Level Of Nerve Ring Research Articles

Description of Aphelenchoides yixingensis n. sp. (Tylenchina: Aphelenchoididae) found in Pinus massoniana from China, and proposal for genus Ptychaphelenchus as a synonym of Aphelenchoides

Summary Aphelenchoides yixingensis n. sp. found in Chinese red pine (Pinus massoniana) in Yixing city, Jiangsu Province, P.R. China, is described. It is characterised by a very slim body (a = 50.8 (41.3-63.8) and 49.3 (42.3-55.1) for males and females, respectively), three (occasionally five) lateral lines in the lateral field, a short stylet (9-12 μm), the excretory pore located at the level of nerve ring, the vagina is not sclerotised and the vulva has slightly protruding lips and lacks a flap, the post-uterine sac is well developed and forms ca 29.0% (24.1-34.1%) of the vulva to anus distance. The spicules are smoothly arcuate, the apex and rostrum rounded and short, and the dorsal limb is 20.5 (16.9-22.2) μm long, the distal end bluntly rounded. Spicule sheath-like structure is present, triangular and outstretched when heat-killed in some individuals. The male tail bears three pairs (2 + 2 + 2) of caudal papillae. The tail of both sexes is sub-cylindrical, the terminus bearing a bluntly pointed mucron with tiny nodular protuberances, mainly at the distal part. The new species belongs to the Group 2 category of Aphelenchoides species sensu Shahina and is defined as A2-B1-C1-D1-E2-F2 according to the categorisation codes of OEPP/EPPO. Phylogenetic analysis based on 18S and 28S D2-D3 of rDNA, along with ITS and mtCOI, confirmed its status as a new species. A proposal for genus Ptychaphelenchus as a synonym of Aphelenchoides is also discussed.

Aphelenchoides tenuis n. sp. (Tylenchina: Aphelenchoididae) found in loblolly pine logs imported from the USA

Summary Aphelenchoides tenuis n. sp. found in loblolly pine (Pinus taeda L.) logs imported from the USA, is described. It is characterised by a very slim body (a = 56.8 (45.8-67.2) and 49.1 (42.2-54.2) in males and females, respectively), three incisures in the lateral field, short stylet (9-12 μm), the excretory pore located at the level of nerve ring, the vagina is not sclerotised, the vulva has slightly protruding lips and lacks a flap and the post-uterine sac is well developed, forming ca 36.2 (28.4-48.2)% of the vulva to anus distance. The spicules are smoothly arcuate, the apex and rostrum are rounded and well developed, and the dorsal limb is 23.3 (21.1-25.5) μm long, without a hook-like structure at the distal tip. The male tail bears three pairs (2 + 2 + 2) of caudal papillae. The tail of both sexes is sub-cylindrical, the terminus bearing a bluntly pointed mucron with tiny nodular protuberances. The new species belongs to the Group 2 category of Aphelenchoides species sensu Shahina and is defined as A2-B1/2-C1-D1/2-E2-F2/3 according to the categorisation codes of OEPP/EPPO. Phylogenetic analysis based on 18S and 28S D2-D3 of rDNA, along with ITS and mtCOI, confirmed its status as a new species.

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.

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.

Martininema semicordatae n. sp. (Nematoda: Aphelenchoididae) associated with Ficus semicordata in China

Summary A new nematode species was recovered from the syconia of Ficus semicordata from Xishuangbanna Tropical Botanical Garden, Yunnan Province, China. It is described herein as Martininema semicordatae n. sp. and is characterised by having the combined characters of a long post-vulval uterine sac, excretory pore located at nerve ring level, amoeboid sperm, three pairs of subventral papillae on the male tail, rounded male tail tip with mucron, absence of gubernaculum (= apophysis), and a recurved, rose-thorn-shaped spicule lacking a terminal cucullus. Martininema semicordatae n. sp. differs from other sequenced species by differences in the partial small subunit (SSU) rRNA gene and D2-D3 expansion segments of the large subunit (LSU) rRNA gene. Phylogenetic analysis with LSU D2-D3 expansion segment sequences suggested that M. semicordatae n. sp. is clustered in a highly supported monophyletic clade with M. guangzhouense, M. fistulosus and M. baculum, and shares a common ancestor with these three species.

