Doctoral Dissertation Improvement: Plio-Pleistocene Hominin Teeth from Dmanisi, Georgia

第一个离开非洲家园的人类物种的身份和这一事件的时间仍然存在极大的争议。问题在于，很少有关键年代的遗址既有重要的原始人遗骸，又有地质背景下的文物，可以可靠地确定年代。乔治亚共和国的德马尼西遗址挑战了人们对中国和爪哇其他可能是早期遗址的质疑，并增加了我们对非洲第一批原始人迁徙的理解。德玛尼西可以追溯到最早的更新世(1.77英里)，是一个拥有丰富古生物和考古证据的遗址，它从世界上任何一个地方的单一层面产生了最大的早期人类遗骸样本。此外，这些化石在形态和时间上都处于早期直立人和晚期直立人之间的中间位置。许多研究表明，有关牙冠和牙根大小的信息以及对形态特征的观察可以对更新世古人类的分类学、系统发育和功能分析做出重大贡献。这项研究的重点是德马尼西遗址不断增长的人族牙齿样本。德马尼西的牙齿样本现在包括来自三个下颌骨、两个颅骨和一些孤立发现的牙齿，这些样本加在一起至少代表了3个人。许多标本目前尚未出版。所有这些都将通过描述和测量，借助数字摄影和放射照相等成像技术进行记录。然后将分析变异模式，以确定牙齿之间的度量和形态差异是否可能反映物种间或物种内的差异，包括性别之间的差异。德马尼西的牙齿遗骸将与来自东非和东南亚的其他早期直立人牙齿进行比较，并与图尔卡纳盆地和奥杜瓦伊峡谷的早期人类标本进行比较。这项分析将记录能人和早期直立人的牙齿变异范围，确定Dmanisi标本在该范围内的位置，并帮助识别Dmanisi样本与其他原始人类群体之间任何可能的系统发育(祖先-后代)关系。这项关于牙列的定量工作将有助于更好地理解人的种群内和种群间的变异以及人属最早成员的分类学。这项研究还将提供一个独特的数据集，用来评估有关原始人类从非洲家园迁徙的情景以及最早的欧亚人的古生物学。项目资金的更广泛影响是，它将允许合作伙伴前往格鲁吉亚对牙科材料进行分析，并允许与格鲁吉亚和美国科学家进行合作。这项拟议的研究还为联合PI和参与该项目的其他人员提供了实验室数据收集和分析方面的良好教育机会。

The identity of the first human species to disperse out of the African homeland and the timing of this event remain highly controversial. The problem lies in the fact that few sites of critical age have yielded both significant hominin remains and artifacts from geologic contexts which can be reliably dated. The Dmanisi site in the Republic of Georgia challenges the doubts raised in respect to other, potentially early sites in China and Java, and adds to our understanding of the first hominin dispersals from Africa. Dmanisi, which dates to the earliest Pleistocene (1.77 mya), is a site rich in paleontological and archaeological evidence, and it has produced the largest sample of early Homo remains from a single level at a locality anywhere in the world. In addition, the fossils occupy an intermediate position, both morphologically and temporally, between earliest Homo and later Homo erectus. Many studies have demonstrated that information about tooth crown and root size together with observations of morphological traits can contribute significantly to taxonomic, phylogenetic, and functional analyses of Plio-Pleistocene hominins. This study focuses on the continually growing hominin dental sample from the site of Dmanisi. The Dmanisi dental sample now includes teeth from three mandibles, two crania, and a number of isolated finds, which together represent a minimum of 3 individuals. Many of the specimens are currently unpublished. All will be documented through description and measurement, aided by imaging techniques such as digital photography and radiography. Patterns of variation will then be analyzed to determine if the metric and morphologic differences among the teeth likely reflect interspecific or intraspecific variation, including differences between the sexes. The Dmanisi dental remains will be compared with other early Homo erectus (=ergaster) teeth from East Africa and Southeast Asia, and to specimens of earlier Homo from the Turkana basin and Olduvai Gorge. This analysis will document the range of dental variation for Homo habilis and early Homo erectus, establish the position of the Dmanisi specimens within that range, and help to identify any probable phylogenetic (ancestor-descendant) relationships between the Dmanisi sample and the other hominin groups. This quantitative work on dentition will contribute to a better understanding of intra- and inter-populational hominin variation and the taxonomy of the earliest members of the genus Homo. This research will also provide a unique dataset with which to evaluate scenarios concerning the initial migration of hominins from the African homeland and the paleobiology of the earliest Eurasians. The broader impact of project funding is that it will permit the Co-PI to travel to Georgia for analysis of the dental material and allow for collaboration with both Georgian and US scientists. The proposed research also offers outstanding educational opportunities in laboratory data collection and analysis, to both the Co-PI and others involved in the project.