Free living marine nematodes were sampled from two sandy beaches in Dalian City,in December of 2015,and April,July,and October of 2016.The spatial and seasonal variations of marine nematode species diversity(based on ...Free living marine nematodes were sampled from two sandy beaches in Dalian City,in December of 2015,and April,July,and October of 2016.The spatial and seasonal variations of marine nematode species diversity(based on species abundance dataset)and functional diversity(based on functional traits dataset:feeding types and life history strategies)were investigated to understand the environmental drivers and how they respond to specific environmental variations.Sediment granularity was revealed to be the main environmental factor causing spatial differences in nematode diversity indices between the two beaches.Species diversity indices,namely species number,Margalef index,Shannon-Wiener diversity index(H’),were higher in fine-grained sediments,while the functional diversity indices,including functional evenness,functional dispersion,and Rao’s quadratic entropy index(RaoQ),were higher in coarse-grained sediments.Nematode species diversity indices also fluctuated with seasonal variations of temperature,dissolved oxygen,pH,salinity,and sediment chlorophyll-a within the study beaches.However,functional diversity indices did not show significant seasonal variations and exhibited weak correlation with the studied environmental variables.Overall,the functional diversity indices were negatively correlated with the species diversity indices,suggesting an inconsistent response to environmental changes.A decrease in nematode species diversity in coarse sands,accompanied by an increase in functional diversity,can be regarded as an early warning signal of environment disturbance.If more biological traits are involved in calculating functional diversity indices,it will be helpful for the future study of the internal connections of species diversity and functional diversity.展开更多
Marine free-living nematodes were investigated at 13 sampling stations divided into three transects in the northern Taiwan Strait in February 1998. One hundred species of marine nematodes belonging to 91 Genera 28 Fa...Marine free-living nematodes were investigated at 13 sampling stations divided into three transects in the northern Taiwan Strait in February 1998. One hundred species of marine nematodes belonging to 91 Genera 28 Families 3 Orders were identified and were first recorded in the northern Taiwan Strait. The dominant species were Vasostoma sp., Sabatieria sp. 1, Linhystera sp. 1, Spilophorella sp., Daptonema sp., Halalaimus sp. and Dorylaimopsis variabilis. Their main densities were all over 4 950 ind./m2. According to mean density at transects, marine nematode density decreased from coastal Weitou to off Minjiang Estuary, which was similar to polychaete distribution in northern Taiwan Strait. The selective deposit feeder (1A) was the dominant food type of marine nematodes in the northern Taiwan Strait, but non-selective deposit feeders (1B) and epigrowth feeders (2A) occupied high proportion, indicating diverse feeding types of marine nematodes in the northern Taiwan Strait. Some environmental factors such as currents are discussed.展开更多
One new species of free-living marine nematode of the genus Curvolaimus, Curvolaimus filiformis sp. nov. from the Huanghai Sea is described and illustrated. This new species is characterized by the buccal cavity teeth...One new species of free-living marine nematode of the genus Curvolaimus, Curvolaimus filiformis sp. nov. from the Huanghai Sea is described and illustrated. This new species is characterized by the buccal cavity teeth, large amphids and two ventral seta at the conical part of tail. Meanwhile, two new records of genus Halalaimus, Halalaimus longicaudatus and H. isaitshikovi are fast reported in China. Types are deposited in the College of Marine Life Sciences, Ocean University of China.展开更多
Free-living marine nematodes were sampled and studied at a grid of 22 stations (from 32°29.35′ to 37°0.56′N, 122°0.37′ to 125°1.16′ E) in the southern Huanghai Sea in January 2003. Nematode a...Free-living marine nematodes were sampled and studied at a grid of 22 stations (from 32°29.35′ to 37°0.56′N, 122°0.37′ to 125°1.16′ E) in the southern Huanghai Sea in January 2003. Nematode abundance varied from 50.5 to 127.2 ind./cm^2 [(83.1 ±24.7) ind./cm^2] at different stations, 80.1% of the total nematodes were in the surface layer (0-2 cm) of sediments. Two hundred and twenty-three species or taxa of marine nematodes belonging to 145 genera, 32 families and four orders were identified and first recorded in the Huanghai Sea. The common dominant species were Dorylaimopsis rabalaisi, Terschellingia longicaudata, Sphaerolaimus bolticus, Metalinhomoeus longiseta, Quadricoma scanica, Prochromadorella sp., Paramonohystera riemanni, Marylynnia sp. 1, Vasostoma spircaum, Halalaimus spp., Pierrickia sp. 1 and Promonhystera faber. Nematode diversity was correlated with sediment granularity. Pearson correlation analysis showed that Shannon-Wiener index had highly significant positive correlation with a sand content and negative correlation with a silt-clay content (P〈0.01); species richness index (d) had significant positive correlation with the sand content and negative correlation with the silt-clay content (P〈0.05). The diversity of the southern Huanghai Sea was lower than that in the center of Bohai Sea, but the dominance was higher.展开更多
One new species of free-living marine nematodes Cephalanticomafilicaudata sp. nov. from the Huanghai Sea, China is described and illustrated. Cephalanticomafilicaudata sp. nov. is characterized by well developed cepha...One new species of free-living marine nematodes Cephalanticomafilicaudata sp. nov. from the Huanghai Sea, China is described and illustrated. Cephalanticomafilicaudata sp. nov. is characterized by well developed cephalic capsule, three teeth at the anterior of oesophagus, excretory pore opens posterior to cervical setae, only two cervical setae per file, body length longer than 5 200 μm, tail long and no ventral-lateral seta between the supplement and the cloacal opening. Types are deposited in the College of Marine Life Sciences, Ocean University of China.展开更多
