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1.
Chinocythere was established as a new genus in 1978 based on fossil ostracodes found from the Palaeogene Shahejie and Dongying Formations along the coastal region of the Bohai Sea. It was also found from the Palaeogene Weizhou and Liushagang Formations of the continental shelf in the northern part of the South China Sea as well as from the early Oligocene Nadou Formation in the Baise basin in Guangxi. In historical geology, Chinocythere first appeared and flourished in Eocene and then gradually declined and became extinct in Oligocene. Despite of its narrow horizontal distribution and limited vertical extension in the geologic section, there are a great many of varieties in this genus, with up to 87 species already published representing the coastal region of the Bohai Sea alone, this in a sense, affords us an invaluable condition for the study of its evolution.  相似文献   

2.
The purpose of this study was to estimate the spatial and temporal variation of microalgae in the South China Sea and to demonstrate the environmental factors controlling the diversity of microalgae by GIS (geographic information system)-based analysis of 18S rDNA sequences. Six 18S rDNA libraries were constructed from environmental samples collected at different sites in the study area, and more than 600 18S rDNA sequences were determined. The rDNA sequence data were then analyzed by DIVA-GIS software to display the spatial and temporal variation of phytoplankton’s composition. It was shown that the autotrophic eukaryotic plankton dominated over the heterotrophic cells in most of our clone libraries, and the dominating phytoplankton was Dinophyceae except for Bacillariophyta at the Xiamen harbor. The percentages of these two groups were controlled by water temperature and salinity. Our results also revealed that the species composition of Chlorophyta showed a close relationship with latitude, changing from Prasinophyceae at the high latitude to Trebouxiophyceae at the low latitude. Several newly classified picoplankton lineages were first uncovered in the South China Sea, including the pico-sized green alga Ostreococcus sp. and Picochlorum eukaryotum, and picobiliphytes, which was just discovered in 2007 with unknown affinities to other eukaryotes. Their spatial and temporal variation were also analyzed and discussed.  相似文献   

3.
The population density of the white-tailed sea eagle Haliaeetus albicilla is very low in many countries. In last twenty years, the sea eagle population in South Bohemia was restored by strict protection subsidized by reintroduction, The active help consisted of feeding during winter and building of artificial nests. A new sea eagle breeding population arose in the Treboǎ basin area in the early 1980' s. Until this time sea eagles had used former breeding places only for wintering, probably coming from the Baltic. The South Bohemian sea eagle population is very unique: it exists in a densely man-occupied landscape, mainly in areas with very intensive carp breeding in artificial fishponds and was partly artficially (help to wintering birds and reintroduction of some individuals) restored. The experience from South Bohemia may have importance for populations of the sea eagle in other areas of its occurence, primarily in the continental conditions [ Current Zoology 55 (5) : 315 - 318, 2009].  相似文献   

4.
We provide confirmed photographic evidence for the previously overlooked occurrence of the polyphyletic Asian gecko genus Cnemaspis from Gunung Mulu National Park, the world-renowned UNESCO natural heritage site in northern Sarawak, East Malaysia. This new record from Sarawak province represents a remarkable range extension for Cnemaspis cf. kendallii by 550 km to the northeast and denotes the most northern occurrence of the genus in Borneo. Our new finding makes it very likely that these gekkonid lizards also inhabit appropriate limestone karst habitats in adjacent Sabah, Brunei, and Kalimantan. Given the visible differences in the Mulu specimen compared to those from the remaining distribution range on Borneo and the Malaysian Peninsula together with the fact that numerous Cnemaspis species are restricted to small areas, it seems plausible that another undescribed, rather cryptic and possibly locally endemic Bornean species is involved. Lastly, the new record contributes to the importance of the Mulu National Park as a major conservation area in East Malaysia of international concerns.  相似文献   

