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1.
西藏北部安多地区中侏罗统(巴通阶-卡洛夫阶)菊石   总被引:1,自引:0,他引:1  
最近从藏北安多地区中侏罗统发现较丰富的菊石类化石,巴通期的菊石有OxyceritesoppeliElmi,Ho moeoplanulitescf. homoeomorphus(Buckman),H. cf. acuticosta(Roemer), Choffatiacf. vicentiMangold, Siemiradzkiacf. matisconensis(Lissajous), Proceritessp., Neuquenicerascf. yokoyamaiKobayashiandFukada和Indosphinctessp.。卡洛夫期的菊石有Oxyceritescf. subcotarius(Oppel), Macrocephalites? sp., Homoeoplanulitescf. furculus(Neumayr),Indospinctes(Elatmites) cf. reveliMangold和Reineckeitessp.。其中Indosphinctes,Indospinctes(Elatmites),Neu queniceras,Siemiradzkia和Procerites等属(或亚属)在西藏北部地区为首次报道。安多地区中—晚巴通期和早卡洛夫期菊石动物群凸现较强的地方性色彩; 晚巴通期ORBIS菊石带和早卡洛夫期KOENIGI菊石带是藏北地区菊石动物群扩散的重要时期。  相似文献   

2.
白垩纪双壳类Isodomella在藏北的发现及其意义   总被引:2,自引:0,他引:2  
文世宣 《古生物学报》1992,31(4):377-394
产于西藏北部改则县川巴和麻米附近的1个双壳类动物群,包括 Isodomella choinbaensis sp. nov. 和 Caestocorbula (Parmicorbula) perlonga sp. nov. 等9种,时代为早白垩世 Valanginian 至早 Aptian 期.从 Isodomella 揭示出的铰齿看,它应归入 Corbiculidae 科;所共生的种类反映 Isodomella 为与正常海有密切联系的半咸水生活的种类.Isodomella 被认为是日本特有的属,在日本以外尚属首次发现.这个属的动物从日本到藏北的迁移路线,很可能是经我国台湾、南海,绕中南半岛折向西北,又经我国滇西、藏东到达藏北的.这个动物群与东特提斯北部边缘的动物群联系密切,说明川巴和麻米所在的拉萨地块当时已是欧亚大陆的一部分.  相似文献   

3.
在奥陶纪末生物大灭绝的两幕之间,海洋底域繁盛着赫南特贝腕足动物群(Hirnantia Fauna)。它数量丰富,分布广泛,历程短暂。以往国内外学者研究这个动物群时,常把有铰类腕足动物作为重点,而无铰类只被简单描述或列出名单,整体面貌不明。无铰类化石尽管材料有限、研究基础薄弱,但只就属的数目而言,占据了全球赫南特贝动物群总属数的近1/5,其群落、演化和环境意义不可小觑。文中专门记述上扬子区(华南古板块)观音桥层(赫南特早中期)与缅甸曼德勒地区(滇缅马苏古地体)Hwe Mawng紫色页岩段(赫南特中期)所产赫南特贝动物群的无铰类化石,计有3目、4超科[Linguloidea(舌形贝超科)、Discinoidea(平圆贝超科)、Craniopsoidea(似髑髅贝超科)和Cranioidea(髑髅贝超科)]的10属、12种,包括5个命名属种[Plectoglossa cf. davidsoni (Barrande),Schizotretinia cf. euxina (Havlí?ek), Pseudopholidops partibilis (Rong),Petrocrania cribrum (Temple),Xenocrania haimei (Reed)]和7个未定种(Trematis sp.,Paracraniops sp.,Acanthocrania sp.,Petrocrania? sp. 1,Petrocrania? sp. 2, Pseudolingula? sp. 和Orbiculoidea sp.),其中,Pseudolingula? sp.和Orbiculoidea sp.两个未定名种因标本不佳,未正式描述。其中,以Pseudopholidops最为常见,其次是Xenocrania和Petrocrania。前两属是华南、滇缅马苏、波罗的卡、阿瓦隆尼亚、佩鲁尼卡等古板块或地体赫南特贝动物群的常见分子。它们已知限于南、北纬30°之间的低纬度地区,这可能与化石采集和研究程度有关,但更可能反映奥陶纪末全球气候仍存在分异现象。研究识别了奥陶纪晚期无铰类腕足动物7个目,可归为3个类群:灭绝目(仅神父贝目Paterinida)、消减目(多样性与丰度大幅衰减,尤其是三分贝目Trimerellida和乳孔贝目Acrotretida在Hirnantian销声匿迹)和延续目(适应能力强、忍耐阈值高,成功穿越大灾难的首幕)。这些分类单元对研究奥陶纪-志留纪交界期腕足动物群的多样性、群落生态、生物地理及宏演化等有重要意义。  相似文献   

