DISSERTATION RESEARCH: Evolution of the Cranial Cavity in Mammals and Extinct Cynodonts

德克萨斯大学奥斯汀分校的Timothy Rowe博士和Ted Macrini先生获得了一项资助，用于研究近代哺乳动物的脑壳、颅腔和大脑的进化，以及它们在犬齿动物中一些最近的已灭绝近亲。不同的感觉方式、内脑容量和智力的相对重要性将被评估为最近和灭绝的标本，选择代表过去2亿年的哺乳动物多样化。x射线计算机断层扫描（CT）将通过检查数字模型或脑壳的三维填充物来定量地探索感觉敏锐度、行为和智力的不同组成部分。大脑很少（如果有的话）变成化石，但大脑的体积和外部形状通常被包裹在颅腔内的脑壳的骨头保存下来。直到最近，在不破坏标本的情况下，基本上无法获得自然内模。x射线CT可以无损地恢复活的和灭绝的物种的颅内表面和体积，以前从未以这种方式研究过。将比较最近物种的模型和实际大脑，以及那些系统发育位置相对受限的灭绝物种之间的比较。扫描将由德克萨斯大学高分辨率CT设备进行，这是一个由nsf赞助的多用户设备。这项研究将为研究哺乳动物行为和智力进化的广大受众产生大量高质量的数字数据和可视化。在这项研究中产生的数据也可能有助于解决哺乳动物系统学中持续存在的问题。本研究产生的遗留数据将通过www.DigiMorph.org（美国国家科学基金会赞助的脊椎动物形态学数字图书馆）进行分发。

Abstract for DEB-0309369A grant has been awarded to Dr. Timothy Rowe and Mr. Ted Macrini of The University of Texas at Austin to study the evolution of the braincase, endocranial cavity, and brain in Recent mammals and some of their closest extinct relatives within Cynodontia. The relative importance of different sensory modalities, endocranial capacity, and intelligence will be assessed for selected Recent and extinct specimens, chosen to represent the last 200 million years of mammalian diversification. X-ray computed tomographic (CT) scanning will be used to quantitatively explore different components of sensory acuity, behavior, and intelligence through the examination of digital endocasts, or three-dimensional infillings of the braincase. Brains rarely, if ever, fossilize, but brain volume and external shape are often preserved by the bones of the braincase that enclose the endocranial cavity. Until recently natural endocasts were largely unobtainable without destroying the specimen. X-ray CT permits non-destructive recovery of endocranial surfaces and volumes from living and extinct species never before studied in this capacity. Comparisons will be made between endocasts and actual brains in Recent species, and between those extinct species whose phylogenetic positions are relatively well constrained. Scanning will be performed by the University of Texas High-Resolution CT Facility, an NSF-sponsored Multi User Facility.This study will generate large volumes of high quality digital data and visualizations of interest to the wide audience that studies the evolution of mammalian behavior and intelligence. Data generated in this study may also help resolve persistent problems in mammalian systematics. Legacy data generated by this study will be distributed via www.DigiMorph.org, an NSF-sponsored Digital Library of Vertebrate Morphology.