Morphological and molecular characteristics of two species of Psilnchus (Nematoda: Psilenchidae) from the Taf region of Lorestan province, Iran

The species of the genus Psilenchus are weak parasites of plants and mosses that feed on hairy roots and epidermal cells of root.Previously, the members of the genus were placed in the family Tylenchidae because of having weak stylet and elongate tail, but because of the didelphys uterus and the presence of phasmid on the tail, they were more similar to the members of the supper family Dolichodoroidea, so "Psilenchidae", as a new family with two subfamilies Antarctenchinae (Stylet knobbed and vulva with lateral membranes and epiptygma) and Psilenchinae (Stylet not knobbed and vulva without lateral membranes and epiptygma) was established.The genus Psilenchus currently has 21 valid species (only four species have been sequenced), of which 10 species have been recorded from Iran.About 100 samples were collected from the rhizosphere of fruit and forest trees in Taf region of Khoramabad county in 2022 and 2023.The nematodes were extracted using tray method and after fixation, permanent slides were prepared.The morphological and morphometric characteristics of the samples were examined, then a molecular study was performed using the D2-D3 28S rDNA marker.Two species, Psilenchus curcumerus and P. vinciguerrae, were identified with one and two sequences, respectively.This is the first report of these two species from the region.These two species were confirmed based on morphometric and morphological characteristics and phylogeny studies.