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1.
Seagrass habitats are structurally complex ecosystems, which support high productivity and biodiversity. In temperate systems the density of seagrass may change seasonally, and this may influence the associated fish and invertebrate community. Little is known about the role of seagrass beds as possible nursery areas for fish and invertebrates in China. To study the functioning of a seagrass habitat in northern China, demersal fish and invertebrates were collected monthly using traps, from February 2009 to January 2010. The density, leaf length and biomass of the dominant seagrass Zostera marina and water temperature were also measured. The study was conducted in a Seagrass Natural Reserve(SNR) on the eastern coast of the Shandong Peninsula, China. A total of 22 fish species and five invertebrate species were recorded over the year. The dominant fish species were Synechogobius ommaturus, Sebastes schlegelii, Pholis fangi, Pagrus major and Hexagrammos otakii and these species accounted for 87% of the total number of fish. The dominant invertebrate species were Charybdis japonica and Octopus variabilis and these accounted for 98% of the total abundance of invertebrates. There was high temporal variation in species composition and abundance. The peak number of fish species occurred in August–October 2009, while the number of individual fish and biomass was highest during November 2009. Invertebrate numbers and biomass was highest in March, April, July and September 2009. Temporal changes in species abundance of fishes and invertebrates corresponded with changes in the shoot density and leaf length of the seagrass, Zostera marina. 相似文献
2.
Distribution of dominant zooplankton species along a latitudinal gradient in China sea during spring
Dominant species of zooplankton community vary with latitude. Though China possesses a vast coastal area in northwestern Pacific, studies on the latitudinal dominant species gradient are rare. We collected zooplankton samples from Haizhou Bay(34.56?–35.19?N, 119.51?–120.30?E), Yueqing Bay(28.14?–28.38?N, 121.10?–121.21?E) and Dongshan Bay(23.65?–23.90?N, 117.45?–117.60?E) in May 2012 and May 2013 to preliminarily characterize the latitudinal dominant species distribution. All the samples were collected vertically using a 0.505 mm mesh plankton net with 0.8 m in mouth diameter from bottom to surface. Calanus sinicus, Aidanosagitta crassa, Labidocera euchaeta, Zonosagitta nagae, Acartia pacifica and Paracalanus parvus were found to be dominant. C. sinicus was the most dominant species and the unique one occurred in all three bays. With latitude decreasing, both the abundance and proportion of C. sinicus declined sharply. Cluster analysis showed that the 6 dominant species could be divided into 3 groups, based on their occurrences in the three bays. Our results suggested that the distribution of dominant species along the coast of China has a significant latitudinal gradient. C. sinicus which widely distributes in the coastal water of the northwestern Pacific can well adapt to the temperature at different latitudes. The high abundance in Haizhou Bay indicated that C. sinicus was an exemplary warm-temperate species, and more commonly occurs in the north of China seas. The ecological characteristics of dominant species change from warm-temperate type in high-latitudinal bays to warm water type in low-latitudinal bays. 相似文献
3.
Status of two <Emphasis Type="Italic">Coreius</Emphasis> species in the Three Gorges Reservoir,China
Dam construction alters natural flow regimes which, in turn, cause significant changes in fish communities during and after impoundment. The construction of the Three Gorges Reservoir, from impoundment of the Changjiang (Yangtze) River, China, may have affected native fish species. Thus, the status of two lotic freshwater fish species, Coreius heterodon and C. guichenoti, were monitored in the Three Gorges Reservoir, including fish abundance, individual composition, growth, condition, and mortality. Data on both species were gathered from upstream, midstream and downstream areas of the reservoir and, where available, from studies published before and after dam construction. Lower abundance, slower growth, a less diversified age structure, poorer fish condition (indicated by hepatosomatic index) and higher mortalities were recorded in sites nearest the dam compared with upstream areas. Furthermore, after final impoundment, individual Coreius species inhabiting the area changed, with young individuals becoming more abundant, while upstream of the reservoir the two Coreius species became smaller at a given age. The results show that the status of the two Coreius species was subject to dramatic changes after impoundment. 相似文献
4.
