伤齿龙(Troodontids)筑巢产卵的行为

应用薄壳理论研究中国和北美西部出土的晚侏罗世至晚白垩世伤齿龙蛋以平卧和竖立两种方式埋在沙土中受压破损的抵抗能力 ,分析伤齿龙蛋在蛋窝中特有的排列方式与其蛋壳的抗失稳能力之间的关系。结果表明 ,由于伤齿龙蛋壳很薄 ,其抗失稳能力很差 ,如果这种蛋以横卧方式埋在沙土中就可能在很小载荷下因失稳屈曲而破裂 ;但是 ,如果把蛋竖立起来埋在沙土中 ,则蛋的抗破碎能力比把它们平放埋在沙土中要高出 4～ 5倍。从而认为 ,伤齿龙在筑巢产卵时把一个个蛋竖立起来埋在沙土中是为解决其低强度蛋壳在保护胚胎 ,避免外力损伤和在卵的孵化后期幼雏能够破壳而出这两方面的矛盾而采取的一种保护性措施 ,说明这些体征很像鸟类的兽脚类恐龙 ,其智商可能比人们想象的要高。在此基础上 ,探讨和复原了伤齿龙筑巢产卵的行为。     

THE DIET OF OSTRICH DINOSAURS (THEROPODA: ORNITHOMIMOSAURIA)

Abstract:  The diets of ornithomimosaurian dinosaurs (Theropoda: Ornithomimosauria) have proved to be contentious owing to a dearth of unambiguous evidence in support of carnivory, omnivory or herbivory. Re-assessment of anatomical, taphonomical and palaeoecological evidence, and estimates of daily minimal energy budgets for two derived ornithomimosaurian genera, indicate that suspension-feeding and carnivory were unlikely. The combined presence of a keratinized rhamphotheca and gastric mill is strongly indicative of a herbivorous habitus for these dinosaurs. Herbivorous and omnivorous forms are rare among the non-avian Theropoda, but are more common than previously suspected. Rejection of carnivorous habits for derived ornithomimosaurs redresses apparent discrepancies in the relative abundances of the herbivore and carnivore guilds of several Late Cretaceous faunas.     

THE DINOSAUR PROJECT——AN INTERNATIONAL COOPERATIVE PROGRAM ON DINOSAURS

<正> The dinosaurs of China are among the most exciting in the world. An appreciation of the anatomy of Chinese dinosaurs has become a central element in modern studies of dinosauriah evolution (Russell 1987), and the world's palaeontologists have paid a great deal of attention to China because of her abundant dinosaur resources. The Dinosaur Project, originally called the Canada-China Dinosaur Project (CCDP), was organized in 1985. In that year, the Ex Terra Foundation, Alberta, signed an agreement establishing the project with three core partners: The Tyrrell Museum of Palaeontology in Drumheller, The Natiolaal Mu-     

FORELIMB POSTURE IN DINOSAURS AND THE EVOLUTION OF THE AVIAN FLAPPING FLIGHT-STROKE

Ontogenetic and behavioral studies using birds currently do not document the early evolution of flight because birds (including juveniles) used in such studies employ forelimb oscillation frequencies over 10 Hz, forelimb stroke-angles in excess of 130°, and possess uniquely avian flight musculatures. Living birds are an advanced morphological stage in the development of flapping flight. To gain insight into the early stages of flight evolution (i.e., prebird), in the absence of a living analogue, a new approach using Strouhal number     was used. Strouhal number is a nondimensional number that describes the relationship between wing-stroke amplitude ( A ), wing-beat frequency ( f ), and flight speed ( U ). Calculations indicated that even moderate wing movements are enough to generate rudimentary thrust and that a propulsive flapping flight-stroke could have evolved via gradual incremental changes in wing movement and wing morphology. More fundamental to the origin of the avian flapping flight-stroke is the question of how a symmetrical forelimb posture—required for gliding and flapping flight—evolved from an alternating forelimb motion, evident in all extant bipeds when running except birds.     

广东省南雄盆地白垩系—第三系交界恐龙绝灭问题

广东省南雄盆地中的红层可划分为三个群五个组,大致代表了晚白垩世—始新世的沉积.根据绝对年龄、古地磁测定结果和脊椎动物化石组合性质的综合分析,位于地磁极性带 29R 上部的坪岭组和上湖组之间的分界线被确定为 K/T 界线.对晚白垩世恐龙蛋的研究表明,不同"种"的恐龙蛋是在地磁极性带 29R 的中、下部,也就是说在白垩系—第三系交界之前20～30万年期间绝迹的.而且在这一时期内,所有已发现的蛋壳中,绝大多数蛋壳的厚度和显微结构都显示出明显的病理特征,例如根据随机取样统计,Macroolithus yaotunensis 蛋壳异常结构的出现率,最高可达75%.产生病态恐龙蛋壳的生理机制可以根据发生在现生鸟类的相同病理特征来解释.进一步分析恐龙蛋壳的微量元素和稳定同位素组成,结果显示, Pb, Cu, Mn 等9种元素丰度变化在这一时期达到最大峰值, δ~(18)O 也出现正异常.在这一基础上提出,微量元素的污染和气候突然的变化妨碍了正常蛋壳结构的形成,导致了恐龙的绝灭.这一绝灭过程大约经历了20～30万年.     

关于辽西孔子鸟层时代的讨论

ＳｗｉｓｈｅｒⅢ等报道的辽西孔子鸟层同位素年龄（１２４．６Ｍａ）的准确性存在可疑处,其取样点地层受后期侵入岩床的烘烤,因此“巴列姆期”的时代结论不可靠;罗清华等的取样点和数据（１４７Ｍａ）较为可信。对义县组动物群与欧洲Ｓｏｌｎｈｏｆｅｎ层动物群的对比讨论,表明两生物群基本同时代（Ｔｉｔｈｏｎｉａｎ期）,并不是“超过２０Ｍａ”的“长寿动物群”。     

AS系列佐剂

AS01、AS02、AS03和AS04是由葛兰素史克公司研制的人用疫苗佐剂,属于AS(adjuvant system,AS)系列佐剂。AS01是一种包含单磷酸酰脂质A(3-O-desacyl-4'-monophosphoryl lipid A,MPL)和皂素QS-21的脂质体佐剂,已被用于疟疾疫苗。AS02是含有MPL和QS-21的水包油乳化剂。AS03是包含α-生育酚、角鲨烯、Tween 80的水包油乳化剂,已被用于流感疫苗。AS04是含MPL的铝佐剂,已被用于人乳头瘤病毒疫苗和乙型肝炎病毒疫苗。