Paralongidorus iranicus n. sp., a new bisexual species of the genus, is described and illustrated by light microscopy, scanning electron microscopy and molecular studies from specimens collected in the rhizosphere of Scots pine (Pinus sylvestris) from the Caspian (Khazar) seashore, Nour, northern Iran. Paralongidorus iranicus n. sp. is characterised by the large body size (7.8-11.4 mm), a rounded lip region, clearly set off by a collar-like constriction at level of, or slightly posterior to, the amphidial aperture, and bearing a very large, stirrup-shaped, amphidial fovea, with conspicuous slit-like aperture, a very long and flexible odontostyle ca 170 μm long, guiding ring located at 34 μm from anterior end and males with spicules ca 80 μm long. In addition, data from an Iranian population of P. bikanerensis recovered from the rhizosphere of palm (Phoenix dactylifera L.) in Bam, Kerman province, south-eastern Iran, agree very well and are very close to the original description of the species from India. The D2 and D3 expansion regions of 28S rRNA gene, ITS1, and 18S rRNA sequences were obtained for P. iranicus n. sp. and P. bikanerensis. Phylogenetic analyses of P. iranicus n. sp. and P. bikanerensis rRNA gene sequences and of Longidorus spp. sequences published in GenBank were done using Maximum Likelihood and Bayesian inference. Paralongidorus species (including P. iranicus n. sp.) clustered together; however, P. bikanerensis clustered within Longidorus spp. and was clearly separated from all other Paralongidorus spp. in trees generated from the D2-D3 expansion segments of 28S and partial 18S data set, respectively.