Post-vulval Uterine Sac Research Articles

Discovery and Characterization of Four Aphelenchid Species from Cultivated Regions of Southern Alberta, Canada.

The nematode family Aphelenchoididiae is considered fungal-feeding, predatory, or root hair feeders. Some members of this family are universally present in agricultural landscapes and are an integral part of soil health and conservation studies. In the present soil nematode biodiversity survey, we detected four species of the genera Aphelenchus, Aphelenchoides, and Robustodorus. Because fungal-feeding nematodes from southern Alberta have not previously been reported, we conducted a detailed morphological and molecular investigation, identifying these species as Aphelenchus avenae, Aphelenchoides limberi, Aphelenchoides prairiensis n. sp. and Robustodorus paramegadorus n. sp. The first two species we document as new records from southern Alberta, whereas A. prairiensis n. sp. and R. paramegadorus n. sp. we describe in detail as new taxa. Briefly, A. prairiensis n. sp. is an amphimictic species having 4 lateral lines; hemispherical anteriorly flattened lip region; delicate stylet and swelling-like stylet knobs; excretory pore at the posterior edge of nerve ring. Female tail conical, gradually tapering towards a truncated end with single mucro. Spicule 23.0 (20.0-25.0) µm long having elongated rounded condylus, small, blunt conical rostrum, and lamina that gradually tapers towards the rounded distal end; three pairs of caudal papillae were present on the male tail. Robustodorus paramegadorus n. sp., is a parthenogenetic species with 3 lines in the lateral fields; lip region rounded, anteriorly flattened; stylet robust, with knobs rounded to bean-shaped; excretory pore located posterior to nerve ring; reproductive components were quite indiscernible with a short 24.0 (18.0-27.0) µm post-vulval uterine sac; tail conical, ending with pointed to wedge-shaped tip. We performed molecular characterizations for each species and constructed phylogenetic trees to study the phylogenetic relationship of these aphelenchid species. The discovery of A. prairiensis n. sp. and R. paramegadorus n. sp. indicates that soil nematode diversity is relatively unexplored in southern Alberta. The findings of this study will significantly enhance the identification processes and may contribute towards future soil health and biodiversity efforts.

Unveiling two novel Ditylenchus (Nematoda: Anguinidae) species inhabiting the growing medium of Rhododendron simsii imported from Japan

Summary The present study describes two new Ditylenchus species, isolated from the growing medium of Rhododendron simsii imported from Japan, at the Ningbo plant quarantine laboratory, Ningbo, P.R. China. Ditylenchus parvicauda n. sp. is an amphimictic species. Females have six incisures in the lateral fields, a medium length slim body, a short delicate stylet with asymmetrical stylet knobs, the secretory-excretory (S-E) pore located posterior to the isthmus and in the anterior region of the basal pharyngeal bulb, a posteriorly located vulva (V = 80.9-83.0), post-uterine sac (PUS) tube-like, and the tail cylindrical, tapering gradually towards finely rounded terminus. Males are similar to females in general morphology and have 10.1-14.9 μm long spicules. The second new species, D. gracicauda n. sp. is characterised by having a long and slender body, the presence of a vulval flap, four lines in the lateral field, a narrow and low lip region not offset, the S-E pore located posterior to the isthmus but not in the anterior region of the basal pharyngeal bulb, a posteriorly located vulva (V = 71.1-76.2), a short post-vulval uterine sac short (4.5-9.2 μm), and the tail slender, tapering gradually towards finely rounded to wedge-shaped terminus. The two new species were also characterised molecularly using 18S, ITS and the D2-D3 expansion segments of 28S rRNA genes. Our phylogenetic analyses showed their independent place among available Ditylenchus species. Several Ditylenchus species are regulated pests, and the introduction of these species into a new environment may result in diseases among native plants or vegetation in the area. Therefore, careful attention must be directed towards newly discovered species, particularly those under quarantine observation.

