Cervical Setae Research Articles

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.

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.

One new species of Oxyonchus ( ) (Enoplida: Nematoda) from the Yellow Sea of China

During the diversity assessment of marine nematodes in the China seas, a new species of Oxyonchus (Filipjev, 1927) De Coninck & Schuurmans Stekhoven 1933 was discovered from the Yellow Sea of China. O. boucheri sp. nov. is characterized by cuticle smooth; mouth opening surrounded by three lips separated by deep clefts; cephalic region with developed cephalic capsule; mandibles arch-shaped, rods linked with anteriorly transverse bar, two subventral teeth extend to the mandibles' anterior ends; thick outer and inner labial setae; six files of 2–4 cervical setae; conico-cylindrical tail without terminal seta; curved spicules with tapered distal ends; gubernaculum with dorso-caudal apophysis; a ventral tubular and 6–8 pairs subventral spinous precloacal supplements. The new species differs from other 17 congeners mainly in its conical inner and thick outer labial setae (vs. slender labial setae), files of 2–4 cervical setae present (vs. cervical setae absent), slender spicules with tapered distal ends (vs. spicules with capitulum), both ventral tubular and subventral spinous precloacal supplements (vs. only tubular supplement in males). Updated dichotomous key to the genus Oxyonchus were provided.

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.

Three new species of free-living marine nematodes from the central basin of the South China Sea

ABSTRACT Three new species of free-living nematodes were discovered in the central basin of the South China Sea and are described here as Elzalia longicaudata sp. nov., Minolaimus distalamphidus sp. nov. and Setoplectus minor sp. nov. Elzalia longicaudata sp. nov. is characterised by a longer tail and longer buccal cavity relative to other members of the genus; presence of a circle of four cervical setae; spicules slender and long, which curve as the body bends; and simple gubernaculum with only one section of dorsal apophysis. Minolaimus distalamphidus sp. nov. can be distinguished from congeners by the male having lateral differentiation with six longitudinal rows of large dots; multispiral amphideal fovea with 8.5 turns; pharynx cylindrical without bulb; spicules slightly arcuate; gubernaculum rod-like without apophysis; about 17 sucker-shaped precloacal supplements; and tail conical with long filiform posterior portion. Setoplectus minor sp. nov. differs from its congeners by small body size, anterior third of pharyngeal region attenuated; cephalic setae 2 µm long; amphidial aperture circular or oval; tail elongated conical; male with a single papilliform precloacal supplement. Updated identification keys for species of the three genera are also given. http://www.zoobank.org/urn:lsid:zoobank.org:pub:623BC44A-A07F-420E-AA41-271CF85F64C6

Three new species of Mesacanthion Filipjev, 1927 (Nematoda: Thoracostomopsidae) from Argentine coasts

Three new species of Mesacanthion Filipjev, 1927 were found along Patagonian coasts (Argentina). Mesacanthion bifidum sp. nov. is characterized by short labial and cephalic setae, onchia of equal size, spicule arcuate, and gubernaculum with caudal apophysis, ending in two teeth. The species is related to M. virile (Ditlevsen, 1930) De Coninck & Schuurmans Stekhoven, 1933. However, the spicules and gubernaculum of both species are different in shape. Mesacanthion longigubernaculum sp. nov. is characterized by its long and slender body, striated cuticle, relatively long cephalic and cervical setae, onchia of different sizes, amphidial fovea lentil-shaped, spicule arcuate, gubernaculum surrounding the spicule, and tail conical-cylindrical with terminal setae. Mesacanthion sanantoniensis sp. nov. is characterized by its long and stout body, striated cuticle, long cephalic setae, onchia of different sizes, amphidial fovea pouch-shaped, spicule arcuate, gubernaculum with dorsal apophysis, and tail conical without terminal setae. Following the key of Jeong et al. (2019), the last two species are related to M. pali Wieser, 1959 and M. longissimesetosum Wieser, 1953, so we provide a key to differentiate the four species.

