Photorhabdus africana sp. nov. isolated from Heterorhabditis entomopathogenic nematodes.

One Gram-negative, rod-shaped bacterial strain, isolated from an undescribed Heterorhabditis entomopathogenic nematode species was characterized to determine its taxonomic position. The 16S rRNA gene sequences indicate that it belongs to the class Gammaproteobacteria, to the family Morganellaceae, to the genus Photorhabdus, and likely represents a novel bacterial species. This strain, designated here as CRI-LCT, was therefore molecularly, biochemically, and morphologically characterized to describe the novel bacterial species. Phylogenetic reconstructions using 16S rRNA gene sequences show that CRI-LCT is closely related to P. laumondii subsp. laumondii TT01T and to P. laumondii subsp. clarkei BOJ-47T. The 16rRNA gene sequences between CRI-LCT and P. laumondii subsp. laumondii TT01T are 99.1% identical, and between CRI-LCT and P. laumondii subsp. clarkei BOJ-47T are 99.2% identical. Phylogenetic reconstructions using whole genome sequences show that CRI-LCT is closely related to P. laumondii subsp. laumondii TT01T and to P. laumondii subsp. clarkei BOJ-47T. Moreover, digital DNA-DNA hybridization (dDDH) values between CRI-LCT and its two relative species P. laumondii subsp. laumondii TT01T and P. laumondii subsp. clarkei BOJ-47T are 65% and 63%, respectively. In addition, we observed that average nucleotide identity (ANI) values between CRI-LCT and its two relative species P. laumondii subsp. laumondii TT01T and P. laumondii subsp. clarkei BOJ-47T are 95.8% and 95.5%, respectively. These values are below the 70% dDDH and the 95-96% ANI divergence thresholds that delimits prokaryotic species. Based on these genomic divergence values, and the phylogenomic separation, we conclude that CRI-LCT represents a novel bacterial species, for which we propose the name Photorhabdus africana sp. nov. with CRI-LCT (= CCM 9390T = CCOS 2112T) as the type strain. The following biochemical tests allow to differentiate P. africana sp. nov. CRI-LCT from other species of the genus, including its more closely related taxa: ß-Galactosidase, citrate utilization, urease and tryptophan deaminase activities, indole and acetoin production, and glucose and inositol oxidation. Our study contributes to a better understanding of the taxonomy and biodiversity of this important bacterial group with great biotechnological and agricultural potential.

Xenorhabdus aichiensis sp. nov., Xenorhabdus anantnagensis sp. nov., and Xenorhabdus yunnanensis sp. nov., Isolated from Steinernema Entomopathogenic Nematodes.

Three bacterial strains, XENO-2T, XENO-7T, and XENO-10T, isolated from Steinernema entomopathogenic nematodes, were found to represent novel Xenorhabdus species. In this study, we describe these new species by whole-genome and whole-proteome phylogenomic reconstructions, by calculating sequence identity scores using core genome sequences, and by phenotypic characterization. Phylogenomic reconstructions using ribosomal and house-keeping genes, and whole-genome and whole-proteome sequences show that XENO-2T and XENO-10T are closely related to Xenorhabdus japonica DSM 16522T and that XENO-7T is closely related to Xenorhabdus bovienii subsp. africana XENO-1T and to X. bovienii subsp. bovienii T228T. The dDDH values between XENO-2T and XENO-10T and between XENO-2T and X. japonica DSM 16522T are 56.4 and 51.8%, respectively. The dDDH value between XENO-10T and X. japonica DSM 16522T is 53.4%. The dDDH values between XENO-7T and X. bovienii subsp. africana XENO-1T and between XENO-7T and X. bovienii subsp. bovienii T228T are 63.6 and 69.4%, respectively. These dDDH values are below the 70% divergence threshold for prokaryotic species delineation. The newly described species are highly pathogenic to G. mellonella larvae, grow at pH between 5 and 9 (optimum 5-7), at salt concentrations of 1-3% (optimum 1-2%), and temperatures between 20 and 37 °C (optimum 28-30 °C). Biochemical tests such as lysine decarboxylase, ornithine decarboxylase, urease, gelatinase, citrate utilization, indole and acetoin production, and cytochrome oxidase tests allow to differentiate the novel species from their more closely related species. Considering these genetic and phenotypic divergencies, we propose the following new species: Xenorhabdus aichiensis sp. nov. with XENO-7T (= CCM 9233T = CCOS 2024T) as the type strain, Xenorhabdus anantnagensis sp. nov., with XENO-2T (= CCM 9237T = CCOS 2023T) as the type strain, and Xenorhabdus yunnanensis sp. nov., with XENO-10T (= CCM 9322T = CCOS 2071T) as the type strain. Our study contributes to a better understanding of the biodiversity and phylogenetic relationships of entomopathogenic bacteria associated with insect parasitic nematodes.

