Untitled

long as the humerus plus radius, very large andsubequally long manual claws I and II, and reducedolecranon process on the ulna. But it differsfrom Huaxiagnathus orientalis in having themuch large size, a very long maxillary process ofprem...2008040421在 maniraptoran 型 恐 龙 中 似 鸟 类 呼 吸 机 制 =Avian-like breathing mechanics in maniraptorandinosaurs. ( 英 文 ). Codd J R; Manning P; NorellM A;Perry S F. Proceedings of the Royal SocietyB: Biological Sciences, 2008, 275(1631): 157-161In 1868 Thomas Huxley first proposed thatdinosaurs were the direct ancestors of birds andsubsequent analyses have identified a suite of‘avian’ characteristics in theropod dinosaurs.Ossified uncinate processes are found in mostspecies of extant birds and also occur in extinctnon-avian maniraptoran dinosaurs. Their presencein these dinosaurs represents another morphologicalcharacter linking them to Aves, andfurther supports the presence of an avian-likeair-sac respiratory system in theropod dinosaurs,prior to the evolution of flight. Here we report aphylogenetic analysis of the presence of uncinateprocesses in Aves and non-avian maniraptorandinosaurs indicating that these were homologousstructures. Furthermore, recent work on Canadageese has demonstrated that uncinate processesare integral to the mechanics of avian ventilation,facilitating both inspiration and expiration. Inextant birds, uncinate processes function to increasethe mechanical advantage for movementsof the ribs and sternum during respiration. Ourstudy presents a mechanism whereby uncinateprocesses, in conjunction with lateral and ventralmovements of the sternum and gastral basket,affected avian-like breathing mechanics in extinctnon-avian maniraptoran dinosaurs.2008040422通 过 鹦 鹉 嘴 龙 表 皮 的 独 特 横 断 面 显 示 一 复 杂的 纤 维 结 构 = A unique cross section throughthe skin of the dinosaur Psittacosaurus fromChina showing a complex fibre architecture. ( 英文 ). Lingham-Soliar T. Proceedings of the RoyalSociety B: Biological Sciences, 2008, 275(1636):775-780This paper reports on a unique preservation ofsoft tissues in the ventrolateral region of theplant-eating dinosaur Psittacosaurus from theJehol biota of China. The preservation is of adeep cross section through the dermis, whichincludes multiple layers of collagenous fibres inexcess of 25, among the highest recorded in vertebrates,with a further 15 more layers (poorlypreserved) estimated for the entire height of thesection. Also, for the first time in a dinosaur twofibre layers parallel to the skin surface are preserveddeep within the dermis at the base of thecross section. These fibre layers comprise regularlydisposed fibres arranged in left- and righthandedgeodesic helices, matching the pattern atthe surface and reasonably inferred for the entiresection. As noted from the studies on moderndayanimals, this fibre structure plays a criticalpart in the stresses and strains the skin may besubjected to and is ideally suited to providingsupport and protection. Psittacosaurus gives aremarkable, unprecedented understanding of thedinosaur skin.2008040423羊 齿 和 裸 子 植 物 的 叶 的 In vitro 可 消 化 性 :对 蜥 脚 类 恐 龙 觅 食 生 态 和 饮 食 选 择 的 意 义 =In vitro digestibility of fern and gymnospermfoliage: implications for sauropod feeding ecologyand diet selection. ( 英 文 ). Hummel J; Gee CT; Südekum K H; Sander P M; Nogge G; ClaussM. Proceedings of the Royal Society B: BiologicalSciences, 2008, 275(1638): 1015-1021Sauropod dinosaurs, the dominant herbivoresthroughout the Jurassic, challenge general rulesof large vertebrate herbivory. With body weightssurpassing those of any other megaherbivore,they relied almost exclusively on preangiospermplants such as gymnosperms, fernsand fern allies as food sources, plant groups thatare generally believed to be of very low nutritionalquality. However, the nutritive value ofthese taxa is virtually unknown, despite theirimportance in the reconstruction of the ecologyof Mesozoic herbivores. Using a feed evaluationtest for extant herbivores, we show that the energycontent of horsetails and of certain conifersand ferns is at a level comparable to extantbrowse. Based on our experimental results,plants such as Equisetum, Araucaria, Ginkgoand Angiopteris would have formed a major partof sauropod diets, while cycads, tree ferns andpodocarp conifers would have been poor sourcesof energy. Energy-rich but slow-fermentingAraucaria, which was globally distributed in theJurassic, was probably targeted by giant, highbrowsingsauropods with their presumably verylong ingesta retention times. Our data make possiblea more realistic calculation of the dailyfood intake of an individual sauropod and improveour understanding of how large herbivorousdinosaurs could have flourished in preangiospermecosystems.2008040424鳄 类 Megadontosuchus arduini 的 系 统 发 育 位置 和 tomistomine 的 古 生 物 地 理 = Phylogeneticposition of the crocofylian Megadontosuchusarduini and tomidtomine palaeobio-130