5.
We studied the process of offspring production in queenless colonies of Acromyrmex subterraneus brunneus, and particularly evaluated the ovary development of workers as a function of their age. For this, subcolonies were set up and evaluated at different periods of isolation from the queen (2, 4 and 6 months), besides individually labeled age groups. The subcolonies were assessed according to offspring production and ovaries containing oocytes or not. The evaluations showed worker oviposition and development of males originating from worker-laid eggs. At 2 months' absence of the queen, eggs and larvae were found, with eggs in a higher proportion than larvae. After 4 months, the proportion of eggs had reduced while larvae had increased, and a pupa was found in one subcolony. At 6 months, besides a higher share of larvae, one pupa and one adult male were found. Dissection of workers revealed ovaries containing oocytes during the periods of evaluation. Only a group of medium-sized and large workers, 23.3%, 20.9% and 37.5% of the population from each period assessed in queenless subcolonies respectively, presented developed oocytes in the ovary. The same was observed in colonies with a queen, with 17.6%, 19.6% and 7.8% of the group of dissected workers from each time period, respectively. With respect to worker age, we observed by dissection of the ovary, that the greatest percentage of individuals with ovarioles containing oocytes occurred at 45 days (6 weeks) up to 90 days (12 weeks). These results probably are associated with the workers reproduction and the laying of trophic and reproductive eggs in colonies with and without a queen; these eggs have distinct functions in each situation.  相似文献   

6.
Wan R J  Zhou F  Shan X J  Sun S 《农业工程》2010,30(3):155-165
During June, August and October 2006, there were three multi-disciplinary surveys carried out in the Changjiang River estuary and its adjacent waters (122°00′–125°00′E, 27°50′–34°00′N) by R/V Beidou to study the species composition and abundance of ichthyoplankton (including fish eggs, larvae and juveniles), the spatial distribution of fish spawning ground and their relationship with habitat factors. There were 29, 29 and 25 grid stations sampled in the three cruises, respectively. The ichthyoplankton samples were collected by horizontally towing with a macro-plankton net (mouth diameter 80 cm, length 270 cm, mesh size 0.50 mm) at the sea surface, and the towing speed was 3.0 n mile/h at each sampling station. The towing lasted for 10 min. After hauling for each station, habitat factors including temperature and salinity were measured by Sea Bird-25 CTD. Samples were preserved in 5% formaldehyde solution immediately after sampling for analysis in laboratory. Since the trawl speed could not be accurately evaluated due to the effects of ocean currents and wind-induced wave, the amount of ichthyoplankton was evaluated by actual number of the sampling haul in each station. Ichthyoplankton collected were divided into three categories: dominant species, important species and main species by the index of relative importance (IRI). There are 71 species (including 1200 fish eggs and 2575 fish larvae and juveniles) collected during 3 cruises and 59 species have been correctly identified to species level, which belongs to 50 genera, 37 families and 9 orders; while 5 species can only be identified to genera level, 1 species only identified to family level and 6 species identified to order level. These 59 species identified to species level and 5 species identified to genera level are divided into three ecological patterns, i.e., brackish water species, neritic water species and coastal water species. Warm water species have 34 species in those 59 species identified to species level, accounting for 57.63%, warm temperature species have 25 species, accounting for 42.37%. According to the analysis of IRI, the dominant species are Engraulis japonicus (in June and August, that is important species in October), Scomber japonicus (in August), and Johnius grypotus (in October) during the survey; important species are Cynoglossus joyneri (in June and August), Trichiurus lepturus (in June, August and October), Gonorhynchus abbreviatus (in August), Stolephorus commersonii (in October), Saurida undosquamis (in October) and Saurida elongate (in October), and main species have 12 species in June, 9 species in August and 10 species in October, respectively. The amount of fish eggs and larvae of the dominant species, important species and main species (28 species) are 97.50% and 97.13% of the total amount of fish eggs and larvae, respectively, which are the important composition of fish eggs and larvae in the Changjiang River estuary and its adjacent waters.
In June and August of 2006, if compared with that in corresponding months in 1986, there are great changes in the habitat factors especially for temperature and salinity in the investigating areas: high salinity water from off-shelf is much closer to the coastal areas which results in the dramatic increase of sea surface salinity during all three surveys. Sea surface temperature, on the other hand, decreases distinctively in June, but significantly increases in August. The run-off of the Changjiang River greatly reduced due to the long-term drought in summer 2006, which is responsible for the great changes of habitat factors in the Changjiang River estuary and its adjacent waters. The habitat of the Changjiang River estuary is greatly changed, which consequently has significant influences on the spawning, breeding and the spatial distribution of spawning ground of neritic water species, such as Sardinella zunasi, Thryssa kammalensis, Thryssa mystax, Setipinna taty and S. commersonii ect, and coastal water species, such as Ilisha elongate and Konosirus punctatus ect.  相似文献   