Morphological and molecular characteristics of Bastiania sinensis sp. n., Tripyla aquatica Brzeski & Winiszewska-Ślipińska, 1993 and T. setifera Bütschli, 1873 (Nematoda: Triplonchida) from Shanxi Province, North China

Summary This paper describes a new species of Bastiania, presents a new record and redescribes a known species of Tripyla. These nematodes are all in the order Triplonchida and were collected from Shanxi Province, North China. Bastiania sinensis sp. n. is characterised by having the female with a relatively slender body 1049-1295 μm long, dorsally arcuate after heat relaxation, with outer labial setae and cephalic setae in a single circle, an oval amphid, 7-8 laterodorsal cervical setae scattered in the pharyngeal region, orthometamenes and pseudocoelomocytes present, tail conoid with a mucron 1-2 μm long, two pairs of caudal setae present, a = 58.1-75.5, b = 4.0-4.6, c = 12.7-19.7, c′ = 4.1-7.8 and V = 61.1-67.7. Males were not found. Tripyla aquatica is recorded for the first time from China, and is redescribed. Tripyla setifera has been reported from China but without a detailed description – now provided. In addition, phylogenetic relationships among the species were analysed using data from the near full length small subunit (SSU) and D2-D3 segments of large subunit (LSU) of rRNA genes. Bastiania sinensis sp. n. is monophyletic with the Bastiania sequences available in GenBank, but is on an independent branch supporting its status as a separate species; T. aquatica and T. setifera are monophyletically clustered with known Tripyla species and grouped together with sequences from their respective species.

Descriptions of Deontolaimus holovachovi sp. nov. and Campylaimus zhoui sp. nov. from Chinese sea areas

AbstractTwo new species of free-living marine nematode discovered from an intertidal sandy beach in the Bohai Sea and from a sublittoral region in the East China Sea are described. Deontolaimus holovachovi sp. nov. is characterized by short cephalic setae (2.5–3 μm long); ventrally-unispiral amphidial fovea; excretory pore located at the level with nerve ring; lateral alae present; two pairs of lateral cervical setae present; arcuate spicules 1.5–1.6 cloacal body diameter long, with the proximal half swollen and proximal end hooked, the distal half narrow; gubernaculum with dorso-caudal apophysis; postcloacal sensilla present in males; a midventral caudal papilla with a short seta situated at posterior third of tail length. Campylaimus zhoui sp. nov. is characterized by loop-shaped amphid with very long ventral limb extending along pharyngeal region to level of anterior part of intestine, 4.7–5.2 times the length of dorsal limb; excretory pore opening posterior to the pharyngo-intestinal junction; spicules symmetrical, slightly arcuate without proximal capitulum; gubernaculum with small dorsal apophysis; precloacal supplements absent.

Paragnomoxyala papillifera sp. nov. (Nematoda: Monhysterida) from the Bohai Sea, China

A new free-living marine nematode species of the family Xyalidae from Laizhou Bay of the Bohai Sea, China is described and illustrated herein. Paragnomoxyala papillifera sp. nov. is characterized by large funnel-shaped buccal cavity, circular amphidial fovea located posterior to buccal cavity, straight spicules with slightly curved distal end, gubernaculum absent, four papilliform precloacal supplements, tail conico-cylindrical with two ventral embossments in males and having longitudinal rows of cervical setae and subventral caudal setae in males. The new species is easily identified from other two recorded species in the genus by having papilliform precloacal supplements and ventral embossments along conical portion of tail of males. A pictorial key for three species of Paragnomoxyala and comparative table of three species with important characteristics are provided.

A new species of Microlaimus de Man 1880 (Nematoda: Microlaimidae) from the Black Sea.

Microlaimus sergeevae sp. n. is described and illustrated from the Crimea shelf of the Black Sea. It is characterized by the 1301-1728 μm long body; cuticle with distinct annuli; spicules 34-37 μm long, curved; gubernacular apophyses 20-25 μm long, surrounding distal end of spicules; criptocyrcular amphidial fovea 7-8 μm in diameter; cervical setae present; four submedian rows of pores spreading along the whole body length, and eight precloacal supplements in males. The new species morphologically resembles M.gerlachi Wieser 1954, M. paraborealis Allgen 1940a and M.kaurii Wieser 1954, but differs from them by the length of cephalic setae, size of the body, presence of cervical setae, shape of the gubernacular apophyses, eight tubular precloacal supplements and submedian rows of pores spreading along the whole body length. M.sergeevae sp. n. differs from M.gerlachi by having a smaller amphidial fovea, shorter spicules and gubernacular apophyses. The new species differs from M. paraborealis by having larger value of c. It differs from M. kaurii by having longer spicules and larger values of c and b.

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.

Four new free-living marine nematode species (Sabatieria) from the Chukchi Sea.

