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Hexamermis zirabi sp. n., recovered from a natural habitat of Mazandaran province, north of Iran, is described based on morphological and molecular data. The new species is characterized by its six cephalic papillae; cuticle with distinct cross fibers; conoid or sharply tapered head; mouth terminal; six hypodermal cords; J-shaped vagina oriented to the anterior end of body; uterus with Z-organs or sclerotized bodies; tail similar in both sexes and bluntly rounded; spicules paired, separate, slightly curved, shorter than body width at cloaca, with rounded tip; and male genital papillae arranged in five rows. In addition to the morphological study, molecular phylogenetic analyses using a partial large subunit (28S D2-D3) were also performed, and the new species formed a highly supported (1.00% Bayesian posterior probability (BPP)) clade with Hexamermis popilliae.

A new species belonging to the genus Laimydorus , and a known species of the genus Labronema , collected from the rhizosphere of grassland plants in West Azarbaijan province, Iran, are presented. The new species is characterized by its body length (1.56-1.81 mm in females and 1.39-1.57 mm in males), lip region offset by weak constriction and wider than adjacent body (11-14 μm), odontostyle 17-20 μm long, neck length 312-434 μm, vulva longitudinal (V = 42.2-46.5), uterus well-developed and with Z-differentiations, tail long (219-237 μm, c = 6.9-8.3, c´ = 8.2-10) in females, short and convex-conoid with blunt terminus (19-22 μm, c = 68-72.5, c´ = 0.77-0.84) in males, spicules 40-45 μm long, and 18-20 contiguous ventromedian supplements with hiatus. Molecular analyses, using Bayesian inference based on D2-D3 expansion segments of the 28S rRNA (LSU), placed the new species in a clade comprising representatives of the genera Nevadanema , Dorylaimus , Labronema , Calcaridorylaimus , Mesodorylaimus , and Prodorylaimus , which all belong to Dorylaimidae. In addition, new data (molecular, morphometrics, images, and geographic distribution) are presented for the Iranian population of Labronema vulvapapillatum.

A new species of the genus Talanema , recovered from the northwest of Iran, was described based on morphological, morphometric, and molecular data. Talanema eshtiaghii sp. n. was characterized by its 1.45-1.68 mm long body, lip region offset by constriction and 13-15 μm wide, odontostyle 15-18 μm long, double guiding ring, neck 312-362 μm long, pharyngeal expansion occupying 41-43% of the total neck length, uterus tripartite, and 111-189 μm long or 2.1-3.2 body diameters, vulva transverse (V = 55-58), tail similar in both sexes, conical with a dorsal concavity (30-44 μm, c = 33-56, c' = 1.0-1.6), spicules 49-56 μm long, and 14-18 shortly spaced ventromedian supplements in front of the level of the anterior end of spicules, with distinct hiatus. It was compared to four closely similar species, with emphasis on the most relevant traits to distinguish them. Molecular phylogenetic studies using partial sequence of the 28S rDNA (D2-D3 segment) revealed that the new species forms a clade with other currently sequenced representatives of Talanema , tentatively supporting the monophyly of this genus., (© 2023 Nasir Vazifeh et al., published by Sciendo.)

One new and three known species of the genus Xiphinema from the rhizosphere of fruit trees and rose shrubs in East Azarbaijan province, Iran, are presented based on the morphological, morphometric and molecular characters. The new species is distinguished by its 2.0-2.1 mm long body, relatively flattened lip region with 8.7-10.0 µm width, set off from body contour by a deep constriction, odontostyle 82.5-88.0 µm long, V = 52-54, reproductive system didelphic-amphidelphic with symbiotic bacteria in the reflexed ovaries, tail conoid, dorsally convex with rounded to slightly subdigitate tip (42.0-43.5 µm long, c = 61-65, c' = 1.6-1.8), and males unknown. The new species, X. babaii sp. n., looks very close to X. californicum, and is regarded as its cryptic species, being separated from it using some morphological differences. Their separation was further corroborated using molecular data. Three known species belonging to the Xiphinema americanum group namely X. primum, X. pachtaicum and X. simile were also collected during present study, and new data were provided for them. Xiphinema simile is a new record for the Iran's nematode fauna. Molecular phylogenetic studies using partial sequences of 28S rRNA gene D2-D3 fragments were performed, and the phylogenetic relationships of the new species were discussed., (© 2022. The Author(s), under exclusive licence to Springer Nature B.V.)

Three Iranian populations of Discolaimium dubium are studied, including their morphological and morphometric characterization, molecular analysis (LSU-rDNA) and the description of the male for the first time. For comparative purposes, this species is distinguished by its 1.10 to 1.40 mm long body, lip region offset by constriction and 8 to 10 µm wide, odontostyle 7.5 to 10.5 µm long with aperture occupying 59 to 76% of total length, neck 300 to 362 µm, pharyngeal expansion 127 to 181 µm long or 44 to 46% of the total neck length, uterus simple and 38 to 53 µm or 1.2 to 1.5 times the body diameter long, V  = 52 to 58, tail conical (32-38 µm, c  = 32-43, c'  = 1.6-2.0) with rounded tip and a hyaline portion occupying 14 to 15% of tail length, spicules 30 to 32 µm long, and two or three widely space ventromedian supplements with hiatus. Both morphological and molecular data support its belonging to the genus Aporcella , whose monophyly is confirmed and to which the species is formally transferred as A. dubia (Das et al., 1969) comb. n., (© 2021 Authors.)