Cotylenchus cleo gen. n., sp. n., a new plant-parasitic nematode (Tylenchida: Anguinidae) parasitising on leaves of western sword fern plants from rainforests in Washington State, USA

Summary A new genus and species of anguinid nematode, Cotylenchus cleo gen. n., sp. n., was recovered from leaves of the western sword fern, Polystichum munitum, growing in rainforests in several locations of Olympic National Park, Washington State, USA. This new anguinid nematode induced distinct necrotic and chlorotic symptoms on fern leaves characterised by yellowing, light to brown areas between veins. The new species is characterised by a long and slender body, six incisures in the lateral field, robust stylet (12.0-13.5 μm) with large and rounded knobs, pyriform to elongate and abutting basal pharyngeal bulb, and long conical tail with pointed terminus; females having posteriorly located vulva (V = 74-80%) and well-developed post-vulval uterine sac (26-59 μm) and males having spicules 20-23 μm long. Phylogenetic analysis of the partial 18S rRNA and the D2-D3 expansion segments of the 28S rRNA genes showed that this anguinid nematode formed a separate evolutionary lineage different from all other Anguinidae taxa. The new species was also characterised by sequencing the ITS rRNA and COI genes.

Description of Pauronemoides siddiqii n. gen., n. sp. (Tylenchomorpha, Paurodontidae), a morphological and molecular phylogenetic study

Summary Three populations of Pauronemoides siddiqii n. gen., n. sp. were recovered from three different locations in northwestern and northern Iran from bark and soil samples. The new genus was described and illustrated based upon morphological and molecular characteristics. Pauronemoides n. gen. belongs to the family Paurodontidae and is characterised by the medium-sized body, asymmetrical knobs in stylet base, stem-like extension into intestine, post-vulval uterine sac (PUS) absent or rudimentary, different tail tip shape between sexes, and bursa enveloping tail or reaching to the tail end. The type species, Pauronemoides siddiqii n. gen., n. sp., is mainly characterised by 752-1281 μm body length in females and 660-1085 μm in males, six equally-sized lips, stylet 9-11 μm long with asymmetrical knobs, six incisures in lateral fields forming five bands, three of which (two outers and one central) are wider, and variably lengthened stem-like extension projecting into the intestine. Vulva situated posteriorly (V = 87.7-91.7%), PUS absent. Conical tail with widely rounded end, having a small mucron at tip in females, males with conical tail ending to a narrower tip and bursa enveloping tail completely. The type species of the new genus was compared with all known species of the genera Prothallonema, Paurodontus, Paurodontoides and Paurodontella. Pauronemoides siddiqii n. gen., n. sp. resembles Prothallonema macrocellum and P. mucronatum by having the bulb extension penetrating into the intestine, dimorphism in tail shape of both sexes and bursa enveloping tail, and Paurodontella iranica by tail shape dimorphism between sexes and bursa ending near tail tip. Therefore, the above-mentioned species are transferred to the new genus as Pauronemoides macrocellus n. gen., n. comb. (= Prothallonema macrocellum), P. mucronatus n. gen., n. comb. (= Prothallonema mucronatum) and P. iranicus n. gen., n. comb. (= Paurodontella iranica). In addition to morphological comparisons, molecular phylogenetic analyses were performed using two sequences of small subunit (SSU), and three partial sequences of D2-D3 expansion segments of the large subunit (LSU) rDNA, and the resulting topologies were discussed.

A new sympagic nematode species Daptonema gelida sp. n. (Monhysterida, Xyalidae) from the White Sea landfast ice

A new ice-associated species of Xyalidae family, Daptonema gelida sp. n., is described from the first-year fast sea ice of the Ermolinskaya Inlet, White Sea, Russia. The new species of Daptonema is a morphologically distinct species from other species of the genus. Daptonema gelida sp. n. is characterized by (1) elongated, slender body, (2) short, evenly distributed throughout the body somatic setae, (3) circular amphideal fovea, (4) thin and strongly curved, L-shaped spicules with round-shaped manubrium, (5) gubernaculum with short dorsal-caudal apophysis by triangular-shaped outline, (6) post-vulval uterine sac present, and (7) two short terminal setae. We barcoded partial 18S rRNA gene sequences from the new sympagic species. Phylogenetic reconstructions showed that the specimen of Daptonema gelida sp. n. formed a distinct lineage with high support among other Daptonema species and was genetically related to D. carnulentum, D. setosum, D. hirsutum, Metadesmolaimus sp. and Daptonema spp. We provided a list of valid Daptonema species, including key morphological characteristics of males, and additionally reviewed 30 species inquirenda.

