共查询到19条相似文献，搜索用时 810 毫秒
1.
辽宁北票发现一新的无尾两栖类 总被引：3，自引：0，他引：3
根据一具保存有皮肤印痕的完整骨骼化石，描述了采自辽宁北票黄半吉沟晚侏罗世—早白垩世义县组下部的一新的无尾两栖类，并确立其为一新属、新种—孟氏大连蟾(Dalianbatrachus mengigen．et．sp．nov．)。该化石以其尾杆骨较长，超过荐前椎的总长度，胫腓骨与股骨等长和跗节长小于胫腓骨长的一半而区别于其它两栖类。 相似文献
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发现于辽宁西部凌源大王杖子义县组中的长趾大凌河蜥 ( Dal-inghosaurus longidigitus)新标本 ,保存了较为完整且非常清晰的头后骨骼 ,对它的描述补充了我们对该种蜥蜴背椎、肩带及前肢的认识。大凌河蜥具有至少 2 7枚荐前椎、耻骨长度中等、胫骨远端略凹 ,这些特征表明它无疑应归入坚舌类 ( Scleroglossa)。相对很长的后肢及足部、第 口止庶 骨长于第 口止庶 骨、较粗壮的趾节以及次末端趾节不长于其他趾节等 ,显示出该种蜥蜴适宜于在地面上生活记辽宁西部中生代大凌河蜥(有鳞类)一新头后骨骼化石@姬书安$北京大学地球与空间科学学院!10… 相似文献
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辽宁锦州义县早白垩世义县组发现了一种新型燕鸟(Yanornis)化石.该新型化石具有燕鸟的典型特征,如齿骨直且约占头骨全长的2/3、每侧约含20枚牙齿,颈椎细长,异凹型.愈合荐椎包括9枚脊椎,前肢约为后肢长的1.1倍.近端脚趾较其它趾节长和粗壮.然而,该新型化石部分特征又不同于燕鸟的模式种——马氏燕鸟(Yanornis martini),如其肱骨三角肌脊强烈发育,约为肱骨长度的一半.尺骨、桡骨及手部近等长,均长于肱骨.耻骨联合部较短,与尾综骨等长,不到耻骨长度的1/6.腓骨较长,约为股骨长度的4/5,约为胫跗骨长度的2/3.跗跖骨较短并完全愈合,不及胫跗骨长度一半.根据该新型化石的独特性及其与义县鸟、松岭鸟和马氏燕鸟的特征对比,笔者建立了燕鸟一新种——国章燕鸟(Yanornis guozhangisp.nov.).此外,国章燕鸟(新种)颈部还保存有3条鱼化石,这一特殊现象为研究燕鸟的生活习性和发育模式提供了重要信息. 相似文献
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LU Jun-chang XU Li ZHANG Xing-liao JI Qiang JIA Song-hai HU Wei-yong ZHANG Ji-ming WU Yan-hua 《地质通报》2007,(7)
根据以下特征,建立驰龙类恐龙一新属新种——河南栾川盗龙(Luanchuanraptor henanensisgen.etsp.nov):牙齿后缘每5mm有24个小锯齿;前部背椎椎体具有小的椎体侧孔;后部脉弧的前后突短且为三分支;最后部的尾椎体的椎体前突拉长且包裹与其相邻的前部椎体,两椎体前突之间夹有低的刀片状的神经棘;乌喙骨的内面强烈凹陷;肱骨骨干直,肱骨三角脊几乎占肱骨长度的前部一半。河南栾川盗龙代表除在亚洲戈壁地区及中国东北地区之外发现的第一件驰龙类化石标本。 相似文献
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海龙类前肢化石标本(YIGM SPC V 0832-2)采自于云南省罗平县新寨一带中三叠统安尼阶(Pelsonian亚阶)关岭组二段顶部.其不仅为海龙类在罗平生物群中的首次发现, 而且为长颈型海龙的最早记录.该海龙类新材料虽然保存不全, 但是仍具有一些独特的特征: 桡骨远端两侧边缘平行; 尺骨远端扩展; 11个硬骨化腕骨; 第三掌骨近端内侧缘发育横突; 指式为2-3-4-4-4(?).虽然上述特征尚不足以建立一海龙类新属种, 但是仍然反映了部分海龙类单元在向海洋适应辐射的过程保留有原始爬行类的特征.这些原始特征暗示着部分海龙类可能以营陆生生活为主. 相似文献
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描述了汾河下游早更新世三门组的一件鸡形目鸟类化石.其特征是,跗跖骨近端正面血管孔凹陷非常深,内韧带脊发育,第Ⅱ滑车比雉科其他属向下和向内侧扩展,盾锥形滑车翼内斜,第Ⅳ滑车翼较雉科现生属长,翼向上不延伸,第Ⅰ趾骨槽平滑极不明显,胫跗骨胫内脊向下分出2条,外侧者与胫外脊延长线最终合拢在一起.根据以上特征建立一新属新种--汾阴山西雉Shanxiornis fenyinis gen.et sp.nov.. 相似文献
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本文系统描述了海龙类安顺龙属的一个新种——黄泥河安顺龙(Anshunsaurus huangnihensissp.nov.)。新种采自贵州省兴义市乌纱镇谢米村上三叠统竹竿坡组底部。它与邻区发现的晚三叠世黄果树安顺龙(A.huangguoshuensis)和乌纱安顺龙(A.wushaensis)相比,存在如下相似之处:轭骨呈三射形;荐前椎都约为38枚;颈椎约17枚;趾式为2-3-4-5-4。但是,新种与后两者之间最大的区别是:新种的乌喙骨前缘向前延伸较短,而后腹缘向后延伸较远,而后者的情况刚好相反。新种的乌喙骨的特征与在欧洲发现的中三叠世Askeptosaurus italicus和晚三叠世诺利期Endennasaurus acutirostris的较为相近。以上特征指示新种可能为A.italicus和A.huangguoshuensis的过渡类型。这为长颈型海龙类的系统演化和古地理分布提供重要的证据。 相似文献
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记述了四川盆地西南部晚侏罗世上沙溪庙组顶部的中国盗龙型肉食龙类化石材料,并依此建立一新属新种——犍为乐山龙 (Leshansaurus qianweiensis gen. et sp. nov.)。它以上枕骨中嵴呈尖峰状,额骨最大长度与最大宽度之比约2.86,基蝶骨之基翼骨突细长,环椎间椎体马蹄形,背椎横突相当细长,背椎和荐椎神经棘非常薄,荐椎椎体具有明显的腹嵴,肠骨内侧髋臼缘存在一明显的嵴等特征区别于其他肉食龙类。犍为乐山龙是目前所知四川盆地产出层位最高的肉食龙材料,它的发现扩大了肉食龙类的时代分布和地理分布,对探讨肉食龙的演化具有比较重要的意义。 相似文献
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研究新疆准噶尔盆地奇台地区晚侏罗世石树沟组一接近完整的蜥脚类恐龙右侧股骨,发现其不仅具有典型巨龙型类恐龙特征,而且还有许多独具特征,如经过股骨近端的侧向膨大部分最远点的实际延伸直线与股骨头背面实际延伸直线成约127°夹角;第四转子发育明显,侧视呈土丘状;第四转子位于股干中间偏上靠近内侧;髁间凹发育呈"U"型;远端关节面与骨干间有一小的夹角。虽然只有股骨保存,但根据特征对比及地层时代和地理分布因素,其代表了一种新的大型巨龙型类恐龙,故建立新属新种:奇台傅山龙(Fushanosaurus qitaiensis gen. et sp. nov.)。 相似文献
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JI Shu''an JI Qiang School of Earth Space Sciences Peking University Beijing Institute of Geology Chinese Academy of Geological Sciences Beijing 《《地质学报》英文版》2004,78(4):897-906
