EAPSI: The Anatomy and Evolutionary Relationships of Klamelisaurus Gobiensis and Other Sauropod Dinosaurs of the Middle and Late Jurassic of China

蜥脚类恐龙是有史以来最大的陆生动物。蜥脚类恐龙的体型——以细长的脖子、巨大的身体和充满空气的骨头为特征——出现在侏罗纪中后期，有些进化出的脖子长度超过9米。目前尚不清楚身体形态是如何以及为什么进化的。迄今为止，发现的中国中晚侏罗世蜥脚类恐龙不少于20只。然而，大多数仍有待研究。通过与国际恐龙进化权威机构古脊椎动物与古人类研究所的徐星博士合作，该项目将详尽地记录中国中晚侏罗世一种尚未得到充分研究的蜥脚类动物——戈biklamelisaurus gobiensis的解剖学。来自克兰elisaurus和其他中国蜥脚类动物的新解剖数据将用于提出一个修订的蜥脚类动物进化关系假说，并阐明长颈进化的机制。完全型的克兰elisaurus gobiensis保留了一个很大程度上完整的颅后骨骼。研究人员将花费EAPSI计划的很大一部分来制作克兰elisaurus的专题解剖描述。此外，研究人员将利用一个庞大的形态特征矩阵重新评估蜥脚类动物的进化关系，其中包括许多从未被纳入此类分析的中国蜥脚类动物，特别是解决了克兰elisaurus是异常长颈的Omeisauridae的早期成员的假设。系统发育分析将在TNT和BEAST程序的最大简约性和贝叶斯后验概率最优性准则下进行。由此产生的进化树将用于统计检验关于颈部伸长的不同进化假设的可能性，例如，在脊椎骨颈椎化之前，前颈椎的空气空间增加。该奖项由美国国家科学基金会EAPSI与中国科技部合作资助，支持一名美国研究生的研究。

Sauropod dinosaurs are the largest terrestrial animals ever to have lived. The sauropod body plan--characterized by elongated necks, massive bodies, and air-filled bones--emerged in the Middle and Late Jurassic, some evolving neck lengths exceeding nine meters. It is not known how and why body forms evolve. So far, no fewer than twenty sauropods from the Middle and Late Jurassic of China were found. Yet most remain to be studied. Through collaboration with Dr. Xu Xing of the Institute of Vertebrate Paleontology and Paleoanthropology, an international authority on dinosaur evolution, this project will exhaustively document the anatomy of Klamelisaurus gobiensis, an understudied sauropod from the Middle-Late Jurassic of China. New anatomical data from Klamelisaurus and other Chinese sauropods will be used to produce a revised hypothesis of sauropod evolutionary relationships and illuminate the mechanisms by which long necks evolved.The holotype of Klamelisaurus gobiensis preserves a largely complete postcranial skeleton. The researcher will spend a significant portion of the EAPSI program producing a monographic anatomical description of Klamelisaurus. In addition, the researcher will reassess sauropod evolutionary relationships with a large morphological character matrix that includes numerous Chinese sauropods that have never been included in such an analysis, specifically addressing the hypothesis that Klamelisaurus is an early member of the exceptionally long-necked Omeisauridae. Phylogenetic analyses will be performed under both maximum parsimony and Bayesian posterior probability optimality criteria in the programs TNT and BEAST. The resulting evolutionary trees will be used to statistically test the likelihood of different evolutionary hypotheses regarding neck elongation, e.g., air space increases in anterior cervical vertebrae prior to the cervicalization of dorsal vertebrae. This NSF EAPSI award supports the research of a U.S. graduate student and is funded in collaboration with the Chinese Ministry of Science and Technology.