Four new free-living marine nematode species of the genus Sabatieria are described from the Chukchi Sea. Sabatieria chukchensis sp. n. is characterized by a long body (2052-2326 μm), two pairs of short cervical setae present, amphideal fovea spiral with 2.75-3.25 turns, and seven papilliform pre-cloacal supplements. Sabatieria parvamphis sp. n. is characterized by small amphideal fovea (equal to 55-72% corresponding body diameter), amphideal fovea spiral with 3.25 turns, short cephalic setae (6-7 μm, equal to 31-38% of head diameter), curved gubernacular apophyses, thirteen to fifteen prominent tubular pre-cloacal supplements with distance between adjacent supplements increasing towards the anterior. Sabatieria major sp. n. is characterized by a long body (3879-4255 μm), amphideal fovea spiral with 2.5-3.25 turns, and seventeen to thirty-two small tubular pre-cloacal supplements. Sabatieria multisupplementia sp. n. is characterized by a long body (3967-4294 μm), amphideal fovea spiral with 2.75-3 turns, and forty-one to forty-seven tubular pre-cloacal supplements.

Two new and one known species of Phanodermatidae (Nematoda: Enoplida) from Sagami Bay, Japan.

Two new and one known species of free-living marine nematode belonging to the family Phanodermatidae are described. They were collected during the 12th Japanese Association for Marine Biology (JAMBIO) Coastal Organism Joint Survey off Jogashima, Japan in Sagami Bay, North Pacific Ocean. Phanodermopsis kohtsukai sp. nov. differs from the congeners by the shape of the tail, the longer spicules, and the absence of the gubernaculum. Micoletzkyia nakanoi sp. nov. differs from the congeners by the absence of a circle of cervical setae, the proportion of the tail, the cylindrical gubernaculum without projection, and the position of the vulva. Crenopharynx caudata (Filipjev, 1927) comb. nov. is transferred from the genus Phanodermopsis based on the presence of the long spicules. The morphological characters of the newly collected specimens of C. caudata comb. nov. are in excellent agreement with those shown in the original description of the specimens from Arctic Russia and the previous redescription of the specimens from Skagerrak. The new diagnoses and species lists for these three genera and two dichotomous keys to the males of Micoletzkyia and Crenopharynx are provided.

Paranticoma lepta sp. n. and Elzalia bipectinella Hope amp; Aryuthaka, 2009 from water bodies of Vietnam.

Two nematode species found in water bodies of Vietnam are described and illustrated. Paranticoma lepta sp. n., found in mangroves of the Yen River estuary is morphologically close to P. bendaense Micoletzky, 1930 and P. tricerviseta Zhang, 2005. From the former species it differs by the shorter cephalic setae and shorter tail, more anteriorly located cervical setae and shorter spicules. From the second species it differs by its thicker body, comparatively longer tail, longer spicules and absence of tooth-like structures in stoma. An illustrated description of males and females of Elzalia bipectinella Hope Aryuthaka 2009 is given, originally described from mangrove forest in the Andaman Sea coastal zone of east Thailand. Females of this species are described for the first time.

Paramonohystera weihaiensis sp. nov. (Xyalidae, Nematoda) from the intertidal beach of the Yellow Sea, China

A new species of free-living marine nematode of the genus Paramonohystera was described from the intertidal beach, Weihai. Paramonohystera weihaiensis sp. nov. is characterized by cervical region with a circle of long setae; tail sexual dimorphism, male tail angled dorsally with sharp narrowed of the body at the cloaca, female tail ordinary conico-cylindrical; spicules slender, 2.5 abd long; gubernaculum plate, enlarged distal end with two teeth, without apophysis; precloacal supplements absent; Four caudal gland cells obviously extended to tail. The new species differs from the other fourteen known valid congeners by the combination of its characteristics: a circle of long cervical setae, tail sexual dimorphism, spicules slender, 2.5 abd long, gubernaculum plate with a distal pair of teeth.

A new species of the genus Thalassironus (Nematoda: Enoplida: Ironidae)from the coasts of South Korea.

A new species of the genus Thalassironus de Man, 1889 was discovered during several surveys of the offshore marine ecosystem in Korea. This new species belonging to the family Ironidae, Thalassironus koreanus sp. nov., shares general morphological traits of the genus such as an optically smooth cuticle, buccal cavity consisting of two parts with three movable teeth and thick cuticularized walls, six rounded lips with ten cephalic setae, slit-like amphid and short conical tail with caudal glands present. The new species is most closely related to T. bohaiensis, first discovered in the Bohai Sea, in terms of body ratio (a, b, c, c') and general morphology, but differs by its generally longer and larger body structures, cervical setae at the level of the buccal cavity, paired somatic setae distributed along the body, and longer/larger spicule. A description of Thalassironus koreanus sp. nov., diagnosis of the genus, emended pictorial key for the genus and discussion of important characteristics for the genus is provided.