Description of Ektaphelenchus phoenicis n. sp. (Rhabditida: Ektaphelenchinae), a morphological and molecular phylogenetic study

Summary A new species of Ektaphelenchinae was recovered from the bark of a dead date palm (Phoenix dactylifera) tree, and from a soil sample collected from the rhizosphere of gramineous grasses in Iraq and Iran, respectively. It was assigned to the genus Ektaphelenchus mainly by the lack of a functional anus and rectum, and having a conical posterior body end (tail) in female, not ending to a filiform tip, and males lacking a bursa. The recovered populations were described based on morphological and molecular data. Ektaphelenchus phoenicis n. sp. is characterised by 346-441 μm long females, having three lines in lateral field, a 12.3-15.8 μm long stylet with wide lumen lacking basal knobs or swellings, high lip region separated from the rest of body by a depression, metacorpus elliptical with refractive valve plates almost in the middle to slightly posterior, excretory pore posterior to metacorpus, postvulval uterine sac (PUS) 9.3-14.8 μm long, usually containing sperm, posterior body end (tail) with ventrally bent distal end, males common in population with seven precloacal + cloacal + caudal papillae and slightly elevated cloacal lips under SEM, appearing as a differentiated flap-like structure under LM. The new species was morphologically compared with typologically similar species of Ektaphelenchus with a similar body size, namely: E. golestanicus, E. oleae and E. taiwanensis; a similar female posterior body end, namely: E. cupressi, E. kanzakii, E. prolobos and E. riograndensis; and E. goffarti having a similar postcloacal structure. The phylogenetic relationships of the new species with other relevant genera and species were reconstructed using near full length sequences of small and D2-D3 expansion segments of large subunit (SSU and LSU D2-D3) rDNA. In both inferred phylogenies, the newly generated sequences of Ektaphelenchus phoenicis n. sp. occupied a placement inside a maximally supported clade including sequences of three genera Ektaphelenchus, Ektaphelenchoides and Devibursaphelenchus.

Morphological and molecular characterisation of two free-living bacterivorous nematodes belonging to Rhabditida from South Africa

AbstractA new population of Pseudacrobeles (Pseudacrobeles) macrocystis and Poikilolaimus oxycercus is described from South Africa. Poikilolaimus oxycercus was collected from soil covered by a natural grass in South Africa, which is morphologically similar to the original description. The South African population of P. oxycercus is characterised by having a small size (807–818 µm in males and 703–779 µm in males), female tail cupola-shaped (24–35 µm), and spicule length (27–35 µm). The South African population of P. (P.) macrocystis, collected from natural grass, is characterised by having a small size (611–786 µm), a lateral field with three incisures, lip region with lips bearing seta-like processes and blunt conoid labial probolae, primary and secondary axils smooth, nerve ring and excretory pore at the posterior part of the pharyngeal corpus, spermatheca well developed, postvulval uterine sac poorly developed, female tail conoid-elongate, male tail conoid with thin acute mucro and spicules small (31–36 µm). Measurements and line illustrations of the species are given. In addition, LM, SEM photographs and the phylogenetic position of P. (P.) macrocyctis are provided. The 18S and 28S rDNA analyses show that P. macrocystis is closely related to other species of the genus Pseudacrobeles having lips with seta-like processes. This is the first report of P. (P.) macrocystis from South Africa.

