Amphidial Fovea Research Articles

Two new species of the genus Halichoanolaimus (Nematoda, Selachinematidae) from the intertidal zone of the Yellow Sea, China.

Two new marine nematode species belonging to the genus Halichoanolaimus from the intertidal zone of the Yellow Sea are described. Halichoanolaimussinensis sp. nov. is characterized by amphideal fovea with 2.5-3.0 turns, 20-27% of corresponding body diameters; spicules curved, middle portion broad, tapering distally, 1.4-1.5 cloacal body diameters long; gubernaculum slender consisting of two detached lateral pieces tapering distally; 10-13 papilliform precloacal supplements in two groups, the posterior three supplements smaller and closer to each other, the remaining supplements larger and widely spaced; tail conico-cylindrical with a half cylindrical portion. The second new species, Halichoanolaimuszhangi sp. nov. is distinct by having lateral differentiation present except in anterior half of pharynx which has even punctations, amphideal fovea with 3.0-3.3 turns, spicules curved, gradually narrowing from proximal to distal end with pointed tip, 7 papilliform precloacal supplements, gradually increasing the spacing distance forward, two rows of subventral conical setae situated at the precloacal region, tail elongated, filiform. An updated key to 30 valid species of Halichoanolaimus is provided.

Description of Amphimonhystrella sinica sp. nov. and Cobbia zhangi sp. nov. of the family Xyalidae (Nematoda: Monhysterida) from the Yellow Sea, China

Two new species of free-living marine nematodes belonging to the family Xyalidae are described from the Yellow Sea, China. Amphimonhystrella sinica sp. nov. is characterized by rhomboid-shaped buccal cavity, circular amphidial fovea relatively far from anterior end of body, slender L-shaped spicules with cephalated proximal end and hooked distal end, tubular gubernaculum with ventrally curved apophyses, slender tail conico-cylindrical with half cylindrical distal part. Cobbia zhangi sp. nov. is characterized by having three similar equal-sized teeth, anterior sensilla arrangement 6+10, slightly curved spicules cephalated proximally and tapered distally, gubernaculum rod-like without apophysis, tail with posterior three fourths filiform part. Updated dichotomous keys to species of Amphimonhystrella and Cobbia are given. Considering the descriptions in the present work, the two genera contain now 9 and 12 valid species, respectively; this study complemented the species diversity of nematodes in Chinese sea area.

Description of two new species of Haliplectus Cobb, 1913 (Nematoda, Plectida, Haliplectidae) from mangrove areas of Sandspit backwater, Karachi, Pakistan

Haliplectus shahinae n. sp. and H. sandspitensis n. sp. two free-living marine nematodes of the family Haliplectidae Chitwood, 1951 collected from mangrove areas of Sandspit backwater, Karachi, Pakistan, are being described and illustrated. Both new species belong to a group of species characterized by the presence of a bipartite basal esophageal bulb with striated or unstriated valve plates. H. shahinae n. sp. is characterized by its comparatively shorter body length (0.4–0.44 mm); annulated cuticle; amphidial fovea at 6–9 µm from the anterior end; bipartite basal bulb with unstriated valve plates; reproductive system mono-prodelphic with reflexed ovary, presence of post uterine sac and vulva at 52–57% of body length and tail short conoid, straight, 1.5–1.8 times anal body width long. H. sandspitensis n. sp. is characterized by more than 1 mm body length (1.0–1.2 mm); annulated cuticle; amphidial fovea at 8–12 µm from the anterior end; bipartite basal bulb with striated valve plates; didelphic reproductive system, with the vulva at 40–47% of body length and tail elongated, conoid, 1.4–2.2 times anal body width long. A dichotomous identification key is provided for the valid species of Haliplectus Cobb, 1913.

Data on four species of Longidorus Micoletzky, 1922 (Nematoda: Longidoridae) from southern and southeastern Iran, including description of a new species.