The postcranial skeleton of a new specimen of the long-tailed lizard Dalinghosaurus longidigitus was excavated from the Yixian Formation in Lingyuan, western Liaoning. The new specimen provides more anatomical information about this species, especially about the anterior dorsal vertebrae, shoulder girdle and forelimbs. This lizard can be included within the clade Scleroglossa by its 27 or more presacrals, moderately long pubis, and gently notched distal end of tibia. But the detailed systematic position for this taxon remains undetermined. The features of the much longer hind limbs and pes compared with forelimbs and manus, metatarsal Ⅳ longer than Ⅲ, pedal phalanges robust, and penultimate phalanx not longer than other phalanges etc. suggest that this lizard was a running and ground swelling animal. 相似文献
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The fluvio-lacustrine deposits of the ?Cenomanian-Turonian Candeleros Formation in the northwestern fringe of Patagonia have yielded numerous remains of vertebrates, including anurans. A new, partially articulated immature specimen of a small pipimorph pipoid from the upper part of this unit is described herein. Although incompletely preserved, the morphology and proportions of the skeleton are strongly reminiscent of corresponding elements of the holotype of Avitabatrachus uliana from the lower section of the same formation at a nearby locality, thus suggesting that these specimens might represent the same, or a closely related, taxon. The new specimen is a metamorphosing individual: it has a zygapophyseal articulation between the sacrum and the neural arch of a postsacral vertebra that bears conspicuous transverse processes, and four pairs of ribs. These traits are not present in the available material of A. uliana, but they might have occurred within the normal range of variation of a single species. Although the generic and specific allocation of the new material is uncertain, a parsimony analysis performed to clarify the relationships of A. uliana supports a phylogenetic placement of this taxon outside the crown Pipidae. The evidence provided by the Candeleros anurans confirms the presence of stem pipids in Patagonia in the early Late Cretaceous. 相似文献
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1981年6月,谢守江等在四川珙县巡场火车站采石场的下二叠统栖霞组近底部,采获一大型旋壳鹦鹉螺化石,由王雪龙等提供笔者研究。现将采样地点地层剖面简列于后。 相似文献
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中国已知的豆齿龙类化石有贵州关岭晚三叠世新铺中国豆齿龙、多板砾甲龟龙及云南富源中三叠世康氏雕甲龟龙。记述了一件楯齿龙目豆齿龙亚目的新材料,产自云南富源法郎组竹杆坡段,时代为中三叠世拉丁期,标本(编号C.1924)现收藏于重庆自然博物馆,该标本保存有完整的背甲、尾椎和四肢的部分骨骼,背甲由500多枚小骨板组成,背甲整体结构与康氏雕甲龟龙相似,但背甲中部无沟和脊,背甲骨板表面无放射沟和嵴,排列更加致密,侧壁相对更为发达,由连接紧密的3～4排骨板组成,四肢骨相对于康氏雕甲龟龙来说更为粗壮。根据上述特征,认为是雕甲龟龙属的一个新种——粗壮雕甲龟龙（Glyphoderma robusta sp. nov.）,这是继康氏雕甲龟龙之后在云南富源发现的第二个豆齿龙类物种。 相似文献
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The Last Picture Show does not fall within the genre of the Western, yet the cinematic narrative mourns the loss of the iconic Westerner — a man
— and the passing of his home places that constitute the Old West. This paper is concerned with the ways in which this man
and his places are transformed along with the embryonic but inexorable emergence of the New West — and its attendant demand
for recognition of hitherto unheard voices (e.g., women, Latinos) — that accompanied significant social, cultural and political
