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

合作研究：生物多样性动态的稳健估计：奥陶纪末笔石大规模灭绝的全球与区域模式

• 批准号: 0418790
• 负责人: Charles Mitchell
• 金额: $ 48万
• 依托单位: SUNY at Buffalo
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-08-01 至 2011-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0418790&HistoricalAwards=false
• 关键词: Collaborative; research; Robust; estimation; biodiversity

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.

智力优势——角龙类是最著名的恐龙分支之一，因为它们相对丰富，并且颅骨共性的显着多样性，例如角和褶边，可以诊断该分支的更多衍生成员。巨人症是角龙进化的一种趋势，伴随着逐渐复杂的进食机制和颅骨表现多样性的进化。异时性，特别是超态性已被认为是角龙进化的主要影响因素，以解释高级形态的大尺寸进化和晚期个体发生发生。同样，喂养装置明显的层次复杂性表明通过个体发育和系统发育来进行性格整合的进化。所有这些进化假说都需要对角龙恐龙的发育和系统发育有详细的了解，但到目前为止，年龄估计受到的约束很弱，无法量化，而且对详细系统发育的严格依赖有限。在这项研究中，一种基于组织学切片的化石发育分期创新方法发育质量外推法与基于新树的方法相结合，利用成熟的系统发育学来研究异时性和整合角龙属。基于代表进化枝多样性的七骨干类群的良好采样生长系列，以及角龙类的详细系统发育，我们将研究相对于生长策略的同源性（异时性）的发育时间是否存在相关变化，以及性状块是否存在相关变化。代表满足系统发育和个体发育限制标准的集成模块。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进化中所发挥的作用的假设。通过提供对个体发育中何时表达联征性的量化理解，这项研究将有助于解决与基于幼年正模的物种有效性相关的几个分类学困境并提供对角龙多样性的更准确的理解。更广泛的影响：这项研究代表了对进化过程的新的综合探索在一个著名的恐龙类群中。这项研究的新颖方法和结果有望广泛应用于群体生物学、发育生物学、宏观进化和进化进化等不同领域，并将通过同行评审期刊、专业会议和专业网站上的演示进行传播。该项目将培养两名研究生和两名本科生，研究内容将纳入两位 PI 教授的大学课程中。两位 PI 都参与了自然历史博物馆展品的开发，这项研究的部分内容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项目中。鉴于媒体对恐龙研究的兴趣，毫无疑问将会出现许多向公众传播这项工作成果的机会。