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21.
The Axymyiidae is one of the small families of the suborder Nematocera within the Diptera.Up to date,three genera and seven species of extant axymyiids have been described from the Holarctic Region,including Canada,China,Hungary,Japan,Russia,and USA,with three genera and three species of fossil taxa described from the Middle Jurassic of Daohugou,northeastern China.A new genus Raraxymyia gen.nov.and two new species,R.parallela and R.proxima gen.et sp.nov.from the Middle Jurassic Jiulongshan Formation of Daohugou Village,Inner Mongolia,China,are herein described based on their well-preserved wings and body characters.A revised key to the genera of axymyiids is provided.  相似文献   
22.
Three new species of the extinct genus of Eoptychopterina from the Eoptychopteridae  相似文献   
23.
<正>Juraperla grandis sp.nov.(Grylloblattida:Juraperlidae) is described from the Daohugou locality (Middle Jurassic,China).Its wing venation is very similar to that of Juraperla daohugouensis Huang and Nel,2007 (Grylloblattida:Juraperlidae),in the particular occurrence of a supplementary longitudinal vein in the area between the anterior wing margin and ScP.The larger size of the new specimen,the lower number of CuA1 branches,and the occurrence of two rows of cells between MP and CuA in forewings justify the erection of a new species,J.grandis sp.nov..The material also preserved hind wing and body structures,described for the first time in Juraperlidae.  相似文献   
24.
New Jurassic Pseudopolycentropodids from China (Insecta: Mecoptera)   总被引:2,自引:2,他引:0  
Abstract: In this paper two new species of fossil Pseudopolycentropus Handlirsch, 1906 are described: Pseudopolycentropus janeannae sp. nov. and P. novokshonovi, sp. nov. All of them were recovered from the Middle Jurassic non-marine sedimentary strata of northeastern China. The new material from China reveals that the early diversification of pseudopolycentropodids was well underway by the Middle Jurassic.  相似文献   
25.
A new genus with one new species and five new species of genus Amblomma of fossil ommatids are described and illustrated: Euryomma tylodes gen. et sp. nov., Amblomma cyclodonta sp. nov., Amblomma miniscula sp. nov., Amblomma porrecta sp. nov., Amblomma eumeura sp. nov., and Amblomma protensa sp. nov. All of them were collected from the Upper Jurassic or Lower Cretaceous Yixian Formation of western Liaoning, China. A key to the species of Amblomma is given. The wide epipleural space shows that Euryomma may be a primitive genus in Ommatidae. Many different species of Amblomma occurred within the same sedimentary horizon in this area could be environmental changes caused by frequent volcanic activities during the deposition of the Yixian Formation.  相似文献   
26.
We discuss the present-day sediment transport by rivers, and hence the erosion rate in upstream basins, based on the example of Taiwan Rivers where large datasets are available. After data correction, the values of the suspended sediment load in the lower Kaoping River are nearly three times smaller than those from the literature. On the other hand, we add the bed load evaluated from numerical modelling, despite limitations from data and models. Whereas the contribution of the chemical denudation rate in Taiwan is minor, the bed load is significant and must be evaluated. We point out that biases in data collection may favour high values of suspended load data, and that large series of datasets are needed to reduce uncertainties and smooth the time variability effect. To cite this article: F.-C. Li et al., C. R. Geoscience 337 (2005).  相似文献   
27.
本文从自然天气周期的分类,研究各类周期的韵律与前后关联,提出一种制作季节长期天气预报的办法。  相似文献   
28.
乡村湿地生态保护与恢复模式研究:以常熟市为例   总被引:1,自引:1,他引:0  
由于人类活动的负面影响、不合理的土地利用和难控制的农业污染,乡村地区大量分散的自然湿地或人工湿地正面临着严重的威胁。从湿地生态保护与恢复的角度对常熟市的3个典型乡村湿地的保护发展模式进行了总结与分析,并从区域发展的视角提出了乡村湿地生态保护与恢复模式的五大途径,以解决乡村湿地在生产、生活、生态空间所面临的困境。  相似文献   
29.
江苏省常熟市沙家浜镇是一个以汉民族为主的鱼米水镇。根据沙家浜镇广泛分布的河网水系所展现的"乡镇湿地"这一地域特征,探讨了长江下游农耕文化保育,并提出了湿地生态保育恢复策略。沙家浜湿地小镇的规划可追溯历史、提炼文化、挖掘精髓,力求将湿地生态保育与文化保育相互协调统一,并使湿地产业特色得到显著提升。通过现状及案例分析,重点阐述"沙家浜湿地小镇规划"及"产业发展对策",从而实现湿地产业发展与湿地生态重建。  相似文献   
30.
正Objective This work is designed to improve the quality,visual effect and production efficiency of ecological reconstruction of fossil insects by using various threedimensional software and exploring helpful methodologies  相似文献   
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