Four species of the genus Longidorus were recovered from southern (Bushehr province) and southeastern (Southern Khorasan province) Iran. The first species, L. paratabrizicus n. sp. represents a new member to the genus and is characterised by 4.8-5.6 mm long females with anteriorly flattened lip region separated from the rest of the body by depression, amphidial fovea pocket-shaped without lobes, tail conical, dorsally convex, ventrally almost straight with bluntly rounded tip and males in population. By having similar lip region and tail shape, the new species most closely resembles five species viz. L. artemisiae, L. globulicauda, L. patuxentensis, L. sturhani, and L. tabrizicus. It represents the cryptic form of the last species. The second species belongs to L. mirus, recovered in both southern and southeastern Iran, representing the first record of the species after its original description. As an update to the characteristics of this species, it's all juvenile developmental stages were recovered and described. The criteria to separate L. mirus from two closely related species, L. auratus and L. africanus, are discussed. The third species belongs to L. persicus, a new record in southern Iran. The fourth species, L. orientalis was recovered in high population density in association with date palm trees in Bushehr province. The phylogenetic relationships of the new species and recovered populations of L. mirus and L. persicus were reconstructed using two ribosomal markers and the resulted topologies were discussed.

Two new species of Nematoda: Gairleanema pulchra sp. nov. (Tripyloididae) and Axonolaimus dimorphous sp. nov. (Axonolaimidae) from the Yellow Sea, China

Two new species of Nematoda, Gairleanema pulchra sp. nov. and Axonolaimus dimorphous sp. nov. are described from Rizhao coast, the Yelllow Sea. Gairleanema pulchra sp. nov. is characterized by six inner labial setae with bulbous swelling, six long outer labial setae and four short cephalic setae in one circle, amphidial fovea oval-shaped, spicules L-shaped with proximal end slightly cephalated, gubernaculum boat shaped with proximal end hooked anteriorly, seven oval-shaped precloacal supplements and tail conico-cylindrical. With the species description here two species are considered valid now in genus Gairleanema. Axonolaimus dimorphous sp. nov. is characterized by four long cephalic setae, amphidial fovea elongated loop in males and loop-shaped in females, spicules arcuated, gubernaculum with dorsal apophysis slightly directed to caudal position and tail conico-cylindrical with caudal setae. With the species description here 34 species are considered valid now in genus Axonolaimus.

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.

Oostenbrinkellus gen. n. and a new species of the rare nematode genus Lawtonema Siddiqi, 1998 (Nematoda: Dorylaimida: Tylencholaimoidea) from the Western Ghats

One new genus and a new species belonging to the superfamily Tylencholaimoidea from the Western Ghats, India are described and illustrated. Oostenbrinkellus gen. n. is characterized by being a medium sized nematode with a 0.92–1.3 mm long body; lip region cap-like with distinct labia disc; amphidial fovea cup-shaped, aperture occupying about two-thirds to four-fifths of the lip region diameter; odontostyle 10.5–12.0 µm long, slender, slightly sinuate, mid region bent slight dorsally, anterior beak-like, with a distinct ventral stiffening piece covering the posterior half of the ventral arm; its aperture about one-fifth of the odontostyle length, 1.6–2.0 times the lip region diameter long; odontophore 7.5–9.0 µm long, with distinct basal knobs, total stylet 18.5–20.5 µm; pharynx consisting of an anterior slender part, expanding posteriorly into a short cylindrical basal bulb, 19–25% of total pharyngeal length; female genital system mono-opisthodelphic with anterior uterine sac; tail long filiform both the sexes; males with 24–29 μm long spicules. Lawtonema indicum sp. n. is characterized by having a 1.25–1.28 mm long body; lip region cap-like with distinct labial disc; amphidial fovea cup-shaped, aperture occupying about three-fourths of the lip region diameter; odontostyle 10–10.5 μm long, its tip bent dorsally; odontophore 9.5–10 μm long, total stylet length 19.5–20.0 μm; pharynx expanding gradually into a short cylindrical bulb, 19–20% of total pharyngeal length; female genital system amphidelphic; tail long filiform; male with 24 μm long spicules.