Flavobacterium columnare causes columnaris disease in freshwater fish. In the present study, the antigenic regions of five outer membrane proteins (OMPs), including zinc metalloprotease, prolyl oligopeptidase, thermolysin, collagenase and chondroitin AC lyase, were bioinformatically analyzed, fused together, and then expressed as a recombinant fusion protein in Escherichia coli. The expressed protein of 95.6 kDa, as estimated by 10% sodium dodecyl sulfate-polyacrylamide gel electrophoresis, was consistent with the molecular weight deduced from the amino acid sequence. The purified recombinant protein was used to vaccinate the grass carp, Ctenopharyngodon idella. Following vaccination of the fish their IgM antibody levels were examined, as was the expression of IgM, IgD and IgZ immunoglobulin genes and other genes such as MHC Iα and MHC IIβ, which are also involved in adaptive immunity. Interleukin genes (IL), including IL-1β, IL-8 and IL-10, and type I and type II interferon (IFN) genes were also examined. At 3 and 4 weeks post-vaccination (wpv), significant increases in IgM antibody levels were observed in the fish vaccinated with the recombinant fusion protein, and an increase in the expression levels of IgM, IgD and IgZ genes was also detected following the vaccinations, thus indicating that an adaptive immune response was induced by the vaccinations. Early increases in the expression levels of IL and IFN genes were also observed in the vaccinated fish. At four wpv, the fish were challenged with F. columnare, and the vaccinated fish showed a good level of protection against this pathogen, with 39% relative percent survival (RPS) compared with the control group. It can be concluded, therefore, that the five OMPs, in the form of a recombinant fusion protein vaccine, induced an immune response in fish and protection against F. columnare. 相似文献
5.
This study aimed to evaluate the potential impacts of an introduced clam Mercenaria mercenaria on estuarine ecosystem, and implications for the niche competition with a native clam Meretrix meretrix. The biodeposition, respiration, and excretion rates of M. mercenaria were determined seasonally using a sediment trap and a closed respirator in field. The biodeposition rates of M. mercenaria were 0.06–0.37 g/ (ind.·d), and the respiration rates were 0.31–14.66 mg/(ind.·d). The ammonia and phosphate excretion rates were 0.18–36.70 and 1.44–14.87 μg/(ind.·d), respectively. The hard clam M. mercenaria may discharge dry deposits up to 2.1×105 t, contribute 18.3 t ammonia and 9.0 t phosphate to culture ponds, and consume 7.9×103 t O2 from ponds annually. It suggested that the hard clam M. mercenaria might play an important role in pelagic-benthic coupling in pond ecosystem through biodeposition and excretion. A comparison of the key physiological parameters of the introduced clam M. mercenaria and the native clam Meretrix meretrix suggested that M. mercenaria had a niche similar to that of Meretrix meretrix in Shuangtaizi estuary and might have a potential competition with Meretrix meretrix for habitat and food if M. mercenaria species escaped from the culture pond or artificially released in estuarine ecosystem. 相似文献
6.
The Drake Passage is located between the Antarctic Peninsula and Tierra del Fuego in the south of South America. Surface seawater samples were collected at seven sites in the Drake Passage during the austral summer of 2012. The 16S rRNA sequences were analyzed from 187 isolated bacterial strains. Three phyla, 29 genera and 56 species were identified. The three phyla were Actinobacteria, Firmicutes and Proteobacteria; the Proteobacteria included α-Proteobacteria, β-Proteobacteria and γ-Proteobacteria. γ-Proteobacteria, Actinobacteria and Firmicutes were the dominant class or phyla in terms of quantity and species. Gram-positive bacteria (Actinobacteria and Firmicutes) accounted for 57.8% of all types identified. There were nine dominant genera, including Curtobacterium, Staphylococcus, and Halomonas, and 14 dominant species including Curtobacterium flaccumfaciens, Curtobacterium pusillum, and Staphylococcus sciuri. Of the strains identified, 87.2% were catalase positive or weakly positive. 相似文献
7.
