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1.
山西忻州中新世鼠兔科化石   总被引:3,自引:1,他引:2  
本文记述了山西忻州发现的跑兔属—新种.该种以个体较小, P~2 较简单,无前沟, M~2 后叶无后突, P_3 小,无前内沟与前外沟等特征与属型种 B. forsythmajori 相区别,命名为杨胡跑兔 B. yanghuensis sp. nov..新种在进化水平上较属型种稍原始,但两者显示出较近的系统关系.根据 B. yanghuensis sp. nov. 的进化水平,推断其地质时代可能为中中新世早期,约相当于欧洲 Orleanian 期.  相似文献   

2.
记兰州盆地第三纪中期的爪兽(奇蹄目)化石   总被引:3,自引:1,他引:2  
记述了兰州盆地新发现的三种爪兽化石:Schizotheriumordosium,Phyllotillonhuangheensissp.nov.和Chalicotheriinae亚科未定属种的一类。在咸水河组下段南坡坪地方动物群(早渐新世晚期)中发现S.ordosium。这个种的材料较多,其中有保存完好的下颌吻部。这使我们第一次了解了这个属的吻部的构造:吻部很长、具大的铲形下门齿和双叶形的下犬齿.在咸水河组中段(早中新世)张家坪地方动物群中发现了Phyllotillonhuangheensis和Chalicotheriinaegen.etsp.indet。前者比巴基斯坦Bugti层中的P.naricus个体稍小,形态上也更原始些。这可能表明,张家坪地方动物群在时代上比Bngti稍早。后一类爪兽的性质还不很清楚,但Chalicotheriinae亚科在我国早中新世的出现则无疑义。  相似文献   

3.
江苏泗洪松林庄、双沟和郑集早中新世(山旺期,约与欧洲新第三纪陆相哺乳动物分带MN4相当)的新种泗洪跳兔Alloptoxsihongensissp.nov.是迄今为止该属中出现最早、个体最小的种。该种已有较明显的形态分化。主要表现在p3上。p3在形态和大小上可分为两类。第一美个体较大,珐琅质厚度分化较明显,个别p3的下后尖前端已呈圆钝的角状,具有两个前外沟。第二类个体较小,珐琅质厚度分化较差,下后尖前端浑圆,仅具一个前外沟。由于对Alloptox的系统进化尚无足够的了解,现将其作为同一个种处理。根据上下齿列尤其是p3的形态分析,推测Alloptox可能由晚渐新世的Sinolagomysulungurensis或与其相近的鼠兔进化而来。  相似文献   

4.
描述螃蟹化石29种,包括:2新种,3种以化石形态新出现的现生种及已知种24种。新种:Randallia jingomao sp.nov..Ommatocarcinus sankuei sp.nov.;新以化石形态出现的现生种:Ranilia misakiensis (Sakai),Leucosia pbtisifrons de Haan,Macrophthalmus convexus Stimpson。29种螃蟹化石之大部分出现于台南玉井附近六重溪层,少数种出现于嘉义、内埔、中埔六重溪层,尚有1或2种出现于南投中寮附近石门层、深坑层及高雄大冈山石灰岩。地质时代由中中新世至上新世。  相似文献   

5.
根据在甘肃临夏盆地中中新世早期东乡组地层中发现的1支成年鹿角、3枚颊齿、1枚距骨和1枚跟骨建立了皇冠鹿新种——广河皇冠鹿(Stephanocemas guangheensis sp.nov.)。它是皇冠鹿属中一个体型相当小的种,其鹿角显著掌状化,在成年个体中具有6个角枝。新种鹿角的组合特征区别于皇冠鹿的其他已知种,如中等大小的掌状部和向上伸展的侧枝;掌状部腹面具短的角柄,其横截面为外缘平直的半圆形;未封闭的脱落疤痕浅凹并布满海绵状孔隙。S.guangheensis比早中新世晚期的S.aralensis和S.actauensis进步,但比中中新世的S.palmatus原始。东乡组是临夏盆地中含化石相当稀少的地层,S.guangheensis的发现为确定该组的地层时代提供了新的依据。  相似文献   

