Heterodera vallicola sp n. (Tylenchida : Heteroderidae) from elm trees, Ulmus japonica (Rehd.) Sarg. in the Primorsky territory, the Russian Far East, with rDNA identification of closely related species

Heterodera vallicola sp. n. is described from the rhizosphere and roots of elm plants Ulmus japonica (Rehd.) Sarg. (Ulmaceae Urticales), growing in a forest along the Ilistaija river in the Mikhailovsky district, Primorsky re gion, the Russian Far East. This species belongs to the Humuli group. It di ffers from N. riparia by its more rounded cysts, narrower semifenestral wid th, longer length stylet and longer hyaline part of tail for the second sta ge juveniles. It can be distinguished from H. humuli by having a shorter fe nestral length, and smaller body length females and males. Restriction enzy me analysis of the ITS regions of ribosomal DNA obtained with AluI, Alw26I, CfoI, DdeI, PvuII, and RsaI clearly distinguished H. vallicola sp. n. from H. humuli and N. riparia. Phylogenetic relationships of H. vallicola sp. n . with other Humuli group species are given based on analyses of the ITS se quences.