Description of Laimaphelenchus shanxiensis sp. n. (Rhabditida: Aphelenchoididae) from Shanxi province, P.R. China

Summary Laimaphelenchus shanxiensis sp. n. was recovered from the bark samples of Chinese pine tree (Pinus tabuliformis) in Shanxi province, China. The new species is characterised by having 888-1049 μm long females, the cephalic region with six labial sectors divided by ribs, stylet 11-13 μm long, the excretory pore located at the same level with, or slightly posterior to nerve ring, lateral field with four incisures, post-vulval uterine sac 54-83 μm long, vulva with a well-developed anterior flap, tail having a single stalk at terminus ending to a flat structure with 4-7 finger-like appendages in scanning electron microscopy; male spicules 20-22 μm long and two pairs of caudal papillae present. In addition, molecular phylogenetic trees inferred from the partial small subunit (SSU) and D2-D3 segments of large subunit (LSU) of rRNA genes, revealed that this nematode belongs to the Laimaphelenchus and is different from all currently sequenced species of Laimaphelenchus for their SSU and LSU markers.

Deladenus Bonabensis n. Sp. (Tylenchomorpha: Neotylenchidae) from East Azarbaijan Province, Northwestern Iran: A Morphological and Molecular Phylogenetic Study.

A population of Deladenus, representing a new species, was recovered from Bonab's Ghara-Gheshlagh lagoon. It is mainly characterized by having a long body (1051-1185 μm), long distance of anterior end to pharyngeal glands end (270-312 μm), six lines in lateral fields, and a short mucro-like differentiation on the tail tip. Furthermore, it has a small-sized stylet (8.5-11.0 μm) with three knobs, no postvulval uterine sac, and males with 24- to 28-μm-long tylenchoid spicules and penial tube. With six lateral lines, the new species is comparable with seven species of the genus: D. apopkaetus, D. brevis, D. cocophilus, D. durus, D. obtusicaudatus, D. processus, and D. ulani. It was furthermore compared with D. oryzae with an unknown number of lateral lines and D. aridus, D. obesus, and D. parvus having a different number of lateral lines but similar morphology. In the molecular phylogenic analyses using small and large subunit ribosomal DNA (SSU and LSU D2-D3 rDNA) sequences, the relationships of the new species with other species and genera were not resolved in SSU phylogeny. However, it formed a clade with Deladenus sp. and D. brevis in LSU phylogeny.

Detection and identification of Devibursaphelenchus minor sp. n. isolated in the bark from the USA

Summary Bark in an empty container from the USA was inspected in Ningbo port, China, and a Devibursaphelenchus population was detected. It was processed and identified as Devibursaphelenchus minor sp. n. The new species is characterised by the lateral field with three incisures, female stylet tripartite, 13.9 (12.7-14.6) μm long without basal thickenings, secretory-excretory pore at the same level as nerve ring or slightly posterior, vagina not sclerotised, vulval lips slightly protruding and vulval flap absent. Post-vulval uterine sac (PUS) not well developed, very short and obscure, extending for half vulval body diam. long, anus and rectum indistinct or absent. Posterior body region conical elongated, gradually narrowing, slightly ventrally curved, ending with a bluntly pointed terminus. Male rare, the spicules are arcuate, separate, 8.2 μm along the chord line, with well-developed condylus, triangular rostrum with finely rounded tip, cucullus or apophysis absent. Tail conical, dorsally convex, ventrally slightly concave with bluntly pointed terminus, ventral bursa not confirmed. Two pairs of genital papillae present. It differs from all other species in this genus by extremely short body length of females and males. Molecular phylogenetic analyses based upon rRNA D2-D3 sequences confirmed it as a new species.

Characterisation of Stegelletina salinaria Abolafia & Peña-Santiago, 2003 (Rhabditida, Cephalobidae) from Spain and South Africa including the first molecular study of the species

Summary Stegelletina salinaria is redescribed from Spain and South Africa. Spanish material was collected in sandy soil from the type locality and a nearby area, while one population collected in compost was examined from South Africa. The species is characterised by its small size (0.27-0.41 mm), lateral field with three incisures, lip region with three pairs of dentate lips bearing four tines each, primary axils bearing a large guarding process, secondary axils lacking guarding processes, nerve ring and secretory-excretory pore at isthmus level, spermatheca and post-vulval uterine sac poorly developed, female tail conoid with rounded hyaline terminus and males unknown. The description, light micrographs and scanning electron microscope images, illustrations and molecular analyses are provided. 18S and 28S rDNA sequence analyses show that the isolates of S. salinaria from Spain and South Africa are closely related to each other and to other species of Stegelletina, while also indicating a close relationship with some species of Nothacrobeles, Scottnema and Stegelleta (28S tree) and Zeldia (18S tree).

