Anal Body Diameter Research Articles

Taxonomic and molecular characterization of a new entomopathogenic nematode species, Heterorhabditis casmirica n. sp., and whole genome sequencing of its associated bacterial symbiont

BackgroundNematodes of the genus Heterorhabditis are important biocontrol agents as they form a lethal combination with their symbiotic Photorhabdus bacteria against agricultural insect pests. This study describes a new species of Heterorhabditis.MethodsSix Heterorhabditis nematode populations were recovered from agricultural soils in Jammu and Kashmir, India. An initial examination using mitochondrial and nuclear genes showed that they belong to a new species. To describe this new species, a variety of analyses were conducted, including reconstructing phylogenetic relationships based on multiple genes, characterizing the nematodes at the morphological and morphometric levels, performing self-crossing and cross-hybridization experiments, and isolating and characterizing their symbiotic bacteria.ResultsThe newly discovered species, Heterorhabditis casmirica n. sp., shares 94% mitochondrial cytochrome C oxidase subunit I gene (COI) sequence identity with Heterorhabditis bacteriophora and Heterorhabditis ruandica, and 93% with Heterorhabditis zacatecana. Morphologically, it differs from H. bacteriophora in its infective juvenile phasmids (present vs. inconspicuous) and bacterial pouch visibility in the ventricular portion of the intestine (invisible vs. visible); genital papilla 1 (GP1) position (at manubrium level vs. more anterior), and in its b ratio (body length/neck length), c ratio (tail length/bulb width), and D% [(excretory pore/neck length) × 100]. Other morphological differences include anterior end to the nerve ring distance (77–100 vs. 121–130 μm), V% [(anterior end of vulva/body length) × 100] (46–57 vs. 41–47) in hermaphroditic females; rectum size (slightly longer than the anal body diameter vs. about three times longer), phasmids (smaller vs. inconspicuous), body length (0.13–2.0 vs. 0.32–0.39 mm), body diameter (73–150 vs. 160–220 μm), anterior end to the excretory pore distance (135–157 vs. 174–214 μm), and demanian ratios in amphimictic females. Morphological differences with H. ruandica and H. zacatecana were also observed. Furthermore, H. casmirica n. sp. did not mate or produce fertile progeny with other Heterorhabditis nematodes reported from India. It was also discovered that H. casmirica n. sp. is associated with 'Photorhabdus laumondii subsp. clarkei symbiotic bacteria.ConclusionsThe discovery of H. casmirica n. sp. provides novel insights into the diversity and evolution of Heterorhabditis nematodes and their symbiotic bacteria. This new species adds to the catalog of entomopathogenic nematodes in India.Graphical

Revision of the genus Metoncholaimus (Nematoda: Enoplida) with description of new species from the South China Sea

Summary The family Oncholaimidae comprises ca 350 species of widespread nematodes. They are common in the seas and oceans and are also found in freshwater lakes and rivers. Here we provide the first description of Metoncholaimus species from the South China Sea. Metoncholaimus placatus sp. n. is characterised by the spicules 2.2-2.8 anal body diam. long, gubernaculum small, nearly parallel to the spicules, S-curved. Supplementary organ is composed of transversely elongated prominence with two sensillar structures (receptors). A pictorial key to the species level of Metoncholaimus species is provided. In this study, the D2-D3 domain of the LSU rDNA and the nearly full-length SSU rDNA were selected as targets for species identification. Phylogenetic relationships within the family Oncholaimidae remained unresolved despite of the various sequences analysed in different loci.