Two New Species of Free-Living Nematodes of the Family Linhomoeidae (Nematoda, Monhysterida) from Mangrove Forests in Vietnam

An illustrated description of two species of free-living nematodes of the family Linhomoeidae Filipjev, 1922, new to science, found in the sediments of a thick mangrove forest in the Yen River, Vietnam, is presented. Desmolaimus minor sp. n. is morphologically similar to D. calvus Gerlach, 1956, but has a shorter body, two-separate internal cavity of pharynx, and setiform labial and cephalic sensilla. A review of species of the genus Desmolaimus de Man, 1888 is made, and a pictorial key to determinate valid species of this genus is provided. Terschellingia yenensis sp. n. is similar to T. lissa Timm, 1962 and T. longissimicaudata Timm, 1962. It differs from T. lissa by the presence of precloacal supplements in males, the presence of cervical setae, a longer tail, and shorter spicules; it differs from T. longissimicaudata by a comparatively longer tail, shorter spicules, and a longer dorsal apophysis of gubernaculum.

Two new species of the genus Daptonema Cobb, 1920 (Nematoda: Xyalidae) found in an intertidal seagrass bed on the coast of the Andaman Sea, Thailand, with reference to the taxonomic status of the genus Trichotheristus Wieser, 1956.

Daptonema chonispiculum sp. n. and D. phuketense sp. n. are described from the Ban Pa Khlok seagrass bed, Phuket Province, Thailand. Daptonema chonispiculum sp. n. is characterized by spicules with funnel-shaped proximal ends, and D. phuketense sp. n. is unique in having the third caudal gland filled with fibrous contents. Each new species also differs from most related species in body length, de Man's indices, length of the cephalic setae and somatic/cervical setae, distance of the amphids from the anterior of the body, and length of the spicules. The new species most closely resemble D. hirsutum, D. platonovae, and D. robustum, with similar body lengths, long cervical setae located in the anterior pharyngeal region, small amphids, L-shaped spicules and a gubernaculum with a long dorso-caudal apophysis. Regarding the taxonomic status of Daptonema and Trichotheristus, we agree with the synonymization of Trichotheristus with Daptonema by Tchesunov (1990), based on taxonomic review of Trichotheristus and a comparison of the diagnostic features separating the genera. We propose a new combination, Daptonema galeatum comb. n., and a new name, Daptonema nearticulatum sp. n. for Trichotheristus articulatus Huang Zhang, 2006.

Two new species of Paramphimonhystrella (Nematoda, Monhysterida, Xyalidae) from the deep-sea sediments in the Western Pacific Ocean and adjacent shelf seafloor.

Two new species of marine nematodes, Paramphimonhystrella longispicula sp. n. in the deep-sea sediments from the Philippine Sea in the tropical Western Pacific Ocean with the water depth of 3920-5176 m and P. eurystoma sp. n. in the shelf seafloor from the East China Sea with the water depth of 55-64 m, are described. Both species possess long and slender spicules, which are present only in the congener P. barbula, a species discovered from the continental slope of New Zealand. Paramphimonhystrella longispicula sp. n. can be easily distinguished from P. barbula by the relatively broader buccal cavity, the unequally long cervical setae and a higher number of terminal setae. Paramphimonhystrella eurystoma sp. n. is unique in having a peculiar gubernaculum with two proximal capitula and a peculiar hammer-shaped cuticularized piece posterior to vulva, by which it can be distinguished from P. longispicula sp. n. and P. barbula as well as other congeners. Paramphimonhystrella longispicula sp. n. differs from P. eurystoma sp. n. also by the number of terminal setae (4 vs. 2). A dichotomous key to nine valid species of Paramphimonhystrella is provided.

One new species and one new combination of the family Xyalidae (Nematoda: Monhysterida) from the East China Sea

A new species and a new combination of the family Xyalidae are described from the East China Sea. Elzalia bifurcata sp. nov. is characterized by small body size, relatively long cephalic setae, elongated spicules with bifurcate or y-shaped distal end, simple tubular gubernaculum without apophyses. Elzalia bifurcata sp. nov. differs from the closely related species E. striatitenuis Zhang and Zhang, 2006 and E. mediterranea Vitiello, 1971 by the length of cephalic setae; presence or absence of cervical setae; shape, structure and length of spicules and gubernaculum. Daptonema macrostoma Huang & Xu, 2013 is redescribed and reclassified. The species agrees well with the characters of the genus Paragnomoxyala Jiang & Huang, 2015, such as large buccal cavity; outer labial sensilla papilliform, not setiform; spicules almost straight with slightly curved proximal ends, absence of gubernaculum. Therefore, it is transferred to the genus Paragnomoxyala. As a new combination, the species is named as Paragnomoxyala macrostoma (Huang & Xu, 2013) comb. nov. An emended key to valid species of Elzalia is provided.