Rotylenchus dalikhaniensis n. sp (Nematoda: Hoplolaimidae), a monosexual species recovered from the rhizosphere of Ruscus hyrcanus Woronow in Mazandaran province, northern Iran

A new monosexual species of Rotylenchus is described and illustrated based on morphological, morphometric and molecular studies from northern Iran. Rotylenchus dalikhaniensis n. sp. is characterised by having a continuous, conoid lip region with four, rarely three, annuli, lateral fields regularly areolated in pharyngeal region and irregularly throughout the body except in tail region, rarely with anastomoses at mid-body, body without longitudinal striations, stylet 34-36 mu m long, vulva located at 59-64%, tail with 16-19 annuli and ventral projection, and having no males in population. The differences of the new species with five known species, namely R. breviglans, R. alii, R. pakistanensis, R. echelimae and R. provincialis, are discussed. Phylogenetic analyses using 681 bp partial sequences of D2-D3 expansion region of the 28S and 383 bp ITS1-rRNA genes revealed that the new species formed a clade with some species of Helicotylenchus and Rotylenchus, respectively.