There is considerable concern that isoflavones, such as genistein in fish feed composed of soybean protein, aff ects somatic growth in fish. Our previous works demonstrated that 30 and 300 μg/g dietary genistein had no significant eff ect on growth performance in Nile tilapia (Oreochromis niloticus), but the higher level of genistein (3 000 μg/g) significantly depressed growth. This study was conducted to further examine the eff ects of dietary genistein on the endocrine disruption on growth hormone/insulin-like growth factor-I (GH/IGF-I) axis in Nile tilapia (O. niloticus). Juvenile fish were fed by hand twice daily to satiation with one of four isonitrogenous and isoenergetic diets, each containing either 0, 30, 300 or 3 000 μg/g genistein. Following an 8-week feeding period, plasma GH and IGF-I levels were investigated by radioimmunoassay and gene expression levels of gh, ghrelin, gnrhs, ghr, npy, npyrs, pacap, ghrs, igf-I, igf-Ir, and igfbp3 were examined by real-time PCR. The results show that no significant change in plasma GH and IGF-I levels in fish fed with diets containing 30 μg/g and 300 μg/g genistein. mRNA expression of genes along the GH/IGF-I axis remained unaff ected, except for igf-Ir, which was stimulated by the 300 μg/g genistein diet. While in fish fed the 3 000 μg/g genistein diet, the plasma GH and IGF-I levels decreased, and mRNA expression of gh, ghr2, npyr1, igf-I, and igf-Ir were also significantly depressed. In contrast, npy and igfbp3 mRNA expression were enhanced. This study provides convincing evidence for growth impediment by genistein by disturbing the GH/IGF-I axis in Nile tilapia O. niloticus. 相似文献
8.
The information of trophic relationship is important for studying the Southern Ocean ecosystems. In this study, three dominant krill species, Euphausia superba, Thysanoessa macrura and Euphausia crystallorophias, were collected from Prydz Bay, Antarctica, during austral summer of 2009/2010. The composition of fatty acids in these species was studied. E. superba and T. macrura showed a similar fatty acid composition which was dominated by C14:0, C16:0, EPA (eicosapentenoic acid) and DHA (decosahexenoic acid) while E. crystallorophias showed higher contents of C18:1(n-9), C18:1(n-7), DHA and EPA than the former two. Higher fatty acid ratios of C18:1(n-9)/18:1(n-7), PUFA (polyunsaturated fatty acid)/SFA (saturated fatty acid), and 18PUFA/16PUFA indicated that E. crystallorophias should be classified as a typical omnivore with a higher trophic position compared with E. superba and T. macrura. 相似文献
9.
Effects of nitrogen (N) and phosphorus (P) from different sources and at different concentrations on the growth of Levanderina fissa (= Gyrodinium instriatum) were studied in laboratory conditions. The findings might explain the recurrent blooms of this species in Pearl River Estuary, China. Results showed that nutrient limitation significantly inhibited the growth of L. fissa. The values of specific growth rate (μ max) and half-saturation nutrient concentration (K S) were 0.37 divisions/d and 8.49 μmol L?1 for N, and 0.39 divisions/d and 1.99 μmol L?1 for P, respectively. Based on K S values, dissolved inorganic N level in PRE was sufficient to support the high proliferation of L. fissa, while dissolved inorganic P concentration was far lower than the minimum requirement for its effective growth. L. fissa was not able to utilize dissolved organic N (DON) compounds such as urea, amino acids, and uric acid. However, it grew well by using a wide variety of dissolved organic P (DOP) sources like nucleotides, glycerophosphate, and 4-nitrophenylphosphate. The results from this study suggested that the ability in DOP utilization of L. fissa offers this species a competitive advantage in phytoplankton communities. The high level and continuous supply of DIN, enrichment of DOP, together with warm climate and low salinity in the Pearl River Estuary provided a suitable nutrient niche for the growth of L. fissa, and resulted in the recurrent blooms in the estuary. 相似文献
10.
Photo-protective functions were investigated in phytoplankton assemblages at Kongsfjorden, Svalbard in spring, using their UV-absorbing compounds (mycosporine-like amino acids (MAAs)), xanthophyll pigments (diadinoxanthin (DD) and diatoxanthin (DT)) and < beta >- dimethylsulphoniopropionate (< beta >-DMSP). The dominant phytoplankton species in the inner bay were dominated by Phaeocystis spp. and nanoflagellates, while the offshore waters were dominated by Thalassiosira spp. In the inner bay, UVabsorbing compounds and xanthophyll pigments exhibited higher ratios of MAA to chlorophyll a (MAA:chl a ratio), and both DD and DT to chlorophyll a (DD:chl a ratio and DT:chl a ratio), respectively. Thus, the photoprotective-pigments such as DD and DT appear to complement MAAs in the natural phytoplankton assemblage. However, the ratio of < beta >-DMSP to chlorophyll a (< beta >-DMSP:chl a ratio) did not show a distinct spatial distribution according to environmental factors or interspecies differences. In this study, we found that photoprotective compounds occurred in a manner dependent on the phytoplankton species composition in Kongsfjorden Bay, where Phaeocystis is the dominant species. 相似文献
11.