Simple, inexpensive, and rapid approach to detect changes in the structure of soil free-living nematodes.

A general limitation of ecological investigations based on nematodes is related to the difficult and time-consuming taxonomic identification of species. Therefore, nematologists are investing many efforts to develop alternative approaches as proxies applicable in biomonitoring assessment. Recently, an alternative method that combines morpho-functional traits was proposed for detecting assemblage changes of marine nematodes. In view of the promising results, it was tested the same approach to document taxonomic structure changes of soil free-living and plant parasitic nematodes. Specifically, this attempt was carried out using three data sets that include studies from various European regions and different types of ecosystems: forests, grasslands and maize crops. Multivariate statistical analysis revealed that the simple combination of the four traits (i.e., buccal cavity cuticularization occurrence, amphideal fovea size and shape, morphology of the cuticle and pharynx) in a single code number perfectly mirrors the taxonomic structure trends of the nematode assemblage at genus level. Therefore, we predict that similar results can be also obtained by directly encoding nematode specimens with the selected traits and we point to new important advances if this procedure can be coupled with advanced machine learning.

Two new species of the order Monhysterida (Nematoda) from the sea of China.

Two new marine nematode species belonging to the order Monhysterida are described from the sea of China. Halomonhysterazhangisp. nov. is characterized by its relatively small body size; short anterior sensory setae; small, circular amphidial fovea located at the level of buccal cavity base; funnel-shaped buccal cavity; an excretory-secretory system with a large ventral gland and opening as a very narrow canal just posterior to the level of cephalic setae; slightly curved slender spicules with cephalated proximal end and tapered distal end; rod-like gubernaculum without apophysis; two papilliform precloacal supplements just in front of the cloaca; conico-cylindrical tail with two ventral papillae, each with a seta; and distance between the vulva and anus slightly longer than the tail length. This is the first new species of epiphytic nematode reported in China. The second new species, Stylotheristusflagellicaudatussp. nov., has a relatively shorter body and longer tail; striated cuticle; The anterior sensilla arranged in two circles, the first circle consisting of six inner labial setiform papillae (3-4 µm) and the second circle consisting of 16 long setae (12-19 µm); a transversely oval amphideal fovea; a well-developed muscle around the funnel-shaped buccal cavity; short spicules and a gubernaculum composed of a single piece; and precloacal supplements absent. An updated key to all species of Halomonhystera and pictorial key to all species of Stylotheristus are also given.

Two new species of Hypodontolaiminae (Nematoda, Chromadorida, Chromadoridae) from the Yellow Sea with a phylogenetic analysis in the subfamily.

Two new species of Hypodontolaiminae, Dichromadoramediasp. nov. and Neochromadoraparabilineatasp. nov., were isolated and described from the Yellow Sea, China. Dichromadoramediasp. nov. is characterized by four long cephalic setae, the amphidial fovea transverse oval in the male and slit-shaped in the female, the pharynx with a single posterior bulb, spicules curved and distally bifurcated, gubernaculum jointed, four (1+3) precloacal supplements papilliform, and the tail conical elongated with a short spinneret. Neochromadoraparabilineatasp. nov. is characterized by the buccal cavity with one large hollow dorsal tooth and two small subventral teeth, the pharynx with an obvious posterior bulb, spicules L-shaped and widened medially, gubernaculum boat-shaped, seven cup-shaped and equidistant precloacal supplements, and a long and gradually tapering tail. The phylogenetic analysis of maximum likelihood and Bayesian inference based on rDNA sequences confirmed the taxonomic positions of Neochromadoraparabilineatasp. nov. and Dichromadoramediasp. nov. within Hypodontolaiminae. Tree topology in Hypodontolaiminae shows the genera Neochromadora, Dichromadora, Ptycholaimellus, and Spilophorella as polyphyletic groups, and the genus Chromadorita as a paraphyletic group.