Descriptions of Leptolaimus sinensis sp. nov. and Perspiria brevicaudata sp. nov. (Nematoda) from the Yellow Sea, China

Two new free-living marine nematodes which were collected at silt beach of Rizhao along the Yellow Sea are identified here as Leptolaimus sinensis sp. nov. and Perspiria brevicaudata sp. nov. Leptolaimus sinensis sp. nov. is characterized by annulated cuticle with lateral alae, 2 µm in width; buccal cavity cylindrical; cephalic setae 2 µm long; amphidial fovea unispiral, circular in outline; six to seven evenly spaced tubular precloacal supplements and 23-29 continuous alveolar supplements extending from cloaca to level of the base of buccal cavity; spicules slender, slightly arcuate; gubernaculum with dorso-caudal apophysis; tail conico-cylindrical, about 6 times cloacal body diameter in males and elongated in females, about 9 times anal body diameter in length. Perspiria brevicaudata sp. nov. is characterized by having four cephalic setae and four cervical setae; small buccal cavity with dorsal tooth and minute ventral tooth; amphidial fovea unispiral, looking like double circle in outline, surrounded partially by cuticle striations; spicules arcuate with ventral velum, handle-like proximally and tapered distally; gubernaculum plate-shaped, without apophysis; twelve winged precloacal supplements present. Updated identification keys for group of Leptolaimus species characterized by the presence of both alveolar and tubular precloacal supplements and for species of Perspiria are also given.

Two New Free-Living Marine Nematode Species of the Genus Haliplectus Cobb, 1913 (Haliplectidae) from Mangroves of Shenzhen, Guangdong Province, China

This study presents two new free-living marine nematodes, Haliplectus major sp. nov. and Haliplectus futianisus sp. nov., from a mangrove reservation in Shenzhen, China. Haliplectus major sp. nov. can be distinguished by its total body length of 1615–1998 µm; a cuticle annulated with eight rows of cuticle pores; amphidial fovea at 9–12 µm from the anterior end; a bipartite basal bulb with striated valve plates in both sexes; five to seven closely spaced precloacal supplements in males; a didelphic reproductive system in females, with the vulva at 49.64–52.37% of body length; and sexual dimorphism in tail shape, arcuate-conoid and 2.3–3.2 times anal body diameter long in males and elongate-conid and 3.5–4.2 times anal body diameter long in females. Haliplectus futianisus sp. nov. is characterized by a total body length of 574–655 µm; a cuticle annulated with eight rows of cuticle pores; amphidial fovea at 8–11 µm from the anterior end; a monopartite basal bulb with unstriated valve plates in both sexes; an absence of precloacal supplements in males; and a didelphic reproductive system in females, with the vulva at 42.33–45.63% of body length. The identification was confirmed by analyzing morphological characteristic and 18S rRNA gene sequences. The maximum likelihood (ML) topology was regarded as morphological evidence of H. major sp. nov. and H. futianisus sp. nov. being two distinct species.

Two New Species of Free-Living Marine Nematode of the Genus Anticyathus Cobb, 1920 (Linhomoeidae) from Mangroves Sediment of Shenzhen and Shantou, China

Two new species belonging to the genus Anticyathus were discovered during an ecological investigation of mangrove sediment in China. Anticyathus shenzhensis sp. nov. and Anticyathus communis sp. nov. are both characterized by: annulated cuticles; ten cephalic setae in a circle; buccal cavity lined with six longitudinal reinforcements; amphids in broken circles or cryptic spirals, located at the very anterior of the head; pharynx with anterior cuticularized, gradually enlarging in posterior portion but without bulb; conical tail; arcuate spicules, the distal ends pointed, gradually broadening towards the proximal; gubernaculum has a dorsal–caudal apophysis; female with two opposed, outstretched ovaries. Anticyathus shenzhensis sp. nov. can be distinguished by ten cephalic setae of length about 2–4 µm; amphids diameter about 20–29% of corresponding body diameter; pharynx occupy 0.07–0.10 times of body length; cardia length about 25 µm; tail length 2.5–3.4 times of anal body diameter (abd) in males and 3.4–4.7 abd in females; spicules length 51–59 µm as arc and 0.71–1.04 abd; apophysis length 18–19 µm; female vulva at 52–56% of body length. Anticyathus communis sp. nov. is identified by ten cephalic setae length about 3–5 µm; amphids diameter about 20–32% of corresponding body diameter; cardia 17–27 µm long; tail length 3.6–4.5 abd in male, 5.3–5.5 abd in female; spicules proximal with distinctly cephalated, 0.74–0.96 abd; gubernaculum shape of “L”, consisting of sleeves around spicule and dorsal–caudal apophysis; five to seven pre-anal and seven to ten post-anal almost invisible papilla or papillae-like setae occur on each ventrally submedian line on the posterior body part of male; the tip of male tail with three slight elevation; female vulva at 52% of body length. A dichotomous key for the genus Anticyathus is given and 39 sequences of 18S rRNA gene from ten individuals of Anticyathus shenzhensis sp. nov. are provided in Genbank database.

