共查询到20条相似文献,搜索用时 15 毫秒
1.
Forty embryonic hearts were taken out by anatomical needle from denuded embryos of the ovoviviparity guppy fish that were
dechorioned by mechanic method or by trypsin digestion, and werein vitro cultured. In the cultured hearts, 80% have maintained beatingin vitro for 4 weeks, and the longest record for beating was 142 d. Owing to fish embryo transparency, beating frequency and blood
color changes are easily viewed from the embryonic hearts under a dissecting microscope. The current study established thein vitro culture method of embryonic hearts in guppy fish, which can be used as a model for the study of heart and cardiovascularf
system in vertebrates. 相似文献
2.
3.
4.
研究了2010年4月到5月和2012年6月二次采集自刚果盆地的水样,共发现棘管轮属Mytilina Bory de St.Vincent 1826的8个种,其中2个种 M.crassipes (Lucks,1912) 和 M.trigona (Gosse,1851)是非洲新纪录种; M.macrocera (Jennings,1894)和 M.bisulcata (Lucks,1912)是刚果盆地多个样点的常见种;M.ventralis (Ehrenberg,1830)和M.trigona,在刚果盆地个别样点比较多见;M.michelangllii Reid & Turner,1988, M.crassipes和M. brevispina (Ehrenberg,1830)在此次刚果盆地的调查中非常罕见;描述了一种棘管轮,其形态奇特,可能是新种. 相似文献
5.
A new genus with a new species of fossil elaterid, Paraprotagrypnus superbus gen. et sp. nov., from the Middle Jurassic Jiulongshan Formation in Daohugou Village (N41°18.979′, E119°14.318′), Shantou Township, Ningcheng County, Inner Mongolia, China is described and illustrated. The genus Paraprotagrypnus belongs to the family of Elateridae, subfamily of Protagrypninae and tribe of Protagrypnini. Some primitive characters of the new genus and new species shed light on the ages between the Jiulongshan Formation in Inner Mongolia and the Yixian Formation in the western Liaoning Province of China. The habitat of the new species is briefly discussed. 相似文献
6.
7.
8.
9.
白肩天蛾属(Rhagastis RothschildJordan,1903)在中国分布有9种.于2017年上半年和2018年上半年分别对贵州荔波县茂兰自然保护区和海南乐东县尖峰岭地区进行考察并采集到一些天蛾标本.在对长喙天蛾族(Macroglossini Harris,1839)的标本进行整理之后发现,其中一些标本为宽缘白肩天蛾(Rhagastis acuta Walker,1856),这是该种首次在中国境内被记录.对该新记录种雄性成虫的形态进行了描述且附图,并对中国白肩天蛾属目前已知的种类进行了记述. 相似文献
10.
记述了上海蝶类一新记录种:无趾弄蝶(Hasora anura de Nicéville,1889),简要描述了其形态特征,并提供成虫标本照和雌外生殖器解剖图,给出了上海地区趾弄蝶属分种检索表,同时列出相关生物学和分布信息. 相似文献
11.
A phylogeny of 17 species in the genus Oreolalax is reconstructed based on 21 morphological characters from adult specimens, skeleton specimens, tadpoles and eggs. Four species groups are recognized, of which the O. rugosus species group is the most primitive, the O. weigoldi species group is the second, the O. omeimontis species group is the third and the O. pingii species group is the most recently diversified. Based on the evolutional tendency of the morphological characters on the phylogenetic tree, it is proposed that the evolution of tympanum, tympanic annulus, columella, spoon-like cartilage and the web between toes reflect the habit changes from aquatic to terrestrial. Thus, Oreolalax is regarded as one important representative genus to study further the evolution of morphological characters from aquatic to terrestrial. 相似文献
12.
13.
14.
15.
记述了采自上海的中国新记录种凹腹龟甲轮虫(Keratella procurva Thorpe 1891),该种的特征为:腹部显著凹陷,前端有6刺,其中中间2刺最长,后端有2个不对称的棘刺.并根据光学显微镜(LM)和扫描电子显微镜(SEM)照片描述了该种的形态特征. 相似文献
16.
17.
