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

大规模灭绝，或物种死亡率急剧上升的事件，一再扰乱了地球上生命的多样性。虽然对这些扰动对分类多样性的一般影响有一个很好的认识，但对这些扰动的其他几个方面的认识相对较差，例如灭绝和幸存的分类群之间的系谱关系和大小和形状的变化范围，以及分类群在空间（古生物地理）和时间（地层）上的分布。PIs建议详细研究海洋无脊椎动物，腕足目Terebratulida的一个分支（具有单一共同祖先的生物），在大约2亿年的时间里，该分支经历了四个不同的大灭绝事件：emian末，frasnian末，visean末和permian末。pi的研究将重建terebratulide进化历史的三个组成部分，并解释它们与大灭绝事件中灭绝或生存的关系。早期terebratulide属（下泥盆统至三叠纪）之间的系统发育关系将主要利用基于简约的系统发育推断方法进行重建。在这些大灭绝事件前后，terebratulides的定量形态特征将使用几何坐标和基于轮廓的方法计算和评估。在整理原始文献的分布数据后，将研究伴随这些形态学、系统发育和分类学变化的全球古地理格局。整合pi的三部分研究结果有可能检验一个有趣但相对未经验证的假设，即大规模灭绝是宏观进化的媒介——灭绝生存的选择是否可以在物种或进化枝的层面上进行，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?