Description of Ruehmaphelenchus americanum n. sp. (Nematoda: Aphelenchoididae) found in Loblolly pine from the USA

Summary Ruehmaphelenchus americanum n. sp., isolated from southern yellow pine (Pinus taedae L.) from the USA is described and figured. It is characterised by a relatively stout body (a = 30 for females and males), three lines in the lateral field, both oocytes and spermatocytes arranged in two rows, male spicules relatively small (14-18 μm) with weakly developed condylus and rostrum, short tail with a bluntly pointed tip, seven papilliform genital papillae present, female vulva positioned at ca 82% of body length, vulval lips slightly protruding, post-uterine branch extending two-thirds of vulva to anus distance, tail cylindrical, ca two anal body diam. long, terminus forming a spike-like projection or mucron, 7.6-12.2 μm long, with pointed tip. The new species can be separated from 11 known species (except R. thailandae) by male genital papillae arrangement (the second and third pair adjacent vs separated). Detailed phylogenetic analysis based on 18S and 28S D2-D3 region ribosomal RNA (rRNA) sequences has confirmed the status of this nematode as a new species.

Description of two new and six known amphidelphic species of the genus Dorylaimoides Thorne and Swanger, 1936 (Nematoda: Dorylaimida: Tylencholaimoidea) from the Tropical Rainforest, Western Ghats, India

ABSTRACT Two new and six known amphidelphic species belonging to the genus Dorylaimoides from the tropical rainforest, Western Ghats of India, are described and illustrated. Dorylaimoides brevicaudatus sp. nov. is characterised by having a body 0.99–1.1 mm long; lip region offset by slight depression; odontostyle 7.5–8.5 μm long, ventral arm 5.0–5.5 µm long, dorsal arm 6.0–6.5 µm long; odontophore arcuate, 10.5–12.5 μm long; total stylet length 18.5–20 μm; pharynx expanding gradually into a cylindrical basal bulb, 25–30% of total neck length; female genital system didelphic-amphidelphic; tail convex-conoid with rounded terminus; and males with 24.5–30 µm long spicules. Dorylaimoides silvallis sp. nov. is characterised by having a body 1.3–1.4 mm long; lip region continuous; odontostyle 12.5–13.5 μm long, ventral arm 8.5–9.0 µm long, dorsal arm 9.5–10.5 µm long; odontophore arcuate, 14.5–16.5 μm long, total stylet length 27.5–29.5 μm; pharynx expanding abruptly into a cylindrical basal bulb, 31–35% of total neck length; female genital system didelphic-amphidelphic; tail long filiform, 8.6–9.7 times anal body diameter long; and males with spicules 30–32 µm long. Six known species of the genus Dorylaimoides – D. teres, D. micoletzkyi, D. parvus, D. leptura, D. malabaricus and D. mujtabai – are described and illustrated. Dorylaimoides teres is reported here for the first time from India. http://www.zoobank.org/urn:lsid:zoobank.org:pub:0974BA12-57D5-4AFA-8E89-560ABDEF3AB1 http://www.zoobank.org/urn:lsid:zoobank.org:pub:262D02B9-E5CF-429C-B0DF-D1BB42BDB604

Description of Ruehmaphelenchus taedae n. sp. (Nematoda: Aphelenchoididae) found in Loblolly pine logs from the USA