First Report of Aphelenchoides Bicaudatus (Imamura, 1931) Filipjev and Schuurmans Stekhoven, 1941 Associated with Grass in South Africa.

Aphelenchoides bicaudatus associated with grass in South Africa was identified morphologically and molecularly. This population is characterized by a body length of 409 - 529 μm, a stylet length of 9.5 - 13 μm, a post-vulval uterine sac of 45 - 50 μm, and the characteristic tail bifurcated at the end with one prong longer than the other. Molecular analyses based on the 18S and ITS rDNA data confirmed the primary morphological identification of the A. bicaudatus species. The obtained phylogenetic trees revealed a close positioning of the South African population to other representatives of A. bicaudatus with the maximum (1.00) posterior probability value. Principal component analysis (PCA) also indicated a variation within the populations of A. bicaudatus. This is the first report of A. bicaudatus from South Africa.

Detection and identification of Ektaphelenchoides diversislocis sp. n. isolated from Pinus woodlands of China and Japan

Summary Understanding the occurrence and distribution of parasitic nematodes is crucial – some are economic pests, and some are important predators of their insect associates. In our recent nematode inventory survey, two populations of an ektaphelechid nematode were detected in the branches of Pinus trees; later the same nematode population was detected in plant quarantine examinations of wood packaging material imported from Japan. The species was processed and identified as Ektaphelenchoides diversislocis sp. n. The new species can be characterised by having three lateral lines, stylet long and tripartite, excretory pore at the level of nerve ring, comparatively longer post-vulval uterine sac, indistinct rectum and anus. Female posterior body region conical, gradually narrowing, like a mucron or filiform. Male spicule with well-developed condylus, triangular rostrum, and cucullus absent. The species is morphologically and molecularly close to E. compsi. The new species was characterised with near full-length 18S, 28S D2-D3 regions, and internal transcribed spacer (ITS) rRNA genes and mitochondrial cytochrome oxidase I (COI) gene sequences. The species within the Ektaphelenchoides genus are considered to have predatory roles against insect associates; therefore, the discovery of E. diversislocis sp. n. from local and foreign woodlands warrants increased sampling and research attention.

Characterisation of Ditylenchus paraoncogenus n. sp. (Nematoda: Anguinidae), a new stem nematode parasitising tumble thistle

Summary During a survey, three populations of a new stem nematode were isolated from galls on the shoots of tumble thistle (Gundelia tournefortii) plants in Fars province, Iran, and identified. Ditylenchus paraoncogenus n. sp. is described based on morphometric and morphological characters. It is characterised by having long-sized females, 1252 (943-1628) μm long, narrow lateral fields with six incisures, rather developed stylet 9.9 (9.0-11.3) μm long with round knobs, usually elongate and offset from intestine basal pharyngeal bulb, oocytes in two rows in distal part of ovary, V = 83.3 (80.3-86.2), post-vulval uterine sac 68.1 (46.9-86.1)% of vulva to anus distance long, bursa covering 63.2 (33.3-74.4)% of tail length, spicules 24.7 (21.0-27.9) μm long with minute processes at the base of its manubrium and anteriorly pointed cuticle parts within the lamina, and thick conical tail, usually with a pointed terminus. In addition, the ITS and 18S rDNA sequences of 17 populations of D. destructor, D. dipsaci, D. medicaginis, D. myceliophagus, D. paraoncogenus n. sp., Ditylenchus sp. and Nothotylenchus geraerti plus one population of Anguinidae sp. were analysed. The results showed a close relationship between D. paraoncogenus n. sp. and the stem nematodes D. oncogenus, D. gigas, D. weischeri and D. dipsaci. Ditylenchus species were divided into two clades, one clade comprising stem nematodes and gall-forming nematodes of the family Anguinidae, and the other clade containing fungivorous species. Observations showed that the second-stage juvenile is the dormant stage of D. paraoncogenus n. sp. and can survive in anhydrobiotic condition for at least 4 years.