A new pin nematode, Paratylenchus sinensis n. sp. (Nematoda: Paratylenchinae) in the rhizosphere of white mulberry from Zhejiang Province, China

Pin nematode species are widely distributed and known to be associated with damage to a variety of shrubs, grasses, fruit and flowering trees. So far, no pin nematode species has been reported from Mulberry in China. During this study, a new Paratylenchus species recovered from the rhizosphere of mulberry tree, in Zhejiang Province is described and molecularly characterized. The species can be characterized by having swollen and slender females, four incisures in the lateral field, lip region conoid with anterior end flattened and without submedian lobes. The slender females have stylet 56.2 (50–62) μm long, excretory pore located at the level of nerve ring; vulval region with small advulval flap; tail conoid gradually tapers to form a finely pointed terminus. The swollen females comparatively larger than slender females, vulval lips enlarged, protruding and bulges out from the body contour, the tail is shorter than the slender female ending in a finely pointed terminus. The male is devoid of stylet, spicule 17.5 (16.8–18.2) μm long. Phylogenetic analysis based on partial 18S, ITS and D2-D3 expansion segments of the 28S rRNA gene sequences revealed that this new species grouped within paratylenchid species clade. Morphologically, this new species belongs to the Group 10 of Paratylenchus sensu lato (stylet >40 μm, 4 lateral lines and advulval flaps present).

REDESCRIPTION AND SYSTEMATIC STUDIES ON PROCAMALLANUS (PROCAMALLANUS) ELATENSIS FUSCO & OVERSTREET, 1979 FROM THREE RED SEA SIGANUS SP. FISHES

As part of an on-going study of the helminthes parasitizing fish from the Red Sea; Hurghada, Egypt, Procamallanus (Procamallanus) elatensis Fusco & Overstreet, 1979 was collected from three different Siganus fish species (S. rivulatus, S. luridus & S. sutor). It was morphologically elucidated and examined by light and scanning electron microscopy which indicated evident previous erroneous descriptions of both the anterior position of the excretory pore at nerve ring level and absence of deirids, to be excretory pore somewhat posterior to junction of the oesophageal parts and presence of a posterior pair of deirids, located posterior to mid-body level by small distance.Furthermore, the present detailedcomparisons against the most similar Procamallanus species, casted doubt about the validity of P. sigani Yamaguti, 1935 and P. lonis Yamaguti, 1941 which could be considered as two different biological variations of Procamallanus (P.) elatensis.

Description of Aphelenchoides tabarestanensis n. sp. (Nematoda: Aphelenchoididae) isolated from Pinus brutia in Northern Iran

Summary Aphelenchoides tabarestanensis n. sp. was isolated during a survey of nematodes associated with bark samples of pine trees (Pinus brutia) in Mazandaran province, northern Iran. The new species is characterised by body length of 656 (580-786) μm (females) and 490 (480-500) μm (males), weakly annulated cuticle, four lines in the lateral field, and an offset lip region. The stylet is 10.5 (10-11) μm long and has small basal swellings. The excretory pore is located at nerve ring level and the hemizonid was not seen. The post-vulval uterine sac is 40.8 (38-43) μm long, the spicules are relatively short (18-19 μm in dorsal limb), and the male tail has the usual three pairs of caudal papillae (2 + 2 + 2). The female tail is subcylindrical with two or three minute processes at the tip. The new species belongs to the Group 3 category of Aphelenchoides species and is close to seven known species of the genus, namely: A. asteromucronatus, A. besseyi, A. fujianensis, A. goodeyi, A. ritzemabosi, A. siddiqii, and A. stellatus, but differs by body size, shape of tail mucron, stylet length, size of spicules, and length of post-vulval uterine sac. Phylogenetic analysis based on small subunit (SSU) and partial large subunit (LSU) sequences of rRNA supported the morphological results.

Swedish Plectida (Nematoda). Part 10. The genus Deontolaimus de Man, 1880.