Three species in genus Sabatieria and one in genus Cervonema from the East China Sea were recorded. S. breviseta is characterized by uniformly punctuated coarse dots, large amphids of 5.5 turns (♂) and prominent gube...Three species in genus Sabatieria and one in genus Cervonema from the East China Sea were recorded. S. breviseta is characterized by uniformly punctuated coarse dots, large amphids of 5.5 turns (♂) and prominent gubernaculum median piece. The characters of S. breviseta agree quite well with the European original descriptions and only differ in the male amphid turns (5.5 vs. 4.0 turns) and unmodified preanal supplements (5-7 vs. 6). S. pulchra can be recognized by amphid 2.75 turns, irregularly arranged lateral dots, and the first three supplements anterior to the anus, which are more widely spaced than the following ones. The excretory system of S. breviseta and S. pulchra shows sexual dimorphism. S. celtica is defined by amphids 2.00-2.25 turns, weakly developed pharyngeal bulb, curved apophyses and 12-13 conspicuous supplements. C. deltensis is characterized by amphids 4.75 turns, ovate pharyngeal posterior bulb, sperm dimorphism, 7 thin preanal supplements, and long tail cylindrical portion (50%-53% of tail length). All the three Sabatieria species are for the first time recorded in Chinese waters. C. deltensis was originally isolated from the Bohai Sea and Yellow Sea and newly recorded in the East China Sea.展开更多
A quantitative study on the community structure and biodiversity of free-living marine nematodes and their relationship with environmental factors in the northern South China Sea were carried out based on the samples ...A quantitative study on the community structure and biodiversity of free-living marine nematodes and their relationship with environmental factors in the northern South China Sea were carried out based on the samples collected at five stations in the deep sea (from 313 to 1 600 m) and one station in shallowwaters (87 m) during the cruise in September, 2010. Results showed that the abundance of marine nematodes ranged from 224 to 1 996 ind./(10 cm2). A total of 69 free-living marine nematode genera, belonging to 26 families and three orders, were identified. The most dominant genera were Sabatieria, Linhystera, Aegialoalaimus and Daptonema according to SIMPER analysis. Results of CLUSTER analysis revealed four types of marine nematode community (or station groups) in the sampling area. In terms of trophic structure, non-selective deposit feeders (1B) and selective deposit feeders (1A) were the dominant trophic types with highest genera numbers and abundances, which implied that organic detritus was the main food source of marine nematodes in the northern South China Sea. The percentage of male nematode was low, ranging from 2.22% to 17.81%, while those of juvenile individuals ranged from 36.99% to 82.09%. For genera level diversity of marine nematodes, Shannon-Wiener diversity indices (H') ranged from 3.76 to 4.57 and had highly significant negative correlation with water depth. In general, diversity indices H' at the five stations in deep sea (over 200 m) were lower than that at the station in shallow waters (87 m). BIOENV analysis showed that the most important environmental factor controlling marine nematode communities was water denth.展开更多
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 a...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.展开更多
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 ta...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; guberaaculun slender, simple rod, without apophyses; tubular supplement 34μm long, 2.3 a.b.d. in front of cloaca.展开更多
Mangroves are unique in their biodiversity,but studies on their meiobenthic biodiversity in China are scarce.Despite the importance of mangroves,little work has been done on the classification of nematodes in mangrove...Mangroves are unique in their biodiversity,but studies on their meiobenthic biodiversity in China are scarce.Despite the importance of mangroves,little work has been done on the classification of nematodes in mangrove wetlands.Fujian Province is the most northern point of China’s natural mangrove distribution,and it is also one of the provinces with the earliest constructed mangrove forest.In this paper,two new free-living marine nematode species of Desmodoridae from the Xiamen mangrove wetlands in China are described.Metachromadora xiamenensis sp.nov.is characterized by a cylindrical body,and smooth head capsule set off from the rest of the body.The cuticle is finely annulated and thickened at the midbody.Lateral ridges run from the posterior end of the pharynx to the middle of the tail.The amphid foveae is loop shaped and opens at the top with a double contour amphidial,pharynx with bipartite cuticularized internal cavity.There are 18 tubular precloacal supplements and tail with three small protuberances.Molgolaimus euryformis sp.nov.is characterized by a relatively short and plump body with finely annulated cuticle,which is particularly obvious in the tail.The head is small and wide with intensive striates.The inner and outer labial sensilla are indistinct with short spicules and ventral apophysis,a gubernaculum with a block-shaped hook,a swollen conical-cylindrical tail and an absence of precloacal supplements.展开更多
