Explore the vast range of titles available.

Two populations of a new species of stubby root nematode, Trichodorus cadusiensis n. sp., were recovered from the rhizosphere of oak and plane trees in undisturbed natural forests of Gilan province, north Iran. The new species was illustrated and described based upon morphological and molecular characters. It is mainly characterized by having 592–949 μm long males having a 48–57 μm long onchiostyle, three ventromedian cervical papillae (CP) anterior to secretory-excretory pore (S-E pore), spicules ventrally curved, 34–48 μm long with a widened manubrium, an indented portion anterior to middle of spicules, with or without bristles, and widened blade. The females have a 715–887 μm long body, 49–57 μm long onchiostyle, S-E pore at about middle of narrow part of pharynx and triangular closely adjoining pars refringens vaginae pieces 3–4 μm wide with blunt tips. The new species was morphologically compared to those species of the genus having similarities in males in spicules shape/ornamentation and number of ventromedian cervical papillae, and in females in the shape of pars refringens vaginae pieces, or close phylogenetic relationships viz., T. andalusicus, T. asturanus, T. azorensis , T. beirensis, T. gilanensis, T. iranicus, T. lusitanicus , T. similis, T. velatus and T. viruliferus. In molecular phylogenetic analyses using maximal number of partial large subunit ribosomal DNA (LSU D2-D3) sequences of Trichodoridae, the included sequences of Trichodorus occupied three different placements. The new species formed a clade with T. similis and T. gilanensis in LSU tree with 0.85 Bayesian posterior probability (BPP).

A new species of the dagger nematode genus Xiphinema was recovered from three different points in West Azarbaijan province, northwestern Iran, from the rhizosphere of grasses and described based on both morphological and molecular data. Xiphinema azarbaijanense n. sp. belongs to the Xiphinema non-americanum group and is characterized by having 3.8-5.3 mm long females with long odontostyle (129-151 μm), two equally developed genital tracts with crystalloid bodies in the tubular part of uterus, short tail, four juvenile developmental stages and males absent. It is similar to 14 known species belonging to morphospecies group 6, and is almost indistinguishable from most of them using traditional taxonomy; thus, is part of a complex of cryptic species. Molecular phylogenetic data using two genomic structural (18S, 28S D2-D3) and one ITS1 ribosomal DNA (rDNA) loci were used to separate the new species from close taxa. The new species formed an independent lineage in three reconstructed trees based upon the resolved topologies, and was also morphologically compared with phylogenetically related species.

A population of Xiphinema americanum-group was recovered in association with stone fruit trees in Isfahan province, center of Iran. A reverse taxonomic approach based upon the large subunit ribosomal DNA (LSU rDNA D2-D3) and the mitochondrial cytochrome c oxidase subunit I (COI mtDNA) gene sequences in integration with morphological studies, revealed that the recovered population belongs to Xiphinema santos. The Iranian population was mainly characterized by 1240–1868 μm long females with 60–84 μm long odontostyle, a = 37.2–51.9 and c = 42.8–54.6. It is further characterized by a lip region having a depression in junction with the body, presence of visible endosymbiont bacteria in ovaries under light microscope, dorsally convex and ventrally slightly concave conical tail with a blunt tip and three juvenile developmental stages. This population was similar to the type population in its morphology; however overlapped and extended morphometric data ranges, as well as differences in some indexes were observed. Compared to a Spanish population of this species, the Iranian population had a close morphology, similar morphometric data ranges and identical LSU and COI sequences. In LSU phylogeny, the relationship between the present and some previously sequenced isolates of the species and some isolates of three species X. georgianum, X. laevistriatum and X. citricolum was not resolved. In COI phylogeny, the clade of the Iranian and Spanish populations appeared as an independent lineage inside an unsupported clade including several species. The comparison with other populations of the species was reported and discussed. A second species, X. primum, that is native to Iran, was recovered from a new locality and characterized molecularly.

Longidorus soosanae n. sp. is described and depicted based on morphological and molecular criteria. It was recovered from the rhizosphere of Fagus sp. in Golestan province, northern Iran. The new species is primarily characterized by its anterior region of the body distinctly tapered from the guiding ring towards the anterior end, forming a bottle-shaped appearance. Further, it is characterized by medium-sized females ranging 5.2–7.5 mm long, the lip region not set-off from the rest of the body, flat at the apex and 15–17 μm wide, pocket-shaped amphidal fovea lacking distinct basal lobes, guiding ring at 31–39 μm distance from the anterior end, and an odontostyle and odontophore ranging 92–103 and 59–72 μm long, respectively. The pharyngeal bulb is 92–130 μm long, vulva at 45.8–52.6% of body length and tail short, dorsally more convex-rounded. Males make up to 44% of the adults and are functional, having 50–64 μm long spicules and 9–13 ventromedian supplements. Only the fourth juvenile developmental stage (J4) was recovered. In reliance on morphological perspectives (odontostyle length, lip region shape, body length, guiding ring distance from anterior end, shape of amphidial fovea, shape of tail, index a and male presence/absence), the new species was compared with seven species of the genus including: L. alaskaensis, L. elongatus, L. goodeyi, L. iuglandis, L. juglandicola, L. panderaltum and L. proximus. From molecular perspectives, it is closely related to L. elongatus. Phylogenetic relationships of the new species with other selected relevant genera and species were reconstructed based on small and large subunits (SSU and LSU) and internal transcribed spacer (ITS) sequences and the obtained topologies were discussed.