The genus Deontolaimus de Man, 1880 is revised and the genus Camacolaimus de Man, 1889 is considered a junior synonym of Deontolaimus based on re-examination of type material of Camacolaimus tardus de Man, 1889 and C. barbatus Warwick, 1970. Two known and three new species of Deontolaimus are described from bottom sediments collected in marine habitats of Sweden: Deontolaimus uniformis (Cobb, 1920) comb. n., D. longicauda (de Man, 1922) comb. n., Deontolaimus catalinae sp. n., D. paraguillei sp. n. and Deontolaimus timmi sp. n. Deontolaimus catalinae sp. n. is characterized by body length of 1.3-1.7 mm; anterior-most somatic sensilla located short distance posterior to amphid; cephalic sensilla equal to 0.2 labial region diameter in length; amphidial fovea ventrally-unispiral with one turn, located in front of cephalic sensilla bases; excretory pore located short distance posterior to onchiostyle base; onchiostyle with bluntly rounded tip and subcylindrical body; male with alveolar supplements extending from anterior end to middle of body, tubular supplements absent; spicules 36-40 µm long; and didelphic female reproductive system. Deontolaimus paraguillei sp. n. is characterized by body length of 1.4-1.8 mm; anterior-most somatic sensilla located at level with onchiostyle; cephalic sensilla equal to 0.2-0.3 labial region diameter in length; amphidial fovea ventrally-unispiral with one turn, located at level with cephalic sensilla bases; excretory pore located just posterior to nerve ring level; onchiostyle with bluntly rounded tip and subcylindrical body; male with alveolar supplements extending from anterior end to about three body diameters in front of cloaca, tubular supplements absent; spicules 42-46 µm long; and didelphic female reproductive system. Deontolaimus timmi sp. n. is characterized by body length of 0.7-0.9 mm; anterior-most somatic sensilla located at level with onchiostyle; cephalic sensilla equal to 0.2-0.3 labial region diameter in length; amphidial fovea ventrally-unispiral with one turn, located just in front of cephalic sensilla bases; excretory pore located just posterior to nerve ring level; onchiostyle with triangular tip with bluntly rounded apex and strongly sclerotized dorsal edge, and subcylindrical body; male with alveolar supplements extending from anterior end to anterior part of intestine, tubular supplements absent; spicules 28 µm long; and didelphic female reproductive system. The following nomenclatorial changes are proposed: genera Acontiolaimus Filipjev, 1918, Camacolaimoides De Coninck & Schuurmans Stekhoven, 1933, Camacolaimus de Man, 1889, Digitonchus Cobb, 1920 and Ypsilon Cobb, 1920 are synonimized with the genus Deontolaimus de Man, 1880; Camacolaimus reykjanesi De Coninck, 1943 and Camacolaimus glauxicola Allgén, 1951a are considered junior synonyms of Deontolaimus papillatus de Man, 1880; Camacolaimus barbatus apud Pastor de Ward, 1984 is described as the separate species Deontolaimus catalinae sp. n.; Camacolaimus tardus apud Lorenzen, 1969 is considered to be the separate species Deontolaimus lorenzeni nom. n.; Camacolaimus tardus apud Timm, 1963 is described as the separate species Deontolaimus timmi sp. n.; Camacolaimus barbatus Warwick, 1970 is considered a junior synonym of Deontolaimus tardus (de Man, 1889) comb. n.; Camacolaimus parvus Timm, 1961 is transferred to the genus Deontolaimus as D. parvus (Timm, 1961) comb. n.; Digitonchus cylindricaudatus Chitwood, 1951 is transferred to the genus Deontolaimus as D. cylindricaudatus (Chitwood, 1951) comb. n.; Ypsilon exile Cobb, 1920 is transferred to the genus Deontolaimus as D. exilis (Cobb, 1920) comb. n.; Camacolaimus guillei de Bovee, 1977 is transferred to the genus Deontolaimus as D. guillei (de Bovee, 1977) comb. n.; Camacolaimus longicauda de Man, 1922 is transferred to the genus Deontolaimus as D. longicauda (de Man, 1922) comb. n.; Camacolaimus monhystera Gerlach, 1967 is transferred to the genus Deontolaimus as D. monhystera (Gerlach, 1967) comb. n.; Camacolaimus pontollittoralis Uzunov, 1977 is transferred to the genus Deontolaimus as D. pontollittoralis (Uzunov, 1977) comb. n.; Camacolaimus praedator de Man, 1922 is transferred to the genus Deontolaimus as D. praedator (de Man, 1922) comb. n.; Camacolaimus prytherchi Chitwood, 1935 is transferred to the genus Deontolaimus as D. prytherchi (Chitwood, 1935) comb. n.; Camacolaimus tardus de Man, 1889 is transferred to the genus Deontolaimus as D. tardus (de Man, 1889) comb. n.; Camacolaimus trituberculatus Blome, 1982 is transferred to the genus Deontolaimus as D. trituberculatus (Blome, 1982) comb. n.; and Digitonchus uniformis Cobb, 1920 is transferred to the genus Deontolaimus as D. uniformis (Cobb, 1920) comb. n. A taxonomic review and identification key for species of the genus Deontolaimus are also given.

Description of Aegialoalaimus bratteni sp. n. from Skagerrak and a review of the genus (Aegialoalaimidae, Nematoda incertae sedis).