Two new species of Promonhystera Wieser, 1956 (Nematoda: Monhysterida: Xyalidae) from the South China Sea.

Two new species of free-living marine nematodes from the littoral sediment of the South China Sea are described as Promonhystera papilla sp. nov. and Promonhystera fluctispicula sp. nov. Both new species are characterized by striated cuticle; circular amphideal fovea; anterior sensilla in two circles, inner labial sensilla setiform; funnel-shaped buccal cavity; elongated spicules and conico-cylindrical tail. P. papilla sp. nov. is different from all known species of the genus by longer body length (more than 2.1mm versus less than 1.5 mm in other species), longer spicules (sp/a.b.d. = 4.14.6 versus 2.7) and males with three papilliform precloacal supplements and one small postcloacal papilla (versus absence) and gubernaculum boot-shaped. P. fluctispicula sp. nov. is similar to P. tricuspidata Wieser, 1956 in having similar waved spicules but differs from the latter species by tail conico-cylindrical (versus conical) and simple plate-like gubernaculum without tooth (versus gubernaculum with four distal teeth).

Two new species of Sabatieria de Rouville, 1903 (Nematoda: Araeolaimida: Comesomatidae) from the Southern Ocean.

Two new free-living marine nematode species of the genus Sabatieria de Rouville, 1903 are described from the Southern Ocean using morphological and molecular data. Sabatieria brevicaudata sp. nov. is characterized by body length 14761740 m, short cephalic setae, 1324% corresponding body diameter long, lateral differentiation of body cuticle with only slightly coarser punctations, spiral amphidial fovea with 3 turns, spicules arcuated and 1.31.6 cloacal body diameter long, slightly arcuated gubernacular apophyses, and twelve precloacal supplements, in the form of small pores. Sabatieria multipora sp. nov. is characterized by body length 21392324 m, short cephalic setae (47 m long, 3040% corresponding body diameter long), cuticle with lateral differentiation of distinctly coarser punctations extending from anterior edge of amphidial fovea to anterior of intestine and in the tail region, spiral amphidial fovea with 3 turns, males with spicules 1.92.0 cloacal body diameter long, seventeen fine tubular precloacal supplements with distance between adjacent supplements increasing towards anterior, and with curved gubernacular apophyses. We obtained 18S rDNA and 28S rDNA sequences from the two new species, which are both closely related to other species of Sabatieria. Our analyses also show that several genera of Comesomatidae Filipjev, 1918 do not form monophyletic clades.

New nematode Tahaminaindica gen. nov., sp. nov. (Nematoda, Dorylaimida, Tylencholaimoidea) from the tropical rainforest, Western Ghats.

During a nematological survey in the Western Ghats a new nematode belonging to the superfamily Tylencholaimoida (Dorylaimida) extracted from the rhizosphere of the soil of grasses, is described and illustrated. Tahaminaindicagen. nov., sp. nov. is characterized by females with a body length of 1.3-1.4 mm; lip region 8.0 μm wide, approximately one-fourth of the body diameter at the pharyngeal base; amphidial fovea cup-shaped, about one-half as wide as the lip region diameter. Odontostyle 8.0-9.0 μm long, 1.0-1.1 times lip region diameter; guiding ring simple; odontophore rod-like, 10.5-11.5 μm long with basal thickening or minute knobs-like structure; pharynx consisting of a weakly muscular anterior part, expanding abruptly into a cylindrical basal bulb, occupying about two-fifths to one-half of the total pharyngeal length; female genital system monodelphic-opisthodelphic with anterior uterine sac; vulval opening pore-like, and tail elongated with a slight dorsally curved tip. Males not found.

Three new free-living marine nematode species of the family Comesomatidae from Mangrove wetlands in Jinmen County, Taiwan.