4.
本文对云南省东南部的泸西县白水镇小兴安村上三叠统卡尼阶小凹组菊石类进行了详细研究,共发现菊石9属13种,其中Anasirenites属为华南首次发现。依据各物种组合特征及其地层分布情况,自下而上识别出菊石Trachyceras multituberculatum带和Austrotrachyceras triadicum带,时代对应于晚三叠世早卡尼期的Julian 1和Julian 2。该菊石组合不仅记录了卡尼期Julian期Trachyceratidae的辐射事件,同时该菊石组合与卡尼期特提斯域和泛大洋域的菊石组合均有良好的对比性,并且为华南古地理研究提供了新的补充材料。另外,通过对剖面的岩性特征与菊石生物地层特征分析,认为在滇东南地区由于卡尼期湿润幕事件(CPE)所导致的碳酸盐岩台地消亡起始时间应为Julian 1末期略早于陆源碎屑输入的Julian 2亚期。  相似文献   

5.
在奥陶纪末生物大灭绝的两幕之间,海洋底域繁盛着赫南特贝腕足动物群(Hirnantia Fauna)。它数量丰富,分布广泛,历程短暂。以往国内外学者研究这个动物群时,常把铰合类腕足动物作为重点,而非铰合类只被简单描述或列出名单,整体面貌不明。非铰合类化石尽管材料有限、研究基础薄弱,但只就属的数目而言,占据了全球赫南特贝动物群总属数的近1/5,其群落、演化和环境意义不可小觑。文中专门记述上扬子区(华南古板块)观音桥层(赫南特早中期)与缅甸曼德勒地区(滇缅马苏古地体)Hwe Mawng紫色页岩段(赫南特中期)所产赫南特贝动物群的非铰合类化石,计有3目、4超科[Linguloidea (舌形贝超科)、Discinoidea (平圆贝超科)、Craniopsoidea(似髑髅贝超科)和Cranioidea (髑髅贝超科)]的10属、12种,包括5个命名属种[Plectoglossa cf.davidsoni (Barrande),Schizotretinia cf.euxina (Havlicek),Pseudopholidops partibilis (Rong),Petrocrania cribrum (Temple),Xenocrania haimei (Reed)]和7个未定种(Trematis sp.,Paracraniops sp.,Acanthocrania sp.,Petrocrania?sp.1,Petrocrania?sp.2,Pseudolingula?sp.和Orbiculoidea sp.),其中,Pseudolingula?sp.和Orbiculoidea sp.两个未定名种因标本不佳,未正式描述。还有,以Pseudopholidops最为常见,其次是Xenocrania和Petrocrania。前两属是华南、滇缅马苏、波罗的卡、阿瓦隆尼亚、佩鲁尼卡等古板块或地体赫南特贝动物群的常见分子。它们已知限于南、北纬30°之间的低纬度地区,这可能与化石采集和研究程度有关,但更可能反映奥陶纪末全球气候仍存在分异现象。研究识别了奥陶纪晚期非铰合类腕足动物7个目,可归为3个类群:灭绝目(仅神父贝目Paterinida)、消减目(多样性与丰度大幅衰减,尤其是三分贝目Trimerellida和乳孔贝目Acrotretida在Hirnantian销声匿迹)和延续目(适应能力强、忍耐阈值高,成功穿越大灾难的首幕)。这些分类单元对研究奥陶纪-志留纪交界期腕足动物群的多样性、群落生态、生物地理及宏演化等有重要意义。  相似文献   

6.
浙西、赣东北早二叠世晚期菊石   总被引:7,自引:2,他引:5  
本文系统描述了浙西及赣东北饶南地区早二叠世晚期菊石35种,分别属于18属、8科,其中包括26新种、10新属、4新科,并建立了1新超科。综合分析了菊石动物群的特点,指出它既具有浓厚的特提斯海域的色彩,又具有我国南部区域性的特色,同时还渗进了极少量的北极区的分子。根据菊石的新发现,并结合其他门类化石以及岩石性质,对浙西的丁家山组及赣东北饶南地区的湖塘组重新作了厘订、划分和对比,并对华南若干地区的相当地层作了简要的对比讨论。对浙西的“礼贤煤系”、饶南的“乐平组”以及华南大羽羊齿植物群的时代问题提出了新认识。  相似文献   

7.
牟林 《古生物学报》2011,(4):439-449
基于一些业已报道的Kungurian阶与Roadian阶界线附近的菊石材料进行重新研究,认为中国中、下二叠统界线附近的菊石生物群主要分布在华南和中国西部两个地区.通过与俄罗斯地区同时代的菊石动物群比较后认为中国在这一界线附近的菊石群以地方性的分子为主,主要包括:假海罗菊石亚科(Pseudohaloritinae)和寿昌...  相似文献   