Morphological and Molecular Characterization of Filenchus multistriatus n. sp. (Tylenchomorpha: Tylenchidae) and Data on a Known Species of the Genus from Bushehr Province, Southern Iran.

During a nematological survey in southern Iran, a population belonging to the family Tylenchidae was recovered from a tomato field in Bushehr province. The recovered population belongs to the genus Filenchus, was described and illustrated herein as F. multistriatus n. sp. It is mainly characterized by having a wide and low annulated lip region continuous with adjacent body; amphidial openings confined to the labial plate; four lines in lateral fields forming three bands, with the two outer bands broken by transverse, and the inner one broken by both transverse and longitudinal lines; and median bulb oval with visible valve and elongate-conoid tail uniformly and gradually narrowing toward the distal region, ending in a widely rounded tip. Its morphological and morphometric differences with three closely similar species were discussed. The phylogenetic relationships of the new species with other relevant genera and species were reconstructed using partial sequences of small, and large subunit ribosomal DNA (SSU and LSU rDNA) sequences. Morphometric and morphological data were also provided for an Iranian population of F. sandneri recovered from Bushehr province. Both populations were characterised using SEM data.

Erratum to: Morphological and Molecular Characterization of Filenchus multistriatus n. sp. (Tylenchomorpha: Tylenchidae) and Data on a Known Species of the Genus from Bushehr Province, Southern Iran.

[This corrects the article DOI: 10.2478/jofnem-2023-0008.].

Morphological and Molecular Characterization of Ottolenchus isfahanicus n. sp. (Tylenchomorpha: Tylenchoidea) from Rhizosphere of Gramineous Plants in Isfahan Province, Iran.

A new species from the family Tylenchidae was recovered in the grasslands of Isfahan province, Iran, and is herein described based on morphological and molecular data. Ottolenchus isfahanicus n. sp. is mainly characterized by having a faintly annulated cuticle; elongated, slightly sigmoid amphidial apertures developed metacorpus with distinct valve under LM; vulva located at 69.472.3% of body length; large spermatheca about 2.75 times of corresponding body width; and elongated conoid tail with broadly rounded tip. SEM observations showed that the lip region is smooth; the amphidial apertures are elongated, slightly sigmoid slits; and the lateral field is a simple band. It is further characterized by 477-to-515-µm-long females with delicate 5.7-to-6.9-µm-long stylets with small, slightly posteriorly sloping knobs, as well as functional males, in the population. The new species closely resembles O. facultativus, but is separated from it based on morphological and molecular data. It was further morphologically compared with O. discrepans, O. fungivorus, and O. sinipersici. The phylogenetic relationships of the new species with other relevant genera and species were reconstructed using near-full-length sequences of small subunit and D2-D3 expansion segments of large subunit (SSU and LSU D2-D3). In the inferred SSU phylogeny, the newly generated sequence of Ottolenchus isfahanicus n. sp. formed a clade with two sequences of O. sinipersici and sequences assigned to O. facultativus and O. fungivorus. In the inferred LSU phylogeny, the three newly generated sequences of the new species and LSU sequences of O. sinipersici and O. discrepans formed a clade.

Multigene Sequence-Based and Phenotypic Characterization Reveals the Occurrence of a Novel Entomopathogenic Nematode Species, Steinernema anantnagense n. sp.

