中三叠统巴东组的脊椎动物群以及芙蓉龙的形态、功能以及古生态学研究

The Middle Triassic Badong Formation has yielded two continental vertebrate taxa, the poposaurid archosauriform reptile Lotosaurus adentus and the mastodonsauroid temnospondyl amphibian Yuanansuchus laticeps. Although Lotosaurus is a highly distinctive poposaurid, this taxon has been only briefly described.We propose to undertake a thorough anatomical redescription of Lotosaurus,combined with analyses of its phylogenetic position and aspects of its functional morphology. We will test the possibility that the sail anchored axial muscles used in locomotion, evaluate the mobility of the jaw joint and the force-generating capabilities of the jaw muscles, and assess how the "pillar erect" hindlimb and sprawling forelimb may have operated in walking. Our phylogenetic analysis should provide the best possible assessment of the position of Lotosaurus within Poposauridae, which will have implications for character evolution in poposaurids.Functional analysis will involve scanning specimens to create 3D virtual bones.Physical manipulation of specimens, combined with digital manipulation of virtual bones in Maya, will be used to estimate ranges of motion for joints of interest.Muscles around these joints will be reconstructed, and their ability to create moment will be assessed. Various poposaurids and other taxa will be examined, and some taxa will also be analyzed in functional terms, to clarify inferences made for Lotosaurus and shed light on wider functional trends in archosauriform evolution. Fieldwork will be undertaken in the Badong Formation, with the objectives of recovering more fossil vertebrates, evaluating the taphonomy and sedimentology of fossil localities, and collecting more stratigraphical information. Studying localities from these perspectives will aid inferences about the age, habitat and ecology of Lotosaurus, Yuanansuchus and any newly discovered taxa and about the Middle Triassic diversification of archosauriforms.

)： 中三叠统巴东组已知产出宽头远安鲵以及无牙芙蓉龙。虽然芙蓉龙材料很多，而且很奇特，这个属种几乎没有正式描述过。我们将对芙蓉龙进行全面的形态描述，在此基础上进行系统发育以及形态功能分析。检验背帆用于附着用于运动的肌肉的假说，评估颌关节的活动性以及下颌肌肉的力量大小，确定"柱状直立"的后肢和匍匐的前肢怎样运动。系统发育分析将会更恰当地评估芙蓉龙在波波龙类中的位置，理解相关性状的演化。扫描骨骼建立三维模型用于形态功能分析。操纵实际骨骼以及虚拟骨骼以估计关节运动的幅度。重建关节附近的肌肉，估计其产生的力矩。对比国内外的各种波波龙类以及相关类群，对其中一些进行功能分析，阐明关于芙蓉龙的推论，理解主龙形类中的功能变化。野外工作力图发现更多的标本以及新的类群，评估化石点的埋藏学以及沉积学信息，获取更多地层资料。这些信息将用于确定动物群的时代，生活环境以及生态以及认识中三叠世主龙形类的演化辐射。

本项目旨在研究巴东组出产的四足动物以及化石产地的埋藏环境。通过对早期材料的修理，研究，仔细描述了特化的波波龙类的芙蓉龙的解剖学特征。描述了伴生的离片椎类，命名为茅坪场远安鲵。通过对新暴露的大约90平方米的化石层的研究，揭示芙蓉龙可能因为干旱大量死亡，然后被随后雨季的洪水搬运到不远后的池塘中迅速掩埋下来，然后石化形成了化石。对沉积物中的碎屑锆石进行U-Pb测年，表明化石可能是拉丁期甚至卡尼期。古水流分析、碎屑锆石年龄以及Lu-Hf同位素分析表明沉积物部分来自与华北克拉通和秦岭-大别山构造带，说明当时华北与华南已经连接。华北铜川组发现的化石新材料中，发现了特化的波波龙类，支持了波波龙类在中三叠世大量分化的观点。此外根据火山凝灰岩测年结果表明中国肯氏兽动物群时代为安尼期晚期，而永和鳄的时代为拉丁期早期。通过生物地层对比，这一结果还为其他中三叠世的四足动物组合，如南非的犬颌兽带上部、俄罗斯的引鳄动物群以及新疆的克拉玛依组提供了准确的年龄。