首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   3篇
  免费   0篇
  国内免费   2篇
地球物理   1篇
海洋学   4篇
  2018年   3篇
  2016年   1篇
  2006年   1篇
排序方式: 共有5条查询结果,搜索用时 0 毫秒
1
1.
作者在整理中国科学院海洋生物标本馆馆藏蜑螺科Neritidae标本时,鉴定出产自海南三亚的一新记录属饰纹蜑螺属Vittina Baker,1924和一新记录种:裂蜑螺Vittina pennata(von Born,1778)。文中详细描述了本种的贝壳形态特征,查明了其生活习性和地理分布特点,并与相似种进行了比较和总结。  相似文献   
2.
中国沿海常见蜑螺科贝类的DNA条形码   总被引:1,自引:0,他引:1  
DNA条形码不仅为物种鉴定提供了有效方法,而且也有助于分类学和生物多样性研究。本研究旨在探讨将COI和16S rRNA基因序列应用于中国沿海蜑螺科贝类物种鉴定的可行性,获得了该科3属7种贝类61个个体的COI和16S rRNA基因序列。基于COI基因序列的种内遗传距离为0.00—1.29%,平均为0.67%;属内种间遗传距离为4.62%—19.25%,平均为13.02%;基于16S rRNA基因序列的种内遗传距离为0.00%—0.48%,平均为0.23%;属内种间遗传距离为2.47%—8.48%,平均为6.37%。两种基因序列在所研究的蜑螺中,种内遗传差异均小于种间遗传差异,存在明显的条形码间隙,所有物种在系统发生树上都表现为独立的单系群。结果表明,线粒体COI和16S rRNA基因序列可以作为DNA条形码标准基因对蜑螺科贝类进行有效地物种鉴定。  相似文献   
3.
蜑螺科软体动物系统分类学研究进展   总被引:2,自引:0,他引:2  
蜑螺科是一类广盐性腹足类动物,主要分布在热带和亚热带海域,是潮间带底栖生物群落的重要组成部分之一,该科动物为探讨物种适应辐射及热带海域生物多样性模式提供了重要研究材料。本文对蜑螺科的国内外系统分类学研究现状和趋势进行了回顾与展望。蜑螺类动物为适应不同生境而进化出多样的贝壳形态,仅依据外部形态很容易产生误导或错误鉴定,因此蜑螺科的分类系统以及一些种属的有效性仍存在争议。我国缺乏系统的蜑螺科分类学研究,已报道的种类还不能完全反应中国海实际的物种数。未来需强化标本采集,在传统形态学分类的基础上,借助分子生物学和解剖学等手段,明确中国海蜑螺科种属组成和区系特点,进而完善蜑螺科的系统分类学研究。  相似文献   
4.
A population of Theodoxus fluviatilis L in the littoral zone of Lake Esrom was investigated from November 1977 to February 1979. The population was sampled every month in the winter period and twice during the rest of the year. Biomass was estimated as ash-free dry weight (AFDW) of the organic matter both of the soft parts of the animal and the shell itself. The relation between AFDW (c) and shell length (l) was log c=2.9509×log (l)−1.7120. The population comprised more than 1 year-class, which could be separated by shell length, by a narrow band on the shells and the growth of algae on the shell. The life cycle lasted years. The oldest animals had a shell length of 7.0-7.5 mm. A few individuals who were estimated to be years had a shell length up to 8.6 mm. Population density varied between 575 and 2115 individuals m−2 on the stony substratum. The average was 1160 individuals m−2. Mortality was low during the summer period. In winter many animals died due to the effect of ice and stormy weather on the stony substratum. Growth of the animals was estimated from the shell length. Maximum growth was observed from May to August with no growth during the winter. Egg capsules were found on the stones all year round. New capsules were found from late May to the middle of November. Most freshly laid capsules were observed in May-June and August-September. Capsules from the late summer hatched in spring and capsules laid in the spring hatched in August-September. The average annual net production for the whole population was estimated by three methods. The Allen curve method gave 1.895 AFDW m−2, the growth-increment method gave 1.784 mg AFDW m−2 and the Hynes method 2.284 mg AFDW m−2. Corresponding estimated P/B ratios were 1.29, 1.30 and 1.57. Annual net-production of the four investigated year-classes was 16 mg AFDW m−2 year−1 for 1975, 224 mg AFDW m−2 year−1 for 1976, 1.258 mg AFDW m−2 year−1 for 1977 and 287 mg AFDW m−2 year−1 for 1978. P/B ratios for the three oldest year-classes were, respectively, 0.32, 0.50 and 1.67. A comparison with other investigations on gastropod life cycles, reproduction and P/B ratios is made and differences discussed. Variations are correlated to temperature, and food quality and quantity.  相似文献   
5.
蜑螺科 Neritidae 蜑螺属 Nerita 的一些种类形态近似, 形态鉴定上存在种类混淆、同物异名或错误鉴定等现象。作者在整理中国科学院南海海洋生物标本馆和中国科学院海洋生物标本馆历年来采集的蜑螺科标本时, 对4种隶属于蜑螺属的易混淆种进行了比较研究。通过对标本的反复对比, 分别找出了它们之间外部形态、地理分布以及生活习性方面的差异, 澄清了混淆, 确立了其分类地位: 1) 矮狮蜑螺Nerita chamaeleon Linnaeus, 1758和圆蜑螺Nerita histrio Linnaeus, 1758两者贝壳形态相近, 在我国海区分布重叠, 存在混淆以及错误鉴定的现象, 根据螺旋部以及壳面雕刻可将它们区分开, 即前者壳面螺肋光滑, 后者螺肋粗糙, 而前者螺旋部较后者高; 2) 锦蜑螺 Nerita polita Linnaeus, 1758和杂色蜑螺 Nerita litterata Gmelin, 1791两个种常被混淆在一起, 都鉴定为锦蜑螺, 前者在我国见于台湾、海南岛和西沙群岛, 后者在我国见于台湾、福建、广东、广西和西沙群岛, 其中杂色蜑螺此前在我国仅见于台湾, 本文的报道进一步完善了该种的地理分布信息。  相似文献   
1
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号