The Changjiang River estuary and adjacent waters are one of the most notable regions for red tides/harmful algal blooms in China's coastal waters.In this study,phytoplankton samples were collected and analyzed during the outbreak stage of red tides in May 2009.It was found that dinoflagellates,Prorocentrum donghaiense and Karenia mikimotoi,and diatoms,Skeletonema spp.and Paralia sulcata,were the major taxa dominating the phytoplankton community.Cluster analysis,non-metric multidimensional scaling(NMDS) and analysis of similarities(ANOSIM) was conducted on a data matrix including taxa composition and cell abundance of the phytoplankton samples.The analyses categorized the samples into three groups at a similarity level of 30%.Group Ⅰ was characterized by estuarine diatoms and distributed mainly in the highly turbid estuarine region.Group Ⅱ,which was dominated by the diatom Skeletonema spp.and represented the red tide of Skeletonema spp.,was situated around Group Ⅰ in the sea area west of 122°50'E.Group Ⅲ was characterized by a high proportion of dinoflagellates and was found further offshore compared with Groups Ⅰ and Ⅱ.Group Ⅲ was further divided into two subgroups(Ⅲ-S1 and Ⅲ-S2) at a similarity level of 40%.Group Ⅲ-S1 was characterized by the presence of the benthic diatom P.sulcata,representing phytoplankton samples collected either from the bottom or from the sea area affected by upwelling.GroupⅢ-S2 was dominated by dinoflagellates and represented red tides formed by P.donghaiense and K.mikimotoi.A gradual change of red-tide causative species was observed from the estuary to the offshore sea area,from diatoms to armored dinoflagellates and then unarmored dinoflagellates.Environmental factors associated with each group,and thus affecting the distribution of phytoplankton and red tides,are discussed. 相似文献
12.
This study was conducted to evaluate the performance of six stem taper models on four tropical tree species, namely Celtis luzonica (Magabuyo), Diplodiscus paniculatus (Balobo), Parashorea malaanonan (Bagtikan), and Swietenia macrophylla (Mahogany) in Mount Makiling Forest Reserve (MMFR), Philippines using fit statistics and lack-of-fit statistics. Four statistical criteria were used in this study, including the standard error of estimate (SEE), coefficient of determination (R 2), mean bias \(( \bar E )\), and absolute mean difference (AMD). For the lack-offit statistics, SEE, \(\bar E\) and AMD were determined in different relative height classes. The results indicated that the Kozako2 stem taper model offered the best fit for the four tropical species in most statistics. The Kozako2 model also consistently provided the best performance in the lack-of-fit statistics with the best SEE, \(\bar E\) and AMD in most of the relative height classes. These stem taper equations could help forest managers and researchers better estimate the diameter of the outside bark with any given height, merchantable stem volumes and total stem volumes of standing trees belonging to the four species of the tropical forest in MMFR. 相似文献
13.
The RNA helicase Vasa is an important regulator of primordial germ cell development. Its function in mature fish, especially the hormone-related differences in maturing male fish has seldom been documented. In this study, a full length cDNA sequence of the vasa gene was cloned from Japanese sea bass, Lateolabrax japonicas, and it was named jsb-vasa. Homology analysis showed that jsb-vasa was closely related to its teleost homologs. The spatial distribution of jsb-vasa indicated that it was only highly expressed in testis, showing its germ cell-specific expression pattern. During the testicular development cycle, jsb-vasa was highly expressed during early period of spermatogenesis, and reduced when spermatogenesis advanced. In addition, the jsb-vasa gene expression was significantly inhibited at 6 h, 12 h and 24 h after injecting hCG (human chorionic gonadotropin) and GnRHa (Gonadotropin-releasing hormone analogue), indicating that jsb-vasa gene may play an important role in spermatogenesis of Japanese sea bass, and be under the regulation of external sex hormones. 相似文献
14.