Summary Ruehmaphelenchus taedae n. sp., isolated from Loblolly pine logs (Pinus taedae L.) from the USA, is described and figured. It is characterised by a relatively slim body (a = 42 and 43 for males and females, respectively), three lines in the lateral field, male spicules relatively small (12-18 μm) with high and dorsally bent condylus and weakly developed rostrum, bursal flap absent, short tail possessing a long terminal spike ending in a bluntly rounded tip and 8.7-13.3 μm long, vulva positioned at ca 83% of body length, vulval flap absent, vulval lips slightly protruding, post-vulval uterine branch extending for less than half of vulva to anus distance, and female tail conoid, ca 3-4 anal body diam. long, with 13.7-18.5 μm terminal projection. The new species can be separated from all other species of the genus by the male tail possessing a long terminal spike and the more anterior excretory pore. Detailed phylogenetic analysis based on 28S D2-D3 region sequences confirmed the status of this nematode as a new species.

A new and a known species of the genus Mesorhabditis (Osche, 1952) Dougherty, 1953 associated with the larva of longhorn beetle (Cerambycidae) and ground beetle (Scarabaeidae)

A new and a known species of the genus Mesorhabditis (Osche 1952) Dougherty, 1953 are described and illustrated based on light and scanning electron microscopic observations. The known species M. microbursaris (Steiner 1926) was isolated from the larva of ground beetle (Phyllophaga sp.) and the new species M. denticulatus from the larva of longhorn beetle (Cerambycidae), emerging inside the dead log of Dulbergia sisso. The new species M. denticulatus is characterised by lateral fields with six incisors. Lips with raised setose sensilla. Cheilostom angular bracket-shaped. Metastegostomal swellings with two prominent denticles. Pharyngeal collar indistinguishable. Phasmid posterior to anus. Spicules 1.2–1.6 times anal body diameter long with round capitula, short and narrower calomus. Gubernaculum 50% of spicule length. Bursa rudimentary. GP five pairs, one pair precloacal and four pairs post cloacal, arranged in 1/1 + 1 + 2 configuration. GP4 and GP5 closely placed forming a group. The association between the species of the genus Mesorhabditis and insects is discussed.

A new free-living marine nematode species of the genus <i>Belbolla</i> (Enoplida, Enchelidiidae) from a subtidal zone of the East Sea, Korea, with some ecological and biogeographical information

A new free-living marine nematode species of the genus Belbolla Andrassy, 1973 belonging to the family Enchelidiidae is described based on specimens collected from the sediment of a subtidal benthic environmental habitat in the East Sea, Korea. Belbolla wonkimi sp. nov. differs from its congeners by the combination of the following characteristics: a relatively long body (3263-3396 μm), the absence of ocelli, nine oesophageal bulbs in the posterior pharynx, well-developed two winged precloacal supplements, longer spicule length (115-130 μm, 1.6-1.8 anal body diameter long), and a triangle-shaped shorter gubernacular apophysis (17-18 μm). Comparative tables on the biogeographical and morphological characteristics of Belbolla species are presented. A DIC (differential interference contrast) photomicrograph of the new species is also provided. This is the first taxonomic report on the genus Belbolla from Korean waters.

Aphelenchus yinyuensis n. sp. (Tylenchina: Aphelenchoididae) found in Terminalia sp. in China.

During a nematode biodiversity survey in Hainan Province, China, Aphelenchus yinyuensis n. sp. was detected in the rhizosphere of Terminalia sp. It is characterized by medium-sized a body of adult nematodes, i.e. 793 (639-877) μm and 756 (647-863) μm for females and males, respectively, with low, rounded, not offset lip region. The lateral field has 10 incisures. The excretory pore is located posterior to the nerve ring. The vagina is not sclerotised and the vulva has simple lips without a flap. The PUS is well developed and forms ca 45 to 83% of the vulva to anus distance. Female tail is straight, cylindrical, ca 2.7 times longer than anal body diam, tail tip broad, and bluntly rounded. Males have four pairs of caudal papillae and spicule 28.7 (25.8-32.3) μm long in the chord and well developed bursa, extending to the tail tip. 18S and 28S rRNA phylogenetic analyses were performed for the new species, and the ITS analysis was not performed due to low posterior probability support. Phylogenetically, the new species grouped with Aphelenchus avenae and this is the first new Aphelenchus species ever described from China.

