Ektaphelenchus oleaen. sp. is described and illustrated based on morphological and molecular data from the rhizosphere of an olive tree (Olea europium) from the suburbs of Gorgan, Golestan Province, in northern Iran. The new species is characterised by females 441-652 μm long, stylet 15-19 μm long with wide lumen without basal swelling, labial region set off by a clear constriction, appearing bowl-like, four incisures in lateral field, excretory pore always located posterior to median bulb and anterior to hemizonid, post-uterine sac 43-73 μm long, conoid tail, and the presence of four pairs of male subventral caudal papillae. The new species is typologically similar to species belonging to three genera:Anomyctus,EktaphelenchusandSeinura, by a combination of morphological characters,e.g., head with expanded lips, forming a small bowl-like structure, stylet without knobs or swellings at the base, short conical tail and a vestigial anus and rectum in most individuals. Molecular analysis of the new species was performed using sequences of SSU and LSU ribosomal DNA genes.

Two new species of Seinura are described and illustrated using both morphological and molecular characters. Seinura persica n. sp. is characterized by having females with a distinct cephalic region, stylet 19.5 (18-20) μm long, four incisures in the lateral fields, position of excretory pore anterior to the base of metacorpus, post-uterine sac 54.8 (50-60) μm long, and an elongate-conoid tail with a shallow depression on the dorsal side ending in a sharply pointed tip. Males have body length of 467 and 592 μm, spicules 15 and 16 μm long with a prominent triangular-shaped rostrum, developed condylus and no cucullus. Seinura hyrcania n. sp. is characterized by having an offset lip region, stylet 21.5 (18-24) μm long, three incisures in the lateral fields, excretory pore anterior to the base of the metacorpus, post-uterine sac 19 (12-25) μm long and conical tail ending in a filiform terminus. Morphological and morphometric diagnostic characters together with molecular data based on partial sequences of SSU and LSU of the ribosomal DNA gene are provided for these new species.

Malenchus gilanensis n. sp. is described and illustrated from wood samples from Iran. Morphologically, this new species is characterized by very small body size, cuticle with narrow annuli (0.8–0.9 μm wide at mid-body), lateral field with two lines, originating at the level of the median pharyngeal bulb valve, straight amphidial apertures (similar to members of the subgenus Telomalenchus), sunken vulva with large lateral flaps, prophasmids located almost level with to 9 annuli posterior to the vulva in females, and undeveloped adanal bursa which can be considered as an outgrowth of the lateral field in males. Malenchus gilanensis n. sp. resembles members of subgenus Telomalenchus due to the straight amphidial apertures, prophasmid position and large lateral flaps, but it differs by having two lines in the lateral fields. This new species is morphologically similar to five known species of the subgenus Malenchus: M. acarayensis, M. bryanti, M. parvus, M. nanellus and M. truncatus. The new species can be distinguished from them and other species in the subgenus by having straight amphidial apertures, two lines in the lateral fields, position of prophasmids, and having a very small and undeveloped bursa.

Tylencholaimellus persicus sp. n. is described and illustrated based on morphological and molecular characters. The new species is characterized by its 613-885 μm long body, expanded lip region separated from body contour by a sharp constriction, forming a large disk-like structure, odontostyle and odontophore respectively 12-14 and 6.5-8.0 μm long, female genital system mono-opisthodelphic with relatively long anterior uterine sac (AUS; 50-80 μm in length), position of vulva relative to the body length (V = 36.5-41.5), broadly rounded tail, abundant males in population with 22-25 μm long spicules and one ventromedian copulatory supplement. The new species is compared with five known species of the genus that have a perioral disc, rounded tail and AUS: T. coronatus, T. incertus, T. montanus, T. ozarkensis and T. projectus. Compared to these five species, the new species has an expanded lip region separated from body contour by a sharp constriction, but can further be separated by a combination of morphological and morphometric characters such as odontostyle length, tail shape, differences in ratios c´ and V and male characters. Because of having similar general morphology, the new species was also compared with a species of genus Margollus, M. bokanicus, and the differences between the two species are discussed. In addition to morphological and morphometric data, molecular phylogenetic analyses were performed using partial sequences of the 18S SSU and 28S LSU D2/D3 rDNA segments, in which the new species forms a clade with four species/isolates of Tylencholaimellus in the SSU tree and one isolate of Tylencholaimus in the LSU tree using Bayesian inference (BI).

Zootaxa 4066 (5): 600-600