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。蜥脚类恐龙的身体平面图--以细长的脖子、巨大的身体和充满空气的骨头为特征--出现在侏罗纪中期和晚期，一些进化中的脖子长度超过9米。我们不知道身体形态是如何以及为什么进化的。 迄今为止，中国已发现的中晚侏罗世蜥脚类化石不下20种，但大多数尚待研究。 通过与国际恐龙进化权威古脊椎动物与古人类研究所徐星博士的合作，该项目将详尽地记录中国中晚侏罗世尚未研究的蜥脚类动物--戈壁克拉美利龙的解剖结构。新的解剖学资料将被用来提出一个关于蜥脚类进化关系的修正假说，并阐明长颈进化的机制。戈壁克拉美利龙的正模标本保存了一个基本完整的颅后骨骼。研究人员将花费EAPSI计划的很大一部分时间来制作Klamelisaurus的专题解剖描述。此外，研究人员将重新评估蜥脚类动物的进化关系与一个大型的形态特征矩阵，其中包括许多中国蜥脚类动物从未被包括在这样的分析中，特别是解决假设Klamelisaurus是一个早期的成员异常长颈Omeisauridae。在TNT和BEAST程序中，将在最大简约性和贝叶斯后验概率最优性标准下进行系统发育分析。由此产生的进化树将用于统计学检验关于颈部伸长的不同进化假设的可能性，例如，在颈椎颈化之前，颈椎前部的空气空间增加。该NSF EAPSI奖支持美国研究生的研究，并与中国科技部合作资助。

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.