Species Of Free-living Marine Nematodes Research Articles

Two new nematode species of the family Diplopeltidae Filipjev, 1918 (Nematoda, Araeolaimida) from coast of Vietnam

Two new species of free-living marine nematodes from West Sea (Gulf of Siam), coast of Vietnam, were described and illustrated. Diplopeltula obesa sp. n. differs from D. indica Gerlach, 1962 by possessing shorter and thicker body, comparatively longer tail and shorter cephalic setae, Campylaimus gracilis sp. n. resemble to C. minor Timm, 1961, but differs from the later by having an another shape of amphidial fovea, another position of mouth, longer body and shorter cephalic setae.

Enoplus taipingensis, a new species of marine nematode from the rocky intertidal seaweeds in the Taiping Bay, Qingdao

One new species of free-living marine nematodes Enoplus taipingensis sp. nov. from the rocky intertidal seaweeds in the Taiping Bay, Qingdao is described and illustrated with scanning electron microscopy observation and 18S rRNA gene sequence analysis. Enoplus taipingensis is characterized by special arrangement of lateral setae on the tail, three cervical setae, distal structure on the supplement, and much longer body length with bigger De Man ratio “a”. Type specimens are deposited in the College of Marine Life Science, Ocean University of China.

A New Species of Deep-sea Nematode, Micoletzkyia mawatarii sp. nov. (Nematoda: Enoplida: Phanodermatidae) from Northern Japan

A new species of free-living marine nematode, belonging to the genus Micoletzkyia Ditlevsen, 1926 (Phanodermatidae Filipjev, 1927), is described from the deep sea off the coast of Hokkaido, northern Japan. Micoletzkyia mawatarii sp. nov. resembles M. magna Vitiello, 1970 and M. longispicula Huang and Cheng, 2012 in the shape of the tail and gubernaculum, but differs from the former in body width and in length of the cephalic setae, and from the latter in body length, proportional length of the tail, position of the nerve ring, and shape of the precloacal supplement. Micoletzkyia mawatarii sp. nov. also resembles M. parelegans Allgen, 1954 in its large body size, but differs from it in esophagus length, shape of the gubernaculum, size and position of the precloacal supplement, and in having a longer tail.

One new free-living marine nematode species of genus Cephalanticoma from the South China Sea

One new species of free-living marine nematode Cephalanticoma brevicaudata sp. nov. from the South China Sea is described. Cephalanticoma brevicaudata sp. nov. is characterized by spindle body with relatively short tail; head with cephalic capsule; three teeth at anterior of pharynx; excretory pore opens posterior to cervical setae; three cervical setae per file; spicules arcuate, cephalate and ventrally bent proximally, and blunt distally, 1.8 a.b.d. long, without ventral ala; gubernaculun slender, simple rod, without apophyses; tubular supplement 34 µm long, 2.3 a.b.d. in front of cloaca.

Two new free-living marine nematode species of Chromadoridae (Nematoda: Chromadorida) from the Yellow Sea, China

Two new species of free-living marine nematodes, Ptycholaimellus ocellatus sp. nov. and Prochromadorella gracilis sp. nov. from the Yellow Sea, China are described. Ptycholaimellus ocellatus sp. nov. is characterized by the presence of ocelli, an abruptly narrowing anterior cervical region, a cuticle with transverse rows of punctations, a lateral differentiation with two longitudinal rows of thick elongate dots, and voluminous ventral gland with a large ampulla. Prochromadorella gracila sp. nov. is characterized by the combination of lateral differentiations in the anterior pharyngeal region, a small conical stoma with outstretched teeth, slit-like amphidial fovea, and five pre-cloacal supplements.

A new genus and two new species of marine free-living nematodes from the coastal waters of Southern Vietnam

A new genus and two new species of free-living marine nematodes from sediments in the coastal zone of the South China Sea (Vietnam) are described. Cyartonemoides gen. n. morphologically resembles Cyartonema Cobb, 1920, but differs from it in having a well-developed cephalic capsule. Cyartonemoides foetidus gen. n., sp. n. is the type and the only species of the genus. Campylaimus abnormis sp. n. differs from all species of the genus Campylaimus Cobb, 1920 by the shape of the amphidial fovea and shorter lateral fields.