7.
Drosophila lacertosa is widely distributed from northern India to Far East of Russia throughout China. We have studied geographical distributions of three kinds of chromosomal karyotypes, type D (2n=10, 4 pairs of V-shaped metacentric chromosomes and a pair of micro-chromosomes), type L (2n=10, 5V with a pair of large-sized hetero-chromatic autosomes) and type M (2n=10, 5V with middle-sized ones). Type D was found exclusively in local populations of D. lacertosa distributed in Yun-Gui Plateau, southwestern China. Both type L and M have a wide range of distribution, and the former occurred in subtropical regions of China including Taiwan Island, whereas the latter in cool temperate regions of East Asia covering Far East of Russia, Korea and the Japan Islands. A strong premating isolation was detected between flies with type D and those with type L or M. These data demonstrate that genetic differentiation leading to cryptic speciation might have occurred in natural populations of Drosophila lacertosa.  相似文献   

8.
 In a first synoptic evaluation, the temporal and spatial distribution of bacterioplankton and chlorophyll-a were determined in the German Wadden Sea. Three surveys were undertaken in winter, spring, and summer of 1994 using up to eight ships simultaneously between the river Ems and Sylt island. Despite intensive hydrodynamic mixing of the Wadden Sea water, spatial gradients were obvious. The abundance of bacterioplankton ranged from 0.4 to 26×105 ml–1 and chlorophyll-a varied between <0.1 and 79 μg l–1. In winter, relatively homogeneous distribution patterns of both parameters with small gradients were found. Highest chlorophyll-a values connected with a highly patchy structure were observed in spring, while in summer both total chlorophyll-a values and the complexity of the distribution pattern had decreased. In contrast, bacterial numbers increased steadily from January to July with the highest bacterial densities and greatest patchiness observed in summer. Moreover, in some regions of the Wadden Sea, a trophic succession of algae as carbon producers and bacteria as consumers was evident. Correlation analysis verified the relationship between bacteria and chlorophyll a, indicating bottom-up control of bacterial abundance in the northern part of the German Wadden Sea. Since the observed regression slope is remarkably low (0.12–0.46) compared to literature values (0.5–0.8), we suggest that the link between phytoplankton and bacteria found here is a special characteristic of the Wadden Sea as a transition zone between the coastal region and the outer North Sea. Received: 26 May 1998 / Accepted:12 November 1998  相似文献   

9.
The environmental regulation of plcoplankton distribution in the northern South China Sea was examined In winter and summer of 2004. The average abundance of Synechococcus, Prochlorococcus, and heterotrophlc bacteria was lower In winter (30, 21, and 780×10^3 cells/cm^3, respectively) than In summer (53, 85, and 1 090×10^3 cells/cm^3, respectively), but the seasonal pattern was opposite for plcoeukaryotlc phytoplankton (4 500 and 3 200 cells/cm^3 In winter and summer, respectively). Synechococcus, picoeukaryotes, and bacteria were most abundant in the nutrient-rich coastal zone and continental shelf, but Prochlorococcus was most abundant In the continental slope and open ocean. The vertical distribution of each photosynthetic group and heterotrophlc bacteria changed between the two seasons. Synechococcus populations with apparently different phycoerythrobilin content occurred at many stations In the summer. In addition, two different populations of Prochlorococcus were found: (i) small, weakly fluorescing cells in the surface layer; and (ii) larger, strongly fluorescent cells In the deep layer. The distribution pattern of photosynthetic plcoplankton and heterotrophlc bacteria depends on environmental effects and their ecophyslologlcal differences. The distribution of Synechococcus appeared to be related to nutrient availability, whereas the distribution of Prochlorococcus appeared to be limited by temperature. Synechococcus was the only plcophytoplankton with a consistent strong relationship with bacteria.  相似文献   

