Collaborative research: Robust estimation of biodiversity dynamics: Global versus regional patterns in the end Ordovician mass extinction of graptolites

智力优势-角龙类是最著名的恐龙分支之一，因为它们的相对丰富，以及颅部突触形态的显着多样性，如角和褶边，诊断出该分支的更多衍生成员。巨人症是一种无角目动物进化的趋势，伴随着进食机制的逐渐复杂化和颅骨显示的多样性。异时性，特别是变态被认为是角龙类进化的主要影响因素，以解释向大型和晚期个体发育发生的进化。同样，进食器官明显的等级复杂性表明了通过个体发育和生殖发育的性格整合的进化。所有这些进化假说都需要对角龙类恐龙的发育和进化过程有详细的了解，但到目前为止，对年龄的估计受到很大的限制，没有量化，严格依赖于详细的进化过程。一种基于组织切片和发育质量外推的化石发育分期的创新方法与noveltree相结合，基于方法研究heterochrony和整合使用一个完善的Ceratopsia的系统发育。基于良好的采样增长系列的七个骨干类群代表的多样性的分支，和详细的ceratopsians，我们将研究是否有相关的转变发育timingof synapomorphies（heterochrony）相对于生长策略，以及如果块的字符代表集成模块，满足标准的是ceratopsians和个体发育的限制。这些定量研究将使我们能够评估先前关于异时性和整合在角龙类进化中所起作用的假设。通过提供对个体发育中何时表达突触变体的定量理解，这项研究将有助于解决与基于幼年全型的物种有效性相关的几个分类学难题，并提供对角龙类多样性更准确的理解。这项研究代表了一个新的综合性探索的进化过程中一个著名的恐龙组。本研究的新方法和结果有望广泛应用于种群生物学、发育生物学、宏观进化和进化-发育等领域，并将通过同行评审期刊、专业会议上的演讲和专业网站传播。两名研究生和两名本科生将通过该项目接受培训，研究的各个方面将纳入两个PI教授的大学课程中。这两个PI都参与了自然历史博物馆的展品开发，这项研究的一部分将被纳入两个正在进行的展览项目，以及相关的教育网站和编程。鉴于媒体对生物多样性研究的兴趣，毫无疑问，将有许多机会向公众传播这项工作的成果。

Intellectual Merit- Ceratopsians are among the best known of dinosaur clades due to theirrelative abundance, and the remarkable diversity of cranial synapomorphies such as hornsand frills that diagnose more derived members of the clade. Gigantism is a trend inceratopsian evolution that is accompanied by the evolution of progressively morecomplex feeding mechanisms and cranial display diversity. Heterochrony, and inparticular peramorphosis have been proposed as major influences in ceratopsianevolution to explain the evolution towards large size and late ontogenetic genesis of thedisplay in advanced forms. Likewise, the apparent hierarchical complexity of the feedingapparatus suggests an evolution of character integration through both ontogeny andphylogeny. All of these evolutionary hypotheses require detailed knowledge of both thedevelopment and phylogeny of ceratopsian dinosaurs, but so far age estimates have beenpoorly constrained and non-quantified and rigorous reliance on detailed phylogenieslimited.In this study, an innovative approach to developmentally staging fossils based onhistological sectioning and Developmental Mass extrapolation is combined with noveltree-based methods toward studying heterochrony and integration using a well-established phylogeny of Ceratopsia. Based on well-sampled growth series of seven-backbone taxa representing the diversity of the clade, and a detailed phylogeny ofceratopsians, we will examine whether there are correlated shifts in developmental timingof synapomorphies (heterochrony) relative to growth strategies, and also if blocks ofcharacters represent integrated modules that fulfill criteria for being phylogenetically andontogenetically constrained. These quantitative studies will allow us to evaluate previoushypotheses on the role heterochrony and integration have played in ceratopsian evolution.By providing a quantified understanding of when in ontogeny synapomorpies areexpressed this research will help to resolve several taxonomic quandaries related to thevalidity of species based on juvenile holotypes and provide a more accurateunderstanding of ceratopsian diversity.Broader Impact: This research represents a new integrative exploration of evolutionaryprocesses in a well-known group of dinosaurs. The novel methods and the results of thisresearch promise to be widely applicable to fields as diverse as population biology,developmental biology, macroevolution and evo-devo, and will be disseminated throughpeer -reviewed journals, presentations at professional meetings and professional web-sites. Two graduate and two undergraduate students will be trained through this project,and aspects of the research will be incorporated into university courses taught by bothPIs. Both PIs are involved with developing exhibits for natural history museum, andparts of this research will be incorporated into two ongoing exhibit projects, andassociated educational web-sites and programming. Given the media interest in dinosaurresearch, many opportunities to disseminate results of this work to the public will nodoubt arise.