对中国鲿科鱼类系统分类学研究中发现,凹尾拟鲿为一不同于细体拟鲿(P. pratti)的有效种,仅分布于长江上游。凹尾拟鲿胸刺前缘光滑无锯齿,颌须较短,后伸不超过胸鳍起点,本属中同时具有这两个特征的还包括18个有效种。在这18个物种中,乌苏里拟鲿(P. ussuriensis)、长脂拟鲿(P. adiposalis)、短尾拟鲿(P. brevicaudatus)和越南拟鲿(P. kyphus)与凹尾拟鲿一样,具有中等分叉的尾鳍。凹尾拟鲿与乌苏里拟鲿和长脂拟鲿的区别在于游离脊椎骨数目和背刺长短等性状上,与短尾拟鲿和越南拟鲿在背刺后缘程度、枕骨棘与项背骨间的间距上存在差异。凹尾拟鲿与细体拟鲿在形态上最为相似,但在体高、背鳍前长、脂鳍高及尾柄高等性状上存在差别。同时,在颅骨、犁骨、项背骨及腰带等骨骼特征上也存在较大差异。 相似文献
18.
记述中国圆痕叶蝉亚科纤细叶蝉属1新种:中性纤细叶蝉(Igerna mesialis sp.nov.);2新纪录种:西隆纤细叶蝉(Igerna shillongensis Meshram rec.nov.)、威尔逊纤细叶蝉(Igerna wilsoni Viraktamath rec.nov.).新种与美丽纤细叶蝉(Igerna channa Viraktamath,Dai&Zhang)相似,但前者阳茎干两边缘平行,至端部1/4处变窄;阳茎干上的短突起指向基腹侧;阳茎干上的长突起在基部侧缘,指向背侧;性孔位于阳茎干近中部.新种模式标本及新纪录种的检视标本保存于贵州大学昆虫研究所(GUGC). 相似文献
19.
算子理论是解析函数空间理论研究的重要内容,为了寻找通过探讨联立算子与函数空间的方法研究算子以及函数空间的有效途径,假设为单位圆盘Δ上的一个解析自映射,正规权Bloch空间μ-B是单位圆盘Δ上的一个Banach空间,定义C_Ф∶C_Ф(f)=f■Ф为μ-B上的复合算子,对所有的f∈μ-B,并由积分算子以及复合算子推广得到积分型算子J_hC_Ф和C_ФJ_h,主要讨论了正规权Bloch空间到Q_(T,S)空间的积分型算子J_hC_Ф的有界性和紧性,以及正规权Bloch空间到Q_(T,S)空间的积分型算子C_ФJ_h的有界性,并给出了相关的充要条件。 相似文献
20.
We report the results of a comparative study of n-alkane biomarkers and pollens in lacustrine and peat deposits at Dingnan, Jiangxi Province in southern China, and discuss
the likely causes for the discrepancy in the interpretations of the n-alkane biomarker and pollen records in terms of climate and vegetation change. The results show that past changes in climate
and vegetation revealed by the n-alkane record are not always consistent with the pollen assemblage record in the whole section. Biomarkers do not permit
direct identification of the plant family and/or genus and mainly record compositions of local plant remains, while pollens
mainly reflect the regional vegetation change. Biomarkers and pollen records complement each other, providing a better picture
of local and regional environments. Furthermore, biomarkers are more sensitive than pollen to climatic and vegetational change.
Several climatic events are clearly identified by the n-alkane biomarker proxies, such as C31/(C27+C29+C 31) ratio and can be correlated to the North Atlantic Heinrich event, B/A, YD and two dry-cool events during the early Holocene
such as the periods of 9850 to 9585 cal a B.P. and 8590 to 7920 cal a B.P. These events are consistent with those found in
the surrounding regions, suggesting that the regional climate was coupled with global-scale abrupt climatic events. Our results
suggest that biomarker and pollen data can record the more detailed climate and vegetation information, thus improving the
resolution and precision of vegetation and climate reconstruction.
Supported by National Natural Science Foundation of China (Grant No. 40602004) and National Basic Research Program of China
(Grant No. 2004CB720200) 相似文献