Two populations of Xiphinema persicum n. sp. belonging to the X. americanum-group, were recovered from Semnan province, and described and illustrated based upon morphological, morphometric and molecular data. The type population of the new species is characterized by 2233–2736 μm long females, offset lip region, anteriorly flat to slightly rounded and separated from the rest body by constriction, 82–87 μm long odontostyle, two equally developed genital branches with visible endosymbiont bacteria in ovaries under light microscope, vulva at 52.8–55.5%, 27–32 μm long dorsally convex and ventrally straight to slightly convex tail with a rounded tip, or having a wide mucro-like differentiation, rare male with six ventromedian supplements and four juvenile developmental stages. The new species was morphologically compared with six similar species, X. bricolense, X. californicum, X. incertum, X. pachtaicum, X. santos and X. simile. The latter species has closest morphology and phylogenetic affinities to the new species in both large subunit and internal transcribed spacer 1 (LSU and ITS1 rDNA) trees; but X. persicum n. sp. has four juvenile developmental stages (vs. three), longer odontostyle, and posteriorly located guiding ring compared to it. The phylogenetic relationships of the endosymbiont bacterium of the new species with other isolates was reconstructed using the partial sequences of 16S rDNA.

Three populations of Xiphinema primum n. sp. and two populations of X. pachtaicum were recovered from natural forests and cultural regions of northern Iran. Both species belong to the X. americanum-group and were characterized by their morphological, morphometric and molecular data. The new species, which was recovered in three locations, belongs to the X. brevicolle-complex and is characterized by 2124-2981 μm long females with a widely rounded lip region separated from the rest of the body by a depression, 103-125 μm long odontostyle, two equally developed genital branches with endosymbiont bacteria inside the ovary, which are visible under light microscope (LM), vulva located at 51.8-58.0%, the tail is 26-37 μm long with a bluntly rounded end and four juvenile developmental stages. It was morphologically compared with nine similar species viz. X. brevicolle, X. diffusum, X. incognitum, X. himalayense, X. luci, X. parabrevicolle, X. paramonovi, X. parataylori and X. taylori. The second species, X. pachtaicum, was recovered in two geographically distant points close to city of Amol. Molecular phylogenetic studies of the new species were performed using partial sequences of the D2-D3 expansion segments of the large subunit ribosomal RNA gene (LSU rDNA D2-D3), the internal-transcribed spacer rDNA (ITS = ITS1+5.8S+ITS2), and the mitochondrial cytochrome c oxidase I gene (COI mtDNA) regions. The Iranian population of X. pachtaicum was also phylogenetically studied based upon its LSU rDNA D2-D3 sequences. Both species were also inspected for their putative endosymbiont bacteria. Candidatus Xiphinematobacter sp. was detected from two examined populations of the new species, whereas the second endosymbiont bacterium, detected from three examined isolates of X. pachtaicum, was related to the plant and fungal endosymbionts of the family Burkholderiaceae. The phylogenetic analyses of the two endosymbiont bacteria were performed using partial sequences of 16S rDNA. In cophylogenetic analyses, significant levels of cophylogenetic signal were observed using both LSU rDNA D2-D3 and COI mtDNA markers of the host nematodes and 16S rDNA marker of the endosymbiont bacteria.

The genus Dolichodorus was discovered from a natural forest in Gilan province, north Iran, in association with an oak tree. The recovered population represents a new species, and was described and illustrated based upon morphological and molecular data, as D. rex n. sp. It is characterized by 2171–3275 μm long females having offset crown-like cephalic region with well sclerotized cephalic framework, raised perioral disc apparently with a small raised oral plate, 118.5, 130.0 μm long stylet, its conus ca. 55% of the total length and three posteriorly sloping knobs, 291–316 μm long pharynx with a short overlap, secretory-excretory pore at slightly variable position (one-two annuli posterior, or four annuli anterior to metacorpus base), vulva sunken in body, at %50 of the body length, vagina heavily sclerotized with two drop-like refractive pieces close to the vulval opening, 78–104 μm long tail with proximal convex conoid, and conical distal part with pointed to blunt tip; and a 2634 μm long male with 108.5 μm long stylet, 291 μm long pharynx, 20 μm long tail and 53 μm long spicules. In molecular phylogenetic analyses using partial sequences of the small, and D2-D3 expansion segments of the large subunit ribosomal DNA, the new species formed a clade with two other currently sequenced species of the genus in both phylogenies.