Three new free-living marine nematode species of the genus Micoletzkyia (Phanodermatidae) from China Sea

Three new species of free-living marine nematodes Micoletzkyia longispicula sp. nov., Micoletzkyia filicaudata sp. nov. and Micoletzkyia nanhaiensis sp. nov. from the Yellow Sea and the South China Sea are described. Micoletzkyia longispicula sp. nov. is characterized by spicules elongated and straight, 7 a.b.d. long, pear-shaped proximally and pointed distally; gubernaculum conical, without apophysis, and tubular supplement headlike proximally. Micoletzkyia filicaudata sp. nov. is characterized by slender body with relatively long filiform tail (8.1 a.b.d.), spicules elongated and straight (4.4 a.b.d.), cephalate proximally and pointed distally, gubernaculum tubular, with dorsal apophysis. Micoletzkyia nanhaiensis sp. nov. is characterized by spicules slender and curved, 2.5 a.b.d. long, cephalous proximally and chapiter-shaped distally, and gubernaculum with relatively long dorsal apophysis. A key for all known species of Micoletzkyia is proposed.

Two new free-living marine nematode species of Xyalidae (Monhysterida) from the Yellow Sea, China

Two new species of free-living marine nematodes Paramonohystera eurycephalus sp. nov. and Steineria sinica sp. nov. from the Yellow Sea, China are described. Paramonohystera eurycephalus sp. nov. is characterized by relatively wide head diameter (33 μm in width), large cup-shaped buccal cavity; presence of numerous long cervical setae; amphidial fovea 18–20 μm in diameter; spicules slender, arcuate, 3.1–3.2 anal body diameter; gubernaculum tubular with a distal hook; five to six minute precloacal supplements. Steineria sinica sp. nov. is characterized by eight groups of three subcephalic setae at almost same level as cephalic setae; eight groups of two long cervical setae situated between subcephalic setae and amphidial fovea; amphidial fovea round, 35% of corresponding body diameter, about one head diameter from anterior end; spicules slender, cephalate proximally and taper distally; gubernaculum pipe-shaped with dorsocaudal apophysis; tail conico-cylindrical with three long terminal setae.

Two new free-living marine nematode species of the genus Pseudosteineria (Monohysterida: Xyalidae) from the Yellow Sea, China

Two new species of free-living marine nematode, Pseudosteineria sinica sp. nov. and Pseudosteineria zhangi sp. nov., from the Yellow Sea, China are described. Pseudosteineria sinica sp. nov. is characterized by body spindle-shaped, cuticle distinctly annulated; amphidial fovea not visible; spicules unequal in length, the longer one divided into two sections jointed in the middle, the shorter one simple, without indentation; both spicules curved with proximal capitulum, tapered distally; gubernaculum with a dorso-caudal apophysis. Pseudosteineria zhangi sp. nov. is characterized by eight groups of relatively short subcephalic setae; amphidial fovea circular, lying at level of grouped subcephalic setae; spicules paired, equal in length, dissimilar in shape; right spicule slender, left one with a large manubrium proximally; gubernaculum bucket-shaped, with a dorsal apophysis. A key to species is provided for the 13 valid species of the genus.

New free-living marine nematode species (Nematoda: Desmodoridae) from the coast of New Zealand

Pseudochromadora reathae n. sp. is described from intertidal sand in Otago Harbour (southern New Zealand), and Pseudodesmodora lacrima n. sp. is described from subtidal sediment in the Firth of Thames (northern New Zealand). Pseudochromadora reathae n. sp. differs from other species of the genus through the combination of the following characters: sexual dimorphism in the shape of the apertura amphidialis, no interdigitation of body annuli at level of lateral alae, presence of eight longitudinal rows of somatic setae, and conspicuous pre-cloacal supplements consisting of star-shaped projections flanked by two cuticularised pieces. Pseudodesmodora lacrima n. sp. is characterised by the presence of large unispiral amphids on amphidial plates, conspicuous ducts in the head region, low a values, and short cephalic setae.

Two new free-living marine nematode species of the genus Paramarylynnia (Chromadorida: Cyatholaimidae) from the Yellow Sea, China

Two new species of free-living marine nematodes Paramarylynnia filicaudata sp. nov. and Paramarylynnia stenocervica sp. nov. from the Yellow Sea, China are described. Paramarylynnia filicaudata sp. nov. is characterized by a homogeneous cuticle with transverse rows of even dots; spicules boat-shaped, swollen in the middle and gradually tapering towards both ends; tail conical with a long filiform terminal portion and without subventral setae on the conical part. Paramarylynnia stenocervica sp. nov. is characterized by the marked narrower anterior part of the neck region; heterogeneous cuticle with transverse rows of punctations and the punctations of anterior contracted portion larger and more widely spaced than the remaining portion; spicules curved and cephalate proximally; gubernaculum boat-shaped, swollen in the middle and gradually tapering towards both ends, five small tubular precloacal supplements.