Characterization of three plant or fungal feeding nematodes (Nematoda, Rhabditida, Tylenchomorpha) from coastal dunes in Spain including the SEM study of these species

Three known species, Aphelenchus avenae, Ditylenchus myceliophagus and Tylenchorhynchus aduncus (Rhabditida, Tylenchomorpha), are described from sand coastal dunes in Spain associated to the rhizosphere of xerophilic plants. A. avenae is characterized by having stylet with 16–22 µm long, pharyngeal dorsal gland overlapping the intestine, postvulval uterine sac about 2.5 times the body diameter, female tail short conoid with rounded tip bearing the phasmid and male bursa well developed. D. myceliophagus is characterized by having lateral field with four incisures, stylet 7–8 µm long, basal bulb irregularly pyriform, tail of both sexes similar with rounded tip and bursa of the male reaching about three-quarters of tail length. T. aduncus is characterized by its lateral field with six incisures, stylet 15–18 μm long, spicules with bifurcate tip and distal ventral crest, and gubernaculum with hook-like manubrium. New morphological, including SEM study, and morphometrical data are included for the three species. Also, phylogenetic analysis based on 18S and 28S rDNA is included for two of the species studied. Additionally, two species belonging to the superfamily Aphelenchoidea are transferred to other genera: Aphelenchus assamensis to the genus Aphelenchoides and Aphelenchoides dhanachandi to the genus Potensaphelenchus.

Description of Laimaphelenchus piceae sp. n., a new evidence of cryptic speciation, and L. sinensis Gu et al., 2020 (Rhabditida: Aphelenchoididae), a record from Shanxi province, north China

Summary This contribution deals with the record and description of one new species and record of one known species of the genus Laimaphelenchus from Shanxi province, north China. The type population of L. piceae sp. n. is characterised by having females 642-807 μm long, the cephalic region with six labial sectors divided by ribs, stylet 12-14 μm long, lateral field with four incisures, postvulval uterine sac (PUS) 114-161 μm long, vulva with a well-developed anterior flap, tail with a single stalk at tip, bearing four pedunculate tubercles, each tubercle including 5-7 finger-like protrusions; males spicules 18-24 μm long and three pairs of caudal papillae present. The new species looks closely similar to L. persicus, representing its cryptic species, being separated by differences in some morphological indices and partial large subunit (LSU) rDNA sequences. Its morphological differences from other relevant species were discussed. L. sinensis was also recorded from Shanxi province for the first time. The phylogenetic relationships of the recovered populations were reconstructed using sequences of the near full length small subunit (SSU) and D2-D3 segments of LSU rDNA, and the relationships of both species were discussed.

Description of Cryptaphelenchus recticaudatus n. sp. (Aphelenchoidea: Ektaphelenchinae) in Pinus elliottii from the USA

Summary Cryptaphelenchus recticaudatus n. sp. is described and illustrated in Pinus elliottii from the USA. The new species is characterised by the female body 310-431 μm long with distinctly annulated cuticle, lateral fields with four lines, lip region separated from the body by a shallow depression, delicate stylet with small knobs, post-vulval uterine sac short, and rectum and anus invisible. Males are 228-314 μm long, spicules 9.8-12.4 μm long with a well-developed and broad condylus, and seven caudal papillae arranged as a single (P1) and pair (P2) of precloacal papillae plus two pairs of postcloacal papillae. Based upon the general female morphology, the new species most closely resembles C. baujardi and C. iranicus. The morphological differences with the aforementioned species and other species of the genus are discussed. The phylogenetic analyses based on small (SSU) and large subunit (LSU) D2-D3 expansion segments of ribosomal DNA of different individuals of the new species revealed that the new species fell into the Cryptaphelenchus clade in both SSU and LSU trees. The monophyly of the genus was retained after adding newly generated sequences of the new species.