10.
Wang D R  Wu Z J  Li Y C  Chen J R  Chen M 《农业工程》2011,31(5):254-258
Xisha Islands, located in the northern part of South China Sea, consist of more than 20 islands and atolls. The coral reef of Xisha Islands belongs to the typical ocean distribution of world’s coral reefs, its ecosystem is the most typical in our country and hermatypic coral species are about three-quarters of the total coral species in China. It is addressed with the oldest coral reef community which of the most original and valuable in China. The previous research shows that the islands studded in South China Sea such as Xisha Islands have important influence on the formation of coral reefs along the mainland coast by multiplying and migrating from south to the north. It is supplementary sources of coastal coral larvae in Hainan and Guangdong. Therefore, carrying out the monitoring of coral reef community ecosystem is of great significance to the ecological protection. By the Manta tow and the Line Intercept Transect method, five stations (Xisha Yong xing dao, Shi dao, Xisha zhou, Zhao Shu dao and Bei dao) on Xisha ecological monitoring area were monitored continually from 2005 to 2009. We compared the index changes of Hermatypic coral’s species, coverage and recruitment, and combining with Condition Index, Succession Index, and the variation trend of hard coral in Xisha were analyzed.
The results show that, from 2005 to 2009, the coverage of living hermatypic corals in ecological monitoring area is sharply reduced from 68.19% to 7.93%, while the dead coral coverage is sharply increased from 4.70% to 72.90%. Coral recruitment is reduced from 1.18 ind/100 m2 to 0.07 ind/100 m2, hermatypic coral species decreased from 87 to 35. In 2005, the health of coral reefs was very good, and the Condition Index was 1.097. However, the Condition Index cut down to a very low degree in 2009. It was only ?0.880. The Succession Index belonged to “very low degree” from 2005 to 2009, and the numerical value was gradually reduce from ?0.984 to ?1.876.
As a whole, hermatypic corals are serious degrade regionally and caused great change to the coral structure and biodiversity, this will lead to a continuous degradation of coral reefs.  相似文献   

11.
The northern sea area of the South China Sea is situated between 107.5°~122.5°East longitude and 17°~25° North latitude with high temperature and a large quantity of rainfall which belongs to the oceanic climate of the torrid zone and subtropical zone. From September, 1994 to June, 1998,during the research on the species of Horseshoe crab within the scope between the south from North gulf and the north to Xiamen, choosing Xiamen, Shantou, Wuchuan, Donghaidao and Qishui as fixed positions and irregularly going to Xuwen and Suixi in Guangdong province and Fangcheng in Guangxi province, we found that there was only Tachypleus tridentatus in the northern sea area of the South China Sea and the sea area from Wuchuan to Xiamen, and found that there were two species of horseshoe crab which were Tachypleus tridentatus and Carcinoscorpius rotundicauda in the southern area to East Sea Island, referring to East Sea Island, Qishui, Xuwen, Suixi and Fangcheng, most of which were Tachypleus tridentatus, and found a great number of larvae of Tachypleus tridentatus including zooids with different sizes from 7cm bodily length to mature. In Minan we found not only big colonies of adult Carcinoscorpius rotundicauda, but also a great number of larvae of Carcinoscorpius rotundicauda with different body size from 7cm body length to maturity. All these show that the northern sea area of the South China Sea is the area where both Tachypleus tridentatus and Carcinoscorpius rotundicauda distribute and reproduce. On January 1st, 1998 at the town of Qishui in Leizhou, we found an adult male Horseshoe crab and majority of its eggs was immature, while the eggs with above 4mm diameters were only 0.87 percent but the eggs with below 1.0mm diameter was 58 percent(1 160 pills). It shows that Qishui is a place where Tachyplers tridentatus survive in the winter.  相似文献   