A new free-living marine nematode species of the genus Rhinema belonging to the family Monoposthiidae was collected from marine sediments in the Qiongzhou Strait of the South China Sea,and it is described here as Rhin...A new free-living marine nematode species of the genus Rhinema belonging to the family Monoposthiidae was collected from marine sediments in the Qiongzhou Strait of the South China Sea,and it is described here as Rhinema longispicula sp.nov.The new species is characterized by coarsely annulated cuticle with 12 longitudinal ridges(alae)marked as reversed V-shaped.The first and second annuli broader and form a kind of a cephalic capsule.The amphideal fovea circular,situated in the middle of the broad second annulus,not surrounded by dense annulations.Buccal cavity cylindrical with a large dorsal tooth.Pharynx with a prominent anterior pharyngeal bulb and an elongated terminal bulb.Elongate spicules strongly curved,with cephalated proximal end and pointed distal end.Gubernaculum boat-shaped,without apophysis.A long and blunt precloacal seta present.Female with two opposed,outstretched ovaries.展开更多
Maturity index(MI), based on nematode life strategies, has been proposed in 1990 to assess the possible variations of the terrestrial and freshwater nematode assemblages induced by anthropogenic activities. It was s...Maturity index(MI), based on nematode life strategies, has been proposed in 1990 to assess the possible variations of the terrestrial and freshwater nematode assemblages induced by anthropogenic activities. It was subsequently applied also to marine ecosystems and, even if comparatively not yet very popular, it offers a good method to assess the ecological quality in relation to a wide range of anthropogenic drivers. However, few data are available on its response to physical stress, a key factor especially in the coastal areas. In this study, marine nematode genera from two study cases carried out in Maldives are used to test both MI and life strategy traits(i.e.,c-p classes) for detecting the effects of physical disturbance. The results confirm that nematodes are well adapted to physical stress showing a general high rate of recovery. C-p scaling and MI did not seem to be appropriate for revealing this disturbance type probably because there are no empirical evidences on the life strategy of several genera, and a possible differential response to various disturbance types may be hypothesized.展开更多
A hierarchical diversity index—taxonomic distinctness index Δ +, which was first defined by Warwick and Clark in 1998, was employed to evaluate the pollution status of the Bohai Sea with freeliving marine nematodes...A hierarchical diversity index—taxonomic distinctness index Δ +, which was first defined by Warwick and Clark in 1998, was employed to evaluate the pollution status of the Bohai Sea with freeliving marine nematodes. The result showed that the Bohai Bay and other coastal sampling sites might be affected by oil and gas production and other anthropogenic influences. In other words,anthropogenic disturbance was affecting this component of the benthos in these locations. And most offshore sampling sites in the middle of the Bohai Sea were clear and unpolluted.展开更多
Two new free-living marine nematode species from the mangrove wetlands of Fujian Province, China are identified and illustrated. Sabatieria conicoseta sp. nov. is characterized by its short conical somatic setae. Ther...Two new free-living marine nematode species from the mangrove wetlands of Fujian Province, China are identified and illustrated. Sabatieria conicoseta sp. nov. is characterized by its short conical somatic setae. There are 12-15 tubular pre-cloacal supplements and 12-15/Jm long straight gubernacular apophyses. Dorylaimopsis papilla sp. nov. is characterized by spicules which are 1.5-1.8 a. b. d, long with media cuticularized strip along entire spicules, and have a cephalated proximal end with small hooked. There are 16-18 small papillate precloacal supplements and 37-40 μm long dorso-caudal gubernacular apophyses.展开更多
Two new species of free living nematodes Tripyloides mangrovensis n. sp. and Tripyloides amoyanus n. sp. of genus Tripyloides de Man, 1886 are described from mangroves of the Tong'an Bay and Haimen Island in the Xiam...Two new species of free living nematodes Tripyloides mangrovensis n. sp. and Tripyloides amoyanus n. sp. of genus Tripyloides de Man, 1886 are described from mangroves of the Tong'an Bay and Haimen Island in the Xiamen Bay, China. The two species are both characterized by six stout outer labial setae, male without preanal papillae, tail conico-cylindrical without swollen terminally. Tripyloides mangrovensis n. sp. can be additionally by its buccal cavity consisting of two parts, amphid circular, distinct proximal conical and distal slender cylindrical portions, 2/3 of the tail cylindrical. Tripyloides amoyanus n. sp. is distinguished by buccal cavity consisting of three parts with small tooth, amphid small, rounded, like a comma-shaped loop, 1/3 of the tail cylindrical, gubernaculum with four denticles.展开更多
Two new species of free-living marine nematodes of the genera Hopperia and Nemanema are described from the sublittoral sediment of the East China Sea. Hopperia macramphida sp. nov. is characterized by having large amp...Two new species of free-living marine nematodes of the genera Hopperia and Nemanema are described from the sublittoral sediment of the East China Sea. Hopperia macramphida sp. nov. is characterized by having large amphidial fovea with five turns; arcuate spicules with enlarged proximal end and central internal lamella extending one third of spicule length from proximal end; gubernaculum with bent apophyses, six papilliform precloacal supplements; and conico-cylindrical tail with swollen tip and terminal setae. Nernanema minutum sp, nov. is characterized by relatively smaller body size in the genus; large oval amphidial fovea; conical tail; slender spicules with alae and hooked proximal end; ring-like gubernaculum; and papilliform precloacal supplements with three short setae. An updated dichotomous key is provided for the 17 species of Hopperia.展开更多
