Abstract:
Specimens of three undescribed spiral nematodes. Helicotylenchus disocephalus n.sp., H. microtylus n.sp. and Rotylenchus goldeni n.sp., were collected from soil around the roots of wheat and pistachio from Muzaffarabad and Quetta, Pakistan respectively, and are described and illustrated. H. discocephalus n.sp., is characterized by a combination of characters which separates it from all the other species of the genus Helicotylenchus viz., truncate head with 4-5 distinct annules and a conspicuour labial disc, short stylet and female tail having a characteristically elongate ventral projection which sometimes is mucronate or simply tapers to tip. H. microtylus n.sp. is distinguished from the other species of the genus by its rounded and elevated head, smaller stylet, distinctive tail shape with lesser number of tail annules, adanal position of phasmids, functional spermatheca and absence of males R. goldeni n.sp., is distinctive by a conoid, rounded head with indistinct annules, smaller stylet with massive and rounded basal knobs, dorso-convex tail bearing 4-9 annules, phasmid anus level and presence of functionalspermatheca and males.
