Middle-to-Late Jurassic terrestrial vertebrates of China: Systematics and geochronology

中国的中晚侏罗世陆生脊椎动物：系统学和年代学PI：詹姆斯·M·克拉克，乔治华盛顿大学合作者：凯瑟琳·A·福斯特，广东工业大学；许醒，中国科学院，中国科学院，晚侏罗世中早期(1.76-1.56亿年前)的陆生脊椎动物化石在世界上鲜为人知，但中国的石树沟组保存了这个时代的大量关节骨骼。这是现代陆地脊椎动物史上的一个重要时期，因为现代哺乳动物、蜥蜴、海龟和火蜥蜴的最古老出现年龄是这个年龄或稍大一些，而侏罗纪晚期最古老的鸟类始祖鸟的存在表明鸟类大约在这个时候进化。白垩纪繁盛的恐龙的主要谱系(角龙、甲龙、鸟脚类、新龙类和腔尾龙)也在这个时候出现。2001-2006年，GWU和中国科学院联合考察石树沟组，2004-2006年由NSF资助，收集了450多个脊椎动物化石，并记录了该组的地质情况。我们对岩石进行了放射性测年，表明该地层跨越了中上侏罗统界线。在我们的发现中，有最古老和最原始的霸王龙(关龙武彩)和角龙(银龙)恐龙，来自亚洲的第一只角龙兽脚类恐龙(利马龙)，以及奇怪的alvarezsaurid兽脚类恐龙中最古老和最原始的成员。该藏品中的化石为鸟类的起源提供了重要证据，为兽脚亚目动物的手指身份产生了新的假说，并记录了在始祖鸟之前1000万年鸟类近亲的多样化。两个不同寻常的遗址保存着Ming的证据，这是一种非常不寻常的保存环境。在此，我们请求支持1)未描述的化石的研究，包括一种基本蜥蜴、一种原始哺乳动物、一种罕见的新海龟和一种新的马尼拉龙兽脚类恐龙的几乎完整的骨骼，2)几个重要恐龙物种的详细描述的准备，3)石树沟组底部岩石、准噶尔盆地其他地方和四川中侏罗世沙溪庙组岩石的放射性年龄(ID-TIMS)测定，中国，以及4)继续在石手沟组，特别是组的下部寻找化石。该项目的参与者包括地球科学界代表性不足的群体(两名女性和一名美洲土著人)。

Middle-to-Late Jurassic terrestrial vertebrates of China: Systematicsand geochronologyPI: James M Clark, George Washington University Co-PIs: Catherine A. Forster, GWU; Xu Xing, Chinese Academy of Sciences Land-living vertebrate fossils from the Middle and early Late Jurassic (176-156 million years ago) are very poorly known worldwide, but the Shishugou Formation of NW China preserves abundant articulated skeletons from this age. This is an important time in the history of modern land vertebrates, because the oldest occurrences of modern mammals, lizards, turtles, and salamanders are this age or slightly older, and the presence of the oldest bird Archaeopteryx later in the Jurassic indicates that birds evolved at about this time. The major lineages of dinosaurs that flourished in the Cretaceous (ceratopsians, ankylosaurs, ornithopods, neosauropods, and coelurosaurs) also appear at this time. From 2001-2006 joint expeditions by GWU and the Chinese Academy of Sciences to the Shishugou Formation, funded in 2004-2006 by the NSF, collected over 450 vertebrate fossils and documented the geology of the formation. We radiometrically dated rocks indicating the formation spans the Middle-Upper Jurassic boundary. Among our discoveries are the oldest and most primitive tyrannosauroid (Guanlong wucaii) and ceratopsian (Yinlong downsi) dinosaurs, the first ceratosaurian theropod dinosaur from Asia (Limusaurus inextricabilis), and the oldest and most primitive member of the bizarre alvarezsaurid theropods. Fossils in this collection bear important evidence on the origin of birds, generating a new hypothesis for the identity of the fingers present in theropods and documenting the diversification of the closest relatives of birds 10 million years prior to Archaeopteryx. Two extraordinary sites preserve evidence of miring, a highly unusual preservational milieu. Here we request support for 1) studies of undescribed fossils, including nearly complete skeletons of a basal lizard, a primitive mammal, an unusual new turtle, and a new maniraptoran theropod dinosaur, 2) preparation of detailed descriptions of several important dinosaur species, 3) radiometric dating (ID-TIMS) of rocks at the base of the Shishugou Formation, in contemporary rocks elsewhere in the Junggar Basin, and in the Middle Jurassic Shaximiao formations of Sichuan, China, and 4) continued exploration for fossils in the Shishugou Formation, especially in the lower part of the formation. Participants in this project include underrepresented groups in Earth Sciences (two females and a native American).