EAGER: Digital Cranial Atlas of Pachycephalosaurid Dinosaurs

Mark Goodwin加州大学伯克利分校厚头恐龙，或称穹顶恐龙，其特征是有一个独特的高度充气的穹顶，带有相关的头骨装饰。它们主要产于北美和中亚的西部内陆上白垩纪(1亿-百万年前)。尽管博物馆收藏的穹顶、头骨和部分头骨的样本越来越多，但在研究粗头龙的学生中，关于个体变异、个体发育(生长和发育)、穹顶功能和系统(它们如何相互联系)的问题仍然存在相当大的不确定性和争论。生长阶段之间的形态或形状差异由于延展的新生和后期异速生长而增加，导致幼体看起来与相同类群的成体非常不同。这种极端的颅骨生长轨迹模式可能会模糊进化关系，导致不确定的系统发育特征选择，并可能夸大恐龙多样性的估计，导致白垩纪末期灭绝事件。因此，在进行比较颅骨形态、变异、个体发育和系统学的高级分析之前，确定大头龙头骨的相对生长阶段是至关重要的。该项目将开始利用非破坏性高分辨率X射线计算机断层扫描(HRCT)建立北美粗头龙类恐龙的数字头像图集，以：(1)确认生长发育的内部和外部模式，并确定颅骨(头骨)个体发育(生长)变化的程度；(2)重新评估和测试反对的假说和相关的分类学、古生物学和古生物地理学问题；(3)加强最近的组织学研究，扩大比较颅骨形态计量学分析；(4)通过在www.ucmp.berkeley.edu上提供数字头骨图集，促进进化生物学、古生物学、公共教育和外联工作。德克萨斯大学高分辨率X射线CT设备(UTCT)的PI确认了概念验证测试扫描和有限的全程扫描选择的厚头龙头骨。这项研究将获取落基山脉博物馆、皇家安大略博物馆、皇家泰雷尔古生物博物馆和加州大学古生物学博物馆中几乎所有反映北美粗头龙多样性的厚头龙物种的头骨。PI将使用NSF赞助的设施来完成这项工作，并将开发一个更大的地理信息学项目的原型。布罗德影响：该项目将以多种方式服务于更广泛的受众。加州大学伯克利分校本科生研究学徒计划(URAP)的学生将参与建立数字地图集，从而获得数字化的新技能，并从古生物学的角度直接参与科学研究。这个项目将有助于拓宽他们作为加州大学伯克利分校本科生的知识基础和研究经验。国际和平研究所将监督地图集用户指南的编制工作，这将使高中和本科生都能使用这些数据，并可在为联合大学《理解科学》网站编写的案例研究中使用这些数据。

EAGER: A Digital Cranial Atlas of Pachycephalosaurid DinosaursMark GoodwinUniversity of California, BerkeleyThe Pachycephalosauria, or dome-headed dinosaurs, are characterized by a distinctive highly inflated dome with associated skull ornamentation. They are known primarily from the Upper Cretaceous (100-64 million years ago) Western Interior of North America and central Asia. Despite increasing sample sizes of domes, skulls and partial skulls in museum collections, considerable uncertainty and debate persist among students of pachycephalosaurs in regard to individual variation, ontogeny (growth and development), dome function, and systematic (how they are related to one another). Morphological or shape disparity between growth stages is increased by extended neoteny and late stage allometric growth in the Marginocephalia (pachycephalosaurids + ceratopsids), resulting in juveniles that look very different from adults of the same taxa. This pattern of extreme cranial growth trajectories potentially obscures evolutionary relationships, contributes to uncertain phylogenetic character selection, and may inflate dinosaur diversity estimates leading up to the terminal Cretaceous extinction event. Thus, it is critical to identify the relative growth stage of a pachycephalosaur cranium preceding any advanced analysis of comparative cranial morphology, variation, ontogeny and systematics. This project will begin to build a digital cranial atlas of North American pachycephalosaurid dinosaurs using non-destructive high-resolution X-ray computed tomography (HRCT) to: (1) confirm internal and external patterns of growth and development and determine the extent of cranial (skull) ontogenetic (growth) variation; (2) reevaluate and test opposing hypotheses and associated taxonomic, paleobiologic, and paleobiogeographic questions; (3) enhance recent histological studies and expand comparative cranial morphometric analyses; (4) advance evolutionary biology, paleontology, public education and outreach by serving the digital cranial atlas on www.ucmp.berkeley.edu. Proof of concept test scans and limited full scans of select pachycephalosaurid skulls were confirmed by the PI at the University of Texas High-Resolution X-ray CT Facility (UTCT). Skulls of nearly all pachycephalosaurid species in the Museum of the Rockies, Royal Ontario Museum, Royal Tyrrell Museum of Paleontology, and the UC Museum of Paleontology reflecting 100% of North American pachycephalosaur diversity will be accessed for this study. The PI will be using a NSF sponsored facility to do this work and will be developing the prototype of a larger geoinformatics project.Broader Impacts: This project will serve a broader audience in multiple ways. Students from the UC Berkeley undergraduate research apprentice program (URAP) will be engaged in building the digital atlas thus gaining new skills in digitization and engaging directly in scientific research from a paleobiological perspective. This project will serve to broaden their knowledge base and research experience as a UC Berkeley undergraduate. The PI will oversee the development of a user's guide to the atlas, which will allow the data to be used by students at both the high school and undergraduate levels and within a case study to be developed for UCMP's Understanding Science website.