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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
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Three new species of the extinct genus of Eoptychopterina from the Eoptychopteridae 相似文献
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A New Species of the Family Juraperlidae(Insecta:Grylloblattida)from the Middle Jurassic of China 总被引：1，自引：1，他引：0
<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
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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
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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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1.IntroductionGreat efforts have been devoted to the protection of coastal areas over many years by erectingdikes,seawalls,groin systems,and detached breakwaters.The sea walls,jetties,detached breakwa-ters,etc.are traditionally adopted as absorbingfacilit… 相似文献
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采用共培养的方法,研究了塔玛亚历山大藻和中肋骨条藻种群竞争关系对UV-B辐射增强的响应变化.结果表明,不同的接种密度对塔玛亚历山大藻和中肋骨条藻种群竞争有明显的影响.当塔玛亚历山大藻和中肋骨条藻的接种比例为A∶S = 1∶4时,中肋骨条藻在竞争中占优势; 当接种例为A∶S = 1∶1时,虽然塔玛亚历山大藻在竞争中占优势,但也受到了中肋骨条藻的抑制; 接种比例为A∶S = 4∶1时,塔玛亚历山大藻的生长竞争优势更加明显.UV-B辐射增强(在预备实验的前提下,选择1.4J/m2)可改变塔玛亚历山大藻和中肋骨条藻种群竞争的关系,使塔玛亚历山大藻种群竞争能力降低,中肋骨条藻种群竞争能力大大提高,从而导致处理Ⅰ(A∶S = 1∶4)中,中肋骨条藻在竞争优势更加明显,在处理Ⅱ(A∶S = 1∶1)中,中肋骨条藻在竞争中占一定的优势. 相似文献
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Abstract— The Sm-Nd systematics of whole-rock and mineral separate samples from nakhlite Governador Valadares define a good 147Sm-143Nd mineral isochron age of 1.37 ± 0.02 Ga. This age is in excellent agreement with the 39Ar-40Ar and Rb-Sr ages obtained previously for this meteorite. However, the Rb-Sr isotopic data for our sample show that the isotopic system is disturbed. The lack of isotopic equilibrium is probably caused by the weathering of the sample as indicated by the presence of secondary alteration phases. The whole-rock and acid-washed mineral data yield a Rb-Sr age of 1.20 ± 0.05 Ga, which probably represents a lower limit to the crystallization age of the rock. The petrographic evidence indicates that this meteorite is a clinopyroxene cumulate that probably crystallized in a subsurface sill (McSween, 1994). Thus, the Sm-Nd isotopic age probably represents the age of such a magmatic event. The initial ε143Nd value determined for the rock at 1.37 Ga is +17 ± 1, indicating that the parent magma of the rock came from a light-rare-earth-element-depleted source of 147Sm/144Nd = ～0.237 based on a simple two-stage evolution model. Results of the same model calculation for the initial 87Sr/86Sr ratio of the rock suggest that its source material was depleted in 87Rb/86Sr by ～50% relative to the estimated martian value at 1.37 Ga. Both the high Sm/Nd and low Rb/Sr values support a clinopyroxene-rich cumulate source for the genesis of the nakhlite Governador Valadares. Furthermore, our Sm-Nd age and ε143Nd data and the previously published ε142Nd datum for the rock (Harper et al., 1995) are consistent with early differentiation of the parent planet, formation of cumulate sources ～4.56 Ga ago, and late melting of the sources and formation of the rock ～1.37 Ga ago. The good agreement of isotopic ages and petrographic features among Governador Valadares, Nakhla, and Lafayette strongly suggests that all three nakhlites have undergone similar evolutionary histories. The nakhlite age data suggest that isotopic heterogeneity in the martian mantle sources existed up to ～1.37 Ga ago and early mantle structures probably have not been disturbed for a significant portion of martian history. 相似文献
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New Fossil Beetles of the Family Ommatidae （Coleoptera： Archostemata） from the Jehol Biota of China 总被引：2，自引：2，他引：0
TAN Jingjing REN Dong SHIH Chungkun GE Siqin 《《地质学报》英文版》2006,80(4):474-485
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