Three new species of Dichromadora (Nematoda: Chromadorida: Chromadoridae) from the Yellow Sea, China

Three new species of free-living marine nematodes belonging to Dichromadora Kreis: Dichromadora major sp. nov., Dichromadora multisetosa sp. nov., Dichromadora sinica sp. nov. from the Yellow Sea, China are described and illustrated. Dichromadora major sp. nov. is characterized by the combination of the presence of a clearly anterior pharyngeal bulb, crescent-shaped amphides, nine precloacal supplements, arcuate spicules and gubernaculum with a lateral swelling about the middle. Dichromadora multisetosa sp. nov. is characterized by the presence of a clearly anterior dorsal pharyngeal bulb and rounded posterior one, long somatic setae and a broad dorsal caudal apophysis of gubernaculum. Dichromadora sinica sp. nov. is characterized by the presence of double posterior pharyngeal bulb, four longitudinal files of lateral punctations, spicules with distal hook, four (3 + 1) precloacal supplements and paired subventral double-jointed postcloacal papillae in males.

Two new species of Xyalidae (Nematoda) from the Yellow Sea, China

Two new species of free-living marine nematodes, Daptonema longiapophysis sp. nov. and Cobbia sinica sp. nov. from the Yellow Sea, China are described and illustrated. Daptonema longiapophysis sp. nov. is characterized by spicules with a projection on the ventral and dorsal side respectively and the length of the gubernacular apophysis longer than the length of spicules. Cobbia sinica sp. nov. is characterized by one big dorsal tooth, long conico-cylindrical tail and gubernaculum with a small dorsal apophysis.

Three New Species of Free-living Marine Nematodes (Nematoda: Enoplida) from Northern Japan

Three new species of free-living marine nematodes, belonging to three genera, Epacanthion Wieser, 1953, Enoplolaimus De Man, 1893 (both family Enoplidae Dujardin, 1845), and Oncholaimus Dujardin, 1845 (family Oncholaimidae Filipjev, 1916), are described from northern Japan. Epacanthion quadridiscus sp. nov. is most similar to Epacanthion enoploidiforme (Gerlach, 1953), E. gorgonocephalum Warwick, 1970, and E. georgei Inglis, 1971 in spicule length and the absence of a precloacal supplement, but differs from them in the shape of the gubernaculum and the arrangement of the subcephalic and cervical setae in the male. Enoplolaimus longigubernaculum sp. nov. differs from all of its congeners in having a long and straight gubernaculum. Oncholaimus secundicollis sp. nov. is distinguished from all of its congeners by the presence of a precloacal papilla, postcloacal papilla, and tail papilla in the male.

Description ofOncholaimus moanaesp. nov. (Nematoda: Oncholaimidae), with notes on feeding ecology based on isotopic and fatty acid composition

A new free-living marine nematode species,Oncholaimus moanaesp. nov., is described from intertidal fine sand in southern New Zealand.Oncholaimus moanaesp. nov. can be distinguished from other species of the genus by the presence of a pre-cloacal papilla bearing four pairs of short, stout spines, a post-cloacal papilla, long (>70 μm) spicules, and a demanian system with two openings situated laterally at level of uvette. The δ13C signature ofO. moanaesp. nov. suggests that benthic microalgae are the main carbon source for this species, but an elevated δ15N signature suggests predatory feeding habits. The fatty acid composition ofO. moanaesp. nov. is rich in highly unsaturated fatty acids, which are likely to originate from heterotrophic protists (e.g. ciliates). The data obtained in this study suggest, for the first time, that marine nematodes can be a high quality food source (i.e. rich in highly unsaturated fatty acids) to predators. Large nematodes living near or at the sediment surface, in particular, may represent an important trophic link between heterotrophic protists and higher trophic levels in marine sediments.

A new genus and new species of free-living marine nematodes from the Yellow Sea, China

A new genus and one new species of free-living marine nematodes Paramarylynnia gen. nov., Paramarylynnia subventrosetata sp. nov. from the Yellow Sea, China are described and illustrated. Paramarylynnia gen. nov. is characterized by a cuticle with transverse rows of even dots; absence of lateral differentiation; gubernaculum large and dilated at the distal end, no distal dentation; precloacal supplements absent; tail conico-cylindrical.The type species of Paramarylynnia gen. nov. is Paramarylynnia subventrosetata sp. nov.