Three entomopathogenic nematode populations were isolated from agricultural fields in the Anantnag district of Jammu and Kashmir (India). Sequences of multiple gene regions and phenotypic features show that they are conspecific and represent a novel species. Molecular and morphological features provided evidence for placing the new species into the "Kushidai" clade. Within this clade, analysis of sequence data of the internal transcribed spacer (ITS) gene, the D2D3 region of the 28S rRNA gene, the mitochondrial cytochrome oxidase I (mtCOI) gene, and the mitochondrial 12S (mt12S) gene depicted the novel species as a distinctive entity closely related to Steinernema akhursti, S. kushidai, and S. populi. Phylogenetic analyses also show that the new species is a sister species to S. akhursti, and these two species are closely related to S. kushidai and S. populi. Additionally, the new species does not mate or produce fertile progeny with any of the closely related species, reinforcing its uniqueness from a biological species concept standpoint. The new species is further characterized by the third-stage infective juveniles with almost straight bodies (0.7-0.8 mm length), poorly developed stoma and pharynx, and conoid-elongate tail (49-66 µm) with hyaline posterior part. Adult females are characterized by short and conoid tails bearing a short mucron in the first generation and long conoid tails with thin mucron in the second generation. Adult males have ventrally curved spicules in both generations. Moreover, the first-generation male has rounded manubrium, fusiform gubernaculum, conoid and slightly ventrally curved tails with minute mucron, and the second generation has rhomboid manubrium anteriorly ventrad bent, and tails with long and robust mucron. The morphological, morphometrical, molecular, and phylogenetic analyses support the new species status of this nematode, which is hereby described as Steinernema anantnagense n. sp. The bacterial symbiont associated with S. anantnagense n. sp. represents a novel species, closely related to Xenorhabdus japonica. These findings shed light on the diversity of entomopathogenic nematodes and their symbiotic bacteria, providing valuable information for future studies in this field.

Description of Boleodorus Bushehrensis n. Sp. (Rhabditida: Tylenchidae) from Southern Iran, and Observations on a Commonly Known Species.

A new species of the genus Boleodorus, recovered from southern Iran, is described and illustrated based upon morphological and molecular data. B. bushehrensis n. sp. is mainly characterized by having a wide and low cephalic region (which is continuous with the adjacent body), the oral aperture in a depression in side view under a light microscope, four lines in the lateral field, weak metacorpus with a vestigial-to-invisible valve, and short (26-38 mm long) hooked tail with rounded tip. The females are 334-464 mm long and have a spherical spermatheca filled with spheroid sperm; males have 11.5- to 12.0-mm-long spicules and weakly developed bursa. The new species has an annulated low cephalic region, four large cephalic papillae, and small crescent-shaped amphidial openings when observed by scanning electron microscopy (SEM). Its morphological and morphometric differences with seven known species are discussed. The phylogenetic relationships of the new species with other relevant genera and species have been studied using partial sequences of small and large subunit ribosomal DNA (SSU and LSU rDNA). In both the SSU and LSU phylogenies, the sequences of B. bushehrensis n. sp. and other Boleodorus spp. formed a clade. A second species, B. thylactus, when studied under SEM, has a raised, smooth cephalic region, four large cephalic papillae, and oblique amphidial slits, with the oral opening in a depression.

Steinernema Africanum n. Sp. (Rhabditida, Steinernematidae), a New Entomopathogenic Nematode Species Isolated in the Republic of Rwanda.

Alternatives to hazardous insecticides are urgently needed for an environmentally friendly and effective management of insect pests. One such option is the use of entomopathogenic nematodes (EPN). To increase the availability of EPN with potential for biocontrol, we surveyed agricultural soils in the Republic of Rwanda and collected two Steinernema isolates. Initial molecular characterization showed that they represent a new species, for which we propose the name S. africanum n. sp. To describe this new species, we reconstructed phylogenetic relationships, calculated sequence similarity scores, characterized the nematodes at the morphological level, conducted crossing experiments, and isolated and characterized their symbiotic bacteria. At the molecular level, S. africanum n. sp. is closely related to S. litorale and S. weiseri. At the morphological level, S. africanum n. sp. differs from closely related species by the position of the nerve ring and also because the stoma and pharynx region is longer. The first-generation males have ventrally curved spicules with lanceolate manubrium and fusiform gubernaculum and the second-generation males have rounded manubrium and anteriorly hook-like gubernaculum. Steinernema africanum n. sp. does not mate or produce fertile progeny with any of the closely related species.

Redescription and phylogenetic analysis of the type species of the genus Panagrellus Thorne, 1938 (Rhabditida, Panagrolaimidae), P. pycnus Thorne, 1938, including the first SEM study.