6.
本文报道采自香港的蜘蛛目跳蛛科4新种及香港的1新记录种:铜头菱头蛛Bianoraeneiceps(Simon,1901);香港菱头蛛,新种Bianorhongkongsp.nov.;香港伊蛛,新种Iciushongkongsp.nov.;香港兰戈纳蛛,新种Langonahongkongsp.nov.;香港盘蛛,新种Pancoriushongkongsp.nov。迄今香港已知跳蛛24种。  相似文献   

7.
记述了在现代东洋界发现的鼩鼱类一新种:江南贝列门德鼩Beremendia jiangnanensis sp.nov.。化石产自长江以南安徽繁昌早更新世早期人字洞古人类遗址。新种的体型比该属已知种大;形态特征比我国渤海种B.pohaiensis原始,但比欧洲早上新世的B.fissidens进步。贝列门德鼩是喜湿耐冷的北方型动物,最早发现于欧洲北部上新统,曾广泛分布于欧洲和中亚高纬度地区,种群密度大,中更新世完全绝灭;它在东亚出现较晚,零星发现于华北早更新世地层中,其起源尚不清楚。新种乃是人字洞动物群的主要成员之一,该动物群由70多种哺乳动物组成。动物群的生态类型分析和分类统计表明,它与以往发现的早更新世南、北动物群及当地现代动物群截然不同,具有东洋界和古北界交错带动物群的特色,但动物组合特征为北方动物稍占优势,北方色彩较浓。贝列门德鼩和三门马(Equus sanmeniensis)、次兔(Hypolagus)、科氏仓鼠(Kowalskia)、模鼠(Mimomys)等大量北方型动物在我国东洋界的出现,足以说明第四纪早期有一次明显的降温事件。寒冷气候促使北方动物大规模南迁,古北区动物地理区系的界线在早更新世时要比目前更靠南;而且在古北界与东洋界之间确实存在南、北动物过渡带,其界线大致南移至现在的长江以南。贝列门德鼩在我国现代东洋界地区的首次发现,为研究该属的系统演化,探讨上新世一更新世气候转型时期鼩鼱类扩散事件及我国第四纪动物地理区系的演变将提供重要的信息。  相似文献   

8.
本文记述了宁夏同心发现的中鬣狗—新种, Percrocuta prtmordialis sp. nov..文中讨论了 Percrocuta 属的含义,新种在该属中的地位及特征.作者认为, Percrocuta 只应包含那些生存于中中新世的小至中等个体的特化的鬣狗,而不包括那些后期的巨型鬣狗.新种个体小,在头骨上显示出一系列原始性状,是该属目前所知最原始的一个种.  相似文献   

9.
记述了在山东早始新世地层中发现的一种仿齿兽类──亚洲脊兽(新属、新种)(Lophocionasiaticusgen.etsp.nov.),肯定了伪齿兽类在亚洲的存在。新种在牙齿形态上与北美的Ectocion接近,但脊齿化程度较高,表现在上自齿上有初始的后脊,从次尖向不同方向伸出三条清晰的棱脊。这些特征使新属容易与其他已知伪齿兽类相区别。  相似文献   

10.
湖北房县豕齿兽一新种   总被引:1,自引:0,他引:1  
记述了在湖北省岳县罗家沟始新世地层中新近发现的哺乳类,其中包括踝节目豕齿兽科豕齿兽属一新种──房县豕齿兽(Hyopsodusfangxianensissp.nov.)依据该新种的进化水平,进一步确定产化石的油坪组的地质时代为早始新世,但就化石层本身来说,很可能是早始新世晚期。  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   

14.
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   

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Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.  相似文献   

18.
Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.  相似文献   

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.
肝癌中HBV和HCV基因和抗原的分布及意义   总被引:1,自引:0,他引:1  
采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细  相似文献   

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