Redescription of Ektaphelenchoides compsi Baujard, 1984 (Tylenchina: Aphelenchoididae) isolated from Pinus massoniana in Fujian Province, China

Summary Ektaphelenchoides compsi is redescribed morphologically with new molecular characterisation. It was isolated from a dead Pinus massoniana tree in Ningde City, Fujian Province, China. Detailed morphology of the spicule, female gonad, hemizonid position, arrangement of male caudal papillae and female tail terminus shape are documented. It is characterised by a lateral field with three lines (forming two bands), tripartite stylet 17.8 (17.0-19.4) μm long without basal thickenings, metacorpus rectangular with anterior 40% granular and posterior part weakly muscular, metacorpal valve slightly posterior to middle of metacorpus, excretory pore at level of nerve ring, vagina with thickened walls and strongly developed muscular bundles, vulval lips slightly protuberant, vulval flap absent, distal region of post-vulval uterine sac appearing as a weakly developed oogonia, anus and rectum indistinct, female posterior part (‘tail’) dorsally convex, conical, terminal region contracted into a bluntly pointed tip. The spicules are arcuate, 15.6 (14.3-16.3) μm along the chord, lamina smoothly curved to distal end, capitulum slightly concave, condylus well-developed with broadly rounded tip and slightly depressed at dorsal end, rostrum triangular with finely rounded tip, cucullus absent, and with seven caudal papillae present. The near full length 18S and 28S D2-D3 regions of rRNA genes sequences were characterised. The phylogenetic analyses revealed that the Fujian population of E. compsi grouped with the Zhejiang population of E. compsi, both being morphologically identical.

Devibursaphelenchus alienae n. sp. isolated from the bark of dead Quercus aliena in Japan

Summary A new Devibursaphelenchus species isolated from the bark of a dead Quercus aliena, which had been infected and killed by Japanese oak wilt, was collected in Shiga, Japan. The new species is characterised by the relatively large body in males (661-768 μm) and females (893-1071 μm), conspicuous male bursal flap, male spicule with long condylus and wide blade, female post-vulval uterine sac (PUS) 39-54 μm or 1.6-2.3 times the vulval body diam. long, vestigial female anus, and female tail forming a strongly ventrally recurved elongate conoid with bluntly pointed or narrowly rounded terminus. The new species is typologically similar to D. lini, sharing a large body, conspicuous bursal flap, long PUS, and spicule shape, but can be distinguished from it by the absence of variation in the female tail shape, i.e., the tail of the new species is always long and strongly ventrally curved, while the tail shape varies more in D. lini. A previous molecular phylogenetic analysis suggested that the new species is fairly close to D. lini, but can be distinguished from it by the 1.0% (16 bp) difference within 1.6 kb of the 18S and 3.7% (26 bps) difference within 0.7 kb of the D2-D3 LSU ribosomal RNA genes. The newly found nematode is described and illustrated herein as D. alienae n. sp.

Two new insect-associated tylenchids, Sychnotylenchus hibisci n. sp. and Neoditylenchus xiphydriae n. sp. (Tylenchomorpha: Anguinidae), from Japan

Summary We isolated two tylenchid species belonging to the Sychnotylenchinae, Sychnotylenchus hibisci n. sp. and Neoditylenchus xiphydriae n. sp., from the bark beetle Ernoporus corpulentus and wood wasp Xiphydria ogasawarai, respectively. Sychnotylenchus hibisci n. sp. is characterised by its moderately stout body in both male and female, gubernaculum to spicule length ratio of one-third or less, crustaformeria structure composed of four columns with six large, rounded cells, and a broad female tail with a rounded terminus. The new species is closely related to S. ulmi, with which it shares body shape and gubernaculum to spicule length ratio, but is distinguished by the female tail shape and several morphometric values. Neoditylenchus xiphydriae n. sp. is characterised by its oval to leaf-shaped male bursa, male tail tip reaching the distal end of, and protruding beyond the bursa, a long post-vulval uterine sac (PUS), and a conical female tail with a narrowly rounded terminus. The species is typologically similar to N. pinophilus but is distinguished by its male spicule shape, gubernaculum to spicule length ratio, and longer PUS. Phylogenetically, the Sychnotylenchinae belongs under the Anguinidae (superfamily Sphaerularioidea) and is closely related to several Ditylenchus, Neotylenchus, Neomisticius, and Ficotylus species.