The identity of Panagrellus pycnus, the type species of the genus Panagrellus, is discussed after studying specimens from a cultured population collected in Italy that fits the original material of the species. A new characterization is consequently provided as follows: body 0.93-1.32 mm long, lip region continuous with the adjoining body, stoma with gymnostom very reduced, pharynx with not swollen metacorpus, neck 161-203 µm long, excretory pore at level of the metacorpus, post-vulval uterine sac 99-162 µm long or 2.6-3.8 times as long as the body diameter divided in a short tubular proximal part and a long swollen distal part, vulva post-equatorial (V = 63-69), female tail conical elongate with acute terminus (133-170 µm, c = 6.8-8.1, c' = 4.9-7.0), male tail conical elongate with acute terminus (104-137 µm, c = 7.8-10.9, c' = 3.6-5.1), and spicules 70-81 µm long having angular hook-like and very curved ventrad lamina ending in a spatulate tip with a refringent forked axis. The evolutionary relationships of this species and the genus Panagrellus, as derived from the analyses of 18S and 28S rDNA fragments, are discussed. Additionally, the phylogenetic relationships among the members of the infraorder Panagrolaimomorpha is studied, being the genus Tarantobelus transferred to the family Panagrolaimidae and the new subfamily Tarantobelinae n. subfam. is proposed to accommodate it.

Description of Spinocephalus tessellatus n. gen., n. sp. (Rhabditida, Cephalobidae) from Iran, a nematode with a new morphological pattern at lip region.

A new genus and new species of the family Cephalobidae, subfamily Cephalobinae, named Spinocephalus tessellatus n. gen., n. sp. is described from Iran. Body 0.55-0.67 mm long, cuticle with tessellations, lateral field with two tessellated longitudinal wings, lip region with six triangular lips, primary axils deep and V-shaped with two conoid-elongate guard processes that originate from each lip, secondary axils deep and U-shaped with one thorn-like process (labial probolae?) in lateral view with a small rounded protuberance fused to the oral plate having triradiate symmetry more developed at the acute margin toward each primary axil, oral opening hexagonal, amphids large and clearly rounded to slightly oval, stoma cephaloboid with cheilostom with minute and rounded rhabdia, pharynx cephaloboid with corpus subcylindrical and isthmus very long being 1.4-1.7 times corpus length, nerve ring surrounds the isthmus, excretory pore at the level of the isthmus. Female monodelphic-prodelphic, spermatheca as long as the body diam., post-vulval uterine sac 0.8-1.0 times body diameter, tail conoid with small rounded terminus. Male monorchic, spicules 24-26 µm long, gubernaculum 11-14 µm long, tail conical and ventrally curved with small rounded terminus. Morphological, including SEM observations, and molecular (based on 18S and 28S rDNA) analyses revealed its relationship with the genera Acromoldavicus and Nothacrobeles.

Discopersicus hexagrammatus n. sp. (Rhabditida: Tylenchidae), the second species of the genus.

Discopersicus hexagrammatus n. sp., is described and illustrated from a population associated with the rhizosphere of carrot (Daucus carota L.) in Dezful, Khuzestan province, south-western Iran. Based on morphological and morphometric data, the new species is characterized by a 601-734 µm long body, a prominent perioral labial disc and oblique amphidial slits, 10-11 µm long stylet, vulva at 65-67% of body length, 15.5-17 µm long spicules, and an elongate conoid tail with a pointed terminus. It is the second species of the genus Discopersicus and differs from its counterpart D. iranicus, by its anterior position of vulva, shorter stylet, lower M.B. ratio, different shape of tail tip, and shorter spicules in male specimens. A molecular phylogenetic analysis using the D2-D3 expansion segments of 28S rDNA sequences, placed the new species in close relationship with five sequences of the genus Boleodorus.

Morphological and molecular characterization of Filenchus pseudodiscus n. sp. from east Golestan province, north Iran; with an updated phylogeny of Malenchus Andrássy, 1968 (Tylenchomorpha: Tylenchidae).

