Description of Ditylenchus azarbaijanensis n. sp. (Tylenchomorpha: Anguinidae) from West Azarbaijan province, northwest Iran

Ditylenchus azarbaijanensis n. sp. is described and illustrated based upon morphological and morphometric characters. The new species is mainly characterized by having six lines in the lateral field, rudimentary postuterine sac (PUS) ca. 0.2 vulval body width long, anteriorly inclined vagina and conical female tail with a pointed terminus, 48-70 μm long (c = 15-21, c􀀀 = 2.4-3.7). It is further characterized by having fine stylet 7.5-10.0 μm long with small knobs, small pyriform pharyngeal bulb offset from the intestine, and males with 26.5- 31.0 μm long spicules. By having a rudimentary PUS, the new species is morphologically compared with three closely related species, namely Ditylenchus apus, D. deiridus and D. khani. Moreover, morphological differences of the new species with eight similar species of the genus, namely D. arachis, D. convallarie, D. dauniae, D. medicaginis, D. silvaticus, D. tenuidens, D. valveus, and D. virtudesae are presented. The status of the rudimentary or absent PUS of D. deiridus and the new species is also discussed.