Actinonemafalciforrne sp. nov. was discovered from the continental-shelf sediments of the East China Sea. It is characterized by six outer labial setae and four cephalic setae in one circle, complex and heterogeneous ...Actinonemafalciforrne sp. nov. was discovered from the continental-shelf sediments of the East China Sea. It is characterized by six outer labial setae and four cephalic setae in one circle, complex and heterogeneous cuticular ornamentation with lateral differentiation, large and conspicuous amphideal fovea which is transversely ovalshaped, a single anterior testis, two opposed reflexed ovaries, falciform telamon (lateral pieces of gubernaculum), and the lack of spicule and gubernaculum. Within the genus Actinonema, only A. longicaudatum and the new species possess telamon and lack spicule and gubernaculum. Actinonemafalciforme sp. nov. can be easily differentiated from A. longicaudatum by its much shorter body length, the peculiar shape of the telamon and a shorter tail.展开更多
One new species and one new record species of Sphaerolaimus are described.Sphaerolaimus longispiculatus sp.nov.is characterized by body length 2213–2470µm,amphideal fovea 12%–16%corresponding body diameters in ...One new species and one new record species of Sphaerolaimus are described.Sphaerolaimus longispiculatus sp.nov.is characterized by body length 2213–2470µm,amphideal fovea 12%–16%corresponding body diameters in males and 9%–10%corresponding body diameters in females,long slender spicules 2.8–3.8 cloacal body diameters,eight small papilliform precloacal supplements,gubernaculum without apophysis,and tail conico-cylindrical,2.5–3.7 cloacal/anal body diameters long.Sphaerolaimus gracilis is recorded from the first time in the mangroves wetlands,it can be distinguished from the original desceiption by longer spicules(66–71µm vs 56µm)and wider body(a=20.1–21.4 vs 25).展开更多
A grid of 22 stations, giving a broad coverage of the spawning ground of anchovy in the southern Huanghai Sea was selected. Undis- turbed sediments were taken from sampling stations during the cruise in June 2003. The...A grid of 22 stations, giving a broad coverage of the spawning ground of anchovy in the southern Huanghai Sea was selected. Undis- turbed sediments were taken from sampling stations during the cruise in June 2003. The average abundance of meiofauna is (1 584± 686) ind./10cm2, with corresponding biomass (dwt) of (1 086±425)!μg/10cm2. The pattern of abundance of meiofauna is similar to the pattern of biomass. There are 65.88% meiofauna in 0 ̄2 cm sediments, 27.66% in 2 ̄5 cm sediments and 6.47% in 5 ̄8 cm sediments. The Spearman correlation analysis between meiofauna and environmental factors shows that abundance of meiofauna, free living ma- rine nematodes, benthic copepods has significant positive correlations with Chl-a. And the abundance of copepods has significant posi- tive correlations with several factors such as Chl-a, Pha-a, Chl-a plus Pha-a and organic matter. A total of 18 meiofauna groups are i- dentified. Nematode is the most dominant group, average abundance (1 404±670) ind/10cm2, accounting for 88.65%, and the follow- ing groups are also important: benthic copepods (5.48%), kinorhyncha (1.26%), polychaeta (1.07%). By biomass, dominant groups are nematodes (51.72%), polychaeta (21.84%), copepods (14.87%), ostracoda (4.92%), kinorhyncha (3.67%). A total of 90 species of ne- matodes are identified. The species composition of nematodes is listed based on selected two stations 7794 (coastal area) and 10694 (cold water mass in deep waters).展开更多
A quantitative study on meiofauna was carried out along a transect throughout the Changjiang Estuary' s oxygen minimum zone (OMZ) in the East China Sea. There exist two distinct station groups in the OMZ: the fine...A quantitative study on meiofauna was carried out along a transect throughout the Changjiang Estuary' s oxygen minimum zone (OMZ) in the East China Sea. There exist two distinct station groups in the OMZ: the fine-grained hypoxic area and the more fine-grained anoxie area. Meiofauna abundance ranged from ( 101.5±31.0) ind./cm^2 ( hypoxie area) to (369.9±123.9) ind./cm^2( anoxic area) along the transect. Free-living marine nematodes were the numerically dominant meiofauna at every station. The anoxic area differed significantly in meiofauna abundance and vertical distribution pattern from the hypoxic area. Within the anoxic area, nematodes abundance increased and amounted to over 90% of the total meiofauna; about 50% of nematodes were found in the 2-5 and 5-8 cm layers. At hypoxie stations, about over 85 % were restricted to the top 2 cm. Benthic eopepod abundance and dominance decreased consistently with the oxygen gradient. The pattern of meiofauna biomass was similar to that of abundance. The correlation analysis of the meiofauna numbers and environmental parameters indicated that abundance and biomass of total meiofauna and nematodes had significant or highly significant ( P 〈 0.05 or P 〈 0.01 ) correlations with Chl a and Pha a, but no significant ( P 〉 0.05 ) correlations with bottom-water oxygen ( BWO2 ). On the other hand, there was a highly significant positive correlation between benthic eopepod abundance and bottom-water oxygen (P 〈 0.05 ). The investigation on the nematode community structure indicated that two different nematode communities existed in hypoxic and anoxic areas. In certain way, the shift in nematode species composition distinguishes the anoxia to hypoxia. Nematode diversity was generally lower within the anoxic stations than the hypoxic ones, but the difference was not significant. Indices of the nematode community structure varied in relation to the bottom-water oxygen together with bottom-water temperature, Chl a concentration and median grain size of sediment.展开更多
基金This study was supported by the National Natural Science Foundation of China(Nos.41976100,41576153).