Three new free-living marine nematodes, belonging to the genera Dorylaimopsis, Comesoma and Paracomesoma are described from the mangrove wetlands of western Taiwan Island. Dorylaimopsis jinmendaoica sp. nov. is characterized by having a cuticle with lateral differentiation of longitudinal rows of two rows of larger dots in the middle of the body, a spiral amphideal fovea with 2.52.75 turns, excretory pore anterior to nerve ring and 1721 fibriform precloacal supplements. Comesoma quattuordecimsupplementata sp. nov. is characterized by having a spiral amphideal fovea with 2.52.75 turns and 14 fibriform precloacal supplements. Paracomesoma paralissum sp. nov. is characterized by having a spiral amphideal fovea with 3.0 turns and 40 fibriform precloacal supplements. Differentiating characteristics of all known male Dorylaimopsis, Comesoma and Paracomesoma species are also given.

Two new species of Xyalidae Chitwood, 1951 (Nematoda, Monhysterida) from Chinese Sea Area.

Two new nematode species of the family Xyalidae were found in the intertidal zone of the Chinese coast, and they are described here as Daptonema sinica sp. nov. and Metadesmolaimus bulbosus sp. nov. Daptonema sinica sp. nov. is characterised by a relatively large body with a broad funnel-shaped buccal cavity; relatively long cephalic setae; a circular amphidial fovea posterior to the buccal cavity; slender spicules bending into a hook shape in the posterior half; a small plate-like gubernaculum without apophysis; and a conico-cylindrical slender tail with terminal setae. Metadesmolaimus bulbosus sp. nov. can be identified by its large buccal cavity, long cervical setae, multiple bulb-like pharyngeal muscular swellings, conico-cylindrical tail narrowing abruptly immediately posterior to the cloaca, straight clavated spicules with a broad proximal end and hooked distal end, and gubernaculum absent. An updated dichotomous key to the species of Metadesmolaimus is given.

Two New Nematode Species, Desmolaimus magnus sp. nov. (Monhysterida, Linhomoeidae) and Metadesmolaimus robustus sp. nov. (Monhysterida, Xyalidae), from the Yellow Sea, China with Phylogenetic Analyses within Linhomoeidae and Xyalidae

Two new species are described from the Rizhao coast along the Yellow Sea. Desmolaimus magnus sp. nov. is characterized by its relatively large body size, faintly striated cuticle, four long cephalic setae, a wide buccal cavity with cuticularized transverse rings, an amphidial fovea at the junction of the buccal cavity and pharynx, a pharynx without a bulb, curved spicules, a gubernaculum with a dorso–caudal apophysis, and an elongated conical tail. Metadesmolaimus robustus sp. nov. is characterized by its relatively large body size, coarsely striated cuticle, spacious buccal cavity with cuticularized rings, six inner labial sensilla setiform, six outer labial setae, and four long cephalic setae. The pharynx is notably muscularized, and the spicules are straight and jointed with a slightly swollen proximal end and a hooked distal end. The gubernaculum is brownish and comma–shaped, and the tail is conico–cylindrical with terminal setae. Phylogenetic analyses using maximum–likelihood and Bayesin inference, based on small subunit and D2–D3 fragment of large subunit rDNA sequences, place Desmolaimus magnus sp. nov. within the framework of the family Linhomoeidae and Metadesmolaimus robustus sp. nov. within Xyalidae. Topology trees at the family level show genera Desmolaimus and Metadesmolaimus as paraphyletic groups, the genus Terschellingia as a monophylectic group, the genus Theristus as a monophylectic group based on SSU sequence, the genus Daptonema as a monophylectic group based on LSU sequence.

Three new free-living marine nematode species of Subsphaerolaimus Lorenzen, 1978, Halichoanolaimus de Man, 1886 and Belbolla Andrssy, 1973 from mangrove wetlands in Taiwan.

