恐龙和鸟

看到这个题目,亲爱的读者可能会感到困惑。恐龙和鸟之间有什么关系吗？一般来说,在人们的头脑中,恐龙是一类庞然大物,或者凶猛无比,或者非常笨重,总之,与天空中飞翔的美丽而轻巧的鸟类是截然不同的两类动物。实际上,恐龙和鸟类之间的差别不是人们想象的那么大,两...     

长着四个翅膀的恐龙

顾氏小盗龙复原图　　说到恐龙 ,人们自然会想到凶猛的霸王龙或者长着长脖子的马门溪龙 ,这些游荡在中生代大陆上的陆地霸主在地球上统治了近 1 7亿年后于白垩纪末期的大灭绝事件中退出了历史舞台 ,但恐龙的后裔———鸟类———却在这场大灭绝后逐渐繁盛起来 ,乃至成为当今五大脊椎动物类群之一。鸟类最令人诧异的特征之一就是它们高超的飞行能力。每当人们看见鸟类翱翔于蓝天之中时 ,不禁为它们优美的身姿和轻灵的体态所折服。庞大笨重的恐龙是如何演化为美丽轻巧的鸟类的呢 ?鸟类如此高超的飞行能力是如何形成的呢 ?科学家们孜孜不倦的工…     

最大的带羽毛恐龙-华丽羽王龙

1861年发现的第一枚始祖鸟化石让人们看到了最古老的羽毛的样子,也让科学界相信远在一亿五千万年前地球上就出现了鸟类的踪影。     

辽宁早白垩世义县组一原始鸟脚类恐龙

初步记述了采自辽西地区早白垩世义县组新的原始鸟脚类恐龙化石材料,并依此建立一新属新种上园热河龙（Jeholosaurus shangyuanensis gen. et sp. nov.）。化石产于北票市上园镇陆家屯义县组下部第一段灰白色凝灰质砂岩中,同一层位产出过大量鹦鹉嘴龙化石。上园热河龙的主要鉴定特征包括6个前上颌齿,鼻骨背面发育小孔,前齿骨约为前上颌骨主体长度的1.5倍、未发育股骨前髁间沟、骨不在一平面上,第三趾趾节中第四节最长。上园热河龙具有一些真鸟脚类恐龙的近裔性状,比如眶前孔小,方骨孔大,位于方颧骨侧面,外下颌孔缺失。另外,上园热河龙的股骨近端形态非常接近进步的鸟脚类恐龙。但是上园热河龙发育有6个前上颌齿,上下颌关节处与齿列位于同一水平线,前上颌齿列与上颌齿列位于同一水平线,这些原始特征未见于已知鸟脚类恐龙。上园热河龙确切系统分类位置需要进一步确定。 上园热河龙是义县组中发现的第二种鸟臀类恐龙,增加了这类恐龙在热河生物群中的分异度。     

关于古鸟类的三个为什么?

我是一名高二学生，就读于桃汇县第四中学，我非常钦佩您在生物领域中能有如此建树，同时，我也期望自己完成学业后能为中国生物技术的进步作出自己最大的努力，让中国生物技术领先世界。     

内蒙古发现世界最大似鸟恐龙化石

在6月14日出版的最新一期英国《自然》杂志上,发表了发现于中国内蒙古二连盆地的、从大约8000万年前沉积岩石中产出的巨型似鸟恐龙化石的研究论文。经中国科学院古脊椎动物与古人类研究所和内蒙古国土资源系统的学者长达两年的研究确认。2005年,在我国内蒙古二连盆地晚白垩世二连组地层中发现的一具巨型兽脚类恐龙化石,是当今世界上最大的、罕见的似鸟恐龙化石,并成为在这一盆地近年来发现的第4种新的恐龙属种。     

吉林省中部早白垩世泉头组-原始鸟脚类恐龙

报道了在松辽盆地白垩纪沉积中首次发现的原始鸟脚类恐龙化石,并根据其头部特征建立一新属新种——娇小长春龙(Changchunsaurus parvus gen.etsp.nov.)。化石产于吉林省公主岭市刘房子镇山前泉头组上部紫红色含砾泥质砂岩中,同一层位还产有兽脚类、鳄类、恐龙蛋、哺乳类等化石。娇小长春龙是一种混合了原始的和衍生性状的小型鸟脚类恐龙。它具有某些比多数鸟脚类和头饰龙类要原始的特征,例如,5颗前上颌齿、前上颌骨吻部只有很短一段齿缺、前上颌骨与上颌齿之间的间隙较小、颊齿两侧的釉质对称、前上颌骨腹侧边缘与上颌骨腹侧边缘基本处于同一水平线等。同时,娇小长春龙也具有一些与真鸟脚类类似的进步特征,比如眶前孔小、外下颌孔缺失。娇小长春龙具有颧骨突,这在鸟脚类恐龙中较为罕见,它的颧骨突表面具有鲕状构造,这一特征未见于其他已知鸟脚类。娇小长春龙的前齿骨形态与角龙类接近,腹支明显长于侧支,前齿骨与齿骨的愈合方式同角龙类相似。娇小长春龙的确切系统分类位置需要进一步的工作来确定。     

Downsized Dinosaurs: The Evolutionary Transition to Modern Birds

Living birds are the most diverse land vertebrates and the heirs of a rich chapter in the evolution of life. The origin of modern birds from animals similar to Tyrannosaurus rex is among the most remarkable examples of an evolutionary transition. A wealth of recently discovered fossils has finally settled the century-old controversy about the origin of birds and it has made the evolutionary saga toward modern birds one of the best documented transitions in the history of life. This paper reviews the evidence in support of the origin of birds from meat-eating dinosaurs, and it highlights the array of fossils that connect these fearsome animals with those that fly all around us.     