During a survey in Golestan province, north Iran, two populations belonging to the family Tylenchidae were recovered in association with Quercus sp., and a rotten wood sample of an unidentified forest tree. The first recovered species was mainly characterized by having a disc-like differentiation in the frontal end under the light microscope (LM), proposing it as a tentative member of the genus Discotylenchus. Detailed morphological studies using scanning electron microscope (SEM), however, did not reveal a true disc, but showing the smooth cephalic region, and a narrow annulus behind the cephalic plate. Based upon the cephalic region structure, and by lacking a true disc, the species was identified as a member of the genus Filenchus. This population was further characterized by 555 to 618 µm long females, lateral fields with four incisures, 9 to 10 µm long stylet, spermatheca large, including spheroid sperm, post-vulval uterine sac (PUS) 8 to 12 µm long and gradually tapering to an elongate conoid tail with pointed tip. It was compared with relevant species of Filenchus having four incisures in the lateral fields and similar general morphology. By having a disc-like differentiation in the frontal end under the LM, it was further compared with three similar known species of Discotylenchus. The morphological comparisons with species under two aforementioned genera showed the recovered population belongs to an unknown species, described herein as Filenchus pseudodiscus n. sp. The molecular phylogenetic relationships of the new species using partial small and large subunit ribosomal RNA gene (SSU and LSU D2-D3 rDNA) sequences were reconstructed and discussed. Malenchus gilanensis, the second recovered and studied species was originally established based upon traditional criteria. An updated LSU phylogeny of the genus Malenchus by including M. gilanensis was also presented and its results were discussed.

Laimaphelenchus africanus n. sp. (Tylenchomorpha: Aphelenchoididae) from South Africa, a morphological and molecular phylogenetic study, with an update to the diagnostics of the genus.

A newly recovered population of the genus Laimaphelenchus from a dead maritime pine wood sample in Potchefstroom, South Africa, representing a new species, named L. africanus n. sp., is herein described and illustrated based on morphological and molecular data. The new species is mainly characterized by the following: 750-987 µm long females; a cephalic region with no disc and six cephalic lobs not divided by ribs; a 10.0-12.5 µm long stylet; four incisures in the lateral field; secretory-excretory pore (SE-pore) at slightly posterior to the nerve ring; vulva with a well-developed anterior flap, vagina with two well-developed sclerotized pieces; post-vulval uterine sac (PUS) 63-125 µm long; tail conical, 30-44 µm long, ventrally curved with a subventral stalk in terminus, lacking tubercles, with six to nine small projections at the tip in scanning electron microscopy (SEM); and rare males with 17 µm long spicules. The new species was morphologically compared to those species of the genus with a stalk in tail terminus, lacking tubercles, a vulval flap and four incisures in the lateral field viz., L. liaoningensis, L. preissii, L. simlaensis, L. sinensis, L. spiflatus, and L. unituberculus. Phylogenetically, the new species was placed into the major Laimaphelenchus clade using partial large subunit ribosomal DNA (LSU rDNA D2-D3) sequences. An overall literature review corroborated the presence of the stalk (currently with two main groups) at the tail end is the main characteristic trait delimiting the genus. A compendium based on the characters of the stalk, presence/absence of a vulval flap in females and number of the lateral lines was also established.

Multi-locus phylogenetic analyses uncover species boundaries and reveal the occurrence of two new entomopathogenic nematode species, Heterorhabditis ruandica n. sp. and Heterorhabditis zacatecana n. sp.

Species of the nematode genus Heterorhabditis are important biological control agents against agricultural pests. The taxonomy of this group is still unclear as it currently relies on phylogenetic reconstructions based on a few genetic markers with little resolutive power, specially of closely related species. To fill this knowledge gap, we sequenced several phylogenetically relevant genetic loci and used them to reconstruct phylogenetic trees, to calculate sequence similarity scores, and to determine signatures of species- and population-specific genetic polymorphism. In addition, we revisited the current literature related to the description, synonymisation, and declaration as species inquirendae of Heterorhabditis species to compile taxonomically relevant morphological and morphometric characters, characterized new nematode isolates at the morphological and morphometrical level, and conducted self-crossing and cross-hybridization experiments. The results of this study show that the sequences of the mitochondrial cytochrome C oxidase subunit I (COI) gene provide better phylogenetic resolutive power than the sequences of nuclear rRNA genes and that this gene marker can phylogenetically resolve closely related species and even populations of the same species with high precision. Using this gene marker, we found two new species, Heterorhabditis ruandica n. sp. and Heterorhabditis zacatecana n. sp. A detailed characterization of these species at the morphological and morphometric levels and nematode reproduction assays revealed that the threshold for species delimitation in this genus, using COI sequences, is 97% to 98%. Our study illustrates the importance of rigorous morphological and morphometric characterization and multi-locus sequencing for the description of new species within the genus Heterorhabditis, serves to clarify the phylogenetic relationships of this important group of biological control agents, and can inform future species descriptions to advance our efforts towards developing more tools for sustainable and environmentally friendly agriculture.