Periphytic biofilms in aquaculture waters are thought to improve water quality, provide an additional food source, and improve the survival and growth of some reared animals. In the Asia- Pacific region, particularly in China, artificial reefs are commonly used in the commercial farming of sea cucumbers. However, few studies have examined the epilithic biofilms on the artificial reefs. To gain a better understanding of the succession of epilithic biofilms and their ecological processes in sea cucumber culture waters, two experiments were conducted in culture waters of the sea cucumber Apostichopus japonicus in Rongcheng, China, using artificial test panels. On the test panels of succession experiment, more than 67 species were identified in the biofilms. On the test panels of seasonal variation experiment, more than 46 species were recorded in the biofilms. In both experiments, communities of epilithic biofilms were dominated by diatoms, green algae and the annelid Spirorbis sp. In the initial colonization, the dominant diatoms were Cocconeis sp., Amphora spp. and Nitzschia closterium in June, which were succeeded by species of Navicula, Cocconeis and Nitzschia (July to September), and then by Licmophora abbreviata, Nitzschia closterium and Synedra spp. in the following months. A diatom bloom in the autumn and filamentous green algae burst in the summer were also observed. Ecological indices well annotated the succession and seasonal changes in epilithic communities. Multidimensional scaling (MDS) analysis found significant differences in diatom community composition among months and seasons. Fast growth of biofilms was observed in the summer and autumn, whereas the biomass of summer biofilms was largely made up of filamentous green algae. Present results show that the components of epilithic biofilms are mostly optimal foods of A. japonicus, suggesting that biofilms on artificial reefs may contribute important nutritional sources for sea cucumbers during their growth seasons. Future works should include quantitative determination of the contribution of epilithic biofilms to the diet of A. japonicus, potential roles of epilithic biofilms in regulating the water quality of sea cucumber ponds, and the regulation of epilithic biofilms in sea cucumber culture ponds. 相似文献
15.
Using a coccolith weight analytic software (Particle Analyser), we analyze most abundant coccolith species in a sediment core from the central Western Pacific Warm Pool (WPWP) and calculate coccolith size and weight variations over the last 200 ka. These variations are compared with the trends of sea surface temperature (SST), primary productivity (PP), sea surface salinity (SSS), and insolation. Our results demonstrate that the size and weight of the coccoliths varied in response to variations of these factors, and their average total weight is primarily related to the relative abundance of the dominant species GEO (Gephyrocapsa oceanica). The variation in weight of EMI (Emiliania huxleyi) and GEE (Gephyrocapsa ericsonii) are mainly influenced by nutrients, and the variation of GEM (G. muellerae conformis) and GEO (G. oceanica) weight are mainly influenced by SST. For all of the taxa weight, PP and SST present apparent precession or semi-precession cycles, we consider that the mono-coccolith weight of the Equatorial Western Pacific is primarily affected by precession drived thermocline and nutricline variation. 相似文献
16.
Identification of three common Loliginidae squid species in the South China Sea by analyzing hard tissues with geometric outline method 总被引：1，自引：0，他引：1
The hard tissues of squid can provide important information for species identification. In this study, we used statolith and beak to identify three squid species including Uroteuthis duvaucelii, Loliolus beka, and U. edulis in the South China Sea. Because of the highly overlapping habitat and similar body morphology of the three squid species, we explored four different ways to identify them, by using statolith, upper beak, lower beak and a combination of statolith and beak. An outline geometric morphometric method and stepwise discriminant analysis were used to evaluate the most suitable method for the identification. We found that the combination of statolith and beak had the highest cross validation rate that was 75.0%, 87.5% and 88.7% for U. duvaucelii, L. beka and U. edulis, respectively. Using two beaks had similar results and the lowest cross validation rate was 60.0%, 50.0%, and 73.7% for the upper beak, 46.9%, 58.5% and 75.3% for the lower beak of U. duvaucelii, L. beka and U. edulis, respectively. Analyzing with the statolith had moderate cross validation which was 72.2%, 80.0%, and 87.7% for U. duvaucelii, L. beka and U. edulis, respectively. From the results it is suggested when the entire body of a squid is available, a combination of statolith and beak should be used for the identification. When only one hard tissue is available, species identification can be subjected to large errors. 相似文献
17.
