The Middle to Late Jurassic Terrestrial Vertebrate Faunal Transition in Northwestern China: A Paleontologic, Stratigraphic, and Geochronologic Study

中侏罗世晚期到晚侏罗世早期（从卡洛夫阶到牛津阶）是陆地脊椎动物化石记录中最不为人所知的时期之一。 中国西北部新疆自治区的石树渠组保存了丰富的化石序列，跨越这一时期。 这是现代陆地脊椎动物历史上的一个重要时期，因为许多群体（哺乳动物，鸟类，鳄鱼，有鳞目动物，青蛙，蝾螈）刚刚开始多样化，而泛大陆的单一超大陆及其世界性动物群刚刚开始分裂。 此外，几组恐龙将多样化和统治白垩纪（即，蜥脚类、鸟脚类、剑龙类、甲龙类和腔上龙类）最早出现并辐射于中、晚侏罗世。因此，石树沟组的化石有助于了解现代四足动物和恐龙主要类群之间最基本的关系和早期演化，以及现代动物区系的起源。 该项目将化石的古生物学研究与沉积物和火山沉积物的地层学、古环境学和年代学研究相结合，以记录动物群，并建立一个校正的地层学框架，以反映地层内动物群的变化。2）野外工作，确定地层中分类群的地层和古环境分布以及它们之间的任何相关性3）博物馆研究，记录这些在相关化石和实验室研究中，确定凝灰岩和凝灰岩的年代，并确定它们的地球化学成分。 这些独立的研究路线将被合成为一个校准模型，用于与现有的区域构造和古气候解释相结合的地层中的自然和环境变化。

The late Middle through early late Jurassic (Callovian through Oxfordian) is one of the most poorly known intervals in the terrestrial vertebrate fossil record. The Shishuqou Formation of the Xinjiang Autonomous Region of northwestern China preserves a rich sequence of fossils spanning this period. This is an important time in the history of modern terrestrial vertebrates because many group (mammals, birds, crocodilians, squamates, frogs, salamanders) were just beginning to diversify and the single supercontient of Pangea with its cosmopolitan fauna was just beginning to divide. Furthermore, several groups of dinosaurs that would diversify and dominate the Cretaceous (i.e., sauropods, ornithopods, stegosaurs, ankylosaurs, and coelurosaurs) first appeared and radiated during Middle and Late Jurassic. Thus, fossils from the Shishugou Formation can contribute to an understanding of the most basic relationships and early evolution within the major groups of modern tetrapods and dinosaurs and the beginning of modern faunal provinciality. The four year project proposed here combines palentological studies of the fossils with stratigraphic, peleoenvironmental, and geochronological studies of the sediments and volcanic deposits to document the fauna and establish a calibrated stratigraphic framework for faunal change within the formation.Support is requested for 1) further field work to collect more vertebrate fossils, including a program of screenwashing for microvertabates; 2) field work establishing the stratigraphic and palenivornment distributions of taxa in the formation and any correlations between them 3) museum studies documenting these in the and related fossils and laboratory studies dating the tuffs and bentonites and determining their geochemical composition. These separate lines of research will be synthesized into a calibrated model for fanual and environmental change in the formation that is integrated with existing regional tectonics and paleoclimatic interpretations.