On the identity of Eucephalobus oxyuroides (de Man, 1876) Steiner, 1936 (Rhabditida, Cephalobidae), with an updated taxonomy of the genus and notes about its phylogeny.

The identity of Eucephalobus oxyuroides is discussed after studying two Iberian populations that fit the original description of the species. A new characterization is consequently provided as follows: 0.49 to 0.70 mm long body, lip region continuous with the adjoining body and bearing short probolae prongs, neck 132 to 158 µm long, spermatheca 23 to 47 µm long or 1.0 to 1.8 times the corresponding body diameter, post-vulval uterine sac 40 to 54 µm long or 2.0 to 2.5 times as long as the body diameter, V = 58 to 64, female tail conical elongate with very acute terminus (60-79 µm, c = 7.1-10.0, c' = 4.9-5.8), male tail conical (36-49 µm, c =10.9-14.3, c' = 2.4-3.4) with an elongate acute mucro, and spicules 21 to 22 µm long. Previous records of the species are revised. An emended diagnosis of the genus is proposed, and its taxonomy is updated with a list of species, key to their identification and illustrations. The evolutionary relationships of Eucephalobus, as derived from the analyses of 18S and 28S rDNA fragments, reveals that it occupies a basal position within the subfamily Cephalobidae.The identity of Eucephalobus oxyuroides is discussed after studying two Iberian populations that fit the original description of the species. A new characterization is consequently provided as follows: 0.49 to 0.70 mm long body, lip region continuous with the adjoining body and bearing short probolae prongs, neck 132 to 158 µm long, spermatheca 23 to 47 µm long or 1.0 to 1.8 times the corresponding body diameter, post-vulval uterine sac 40 to 54 µm long or 2.0 to 2.5 times as long as the body diameter, V = 58 to 64, female tail conical elongate with very acute terminus (60-79 µm, c = 7.1-10.0, c' = 4.9-5.8), male tail conical (36-49 µm, c =10.9-14.3, c' = 2.4-3.4) with an elongate acute mucro, and spicules 21 to 22 µm long. Previous records of the species are revised. An emended diagnosis of the genus is proposed, and its taxonomy is updated with a list of species, key to their identification and illustrations. The evolutionary relationships of Eucephalobus, as derived from the analyses of 18S and 28S rDNA fragments, reveals that it occupies a basal position within the subfamily Cephalobidae.

Description of Deladenus brevis n. sp. (Sphaerularioidea: Neotylenchidae) from Iran: a morphological and molecular phylogenetic study.