鸟类用于环境监测的意义及研究进展

对鸟类应用于环境监测的历史和研究方法进行了简要回顾,在种群,种团,群落三个层次上对鸟类用于环境监测的意义进行了综述评述,并对其研究方向予以展望。     

Polar dinosaurs and the question of dinosaur extinction: a brief review

Although the physiology of dinosaurs is still a matter of controversy, there is no doubt that some of them were able to live in environments that were too cold for ectothermic reptiles, as shown by discoveries of Jurassic and Cretaceous polar vertebrate assemblages which contain dinosaurs but lack turtles and crocodiles. This adaptation of dinosaurs to cool climates invalidates hypotheses according to which dinosaur extinction at the end of the Cretaceous was a result of long-term climatic cooling. The pattern seen at the K/T boundary, with the disappearance of dinosaurs and the survival of ectothermic reptiles, is completely different from that seen in Arctic regions during the Late Cretaceous, where ectotherms disappeared, while dinosaurs subsisted, during cooler periods. The idea of an intense and enduring cold spell at the K/T boundary, caused by the Chicxulub impact, is extremely unlikely in view of the pattern of vertebrate extinction (survival of endotherms, extinction of dinosaurs). Models of environmental events following the impact must take this palaeontological constraint into consideration.     

Rhythmic Birds Show a Better Social Integration than Arrhythmic Birds

The activity rhythms of Japanese quail vary from one individual to another. Performing a divergent selection, we obtained one line of quail expressing a robust circadian rhythmicity of feeding activity (R) and one line of quail expressing circadian arrhythmicity of feeding activity (A). We questioned whether the endogenous rhythmicity of an individual could predict its integration in a group. For that, we introduced either an R- or an A-line chick into stable groups of standard chicks. First, we evaluated proximity and synchronization of the introduced chicks on the activities of the other group members. R-chicks remained spatially and temporally closer to other group members than did A-chicks. Second, we evaluated interactions of the introduced chicks and the level of their acceptance by the other group members. R-chicks were more competent to gain access to food than were A-chicks, and separation from their group stressed R-chicks more than A-chicks. Last, successive introductions assessed age effects: before, around, and after dispersal time (～11th day of chicks' life). Most differences between R- and A-chicks were observed between their 7th and 15th day of life. In conclusion, individual endogenous rhythms predict social integration. (Author correspondence: sophie.lumineau@univ-rennes1.fr)     

The species recognition hypothesis explains exaggerated structures in non-avialan dinosaurs better than sexual selection does

Several hypotheses have been proposed to explain “bizarre structures” in dinosaurs and other extinct animals (e.g., mechanical function and several kinds of intra- and interspecific display). Recent evidence and tests for species recognition as a possible driver of these structures have been proposed, in particular as an alternative to traditional hypotheses of function and sexual selection, which have fallen short. Advocates of sexual selection and mechanical function have advanced untested hypotheses claiming that species recognition cannot be an important process in evolution. We address these claims and show that they are based on misreading of the evidence and of previous literature. We also acknowledge that there have been historically differing definitions of sexual selection, which have greatly impeded understanding of the whole phenomenon of mate attraction and choice. Particularly in fossil animals, it is impossible to accept any hypothesis as the “default” that does not require evidence or testing to establish it.     

鸟类的飞翔

本文综述了目前对鸟类飞翔的研究 ,包括飞翔机制、运动学和形态适应等问题。首先讨论动力产生的基础包括翼型运动和气体旋涡以及飞翔需要的动力 ,而后论述振翅飞翔和姿势变换的运动学原理及量化飞翔强度 ,阐明了翼部和尾部外形对飞翔的重要作用 ,并分析了始祖鸟的飞翔能力     

On the finding of ornithomimid dinosaurs (Saurischia, Ornithomimosauria) in the Upper Cretaceous beds of Tajikistan

Fragmentary remains of ornithomimids (Ornithomimidae indet.) from the Lower Santonian (Upper Cretaceous) Kansai locality in northwestern Fergana (Tajikistan) are described, and the composition of its dinosaurian assemblage is updated.     

鸟类线粒体DNA结构特点及在鸟类研究中的应用

介绍了鸟类mtDNA的结构和鸟类mtDNA作为分子标记的特点,并综述了mtDNA作为分子标记在鸟类的种间系统发生关系及分类、鸟类分子钟、地理分布区的推断和种群遗传多样性的研究中应用现状.     

大、小苏干湖湿地鸟类多样性季节变化

2006年分3个季节(春、夏、秋)对大苏干湖、小苏干湖及两湖间河道湿地鸟类物种多样性及数量的季节变动进行了调查,共记录到鸟类11目20科38属47种。其中留鸟5种,迁徙路过鸟10种,夏候鸟32种。春季共记录到24种鸟类,夏季32种,秋季30种。秋季在大苏干湖区活动的鸟类种数最多,多样性指数最大,为3.0891,而小苏干湖区的鸟类多样性指数在3个季节都较低。     

新疆鸟类环志与回收

2001年8月与14－26日在新疆阿勒泰,吐鲁番的8个环志地点进行了秋际鸟类环志工作。环志鸟类233只,约33种,多以莺亚科（Sylviinae)和鸫亚科（Turdinae)的种类为主。其中的新疆歌鸲（Luscinia sp.)等17种鸟类均属于中国首次环志种类,占环志种数的53％。