12.
Tachyplesins and their analogs are antimicrobial peptides composed of 17 or 18 amino acid residues present abundantly in acid extracts of hemocyte debris of horseshoe crabs. We purified here tachyplesin isopeptides from hemocytes of two species of Southeast Asian horseshoe crabs, Carcinoscorpius rotundicauda and Tachypleus gigas, and determined their amino acid sequences. The major tachyplesin isolated from both species was identified, respectively, as tachyplesin I, which had previously been found in hemocytes of the Japanese horseshoe crab (Tachypleus tridentatus). The yield from both species was very high (more than 70 mg per 100 g wet weight of hemocytes), i.e., comparable with that from T. tridentatus. In addition to tachyplesin I, a new tachyplesin isopeptide, named tachyplesin III, was also isolated from T. gigas hemocytes, in which an arginine replaced the 15th lysine of tachyplesin I. The carboxyl-terminal residue of the isolated tachyplesins I and III was confirmed, respectively, to be an arginine alpha-amide by chemical analysis. Furthermore, a tachyplesin peptide derivative with a carboxyl-terminal extension of glycine-lysine was newly found in the hemocytes of C. rotundicauda. It appeared to be an intermediate derived from a tachyplesin precursor during processing to the mature form.  相似文献   

13.
Horseshoe crabs are marine invertebrates well known for their exceptionally low rates of diversification during their entire evolutionary history. Despite the low species diversity in the group, the phylogenetic relationships among the extant species, especially among the three Asian species are still unresolved. Here we apply a new set of molecular genetic data in combination with a wide geographic sampling of the intra-specific diversity to reinvestigate the evolutionary history among the four living limulid xiphosurans. Our analysis of the intraspecific diversity reveals low levels of connectivity among Carcinoscorpius rotundicauda lineages, which can be explained by the estuarine-bound ecology of this species. Moreover, a clear genetic break across the Thai-Malay Peninsula suggests the presence of cryptic species in C. rotundicauda. The limulid phylogeny finds strong support for a monophyletic genus Tachypleus and a diversification of the three Asian species during the Paleogene period, with speciation events well separated in time by several million years. The tree topology suggests that the three Asian species originated in central South East Asia from a marine stem group that inhabited the shallow coastal waters between the Andaman Sea, Vietnam, and Borneo. In this region C. rotundicauda probably separated from the Tachypleus stem group by invading estuarine habitats, while Tachypleus tridentatus most likely migrated northeast along the Southern coast of China and towards Japan.  相似文献   

14.
中国鲎和圆尾鲎血淋巴细胞分类和特征的比较研究   总被引:1,自引:0,他引:1  
&#  &#  &#  &#  &#  &#  &#  &#  &#  &#  &#  &#  &#  &#  &#  &#  &#  &# 《水生生物学报》2015,39(6):1169-1176
为了更好地了解中国鲎(Tachpleus tridentatus)和圆尾鲎(Carcinoscorpius rotundicauda)血淋巴细胞的种类组成和特征差异,综合运用光学显微镜、扫描电镜和粒度仪,较为系统地对两种鲎的血淋巴细胞进行了分类和特征研究,从而为两种鲎的血淋巴细胞和分子生物学研究提供基础资料。根据血淋巴细胞大小、核质比、细胞着色特点、细胞中颗粒存在与否、颗粒的密集程度等,中国鲎和圆尾鲎的血淋巴细胞均可分为大颗粒细胞、小颗粒细胞和透明细胞三种主要类型,且两种鲎的血淋巴细胞均以颗粒细胞为主,透明细胞在血淋巴细胞中所占比例最小,但具有高核质比。两种鲎的同类血淋巴细胞在染色和形态上无显著性差异,但在同一种鲎中,血淋巴细胞密度存在显著的雌雄差异。    相似文献   