8.
文中描述了采自贵州省兴义市乌沙镇泥麦古剖面和安顺市关岭县麻洼剖面三叠系法郎组竹杆坡段的康尼克贝类腕足动物:Koninckella guizhouensis,Koninckella zhenfengensis和Koninckina sp.。结合牙形石、菊石生物地层及同位素测年等证据,对黔西南地区法郎组竹杆坡段的时代进行了详细讨论,认为其下部属拉丁阶(Ladinian),上部属卡尼阶(Carnian),在此基础上对黔西南地区报道的康尼克贝类的层位进行了讨论。综合全球已报导的三叠纪康尼克贝类化石记录可知,该类群于中三叠世起源于中国黔西南地区,在晚三叠世逐渐繁盛并向特提斯洋西部的欧洲地区和特提斯洋中部的西藏地区进行迁移扩散。受三叠纪末期生物大灭绝影响,康尼克贝类的多样性在瑞替期(Rhaetian)显著降低,直至早侏罗世辛涅缪尔期(Sinemurian)才再度复苏。  相似文献   

9.
新疆北部准噶尔盆地东缘巴里坤、西缘托里与西北缘和布克赛尔等地的密西西比亚纪早期地层为一套较深水相的黑色页岩与生物屑泥晶灰岩, 产浮游生活的菊石、牙形类和营底栖固着生活的腕足类、腹足类、双壳类、苔藓虫、无鳞板的单体珊瑚以及孢子等化石。根据鉴定, 该地层时代应属于密西西比亚纪(或称早石炭世)早期, 相当于国际地层表中的杜内阶(Tournaisian)。产出珊瑚分别为: Amplexus gennarenensis sp. nov., Cyathaxonia stereoseptata, Hapsiphyllum crissum, Meniscophyllum irregulare, Rotiphyllum xinjiangense sp. nov., Zaphrentites parallelus (Carruthers), Neozaphrentis sp., fam. gen. et sp. indet.。  相似文献   

10.
详细讨论滇东北奥陶纪的岩石地层和动物群特征,初步建立区内的三叶虫地层序列,据此可靠确定各有关岩组的时代。该地区除普遍缺失早奥陶世早期的沉积外,依次发育了红花园组(特马豆克末期—弗洛初期),湄潭组(弗洛期—达瑞威尔初期),风洞岗组(达瑞威尔早—晚期),十字铺组(达瑞威尔末期—桑比早期)、宝塔组(桑比晚期—凯迪早期),盐津组(晚凯迪早期)、五峰组(晚凯迪晚期)及观音桥组(赫南特期),岩相与黔北的相应岩组可作大致对比,而三叶虫动物群的组成和序列则大体与当时同属扬子陆块西部边缘的沉积区包括滇东、滇东南、黔北、川中、重庆、陕南及安徽和县等地区相似。共记述本区奥陶纪三叶虫计19属27种,分属14科。并对其中的一个新种Hungioides yanjinensis sp.nov.以及两个未命名的新种Abulbaspis sp.nov.和Plaesiacomiasp.nov.作系统描述。Abulbaspis过去仅报道于华北和哈萨克斯坦地区的达瑞威尔阶,而在本地区则产于桑比阶上部—凯迪阶下部;Plaesiacomia广泛分布于达瑞威尔阶—桑比阶西泛冈瓦纳地区,在滇东北的发现不但将该属的分布区域扩大到了东泛冈瓦纳地区,而且因其产出于大坪中期的层段,表明该属可能起源于东泛冈瓦纳,尔后才向西迁移的;这两属在扬子区的首次发现,对于进一步研究奥陶纪不同区块间的三叶虫动物群的扩散和交流具有重要意义。  相似文献   

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It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.  相似文献   

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正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases  相似文献   

17.
Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.  相似文献   

18.
Microbial resistance to antibiotics is an unresolved global concern, which needs urgent and coordinated action. One of the guidelines of the Centers for Disease Control and Preventions (CDC) to combat antibiotic resistance is the development of new antibiotics to treat drug-resistant bacteria. In our effort to find new antibiotics, we report the synthesis and antimicrobial studies of 30 new pyrazole derivatives. These novel molecules have been synthesized by using readily available starting materials and benign reaction conditions. Some of these molecules have shown activity with MIC values as low as 0.78?µg/mL against four bacterial strains; Staphylococcus aureus, methicillin-resistant S. aureus, Bacillus subtilis, and Acinetobacter baumannii. Furthermore, active molecules are non-toxic to mammalian cell line.
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19.
The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.  相似文献   

20.
Cyclin-dependent kinases (CDKs) and Polo-like kinases (PLKs) play key role in the regulation of the cell cycle. The aim of our study was originally the further development of our recently discovered polo-like kinase 1 (PLK1) inhibitors. A series of new 2,4-disubstituted pyrimidine derivatives were synthesized around the original hit, but their PLK1 inhibitory activity was very poor. However the novel compounds showed nanomolar CDK9 inhibitory activity and very good antiproliferative effect on multiple myeloma cell lines (RPMI-8226).  相似文献   

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