Deladenus brevis n. sp. is described and illustrated based upon its morphological, morphometric, and molecular characters. The new species is mainly characterized by its small body size (367-454 µm long females and 350, 391 µm long males) and has small lateral vulval flaps. It is further characterized by having six lines in the lateral fields, cephalic region slightly expanded, narrower adjacent to the body, short 6 to 7 µm long stylet with three posteriorly sloped knobs, no post-vulval uterine sac (PUS), conical tail, narrowing to a rounded tip, and rare males with slender tylenchoid spicules and bursa reaching the tail tip. By having six lines in the lateral fields, the new species was compared with five known species of the genus, namely D. apopkaetus, D. cocophilus, D. durus, D. obtusicaudatus, and D. persicus, having comparable number (six or seven) of lines in the lateral fields. It was further compared with D. pakistanensis having lateral vulval flaps. The differences with above-mentioned species are discussed. In molecular phylogenetic analyses using nearly full length small and large subunit ribosomal DNA (SSU and LSU D2-D3 rDNA) and cytochrome c oxidase subunit I (COI mtDNA) gene sequences, D. brevis n. sp. formed clade with species of the genus with different clade support values in Bayesian inference.Deladenus brevis n. sp. is described and illustrated based upon its morphological, morphometric, and molecular characters. The new species is mainly characterized by its small body size (367-454 µm long females and 350, 391 µm long males) and has small lateral vulval flaps. It is further characterized by having six lines in the lateral fields, cephalic region slightly expanded, narrower adjacent to the body, short 6 to 7 µm long stylet with three posteriorly sloped knobs, no post-vulval uterine sac (PUS), conical tail, narrowing to a rounded tip, and rare males with slender tylenchoid spicules and bursa reaching the tail tip. By having six lines in the lateral fields, the new species was compared with five known species of the genus, namely D. apopkaetus, D. cocophilus, D. durus, D. obtusicaudatus, and D. persicus, having comparable number (six or seven) of lines in the lateral fields. It was further compared with D. pakistanensis having lateral vulval flaps. The differences with above-mentioned species are discussed. In molecular phylogenetic analyses using nearly full length small and large subunit ribosomal DNA (SSU and LSU D2-D3 rDNA) and cytochrome c oxidase subunit I (COI mtDNA) gene sequences, D. brevis n. sp. formed clade with species of the genus with different clade support values in Bayesian inference.

Hemicycliophora ahvasiensis n. sp. (Nematoda: Hemicycliophoridae), and data on a known species, from Iran.

Hemicycliophora ahvasiensis n. sp., recovered from the rhizospheric soil of date palm in Khuzestan province, southwest Iran, is described and illustrated based upon morphological, morphometric and molecular data. The new species is characterized by its sheath, closely fitting most of the body, cuticle with or without numerous irregular lines, sometimes appearing as blocks in distal body region. Lateral field without discrete longitudinal lines, but often with continuous broken striae or anastomoses. Continuous lip region with single annulus, slightly elevated labial disc, stylet with posteriorly sloping knobs. Vulva with or without slightly modified lips, spermatheca with sperm and tail conoid, symmetrically narrowing at distal region to form a narrow conical region. Morphologically, the new species looks similar to H. indica, H. labiata, H. siddiqii, H. tenuistriata and H. typica. The latter species appears more similar to the new species under light microscopy, but could be separated using the scanning electron microscopy and molecular data. The new species was also compared with H. epicharoides and H. dulli, two species with close phylogenetic affinities to it. The phylogenetic relationships of the new species were reconstructed and discussed using partial sequences of the D2-D3 expansion segments of large subunit, and internal transcribed spacer regions (LSU D2-D3 and ITS rDNA). Hemicycliophora conida, the second studied species, was recovered from north Iran and characterized by morphological and molecular data.

Cephalenchus driekieae n. sp. (Nematoda: Tylenchidae) from South Africa, a new member of the genus with a long pharyngeal overlap.

Cephalenchus driekieae n. sp. is described and illustrated based on its morphological, morphometric, and molecular characteristics. This new species is mainly characterized by its short stylet 11.5 to 13.0 µm, and 13.5 to 17.5 µm long pharyngeal overlap extending over the intestine. It could further be delimited by 451 to 526 µm long females with a prominently annulated cuticle, dorso-ventral amphidial openings as shown using scanning electron microscopy (SEM), four lines in the lateral field, anchor-shaped stylet knobs, empty spermatheca, elongate conoid tail with finely rounded tip and males absent. The shortest stylet and long pharyngeal overlap, distinguish this new species from previously described members and update the characteristics of the genus. With four lines in the lateral field, this new species was morphologically compared with four previously described species with this feature and another species with a short stylet. Molecular phylogenetic analyses using the partial small and large subunit ribosomal DNA gene (SSU and LSU rDNA D2-D3) sequences showed that it was clustered with other Cephalenchus spp. in both SSU and LSU trees, retaining the monophyly of the genus. This new species from South Africa updates the biogeography of the genus.Cephalenchus driekieae n. sp. is described and illustrated based on its morphological, morphometric, and molecular characteristics. This new species is mainly characterized by its short stylet 11.5 to 13.0 µm, and 13.5 to 17.5 µm long pharyngeal overlap extending over the intestine. It could further be delimited by 451 to 526 µm long females with a prominently annulated cuticle, dorso-ventral amphidial openings as shown using scanning electron microscopy (SEM), four lines in the lateral field, anchor-shaped stylet knobs, empty spermatheca, elongate conoid tail with finely rounded tip and males absent. The shortest stylet and long pharyngeal overlap, distinguish this new species from previously described members and update the characteristics of the genus. With four lines in the lateral field, this new species was morphologically compared with four previously described species with this feature and another species with a short stylet. Molecular phylogenetic analyses using the partial small and large subunit ribosomal DNA gene (SSU and LSU rDNA D2-D3) sequences showed that it was clustered with other Cephalenchus spp. in both SSU and LSU trees, retaining the monophyly of the genus. This new species from South Africa updates the biogeography of the genus.