文摘Free living marine nematodes were sampled from two sandy beaches in Dalian City,in December of 2015,and April,July,and October of 2016.The spatial and seasonal variations of marine nematode species diversity(based on species abundance dataset)and functional diversity(based on functional traits dataset:feeding types and life history strategies)were investigated to understand the environmental drivers and how they respond to specific environmental variations.Sediment granularity was revealed to be the main environmental factor causing spatial differences in nematode diversity indices between the two beaches.Species diversity indices,namely species number,Margalef index,Shannon-Wiener diversity index(H’),were higher in fine-grained sediments,while the functional diversity indices,including functional evenness,functional dispersion,and Rao’s quadratic entropy index(RaoQ),were higher in coarse-grained sediments.Nematode species diversity indices also fluctuated with seasonal variations of temperature,dissolved oxygen,pH,salinity,and sediment chlorophyll-a within the study beaches.However,functional diversity indices did not show significant seasonal variations and exhibited weak correlation with the studied environmental variables.Overall,the functional diversity indices were negatively correlated with the species diversity indices,suggesting an inconsistent response to environmental changes.A decrease in nematode species diversity in coarse sands,accompanied by an increase in functional diversity,can be regarded as an early warning signal of environment disturbance.If more biological traits are involved in calculating functional diversity indices,it will be helpful for the future study of the internal connections of species diversity and functional diversity.
基金the Key Item of National Natural Science Foundation of China under contract No.49636220.
文摘Marine free-living nematodes were investigated at 13 sampling stations divided into three transects in the northern Taiwan Strait in February 1998. One hundred species of marine nematodes belonging to 91 Genera 28 Families 3 Orders were identified and were first recorded in the northern Taiwan Strait. The dominant species were Vasostoma sp., Sabatieria sp. 1, Linhystera sp. 1, Spilophorella sp., Daptonema sp., Halalaimus sp. and Dorylaimopsis variabilis. Their main densities were all over 4 950 ind./m2. According to mean density at transects, marine nematode density decreased from coastal Weitou to off Minjiang Estuary, which was similar to polychaete distribution in northern Taiwan Strait. The selective deposit feeder (1A) was the dominant food type of marine nematodes in the northern Taiwan Strait, but non-selective deposit feeders (1B) and epigrowth feeders (2A) occupied high proportion, indicating diverse feeding types of marine nematodes in the northern Taiwan Strait. Some environmental factors such as currents are discussed.
文摘One new species of free-living marine nematode of the genus Curvolaimus, Curvolaimus filiformis sp. nov. from the Huanghai Sea is described and illustrated. This new species is characterized by the buccal cavity teeth, large amphids and two ventral seta at the conical part of tail. Meanwhile, two new records of genus Halalaimus, Halalaimus longicaudatus and H. isaitshikovi are fast reported in China. Types are deposited in the College of Marine Life Sciences, Ocean University of China.
文摘Free-living marine nematodes were sampled and studied at a grid of 22 stations (from 32°29.35′ to 37°0.56′N, 122°0.37′ to 125°1.16′ E) in the southern Huanghai Sea in January 2003. Nematode abundance varied from 50.5 to 127.2 ind./cm^2 [(83.1 ±24.7) ind./cm^2] at different stations, 80.1% of the total nematodes were in the surface layer (0-2 cm) of sediments. Two hundred and twenty-three species or taxa of marine nematodes belonging to 145 genera, 32 families and four orders were identified and first recorded in the Huanghai Sea. The common dominant species were Dorylaimopsis rabalaisi, Terschellingia longicaudata, Sphaerolaimus bolticus, Metalinhomoeus longiseta, Quadricoma scanica, Prochromadorella sp., Paramonohystera riemanni, Marylynnia sp. 1, Vasostoma spircaum, Halalaimus spp., Pierrickia sp. 1 and Promonhystera faber. Nematode diversity was correlated with sediment granularity. Pearson correlation analysis showed that Shannon-Wiener index had highly significant positive correlation with a sand content and negative correlation with a silt-clay content (P〈0.01); species richness index (d) had significant positive correlation with the sand content and negative correlation with the silt-clay content (P〈0.05). The diversity of the southern Huanghai Sea was lower than that in the center of Bohai Sea, but the dominance was higher.
基金This work was supported by the National Key Basic Research Program from the Ministry of Science and Technology of China under contract Nos G19990437 and 2002CB412400the National Natural Science Foundation of China under contract No.40576061.
文摘One new species of free-living marine nematodes Cephalanticomafilicaudata sp. nov. from the Huanghai Sea, China is described and illustrated. Cephalanticomafilicaudata sp. nov. is characterized by well developed cephalic capsule, three teeth at the anterior of oesophagus, excretory pore opens posterior to cervical setae, only two cervical setae per file, body length longer than 5 200 μm, tail long and no ventral-lateral seta between the supplement and the cloacal opening. Types are deposited in the College of Marine Life Sciences, Ocean University of China.