Two species of the genus Aporcella, one new and one previously known, collected from cultivated fields in Iran are studied. Description, morphometrics, illustrations (both line and microphotographs) and D2-D3 sequences are provided for Aporcella talebii sp. n., which is characterized by its 1.66-2.02-mm-long body, lip region offset by constriction and 15-17 μm broad, odontostyle 14-17.5 μm long, neck 412-484 μm long, pharyngeal expansion occupying 46-50% of total neck length, uterus simple and 1.6-2.0 times the corresponding body diameter long, V = 52-59, tail conical (40-50 μm, c = 37-47, c' = 1.1-1.4) with a weak but perceptible dorsal concavity at the end and male absent. Morphometrics, microphotographs and D2-D3 sequences of Aporcella simplex are also presented, this being its first Asian record. Molecular analyses confirm the monophyly of the genus, its close relationship with other taxa lacking pars refringens vaginae and the polyphyly of Aporcelaimidae.

Two species of the genus Pungentus , one new and one known, collected in natural vegetation and cultivated soils in northwest of Iran, are studied. Pungentus sufiyanensis n. sp. is characterized by its 1.22 to 1.57 mm long body, offset lip region by a constriction and 7 to 9 μm broad, 18 to 21 μm long odontostyle, 304 to 348 μm long neck, 133 to 161 μm long esophageal expansion, mono - opisthodelphic female genital system without anterior uterine sac, slightly backward directed vagina, absence of pars refringens vaginae , V  = 47 - 54, rounded-conoid caudal region (17.5-23 μm, c  = 65-84, c ´ = 0.7-1) with saccate bodies, and the absence of male. Molecular analysis, based on D2-D3 expansion segments of the 28S rDNA (LSU), confirms the monophyly of the family Nordiidae and suggests the monophyly of the genus Pungentus , with the new species forming a clade with other Iranian species. New data are presented for six Iranian populations of P. engadinensis , and an updated key for the identification of Pungentus species is also provided., Two species of the genus Pungentus , one new and one known, collected in natural vegetation and cultivated soils in northwest of Iran, are studied. Pungentus sufiyanensis n. sp. is characterized by its 1.22 to 1.57 mm long body, offset lip region by a constriction and 7 to 9 μm broad, 18 to 21 μm long odontostyle, 304 to 348 μm long neck, 133 to 161 μm long esophageal expansion, mono - opisthodelphic female genital system without anterior uterine sac, slightly backward directed vagina, absence of pars refringens vaginae , V  = 47 − 54, rounded-conoid caudal region (17.5–23 μm, c  = 65–84, c ´ = 0.7–1) with saccate bodies, and the absence of male. Molecular analysis, based on D2-D3 expansion segments of the 28S rDNA (LSU), confirms the monophyly of the family Nordiidae and suggests the monophyly of the genus Pungentus , with the new species forming a clade with other Iranian species. New data are presented for six Iranian populations of P. engadinensis , and an updated key for the identification of Pungentus species is also provided.

Xiphinema barooghii n. sp. collected from the rhizosphere of common wheat ( Triticum aestivum L.) in Roodghat area, Sufiyan, East-Azarbaijan province, northwest of Iran, is described on the basis of the morphological, morphometric and molecular data. The new species belongs to morphospecies group 6 of the polytomous key prepared by Loof and Luc, 1990. Xiphinema barooghii n. sp. is characterized by having two almost equally developed female reproductive branches with spines in the tubular portion of the uterus, a body length of 3.67-4.25 mm, a flat lip region, rounded cephalic region, separated from body contour by a shallow depression, a spear 215-225 μm long, mid-body diameter of 60-79 μm, vulva (46-48%), a short tail (30-38 µm, c = 103-133, c' = 0.7-0.9), conoid, dorsally convex, ventrally directed with a small terminal peg and a distinct terminal blind canal, the presence of four juvenile stages and the absence of males. The polytomous identification codes of the new species are: A4, B3, C5a, D6, E5, F4, G3, H2, I3, J4, K2, L1. In addition to morphological and morphometric data, molecular analyses of the D2-D3 expansion regions of the 28S rDNA gene placed the new species as a sister species of X. herakliense (Group 5) with 65% Bayesian posterior probability and further separated this species from the other members in group 6. In this study, X. index , X. pachtaicum and X. vuittenezi were also collected and additional data for the species were provided., Xiphinema barooghii n. sp. collected from the rhizosphere of common wheat ( Triticum aestivum L.) in Roodghat area, Sufiyan, East-Azarbaijan province, northwest of Iran, is described on the basis of the morphological, morphometric and molecular data. The new species belongs to morphospecies group 6 of the polytomous key prepared by Loof and Luc, 1990. Xiphinema barooghii n. sp. is characterized by having two almost equally developed female reproductive branches with spines in the tubular portion of the uterus, a body length of 3.67–4.25 mm, a flat lip region, rounded cephalic region, separated from body contour by a shallow depression, a spear 215–225 μm long, mid-body diameter of 60–79 μm, vulva (46–48%), a short tail (30–38 µm, c = 103–133, c′ = 0.7–0.9), conoid, dorsally convex, ventrally directed with a small terminal peg and a distinct terminal blind canal, the presence of four juvenile stages and the absence of males. The polytomous identification codes of the new species are: A4, B3, C5a, D6, E5, F4, G3, H2, I3, J4, K2, L1. In addition to morphological and morphometric data, molecular analyses of the D2–D3 expansion regions of the 28S rDNA gene placed the new species as a sister species of X. herakliense (Group 5) with 65% Bayesian posterior probability and further separated this species from the other members in group 6. In this study, X. index , X. pachtaicum and X. vuittenezi were also collected and additional data for the species were provided.