Collaborative Research: Examining Origination, Extinction, and Recovery in Terebratulide Brachiopods: The Integration of Phylogeny, Morphometrics, and Biogeography

大规模灭绝，或物种死亡率急剧增加的事件，一再扰乱了地球上生物的多样性。 虽然人们对这种扰动对分类多样性的总体影响有了很好的认识，但对这些扰动的其他几个方面却相对缺乏认识，例如灭绝和幸存的分类群之间的谱系关系、大小和形状的变化范围，以及分类群在空间（古生物地理学）和时间（地层学）上的分布。 PI建议详细调查一个分支（生物共享一个共同的祖先）的海洋无脊椎动物，腕足目Terebratulida，在大约2亿年的时间，在此期间，该分支的经验和反弹，从四个不同的大规模灭绝事件：结束埃姆斯，结束弗拉斯，结束维西恩，和结束二叠纪。 PI研究将重建terebratulide进化历史的三个组成部分，并解释它们与灭绝或大规模灭绝事件中的生存有关。 早期terebratulide属（下泥盆统至三叠纪）之间的系统发育关系将重建主要是基于简约的系统发育推断的方法。 将使用几何坐标和基于轮廓的方法计算和评估这些大规模灭绝事件之前和之后的terebratulides的定量形态特征。 全球古生物地理模式，伴随着这些变化的形态，发育，并通过时间的分类将进行研究后，汇编分布数据的主要文献。 整合PI三部分研究的结果有可能测试有趣但相对未经检验的假设，即大规模灭绝作为宏观进化的代理人-灭绝生存的选择是否可以在物种或进化枝的水平上进行，而不仅仅是在个体或种群上？

Mass extinctions, or episodes of dramatically increased species mortality, have repeatedly perturbed the standing diversity of life on Earth. Although there is a good idea of the general effect such perturbations have had on taxonomic diversity, there are relatively poor ideas of several other dimensions of these perturbations, such as the genealogical relationships and the range of variation in size and shape among taxa going extinct and those surviving, as well as taxon distribution in space (paleobiogeographic) and time (stratigraphic). PIs propose to investigate in detail one clade (organisms sharing a single common ancestor) of marine invertebrates, the brachiopod order Terebratulida, over a period of roughly 200 million years during which the clade experiences and rebounds from four distinct mass extinction episodes: end-Emsian, end-Frasnian, end-Visean, and end-Permian. PIs research will reconstruct three components of terebratulide evolutionary history, and interpret them in relation to extinction or survival at mass-extinction events. Phylogenetic relationships among early terebratulide genera (Lower Devonian through Triassic periods) will be reconstructed using primarily parsimony-based methods of phylogenetic inference. Quantitative morphometric characteristics of terebratulides before and after these mass-extinction events will be calculated and evaluated using geometric-coordinate and outline-based methods. Global paleobiogeographic patterns that accompany these changes in morphology, phylogeny, and taxonomy through time will be studied after compiling distributional data from the primary literature. Integrating the results of PIs three-part study has the potential to test the intriguing but relatively untested hypothesis that mass extinctions act as agents of macroevolution - can selection for extinction survival operate at the level of species or clades, rather than simply on individuals or populations?