文摘Three species in genus Sabatieria and one in genus Cervonema from the East China Sea were recorded. S. breviseta is characterized by uniformly punctuated coarse dots, large amphids of 5.5 turns (♂) and prominent gubernaculum median piece. The characters of S. breviseta agree quite well with the European original descriptions and only differ in the male amphid turns (5.5 vs. 4.0 turns) and unmodified preanal supplements (5-7 vs. 6). S. pulchra can be recognized by amphid 2.75 turns, irregularly arranged lateral dots, and the first three supplements anterior to the anus, which are more widely spaced than the following ones. The excretory system of S. breviseta and S. pulchra shows sexual dimorphism. S. celtica is defined by amphids 2.00-2.25 turns, weakly developed pharyngeal bulb, curved apophyses and 12-13 conspicuous supplements. C. deltensis is characterized by amphids 4.75 turns, ovate pharyngeal posterior bulb, sperm dimorphism, 7 thin preanal supplements, and long tail cylindrical portion (50%-53% of tail length). All the three Sabatieria species are for the first time recorded in Chinese waters. C. deltensis was originally isolated from the Bohai Sea and Yellow Sea and newly recorded in the East China Sea.
基金The Fundamental Research Funds for Central Universities of the Ministry of Education of China from Ocean University of China under contract Nos 201362018 and 201462008the National Natural Science Foundation of China under contract No.41006081the Scientific Research Award Foundation for Outstanding Middle-aged and Young Scientists of Shandong Province under contract No.BS2013HZ008
文摘A quantitative study on the community structure and biodiversity of free-living marine nematodes and their relationship with environmental factors in the northern South China Sea were carried out based on the samples collected at five stations in the deep sea (from 313 to 1 600 m) and one station in shallowwaters (87 m) during the cruise in September, 2010. Results showed that the abundance of marine nematodes ranged from 224 to 1 996 ind./(10 cm2). A total of 69 free-living marine nematode genera, belonging to 26 families and three orders, were identified. The most dominant genera were Sabatieria, Linhystera, Aegialoalaimus and Daptonema according to SIMPER analysis. Results of CLUSTER analysis revealed four types of marine nematode community (or station groups) in the sampling area. In terms of trophic structure, non-selective deposit feeders (1B) and selective deposit feeders (1A) were the dominant trophic types with highest genera numbers and abundances, which implied that organic detritus was the main food source of marine nematodes in the northern South China Sea. The percentage of male nematode was low, ranging from 2.22% to 17.81%, while those of juvenile individuals ranged from 36.99% to 82.09%. For genera level diversity of marine nematodes, Shannon-Wiener diversity indices (H') ranged from 3.76 to 4.57 and had highly significant negative correlation with water depth. In general, diversity indices H' at the five stations in deep sea (over 200 m) were lower than that at the station in shallow waters (87 m). BIOENV analysis showed that the most important environmental factor controlling marine nematode communities was water denth.
基金The National Natural Science Foundation of China under contract Nos 4073087440576061 and 41076090
文摘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.
基金The National Natural Science Foundation of China under contract No.30770250the Knowledge Innovation Program of the Chinese Academy of Sciences under contract No.KZCX2-YW-417 to K Xuthe Open Research Cruise offshore China by R/V KE XUE SAN HAO,Institute of Oceanology,Chinese Academy of Sciences (IOCAS) in 2007
文摘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; guberaaculun slender, simple rod, without apophyses; tubular supplement 34μm long, 2.3 a.b.d. in front of cloaca.
基金funded by the National Natural Science Foundation of China (No. 41606119)the Provincial Natural Science Foundation of Fujian (No. 2017J05068)the New Century Outstanding Talents Support Program for Institutions of Higher Learning in Fujian Province and Building Ecological Security for Urban Agglomeration and Integrating Ecological Restoration Techniques for Coastal Zones in Fujian River Deltas (No. 2016YFC0502900)
文摘Mangroves are unique in their biodiversity,but studies on their meiobenthic biodiversity in China are scarce.Despite the importance of mangroves,little work has been done on the classification of nematodes in mangrove wetlands.Fujian Province is the most northern point of China’s natural mangrove distribution,and it is also one of the provinces with the earliest constructed mangrove forest.In this paper,two new free-living marine nematode species of Desmodoridae from the Xiamen mangrove wetlands in China are described.Metachromadora xiamenensis sp.nov.is characterized by a cylindrical body,and smooth head capsule set off from the rest of the body.The cuticle is finely annulated and thickened at the midbody.Lateral ridges run from the posterior end of the pharynx to the middle of the tail.The amphid foveae is loop shaped and opens at the top with a double contour amphidial,pharynx with bipartite cuticularized internal cavity.There are 18 tubular precloacal supplements and tail with three small protuberances.Molgolaimus euryformis sp.nov.is characterized by a relatively short and plump body with finely annulated cuticle,which is particularly obvious in the tail.The head is small and wide with intensive striates.The inner and outer labial sensilla are indistinct with short spicules and ventral apophysis,a gubernaculum with a block-shaped hook,a swollen conical-cylindrical tail and an absence of precloacal supplements.
