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兰州—民和盆地位于中国西北横跨甘肃和青海两省的毗连地区,其中广泛发育出露良好下白垩统河口群。近年来,在该盆地东部的兰州盆地产出了一个前所未知的脊椎动物组合,其中以诸多的足印化石和世界已知最大牙齿的植食性恐龙——巨齿兰州龙(Lanzhousaurus magnidens)为代表,还包括一类宽臀的基干巨龙型类蜥脚类——刘家峡黄河巨龙(Huanghetitan liujiaxiaensis),以及许多其他尚未发表的恐龙、鱼类和龟类。本文报道在该地区河口群中所发现的第二种新的蜥脚类恐龙——炳灵大夏巨龙(新属新种)(Daxiatitan binglingi gen.et sp.nov.)。炳灵大夏巨龙的正型标本现存于甘肃省地矿局第三地质矿产勘查院古生物研究开发中心(兰州)。该标本包括最后的10枚颈椎,10枚背椎,2枚近端尾椎,部分颈肋和背肋,1枚脉弓,右肩胛骨,右乌喙骨和右股骨。估计其颈部长度为12.2m,整个身体长度为26m,使其成为中国乃至亚洲最大的恐龙之一。大夏巨龙是巨龙类的一个基干分子[其支干定义为:与盐龙(Saltasaurus)而不与腕龙(Brachiosaurus)更具亲缘关系的巨龙型类],其以如下特征区别于其他巨龙类分子:颈椎的前关节面后移;肩胛骨骨体的远缘与其长轴斜交;股骨远端髁相对于股骨体向背侧方倾斜10°,而且从远端看,该远端髁处于后内—前侧方向。大夏巨龙独特的股骨构造指示出一种强烈外撇的走步姿态。同时,这种姿态也得到了保存于刘家峡恐龙国家地质公园同一层位(河口群上段)的强烈外转的、宽间距的蜥脚类恐龙行迹的进一步佐证。炳灵大夏巨龙的发现丰富了兰州盆地脊椎动物组合,对研究巨龙类恐龙的起源和早期演化具有重要意义。 相似文献
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The Kokorkom desert extended over an area of 826 km2 in the central-west sector of Neuquén and Río Negro provinces along the area of the backbulge basin within the Andean Foreland basin in the Neuquén Basin. Its deposits constitute the middle-upper section of the Candeleros Formation (Cenomanian) and reach approximately 130 m thick. Tracks are found on wet and dry interdune and within draa slipface deposits. They constitute biogenic deformation structures characterized by folded-up and/or brecciated sandstone levels formed under dry and/or wet substrate conditions with passive filling. The degree of preservation varies, but the identification of digit impression suggests that they were produced by theropods or iguanodontians. 相似文献
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鸟类是现生生物中最具特色的动物之一，以其发育了许多独特的形态特征区别于其他的现生生物，如羽毛、角质喙、中空的骨骼、叉骨、具龙骨突的胸骨、尾综骨、对握状的脚趾等等。长期来人们一直想知道鸟类究竟由哪一类生物演化发展而来。但苦于化石材料的贫乏，鸟类的起源问题一直是个令人头疼的迷团，困扰我们长达140多年。通过回顾自19世纪中期以来世界上各种鸟类起源假说，指出随着中国辽西中华龙鸟、原始祖鸟、尾羽鸟等珍稀化石的发现，国际鸟类起源问题已基本上得到解决。越来越多的人相信：鸟类是由恐龙变来的，现代的鸟类就是恐龙的后代，是长羽毛的“恐龙”。 相似文献
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Xing Lid Ariana Paulina-Carabajal Philip J. Currie Xu Xing Zhang Jianping Wang Tao Michael E. Burns Dong Zhiming 《《地质学报》英文版》2014,88(6):1653-1664
The neuroanatomy of the mid-sized theropod Sinosaurus triassicus from the Lower Jurassic Lufeng Formation, Lufeng Basin in Yunnan Province, China was studied using X-ray computed tomography. The braincase is characterized by a large supraoccipital knob that is capped by a posterior projection of the parietal and two external foramina for the caudal middle cerebral vein, which is completely enclosed by the supraoccipital. The basicranium has well defined, short basipterygoid processes that project ventral to the basal tubera. The basisphenoid is expanded, projects posteroventrally, and is pierced by four pneumatic recesses. The endocranial morphology resembles that observed in other basal theropods—in particular some allosauroids—and has a strongly marked pontine flexure and a large dorsal expansion. The inner ear morphology is also similar to that observed in other basal theropods, with slender semicircular canals. The anterior semicircular canal is 20% larger than the posterior semicircular canal, and the angle formed between them is less than 90° when seen in dorsal view. 相似文献