Sublittoral meiofauna with particular reference to nematodes in the southern Yellow Sea, China

Densities of major meiofaunal taxa were investigated at 34 sampling stations during six cruises by R/V Beidou to the southern Yellow Sea, China from 2000 to 2004, and the community structure of free-living marine nematodes was studied during one of the cruises in 2003. Meiofauna abundance ranged from 487.4 to 1655.3 individuals per 10 cm 2. Nematodes and harpacticoid copepods were the two most dominant groups, contributing 73.8–92.8% and 3.5–18.7%, respectively, to the total meiofauna abundance. One-way ANOVA showed no significant annual fluctuation of meiofauna and nematode abundances from 2000 to 2004 in the southern Yellow Sea. However, two-way ANOVA based on six stations sampled in 4 years (2001–2004) showed that there were significant differences among the six stations and the 4 sampling years for meiofauna, nematode and copepod abundance. Correlation analysis demonstrated that meiofauna abundance was mainly linked to chloroplastic pigments. Other environmental factors could not be ruled out, however. A total of 232 free-living marine nematode species, belonging to 149 genera, 35 families and 4 orders, were identified. The dominant species in the sampling area were the following: Dorylaimopsis rabalaisi, Microlaimus sp.1, Prochromadorella sp., Promonohystera sp., Cobbia sp.1, Daptonema sp.1, Leptolaimus sp.1, Halalaimus sp.2, Aegialoalaimus sp., Chromadorita sp., Parodontophora marina, Parasphaerolaimus paradoxus, Quadricoma sp.1, Campylaimus sp.1, Halalaimus gracilis, Paramesacanthion sp.1, Paramonohystera sp.1, and Metalinhomoeus longiseta. CLUSTER and SIMPROF analyses revealed three main types of nematode community (or station groups) in the sampling area, including I: coastal community, II: transitory community between coastal and YSCWM (Yellow Sea Cold Water Mass), and III: YSCWM community. Each community was indicated by a number of dominant nematode species. Bio-Env correlation analysis between the nematode community and environmental variables showed that water depth, sediment water content, organic matter, chlorophyll a (Chl- a) and phaeophorbide a (Pha- a) were the most important factors to determine the community structure.

Two new species of the genus Elzalia (Nematoda: Monhysterida: Xyalidae) from the Yellow Sea, China

Two new species of free-living marine nematodes of the genus Elzalia, Elzalia gerlachi sp. nov. and Elzalia striatitenuis sp. nov. from the Yellow Sea, China, are described and illustrated. Elzalia gerlachi sp. nov. is characterized by relatively large body length (1540–1740 μm in males; 1510–1780 μm in females), spicules 135–160 μm (3.33–3.90 anal body diameter) and complex gubernaculum. Elzalia striatitenuis sp. nov. is characterized by rather small body size (560–660 μm in males; 570–630 μm in females), short cephalic setae 2.5 μm long (21.4–31.3% of head diameter), spicules 65–85 μm (4.06–4.67 anal body diameter) and relatively simple gubernaculum. The two new species can be distinguished from other species of the genus by length and structure of spicules and gubernaculum. Pictorial and tabular keys to the genus are given.

New species of free-living marine nematodes from the Yellow Sea, China

Three new species of free-living marine nematodes: Oncholaimus multisetosus sp. nov., Sabatieria stenocephalus sp. nov. and Setosabatieria coomansi sp. nov. from the Yellow Sea, China are described and illustrated. The male of Oncholaimus multisetosus sp. nov. is characterized by a tail sharply constricted at the junction of the conical and cylindrical sections; two circles of 12–15 pairs of circumcloacal setae each. In the female, the conical section of the tail gradually tapers in a cylindrical section. Sabatieria stenocephalus sp. nov. is characterized by the pronounced sharp-pointed anterior body, sclerotized tooth-like front edge of buccal cavity and 15 tubular-shaped precloacal supplements with the posterior five more closely spaced. Setosabatieriacoomansi sp. nov. can be separated from the other species of the genus by the number (6–8) of cervical setae per file, the number of precloacal supplements (15) and the absence of central strips in spicules and leaf-like extensions of the cuticle lateral to the cloaca. Types are deposited in the College of Marine Life Sciences, Ocean University of China.

Five new records of free-living marine nematodes in the Yellow Sea

Five species of free-living marine nematodes are redescribed and illustrated as new records in the Yellow Sea of China. These species include one monhysterid,Campylaimus gerlachi in the family Diplopeltidae and four enoplids species,Oxystomina elongata, Oxystomina elegans, Halalaimus lutarus andHalalaimus wodjanizkii in the family Oxystominidae. E-cological and taxonomic remarks are provided and discussed in comparison with the original description. The key to all known species of the genusCampylaimus is given. Our findings have offerred the taxonomic information of nematodes to the benthic ecology and biodiversity studies of the Yellow Sea.