First record of native entomopathogenic nematodes from Montana agroecosystems.

A total of 30 different agricultural fields in the Golden Triangle Region of Montana, USA were surveyed, and 150 soil samples were evaluated for the presence of entomopathogenic nematodes (EPNs). The authors isolated EPNs from 10% of the collected samples. The recovered isolates were identified as Steinernema feltiae and Heterorhabditis bacteriophora by using morphological and molecular analysis. Steinernema feltiae was found from two fields, Kalispell (S. feltiae 1) and Choteau (S. feltiae 2). Steinernema feltiae (1 and 2) differed significantly from each other in terms of morphological characters for infective juveniles (distance from anterior end to excretory pore and nerve ring) and 1st generation males (body length, spicule length, gubernaculum length, oesophagus, tail, and anal body diameter). Steinernema feltiae 2 and H. bacteriophora were recovered from the same field in Choteau. All these species were recovered from wheat fields with sandy clay loam and loam soils with 3.3 to 3.4% organic matter content and pH 8.

Bibliographic revision of Mesacanthion Filipjev, 1927 (Nematoda: Thoracostomopsidae) with description of a new species from Jeju Island, South Korea.

A new species of the genus Mesacanthion Filipjev, 1927 was discovered during a survey of natural beaches of Jeju Island in South Korea. The new species Mesacanthion jejuensis sp. nov. shares general morphology of the genus such as the outer labial and cephalic setae being situated at the middle of cephalic capsule, well-developed mandibles with two columns united by a curved bar, and three equally sized and shaped teeth shorter than the mandibles. The new species belongs to a group of Mesacanthion species in which spicules are shorter than two anal body diameters. The new species is most closely related to M. pannosum, first discovered in Puget Sound, Washington, in terms of having enlarged cervical setae flap at the end of cephalic capsule, spicules which are shorter than 2 anal body diameter, both supplementary organ and gubernaculum. It can be distinguished from M. pannosum by its stronger inner labial setae, longer outer labial setae, and difference in the index value of b and c’. Along with the description of Mesacanthion jejuensis sp. nov., the genus Mesacanthion Filipjev, 1927 is bibliographically reviewed and revised. Including the new species, a total of 48 species are described within the genus; 39 which are valid; eight which are considered to be species inquirenda due to misplacement of genus and poor description; one which is considered nomen nudum. An updated diagnosis of the genus is provided along with a compiled tabular key comparing different diagnostic morphological characters of all valid species, as well as a pictorial key consisting of 21 species with spicules shorter than two anal body diameters.

New and known species of the genus Campylaimus Cobb, 1920 (Nematoda: Araeolaimida: Diplopeltidae) from North European marine habitats