shifts that were beginning to emerge within the country as a whole in the represented early 1950s. His represented sites of
contestation are found within the frame of the small west Texas town of Anarene, created by Larry McMurtry's novel of the
same name as the film, both of which reflect contexts of the era in which they were constructed — the mid 1960s to early 1970s.
We suggest that the film shows a great sensitivity to the ways in which particular masculinities are constituted in specific
places, to the tensions that arise from the changing nature and definitions of masculinity as they are linked to these places,
and with his sense of nostalgia and loss that accompanies his inevitable decline. But there is no clear and empowered place
for women in these new places, only a recontextualized form of a patriarchal order which is not relational and which still
maintains essentialist assumptions of gender. The Old West has taken new shape, much to the chagrin of man, but it is hardly
a New West, with its emerging and representative voices.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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筋土之间的相互作用机制复杂,是土工合成材料加筋加固应用中的核心问题。通过室内拉拔试验,研究了土工格栅与砂土相互作用机制和格栅几何特征对拉拔阻力的影响。初步揭示了格栅横肋和纵肋在拉拔模式下的作用机制和格栅网格刚度对拉拔阻力的影响。结果表明,在拉拔位移较小时,纵肋摩阻力和横肋被动阻力几乎同步增长;在拉拔位移较大时,纵肋摩阻力逐步达到峰值,拉拔力的增量大部分来源于被动阻力的进一步增长。土工格栅拉伸模量和网格刚度是影响筋土界面力学特性的重要因素。 相似文献
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筋材与土体接触面的相互作用较为复杂,它是加筋土工程设计中的关键所在。为了研究筋土界面的作用机制,采用福建标准砂与玻璃纤维土工格栅进行了一系列室内大型直剪试验,较为系统地分析了格栅横肋与纵肋及格栅几何尺寸对于筋土界面强度特性的影响。试验结果表明,格栅的横肋与纵肋在界面强度中均发挥了较大的作用,两者表现为不同的作用机制,当剪切位移较小时格栅横肋的被动阻力和纵肋的摩阻力起到共同承担荷载的作用;随着剪切位移的增大,横肋的被动阻力进一步提升,纵肋发挥了较为显著的提高筋材刚度的框架作用。因此,格栅的纵横肋需要按合理比例搭配才能发挥出较大的筋土界面强度。 相似文献
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Saltasaurine titanosaurs are characterized by their relatively small size compared to other sauropods, extreme postcranial pneumaticity, and dermal armour covering the body. This group has been reported in the Upper Cretaceous of the Lecho, Allen, and Anacleto formations of Argentina. We describe here a new saltasaurine specimen (MACN-Pv RN 233) from the Campanian of the Angostura Colorada Formation (Río Negro Province) that is represented by eight caudal vertebrae and six osteoderms. This specimen is described in detail and its phylogenetic relationships with the other three known saltasaurines, as well as its implications to the knowledge of caudal vertebra and osteoderm anatomy, are discussed. Our results place MACN-Pv RN 233 more closely related to Saltasaurus loricatus and Rocasaurus muniozi than to Neuquensaurus australis. MACN-Pv RN 233 possesses a combination of features that differ from other saltasaurines, but because of the fragmentary nature of the specimen we decided for the sake of taxonomic stability to not erect a new taxon. This specimen shows the first unambiguous evidence of chevron pneumatisation for a sauropodomorph, implying a broader osteological invasion of the diverticula from the abdominal air sac than previously thought for this group of dinosaurs. MACN-Pv RN 233 preserves two osteoderm morphotypes, one similar to those reported for Neuquensaurus australis and Saltasaurus loricatus. This new specimen expands the distribution of the group to a new geological unit and increases the dinosaur diversity known for the Angostura Colorada Formation. 相似文献