基金Supported by the National Natural Science Foundation of China(No.41676146)the Science Foundation of Shandong Provincial Education Department(No.J18LE17)
文摘A new free-living marine nematode species of the genus Rhinema belonging to the family Monoposthiidae was collected from marine sediments in the Qiongzhou Strait of the South China Sea,and it is described here as Rhinema longispicula sp.nov.The new species is characterized by coarsely annulated cuticle with 12 longitudinal ridges(alae)marked as reversed V-shaped.The first and second annuli broader and form a kind of a cephalic capsule.The amphideal fovea circular,situated in the middle of the broad second annulus,not surrounded by dense annulations.Buccal cavity cylindrical with a large dorsal tooth.Pharynx with a prominent anterior pharyngeal bulb and an elongated terminal bulb.Elongate spicules strongly curved,with cephalated proximal end and pointed distal end.Gubernaculum boat-shaped,without apophysis.A long and blunt precloacal seta present.Female with two opposed,outstretched ovaries.
文摘Maturity index(MI), based on nematode life strategies, has been proposed in 1990 to assess the possible variations of the terrestrial and freshwater nematode assemblages induced by anthropogenic activities. It was subsequently applied also to marine ecosystems and, even if comparatively not yet very popular, it offers a good method to assess the ecological quality in relation to a wide range of anthropogenic drivers. However, few data are available on its response to physical stress, a key factor especially in the coastal areas. In this study, marine nematode genera from two study cases carried out in Maldives are used to test both MI and life strategy traits(i.e.,c-p classes) for detecting the effects of physical disturbance. The results confirm that nematodes are well adapted to physical stress showing a general high rate of recovery. C-p scaling and MI did not seem to be appropriate for revealing this disturbance type probably because there are no empirical evidences on the life strategy of several genera, and a possible differential response to various disturbance types may be hypothesized.
文摘A hierarchical diversity index—taxonomic distinctness index Δ +, which was first defined by Warwick and Clark in 1998, was employed to evaluate the pollution status of the Bohai Sea with freeliving marine nematodes. The result showed that the Bohai Bay and other coastal sampling sites might be affected by oil and gas production and other anthropogenic influences. In other words,anthropogenic disturbance was affecting this component of the benthos in these locations. And most offshore sampling sites in the middle of the Bohai Sea were clear and unpolluted.
基金The National Natural Science Foundation of China under contract No.31772416the Science Foundation of Fujian Province under contract No.2017J01450
文摘Two new free-living marine nematode species from the mangrove wetlands of Fujian Province, China are identified and illustrated. Sabatieria conicoseta sp. nov. is characterized by its short conical somatic setae. There are 12-15 tubular pre-cloacal supplements and 12-15/Jm long straight gubernacular apophyses. Dorylaimopsis papilla sp. nov. is characterized by spicules which are 1.5-1.8 a. b. d, long with media cuticularized strip along entire spicules, and have a cephalated proximal end with small hooked. There are 16-18 small papillate precloacal supplements and 37-40 μm long dorso-caudal gubernacular apophyses.
基金The National Natural Science Foundation of China under contract No.41376113the Public Science and Technology Research Funds Projects of Ocean under contract No.201505004the National Key Research and Development Program of China under contract No.2016YFC0502900
文摘Two new species of free living nematodes Tripyloides mangrovensis n. sp. and Tripyloides amoyanus n. sp. of genus Tripyloides de Man, 1886 are described from mangroves of the Tong'an Bay and Haimen Island in the Xiamen Bay, China. The two species are both characterized by six stout outer labial setae, male without preanal papillae, tail conico-cylindrical without swollen terminally. Tripyloides mangrovensis n. sp. can be additionally by its buccal cavity consisting of two parts, amphid circular, distinct proximal conical and distal slender cylindrical portions, 2/3 of the tail cylindrical. Tripyloides amoyanus n. sp. is distinguished by buccal cavity consisting of three parts with small tooth, amphid small, rounded, like a comma-shaped loop, 1/3 of the tail cylindrical, gubernaculum with four denticles.
基金The National Natural Science Foundation of China under contract No.41676146the Natural Science Foundation of Shandong Province under contract No.ZR2014BM008
文摘Two new species of free-living marine nematodes of the genera Hopperia and Nemanema are described from the sublittoral sediment of the East China Sea. Hopperia macramphida sp. nov. is characterized by having large amphidial fovea with five turns; arcuate spicules with enlarged proximal end and central internal lamella extending one third of spicule length from proximal end; gubernaculum with bent apophyses, six papilliform precloacal supplements; and conico-cylindrical tail with swollen tip and terminal setae. Nernanema minutum sp, nov. is characterized by relatively smaller body size in the genus; large oval amphidial fovea; conical tail; slender spicules with alae and hooked proximal end; ring-like gubernaculum; and papilliform precloacal supplements with three short setae. An updated dichotomous key is provided for the 17 species of Hopperia.