15.
16.
东海中南部外海蟹类群落结构特征   总被引:3,自引:0,他引:3  
2006年5月(春)、9月(夏)、11月(秋)和2007年2月(冬)对东海中南部外海(26°00′-28°30′ N,121°00′-126°00′ E)海域蟹类资源进行调查,分析了蟹类的种类组成、优势度、多样性和生物量等群落结构特征.结果表明:本次调查共鉴定蟹类49种,隶属于12科30属;春、秋季,调查海域蟹类种数呈北部高、南部低的特征,夏季各站位的蟹类种数分布较均匀,冬季该海域南北地区蟹类种数的差异较小,但调查海域外侧站位的种数较多;调查海域蟹类的优势种为13种,主要包括:双斑蟳、卷折馒头蟹、武士蟳、细点圆趾蟹、长手隆背蟹、光掌蟳和银光梭子蟹等;调查海域夏季的蟹类多样性指数较低,其他3个季节的差别不大;调查海域蟹类平均渔获资源量为5197.62 g·h-1,夏季(8830.79 g·h-1)﹥春季(4877.50 g·h-1)﹥秋季(4268.30 g·h-1)﹥冬季(2813.87 g·h-1).东海中南部外海蟹类可划分为3个生态群落,即广温广盐生态群落、高温广盐生态群落、高温高盐生态群落.  相似文献   

17.
鲎具有极高的经济价值和科研意义。近年来由于过度捕捞和栖息地受损等原因,亚洲鲎种群数量正急剧下降。鲎漫长的生命周期使得鲎资源的保护和增殖迫在眉睫。生态位模型已经广泛应用于物种的潜在地理分布预测。基于实地调研数据和公开发表的北部湾中国海域中国鲎和圆尾鲎地理分布数据,运用MAXENT模型得到中国鲎和圆尾鲎在广西北部湾(中国部分)的栖息地适宜度指数(Habitat suitability index, HSI),确定了这两种稚鲎在北部湾中国海域潜在适生区。模型分析结果表明,潮间带坡度和地形指数是影响中国鲎分布的主要环境因子,而潮间带底质的有机物含量和植被指数是影响圆尾鲎分布的主要环境因子,根据研究结果建议在两种稚鲎适生区建立保护区,进行人工放流稚鲎,加强对海草和红树林的生态建设,进而促进鲎资源种群恢复和发展。  相似文献   

18.
《Zoology (Jena, Germany)》2015,118(4):221-238
Horseshoe crabs (Xiphosura) have been an object of zoological research for almost 200 years. Although some morphological work on the circulatory system has been done, the three-dimensional structure of this complex organ system has never been shown satisfactorily and some crucial questions remain unanswered. Here, the circulatory systems of juveniles of the horseshoe crab taxa Limulus polyphemus and Carcinoscorpius rotundicauda were investigated using a combination of an injection method and micro-computed tomography. Data were processed and 3D-visualized using reconstruction software. Furthermore, the heart was examined using scanning electron microscopy. Additionally, the histology of some structures was investigated via light microscopy and transmission electron microscopy. The results show the high degree of complexity of the arterial and lacunar systems of Xiphosura and provide insights into their three-dimensional structure and relationship to other organ systems such as the central nervous system. We show that the major lacunae, previously described as vessel-like – though indeed highly ramified – can clearly be distinguished from arteries in histological sections because they have no distinct walls. Similarities and differences between the xiphosuran species and arachnids are highlighted and possible phylogenetic implications and evolutionary scenarios discussed.  相似文献   

19.
中国鲎胚胎血细胞生成的初步电镜观察   总被引:3,自引:0,他引:3  
梁平  程廷楷 《动物学报》1992,38(4):435-439
人工孵育的鲎胚,以光镜和电镜观察其血细胞发生过程。血细胞包括变形细胞和蓝细胞二系列,均可分为原始、幼稚和成熟三阶段。血细胞生成开始于胚胎的附肢原基形成阶段,变形细胞最早见于胚区,蓝细胞先出现于胚外部分。鲎胚中未发现具备组织结构的造血器官,造血系在结缔组织和血腔中进行。  相似文献   

20.
报道了采自中国南海东沙群岛外海的角鲨目鱼类1新纪录种--黑腹乌鲨Etmopterus spinax(Linnaeus, 1758).本种已有记录仅发现于东大西洋海域,本记录是大西洋东部海域以外的首次发现.乌鲨属目前在中国记录有5种,本文编制了这些种类的检索表.  相似文献   

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