Polychaetes provide an excellent food resource for fish and represent the dominant zoobenthos in marine ecosystems. Diel variation in the rates of metabolism and ammonia-N excretion of Marphysa sanguinea were studied. The worms were grouped according to their wet body weight into small (S; 1.24±0.06 g), medium (M; 4.00±0.30 g), and large (L; 8.54±1.08 g) categories. Their weight-specific metabolic rates, based on aerobic respiration (R), were measured at 16°C (±0.2°C) and classed as either routine (R R) or standard (R S) rates. Both respiration types decreased with increasing body weight. Respiration was described by R = a W b, where b was -0.400 9 and -0.532 0 for R R and R S, respectively. Diurnal changes in R S for each group was relatively flat, with a slightly increasing trend with time, but was relatively stable as a whole. R R of the diurnal variation of worms was higher than R S, but both had similar overall trends. The peak values of specific dynamic action (SDA) (R SDA) in the S, M, and L groups were 2.704, 1.149, and 0.682 mg/(g?h), respectively. The durations of SDA were 13, 6, and 6 h, respectively and the energy expenditures of SDA were 377.98, 117.34, and 74.94 J/g, respectively. These data indicate that the metabolic rates were higher in smaller individuals, which is advantageous for their rapid growth. 相似文献
18.
We investigated seasonal variations in cyanobacterial biomass and the forms of its dominant population(M. aeruginosa) and their correlation with environmental factors in the water source area of Chaohu City,China from December 2011 to October 2012. The results show that species belonging to the phylum Cyanophyta occupied the maximum proportion of phytoplankton biomass,and that the dominant population in the water source area of Chaohu City was M. aeruginosa. The variation in cyanobacterial biomass from March to August 2012 was well fitted to the logistic growth model. The growth rate of cyanobacteria was the highest in June,and the biomass of cyanobacteria reached a maximum in August. From February to March 2012,the main form of M.aeruginosa was the single-cell form; M.aeruginosa colonies began to appear from April,and blooms appeared on the water surface in May. The maximum diameter of the colonies was recorded in July,and then gradually decreased from August. The diameter range of M. aeruginosa colonies was 18.37–237.77 μm,and most of the colonies were distributed in the range 20–200 μm,comprising 95.5% of the total number of samples. Temperature and photosynthetically active radiation may be the most important factors that influenced the annual variation in M. aeruginosa biomass and forms. The suitable temperature for cyanobacterial growth was in the range of 15–30°C. In natural water bodies,photosynthetically active radiation had a significant positive influence on the colonial diameter of M.aeruginosa(P0.01). 相似文献
19.
The effects of different phosphorus (P) concentrations (0.36, 3.6, and 36 μmol/L corresponding to low-, middle-, and high-P concentration groups, respectively) and nitrogen (N)/P ratios on the growth and photosynthetic characteristics of Skeletonema costatum and Prorocentrum donghaiense were studied. For both species, the high-P (HP) concentration group showed the greatest algal density and highest specific growth rate. Changes in the maximum efficiency of photosystem II (F v /F m ) were monitored under the various P and N/P conditions. The largest decrease in F v /F m was in the low-P (LP) group in S. costatum and in the HP group in P. donghaiense. There were high rapid light curves and photochemical quantum yields (Φ PSII) for S. costatum in the HP group, while the actual photosynthetic capacity was higher in P. donghaiense than in S. costatum in the MP group. Under eutrophic but relatively P-restricted conditions, P. donghaiense had higher photosynthetic activity and potential, which could cause this dinoflagellate to increasingly dominate the phytoplankton community in these conditions. Under the same P concentration and N/P ratio, P. donghaiense had a larger relative maximum rate of electron transport and higher Φ PS II values than those of S. costatum. These differences between P. donghaiense and S. costatum may explain the interaction and succession patterns of these two species in the Changjiang (Yangtze) River estuary from a photosynthesis perspective. 相似文献
20.
We present a taxonomic study of taxa of the red algae genus Herposiphonia (Rhodophyta, Rhodomelaceae), collected from the coast of eastern Guangdong, China. We made detailed morphological studies and considered recent taxonomic criteria for species delimitation, and are making the first report of five different species on the coast of Guangdong, including a new species. The species identified were H. caespitosa Tseng, H. hollenbergii Dawson, H. pecten - veneris (Harvey) Falkenberg, H. subdisticha Okamura and H. pinnata Ding and Tan sp. nov. H. pinnata sp. nov. is characterized by bright green thalli; most parts of the feathery thalli are free of the substratum; determinate branches and indeterminate branches are arranged in a chaotic sequence; the primary axis has bare segments; the determinate branch has 9–11 periaxial cells per segment; vegetative trichoblasts are abundant; and tetrasporangia are formed on the middle of the determinate branch with 1–8 successive segments in a single rectilinear series. This paper is also the first record of sporophyte plants of H. pecten-veneris. 相似文献