共查询到20条相似文献,搜索用时 31 毫秒
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《BMJ (Clinical research ed.)》1965,1(5441):1060-1062
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Female, male and larva of the new species of black flies, Simulium (Argentisimulium) dolini sp. n. are described. By its morphology the species occupies an "intermediate position" between S. nolleri and S. palustre. In the USSR the species was found in wooded and forest-steppe zones of West Ukraine. 相似文献
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J. G. Chmielewski C. C. Chinnappa J. C. Semple 《Plant Systematics and Evolution》1990,169(3-4):123-150
Patterns of intraspecific variation were examined inAntennaria alborosea
A. E. Porsild,A. corymbosa
E. Nels,A. marginata
Greene,A. microphylla
Rydb.,A. parvifolia
Nutt., andA. umbrinella
Rydb. AlthoughA. alborosea was initially considered arctic in distribution, it became apparent that a southern montane element also exists. Our results suggest that morphological differences between arctic and southern montane specimens represent clinal variation. The additional morphological data for specimens that occur more than 1,500 km south of the species' range as it was initially described result in a better understanding of this once presumed arctic taxon. Morphological variation in the dioecious speciesA. corymbosa, A. marginata, A. microphylla, A. parvifolia, andA. umbrinella was greater between the genders than was geographic variation within each gender. These results demonstrate that both pistillate and staminate specimens must be examined in dioecious species ofAntennaria if morphological variation in the respective species is to be fully understood. Character size or number of broadly distributed species (A. microphylla andA. parvifolia) generally decreased with increasing longitude, whereas characters of species with more restricted distributions (A. alborosea, A. corymbosa, andA. marginata) generally increased in size or number with increasing latitude or longitude.Antennaria umbrinella was an exception in this respect. 相似文献
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《BMJ (Clinical research ed.)》1962,1(5286):1198-1201
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《BMJ (Clinical research ed.)》1962,1(5287):1268-1270
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《BMJ (Clinical research ed.)》1961,1(5234):1235-1242
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拉萨伊蚊 Aedes(Ochlerotatus)lasaensis,sp.nov.发现于西藏拉萨,今将其成蚊与幼虫记述如下: 雄蚊 头顶的皮肤黑色;头顶中部有许多淡黄色窄弯鳞;复眼边缘的窄弯鳞密集而形成一黄色缘饰;眼后鬃位于缘饰后,列为一排,黑色、粗壮、末段不很细、尖端钝;眼间鬃色淡;眼后鬃后有许多直立叉状鳞掺杂在黄色窄弯鳞中;叉状鳞主要集中在头顶的后部。叉状鳞的颜色,三个标本呈现三种情况:(1)几乎全部为淡色的,(2)黑色的显然多于淡色的, 相似文献
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对自然杂志发表的一篇文章的评注 总被引:2,自引:0,他引:2
最近自然杂志(Nature,432:383—386,2004)发表了Chengetal.的文章,首次报道了胡氏贵州龙的生育模式、性双形和可能胎生的证据,这无疑是非常重要的,但认为产胡氏贵州龙的竹杆坡组的时代为中三叠世,这与近年来牙形刺的研究结果不符。牙形刺的研究已充分证明竹杆坡组的时代为晚三叠世的早期(卡尼期)(王成源等,1998;Chen&Wang,2002),比以前认为的时代要晚出现大约一千万年。 相似文献
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A new variety ofDraba oreibata, var.serpentina, is described, illustrated, and discussed. 相似文献