BackgroundThe genus Campylaimus is a broadly distributed but relatively uncommon genus of marine and brackish nematodes with 20 nominal species and one nomen nudum. Many species descriptions and redescriptions are based on very few (single) individuals, which limits our understanding of inter- and intra-specific variability and morphology-based species boundaries.New informationTwo new species were found in the Skagerrak off the west coast of Sweden. Campylaimus triclados sp. n. is characterised by body 0.59–0.69 mm long; cuticle without longitudinal striation; anteriormost edge of the amphid anterior to the oral opening; dorsal limb of the amphid equal to 1.6–2.5 labial region diameters in male, 1.9 labial region diameters in female; ventral limb of the amphid extends towards anterior part of the intestine in male and midpharynx in female, 4.3–5.5 times the length of the dorsal limb in male and 2.2–2.8 times the length of the dorsal limb in female; ventral limb of the amphid is as wide as the dorsal limb; interamphideal space extends further than the posterior end of the dorsal limb but not reaching the posterior end of the ventral limb; secretory-excretory pore opens posterior to the cardia; spicules 19–24 µm long; two precloacal supplements; tail equal to 4.3–5.6 anal body diameters in length, with conoid terminal part. Campylaimus longispiculus sp. n. is characterised by body 0.56–0.65 mm long; cuticle without longitudinal striation; anteriormost edge of the amphid anterior to the oral opening; dorsal limb of the amphid equal to 1.8–2.1 labial region diameters in male; ventral limb of the amphid extends towards anterior part of the intestine in male, 2.8–3.5 times the length of the dorsal limb in male; ventral limb of the amphid is as wide as the dorsal limb; interamphideal space absent; secretory-excretory pore opens posterior to the cardia; spicules 28–35 µm long; two precloacal supplements; tail equal to 4.9–5.3 anal body diameters in length, with clavate terminal part. In addition, following nine species are new records for the fauna of Sweden: Campylaimus amphidialis, C. inaequalis, C. lefeverei, C. minutus, C. orientalis, C. rimatus, C. siwaschensis, C. striatus and C. tkatchevi.

Description of Oscheius indicus n. sp. (Rhabditidae: Nematoda) from India.

A new amphimictic species Oscheius indicus n. sp. is described and illustrated with morphological and molecular data. The species is characterized by a medium-sized and slender body (female: L = 1.1 to 1.5 mm; a = 16.8 to 20.6; b = 5.7 to 7.1; c = 7.5 to 10.4; c’ = 5.0 to 7.6; V = 45 to 51%), presence of four incisures each in the lateral fields with three minute warts, long rectum (2 to 3 anal body diameters), nine pairs of papillae arranged as 1+1+1/3+3 pattern, a prominent double-flapped epipytigma on vulval opening, presence of open leptoderan bursa and crochet needle-shaped spicules place it in the insectivora group. Morphologically, O. indicus n. sp. closely resembles O. carolinensis, O. chongmingensis, O. colombiana, and O. nadarajani. Molecular phylogenetic analysis carried out using ITS and D2/D3 expansion region of 28S rDNA sequences suggests that O. indicus n. sp. is closer to O. chongmingensis and O. rugaonensis. In summary, the morphometrical data, morphological observations and molecular phylogenetic analysis suggested that O. indicus n. sp. is sufficiently different from any known species and is therefore proposed as a new species within the insectivora group.

Six new and one known species of Geomonhystera (Nematoda, Monhysteridae) from moss, an epiphytic plant and soil in México and Ecuador.