Morphological and molecular characterization of Acrobeloides saeedi Siddiqi, De Ley and Khan, 1992 (Rhabditida, Cephalobidae) from India and comments on its status.

Two cultured populations of Acrobeloides saeedi are described from India. Morphologically and morphometrically this material agrees with other species of the Maximus-group (A. bodenheimeri, A. longiuterus, and A. maximus), especially with A. longiuterus. However, molecular studies based on 18 S, 28 S and ITS rDNA confirmed the Indian material is well differentiated from all of these species. According to this, A. saeedi is considered a valid taxon distinguished mainly from A. bodenheimeri by having dextral female reproductive system (vs sinistral), from A. longiuterus by having larger females (1.03-1.57 vs 0.57-0.88 mm) and from A. maximus by having seta-like labial processes (vs absent) and males as frequent as females (vs males very infrequent). Molecular and phylogenetic studies revealed the present specimens to be conspecific to undescribed Acrobeloides sp. population from Iran, and hence, both regarded to be conspecific to each other. In addition, other similar species are revised: Acrobeloides ishraqi is considered new junior synonym of A. saeedi, Acrobeloides mushtaqi is considered new junior synonym of A. bodenheimeri, while Acrobeloides gossypia is also considered junior synonym of A. saeedi.Two cultured populations of Acrobeloides saeedi are described from India. Morphologically and morphometrically this material agrees with other species of the Maximus-group (A. bodenheimeri, A. longiuterus, and A. maximus), especially with A. longiuterus. However, molecular studies based on 18 S, 28 S and ITS rDNA confirmed the Indian material is well differentiated from all of these species. According to this, A. saeedi is considered a valid taxon distinguished mainly from A. bodenheimeri by having dextral female reproductive system (vs sinistral), from A. longiuterus by having larger females (1.03-1.57 vs 0.57-0.88 mm) and from A. maximus by having seta-like labial processes (vs absent) and males as frequent as females (vs males very infrequent). Molecular and phylogenetic studies revealed the present specimens to be conspecific to undescribed Acrobeloides sp. population from Iran, and hence, both regarded to be conspecific to each other. In addition, other similar species are revised: Acrobeloides ishraqi is considered new junior synonym of A. saeedi, Acrobeloides mushtaqi is considered new junior synonym of A. bodenheimeri, while Acrobeloides gossypia is also considered junior synonym of A. saeedi.

Morphological, morphometrical, and molecular characterization of Metarhabditis amsactae (Ali, Pervez, Andrabi, Sharma and Verma, 2011) Sudhaus, 2011 (Rhabditida, Rhabditidae) from India and proposal of Metarhabditis longicaudata as a junior synonym of M. amsactae.

A new population of Metarhabditis amsactae from India is morphologically, morphometrically, and molecularly characterized. This material is characterized by having 0.65 to 1.14 mm length, lips rounded, and grouped in pairs, stoma with metastegostoma bearing setose denticles, pharynx with metacorpus slightly swollen and fusiform, nerve ring, and excretory pore located at isthmus level, female reproductive system didelphic-amphidelphic with vulva equatorial, female tail conical-elongate with acute tip, male tail conical with large and robust posterior filiform part, spicules free with hooked manubrium slightly bent ventrad, gubernaculum with narrow corpus, bursa open leptoderan with eight genital papillae and phasmids posterior to the GP8. Molecular studies based on 18S and 28S rDNA genes are provided for the first time for the species. In addition, integrated morphological, morphometrical, and molecular characters are compared with other previous records of the species. According to our analysis, Metarhabditis longicaudata and other material described as different species are proposed as new junior synonyms of M. amsactae.