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Discopersicus iranicus n. gen., n. comb., previously described from Iran as a new species under the genus Discotylenchus, is illustrated using light microscope and scanning electron microscope (SEM) observations and further studied using molecular characters. SEM studies revealed the newly proposed genus has oblique amphidial apertures on the lateral sides of the lip region. SEM images are also provided for two species of Discotylenchus, namely D. discretus and D. brevicaudatus, as the first SEM study of the genus. These results confirmed longitudinal amphidial aperture type on lateral sides of the lip region in genus Discotylenchus, as noted by Siddiqi while erecting the genus with D. discretus as the type species. Molecular phylogenetic analyses using partial small subunit (SSU) and large subunit (LSU) rDNA sequences revealed the affinity of the genus Discopersicus n. gen. with members of the subfamily Boleodorinae, as supported by morphological characters (mainly, the oblique amphidial opening).

Three species of the family Tylenchidae, including one new and two known species, are described and illustrated. Atetylenchus minor n. sp. is characterised by its short body length of 633 (558-691) μm, MB = 45 (41-46), lateral field with four crenate incisures, stylet 12.0 (11.5-12.5) μm long, without distinct basal knobs but with swollen arms of the shaft at its base, V = 56.3 (53.7-59.3), absence of lateral vulval membranes, and conical tail 57 (51-62) μm long with a rounded tip. Morphological differences of the new species with four known species of the genus, namely A. abulbosus, A. graminus, A. amiri and A. metaporus, are discussed. Molecular phylogenetic studies of the new species using 1089 bp partial sequences of 18S rDNA revealed that the new species formed a clade with an unpublished species assigned to Psilenchus in Bayesian inference (BI) with low Bayesian posterior probability (BPP). This clade forms a sister clade to a major clade containing two species of Psilenchus and several belonolaim species and genera. The same result was achieved using maximum likelihood (ML) analysis. Morphological and molecular phylogenetic studies were also performed on two other species, Malenchus labiatus and Neothada cancellata, using 28S rDNA D2-D3 sequences. In the inferred Bayesian tree, M. labiatus formed a clade with other species of Malenchus with 28S information with maximal support (1.00 BPP), while N. cancellata formed a clade with Boleodorinae, again with maximal (1.00) BPP.

Summary Paurodontella gilanica n. sp. is described and illustrated based on morphological, morphometric and molecular characters. The new species is characterised by its small body size, four lines in the lateral field, weak stylet with minute asymmetrical knobs, female reproductive system lacking a diverticulum but with small post-vulval uterine sac, elongate conoid tail with pointed, sometimes filiform, tip, males common with small spicules and cloacal bursa not reaching tail tip. Morphological differences between the new species and seven known species of the genus, namely P. asymmetrica, P. auriculata, P. balochistanica, P. minuta, P. myceliophaga, P. parapitica and P. persica, are discussed. The new species is also compared with four known species of Paurodontus having four lines in the lateral field. Using a 1123 nt long partial 18S rDNA sequence of the new species to reconstruct the phylogenetic relationships revealed that it formed a clade with members of the Sphaerulariidae and Paurodontidae. Using a 746 nt long partial sequence of the 28S rDNA D2-D3 segment revealed that P. gilanica n. sp. formed a clade with Abursanema iranicum in both Bayesian inference (BI) and maximum likelihood (ML) analyses with 0.99 Bayesian posterior probability (BPP) and 89% bootstrap support value (BS). The morphological affinities of Paurodontella and Paurodontus are discussed.