Six new species of Geomonhystera (Nematoda, Monhysterida: Monhysteridae) Andrássy, 1981, are described and illustrated, five from México and one from Ecuador. The new species have many features in common and in common with at least several other species of the genus. Consequently, those features individually are not very useful for species-level diagnosis. They include the cuticular striation which, under light microscopy, ranges from fine to apparently smooth; however, scanning electron micrographs reveal very fine cuticular striation on all the new species. All the new species have a few body setae scattered along the length of the body and the vulval lips of females are slightly protruding. As for other species of the genus, there is considerable overlap in the ranges of standard morphometric characters so a combination of standard and additional morphometrics, as well as qualitative characters, is necessary for species separation. Geomonhystera mexiquense sp. n., collected from moss on a rock and on the trunk of Quercus crassipes in Juchitepec, México State, México, has outer labial setae that are unsegmented and 44-67% of the head width, the cephalic setae are thin, unsegmented and 31-50% of the head width; the vulval lips protrude slightly. Geomonhystera michoacana sp. n., collected from moss on a rock in Tzararacua National Park, Uruapan, Michoacan State, México, has a very finely-striated cuticle which appears almost smooth and bears rare cervical and caudal setae; the tail is long, 15-17% of the body length, and the rectum also is long, 23-32 (27±2.0) µm. Geomonhystera longispiculata sp. n., collected from an epiphytic plant in the botanical garden of the Ecology Institute in Jalapa, Veracruz State, México, is distinguished from all the species of the genus by the long, slender spicules, 55-85 (75±3.0) µm. The cuticle has conspicuous fine striation and there are somatic setae scattered along the body. Geomonhystera ecuatoriana sp. n., collected from moss on the trunk of Scalesia pedunculata growing on the twin volcanoes of Isla Santa Cruz, Galapagos, Ecuador, has fine cuticular striation and a few small body setae; the unsegmented outer labial setae are 42-54% of the head width and the cephalic setae are thin, unsegmented and 33-45% of the head width; the vulval lips protrude slightly and the vulva-anus distance is 37-48 µm or 2.1-2.5 times anal body diameter. Males of G. ecuatoriana have slightly arcuate spicules, 35 µm long. Geomonhystera galindoi sp. n., collected from moss on the trunk of Quercus peduncularis in San Pablo Ixzayo, Texcoco, México State, México, has fine cuticlar striation and a few fine body setae, the vulval lips are slightly protruding; the vulva-anus distance is 35-50 (41±0.9) µm, 1.5-2.2 (1.9±0.2) times anal body diameter. Males of G. galindoi are slightly ventrally curved with the posterior end strongly curved, giving the body a hook-shaped appearance. Geomonhystera chiautzingoensis sp. n., collected from moss on the trunk of Crataegus mexicana in Chiautzingo, Puebla State, México, has exceedingly fine striation of the cuticle and outer labial and cephalic setae that are less than 50% of the head width. Additionally, G. dubia Siddiqi Shahina, 2004 was sollected in soil samples around a plum tree (Prunus sp.) in the garden of Montecillo Campus, Colegio de Postgraduados, Texcoco, México State, México This species has a small body with fine cuticular striation and a few sparsely-distributed body setae; the outer labial and cephalic setae are unsegmented, 5-8 and 3-5 µm long, 56-80% and 33-50% of the head width, respectively; the vulval lips protrude slightly but are sometimes flush with the body contour.

Description of Pristionchus stercoraris sp. n. and first report of Tylopharynx foetida from India (Nematoda: Diplogastrina)

Pristionchus stercoraris sp. n. and Tylopharynx foetida (Butschli, 1874) Goffart, 1930 of the suborder Diplogastrina are described and illustrated in detail. Both the species were isolated from farmyard manure collected from Baramulla, Jammu & Kashmir, India. P. stercoraris sp. n. is characterized by faint annulations on cuticle, steno– as well as eurystomatous types of stoma, thin-walled cheilostom, long elongate cardia, slender spicules with slightly anteriorly curved distal tip, a boat-shaped gubernaculum with a medial dorsal convex; proximally with an anteriorly directed needle-like extension and distally with a sleeve and eight pairs of genital papillae. Measurements and descriptions of our specimens of T. foetida agree well with that of Butschli (1874). However, slight differences were observed in the length of stoma, tail, anal body diameter, anterior pharynx, and in the position of excretory pore. No species of both Pristionchus and Tylopharynx have so far been reported from India.

A re-description of Longicyatholaimus maldivarum Gerlach, 1964 (Nematoda, Cyatholamidae) with an emended identification key of the genus