Three new species of free-living marine nematodes belonging to the genera Subsphaerolaimus, Halichoanolaimus and Belbolla are described from the mangrove wetlands of western Taiwan Island. Subsphaerolaimus danshuiensis sp. nov. is characterized by a body length of 13451693 m, subcephalic setae 22.565.0 m long, cervical setae 16.533.0 m long, an L-shaped spicule 66.976.4 m long, and a gubernaculum with a caudally-dorsally directed apophysis 16.423.0 m long. Halichoanolaimus sicaoensis sp. nov. is characterized by an amphidial fovea with 3.53.75 turns, a conico-cylindrical tail with the cylindrical portion approximately 3/4 of the total tail length, and 1314 not equidistant papillose precloacal supplements. Belbolla forkyspicula sp. nov. is characterized by seven oesophageal bulbs, a short tail, a spicule with a proximal fork, and two winged supplements. Differentiating characteristics of the genera Subsphaerolaimus, Halichoanolaimus and Belbolla are provided. Types are deposited in the College of Fisheries, Jimei University.

Description of Bolbolaimus major sp. nov. (Nematoda), from the Yellow Sea, China and phylogenetic analysis in Microlaimidae.

Bolbolaimus major sp. nov. is described from Rizhao coast along the Yellow Sea. The new species is characterized by relatively large body size, cuticle strongly annulated, six outer labial sensilla setiform, four cephalic setae long, buccal cavity wide with one large dorsal tooth and two small subventral teeth, amphidial fovea unispiral shaped oval in males and circular in females, spicules curved with swollen proximal end, gubernaculum with anterior-hooked dorso-caudal apophysis, and tail conical with short spinneret. A phylogenetic analysis of maximum-likelihood and Bayesin inference based on rDNA sequences confirms the taxonomic position of Bolbolaimus major sp. nov. within the family Microlaimidae. Tree topology in Microlaimidae shows genus Microlaimus as polyphyletic group and genera in Microlaimidae are closely related.

Description of two new species of Nematoda: Litinium macramphida sp. nov. (Oxystominidae) and Cyartonema breviseta sp. nov. (Cyartonematidae) from the Yellow Sea, China.

Two new species of Nematoda, Litinium macramphida sp. nov. and Cyartonema breviseta sp. nov. are described from the Yelllow Sea. Litinium macramphida sp. nov. is characterized by body relatively long, inner and outer labial sensilla setiform with same length, amphideal fovea large and drop-shaped with amphideal aperture ovoid, spicules short and wide, gubernaculum simple and boat shaped, two precloacal supplements, and tail conical with rounded tip. Cyartonema breviseta sp. nov. is characterized by body short and slender, four cephalic sensilla papilliform, amphideal fovea circular and large, spicules curved and sickle-shaped, gubernaculum with dorsal-caudal apophysis and posterior end anteriorly hooked, and tail conical.

Two new species of Chromadorida (Nematoda) from the intertidal zone of the Yellow Sea, China

ABSTRACT Two new species of free-living marine nematodes were discovered off the coast of the Yellow Sea, China, and they are described here as Actinonema diplobulba sp. nov. and Nannolaimoides brevicaudatus sp. nov. Actinonema diplobulba sp. nov. is characterised by amphideal fovea transverse oval-shaped, pharynx with double posterior bulbs, single spicule slender, arcuate with cephalated proximal end, gubernaculum spinous, and extra hammer-shaped lateral pieces (telamon) present. This species is distinguished from its congeners in having double pharyngeal bulbs and both spicule and telamon. Nannolaimoides brevicaudatus sp. nov. is characterised by a slender body with irregular lateral differentiation, multispiral amphideal fovea with five turns and close to anterior end, spicules arcuate with bent proximal end and tapered distal end, gubernaculum expanded distally and tapered proximally, a precloacal papilla and 14 button-shaped precloacal supplements almost equally arranged, and a conico-cylindrical tail 4.3–4.9 times as long as cloacal body diameter. This species differs from its congeners by having a precloacal papilla and 14 button-shaped precloacal supplements, and a comparatively short conico-cylindrical tail. http://www.zoobank.org/urn:lsid:zoobank.org:pub:D74795FE-168E-4F7F-A78C-08EF5B9783A9