species. Paratylenchus labiosus comes more close to three species namely P. similis, P. tateae and P. italiensis in having certain diagnostic characters such as short stylet less than ۱۸ µm long, concave-conoid head with prominent submedian lobes and tail ending to an acute to finely rounded terminus. However, P. labiosus differs from them in having a spermatheca full of sperm cells and presence of males. Different modes of reproduction (parthenogenesis or amphimixis) may be observed in different populations of some species in this genus, but somewhat unique reproduction behavior of P. labiosus could be considered as a diagnostic character for separation of it from the three closely related species.

Description, plant-parasitic nematodes, reproduction, Sanandej, walnut