基金The Strategic Priority Research Program of the Chinese Academy of Sciences under contract No.XDA11030201the National Natural Science Foundation of China under contract No.41706163China Postdoctoral Science Foundation under contract No.2016M602201
文摘Actinonemafalciforrne sp. nov. was discovered from the continental-shelf sediments of the East China Sea. It is characterized by six outer labial setae and four cephalic setae in one circle, complex and heterogeneous cuticular ornamentation with lateral differentiation, large and conspicuous amphideal fovea which is transversely ovalshaped, a single anterior testis, two opposed reflexed ovaries, falciform telamon (lateral pieces of gubernaculum), and the lack of spicule and gubernaculum. Within the genus Actinonema, only A. longicaudatum and the new species possess telamon and lack spicule and gubernaculum. Actinonemafalciforme sp. nov. can be easily differentiated from A. longicaudatum by its much shorter body length, the peculiar shape of the telamon and a shorter tail.
基金Supported by the National Natural Science Foundation of China(No.31772416)the Natural Science Foundation of Fujian Province(No.2017J01450)。
文摘One new species and one new record species of Sphaerolaimus are described.Sphaerolaimus longispiculatus sp.nov.is characterized by body length 2213–2470µm,amphideal fovea 12%–16%corresponding body diameters in males and 9%–10%corresponding body diameters in females,long slender spicules 2.8–3.8 cloacal body diameters,eight small papilliform precloacal supplements,gubernaculum without apophysis,and tail conico-cylindrical,2.5–3.7 cloacal/anal body diameters long.Sphaerolaimus gracilis is recorded from the first time in the mangroves wetlands,it can be distinguished from the original desceiption by longer spicules(66–71µm vs 56µm)and wider body(a=20.1–21.4 vs 25).
基金supported by the National Key Basic Research Programs from Ministry of Science and Technology of China under contract Nos G1999043709 and 2002CB412400the National Natural Science Foundation of China under contract No.40176033.
文摘A grid of 22 stations, giving a broad coverage of the spawning ground of anchovy in the southern Huanghai Sea was selected. Undis- turbed sediments were taken from sampling stations during the cruise in June 2003. The average abundance of meiofauna is (1 584± 686) ind./10cm2, with corresponding biomass (dwt) of (1 086±425)!μg/10cm2. The pattern of abundance of meiofauna is similar to the pattern of biomass. There are 65.88% meiofauna in 0 ̄2 cm sediments, 27.66% in 2 ̄5 cm sediments and 6.47% in 5 ̄8 cm sediments. The Spearman correlation analysis between meiofauna and environmental factors shows that abundance of meiofauna, free living ma- rine nematodes, benthic copepods has significant positive correlations with Chl-a. And the abundance of copepods has significant posi- tive correlations with several factors such as Chl-a, Pha-a, Chl-a plus Pha-a and organic matter. A total of 18 meiofauna groups are i- dentified. Nematode is the most dominant group, average abundance (1 404±670) ind/10cm2, accounting for 88.65%, and the follow- ing groups are also important: benthic copepods (5.48%), kinorhyncha (1.26%), polychaeta (1.07%). By biomass, dominant groups are nematodes (51.72%), polychaeta (21.84%), copepods (14.87%), ostracoda (4.92%), kinorhyncha (3.67%). A total of 90 species of ne- matodes are identified. The species composition of nematodes is listed based on selected two stations 7794 (coastal area) and 10694 (cold water mass in deep waters).
基金the Ministry of Science and Technology of China under contract Nos 2002CB412400,G1999043709the National Natural Science Foundation of China under contract No.40176033.
文摘A quantitative study on meiofauna was carried out along a transect throughout the Changjiang Estuary' s oxygen minimum zone (OMZ) in the East China Sea. There exist two distinct station groups in the OMZ: the fine-grained hypoxic area and the more fine-grained anoxie area. Meiofauna abundance ranged from ( 101.5±31.0) ind./cm^2 ( hypoxie area) to (369.9±123.9) ind./cm^2( anoxic area) along the transect. Free-living marine nematodes were the numerically dominant meiofauna at every station. The anoxic area differed significantly in meiofauna abundance and vertical distribution pattern from the hypoxic area. Within the anoxic area, nematodes abundance increased and amounted to over 90% of the total meiofauna; about 50% of nematodes were found in the 2-5 and 5-8 cm layers. At hypoxie stations, about over 85 % were restricted to the top 2 cm. Benthic eopepod abundance and dominance decreased consistently with the oxygen gradient. The pattern of meiofauna biomass was similar to that of abundance. The correlation analysis of the meiofauna numbers and environmental parameters indicated that abundance and biomass of total meiofauna and nematodes had significant or highly significant ( P 〈 0.05 or P 〈 0.01 ) correlations with Chl a and Pha a, but no significant ( P 〉 0.05 ) correlations with bottom-water oxygen ( BWO2 ). On the other hand, there was a highly significant positive correlation between benthic eopepod abundance and bottom-water oxygen (P 〈 0.05 ). The investigation on the nematode community structure indicated that two different nematode communities existed in hypoxic and anoxic areas. In certain way, the shift in nematode species composition distinguishes the anoxia to hypoxia. Nematode diversity was generally lower within the anoxic stations than the hypoxic ones, but the difference was not significant. Indices of the nematode community structure varied in relation to the bottom-water oxygen together with bottom-water temperature, Chl a concentration and median grain size of sediment.