BackgroundThe genus Aegialoalaimus de Man, 1907 includes 12 nominal species, of which three species are considered valid, two species were transferred to other genera and seven species have uncertain taxonomic status.New informationNew species, Aegialoalaimus bratteni sp. n. was found in Skagerrak off the west coast of Sweden. It is particularly characterized by the 1.5-1.8 mm long body, short papilliform cephalic sensilla, excretory pore opening just posterior to nerve ring level, spicules that are straight in shape, supplements and gubernaculum absent, separating it from other valid species of the genus. It can be further differentiated from Aegialoalaimus elegans in having longer body (1.5-1.8 mm in A. bratteni sp. n. vs 0.8-1.3 mm in A. elegans), shape and size of spicules (straight and 22-29 µm long in A. bratteni sp. n. vs arcuate and 34 µm long in A. elegans), absence of precloacal supplements (vs seven-eight in A. elegans), absence of gubernaculum (vs present in A. elegans); from A. setosa in having shorter tail (c´=2.6-3.1 in A. bratteni sp. n. vs c´=4.2 in A. setosa), shorter cephalic sensilla (0.5-1.0 µm in A. bratteni sp. n. vs 9 µm in A. setosa), shape and size of spicules (straight and 22-29 µm long in A. bratteni sp. n. vs arcuate and 40-45 µm long in A. setosa), absence of precloacal supplements (vs eight in A. setosa), absence of gubernaculum (vs present in A. setosa); from A. leptosoma in having longer body (1.5-1.8 mm in A. bratteni sp. n. vs 0.5-0.7 mm in A. leptosoma) and other measurements, shape of spicules (straight in A. bratteni sp. n. vs arcuate in A. leptosoma), absence of precloacal supplements (vs three-five in A. leptosoma), absence of gubernaculum (vs present in A. leptosoma). Type specimens of Aegialoalaimus cylindricauda Allgén, 1933 and A. paratenuicaudatus Allgén, 1959 are redescribed and taxonomic status of these two species is re-evaluated. A taxonomic review, tabular compendium and identification key for species of the genus Aegialoalaimus are also given.

Genetic and morphological characterisation of a new species of the genus Hysterothylacium (Nematoda) from Paralichthys isosceles Jordan, 1890 (Pisces: Teleostei) of the Neotropical Region, state of Rio de Janeiro, Brazil

Taking into account the difficulties of taxonomic identification of larval anisakid nematodes based on morphological characters, genetic analyses were performed, together with those usually applied, in order to identify anisakid larvae found in the flounder Paralichthys isosceles from the littoral of the state of Rio de Janeiro, Brazil. The analysis of 1,820 larvae revealed a new species, similar to Hysterothylacium MD, Hysterothylacium 2, Hysterothylacium KB and Hysterothylacium sp regarding the absence of the larval tooth, an excretory pore situated below the nerve ring level, and slender lateral alae. Moreover, the new species differs from Hysterothylacium fortalezae and Hysterothylacium reliquens with regard to the number and size of spines present on the tail end and from Hysterothylacium patagonicus by the absence of interlabia. The maximum parsimony and neighbour joining tree topologies based on the 18S ribosomal DNA gene, complete internal transcribed spacer region and cytochrome oxidase 2 (COII) gene demonstrated that the Brazilian larvae belong to Raphidascarididae and represent a unique genetic entity, confirmed as a new Hysterothylacium species. Furthermore, the new species presents COII genetic signatures and shares polymorphisms with Raphidascarididae members. This is the first description of a new anisakid species from Brazil through the integration of morphological and molecular taxonomy data.

Philometyoides cyprini(ISHII, 1931)n. comb. (Nematoda)Parasitic on the Carp.

This species was first reported by ISHII (1916) under the name of Filaria cyprini. Molphological studies were made on 16 mature female nematodes gathered form the subcutaneous tissue of two year old carp, Cyprinus carpio, in Shimane prefecture in April and May, 1970, and led to the following conclusion.This species should be combined with Philometroides based on the RASHEED opinion (1963) in respect of its cuticular condition and should be, morphologically and ecologically, separated from the other species of the genus Philometroides: P. anguillae (ISHII, 1916), P. maplestonei (TRAVASSOS, ARTIGAS and PEREIRA, 1929), P. masu (FUJITA, 1940), P. plectroplites (JOHNSTON and MAWSON, 1940), P. sanguinea (Run., 1819) and P. seriolae (ISHII, 1931), and some closly related species bearing cuticular bosses on the surface of body; that is Philometra carassii (ISHII, 1931) and P. nodulosa THOMAS, 1929.Description: Body slender and almost uniformly broad except at extremities, 9.012.2 cm long, 0.62.0.90 mm broad; cuticle with numerous minute, irregularly distributed lobelike structures. Head bluntly rounded with four cuticular thicknings, but without any cephalic papillae. Mouth triangular formed with three anterior swellings of esophagus (0.0760.082 mm broad); esophagus, 2.89 3.32 mm long, 0.026 0.039 mm broad, with greatly developed esophageal gland, 0.16 0.21 mm maximum broad, which beginning at about level of nerve ring, 0.210.26 mm from head end. Intestine, about 0.29mm broad, gradually tapered and finally become a solid cord attached to body wall at tail and. Uterus voluminous, occupding most of body cavity; a pair of ovary short and uncoiled, 0.3960 mm Iong, 0.100.18 mm broad. Vulva and anus atrophied. Tail bluntly pointed with two or three cuticular thicknings, or without any shield.