Longicyatholaimus maldivarum was a species erected by Gerlach in 1964 from specimens found in the Maldivian archipelago. Due to the finding of additional representatives of this species, L. maldivarum is re-described with the addition of new morphological details mainly about males, because the information about female in the original description are very scarce. The newly found specimens showed a total body length higher than in the type specimens (1936–2063 µm vs. 1330 µm long) as well as the ratio of the total body length divided by maximum body diameter (22–28 vs. 27). The multispiral amphideal fovea showed 5 turns vs. 4 turns and Gerlach did not notice the presence of sub-ventral teeth that were clearly observed in the present specimens. The copulatory apparatus that perfectly matched the Gerlach description showed a central lamella mainly visible under confocal microscopy. A slightly lower ratio of the spicule length divided by anal body diameter (1 vs. 1.4) and longer gubernaculum (25–32 vs. 25 µm long) were noticed as well. Pre-cloacal supplements appeared very interesting for the presence of stout and conical setae protruding from cup-shaped structures. Supplements were more than in type species (8–9 vs. 7). Also the tail revealed some differences with a lower ratio of its total length divided by anal body diameter 6 vs. 7–8. The current list of 15 valid species of the genus was reduced to 10 species. In detail, we considered Longicyatholaimus heterurus and Longicyatholaimus sp. 3 species inquirendae for the absence of male specimens in the original description. We also excluded L. filicaudatus and L. tenuicaudatus because they were considered species inquirendae by Wieser & Hopper (1967) and L. zosterae because it was transferred by Lorenzen (1972) to the genus Paralongicyatholaimus. The new morphological details observed for Longicyatholaimus maldivarum and the modified number of valid species of the genus required also a revision of the identification key.

Morphological and molecular characterization of Tarantobelus arachnicida gen. n., sp. n. (Nematoda, Rhabditida, Brevibuccidae), a parasitic nematode of tarantulas.

A new genus and new species, Tarantobelus arachnicida, was found in the oral opening of tarantula spiders bred in captivity in Poland. The new species is characterized by having a small body (0.77-0.95 mm long in females and 0.66-0.84 mm in males), cuticle poorly annulated by transverse incisures, lateral field inconspicuous, lips separated with small cuticular flaps topping each lip, stoma panagrolaimoid with gymnostom well developed with robust and refringent rhabdia, pharynx panagrolaimoid with isthmus slightly longer than the basal bulb, intestine with cardiac (anterior) and rectal (posterior) areas with narrower walls. Mature females with intestinal cells including needle crystal packs, excretory pore at isthmus level, female reproductive system panagrolaimoid with post-vulval sac 0.4-0.8 times the length of the corresponding body diameter and having very thick walls, vulva very prominent, female rectum 0.8-1.3 times the length of the anal body diameter, female tail conical with acute tip with phasmids at 58-62% of its length. Male tail conical with long and thin mucro, spicules ventrad bent having rounded manubrium and thick gubernaculum. Description, measurements and illustrations of the new species are provided. Molecular analyses show its relationship with Brevibucca and Cuticonema. On the other hand, Medibulla and its corresponding subfamily Medibullinae, previously in Osstellidae, are transferred to Panagrolaimidae, being Shahnematinae, the junior synonym of Medibullinae. Indocephalobus, recently proposed and located in the family Panagrolaimidae, is considered a junior synonym of Diplogastrellus (Diplogasteromorpha), and its only species, I. zebrae, is considered a junior synonym of D. gracilis. In addition, a key to identification of panagrolaimoid genera is included.

Description of a new species of the genus Caveonchus Siddiqi, 1982 (Nematoda: Dorylaimida) with diagnostic compendium and key to its species

Summary Caveonchus siddiqii n. sp. is described and illustrated based on specimens collected from both India and Japan. It is characterized by having a medium sized body (L= 0.86 - 1.12 mm); labial disc present; amphideal fovea flask-shaped; lip region cap-like, offset by slight constriction; odontostyle 8 - 9 μm, odontophore 10 - 12 μm; pharynx with slender anterior part which expands abruptly into the saccate basal bulb, occupying about 16 - 21 % of total neck length; female genital system mono-opisthodelphic; anterior genital branch 70 - 100 μm or 1.9 - 2.8 times the midbody diameter long; tail short, rounded, hemispheroid, 0.5 - 0.7 anal body diameter long; spicules 30 - 38 μm long; and three spaced ventromedian supplements. Its relationship with all the known species of the genus is discussed. A diagnostic compendium and a key to identification of the species is also provided.