MAISANO, J.A.*; Univ. of Texas, Austin: High-Resolution X-ray CT and the Digital Library of Morphology

The study of morphology has long been hampered by scarcity of specimens, limited access to them, and often their small size. High-resolution X-ray computed tomography (HRXCT) is an industrial refinement of medical CT offering greater penetration and a two-orders-of-magnitude improvement in spatial resolution; this permits the study of the internal morphology of specimens representing the smallest orders of vertebrate size, as well as many non-vertebrates. HRXCT data represent a 3D digital map of a specimen’s structure that can be subjected to a variety of image processing techniques, such as reslicing and animation. Because HRXCT is not intrusive, it provides unprecedented access to the internal morphology of specimens too precious to study destructively, such as holotypes and fossils. Because the data represent density contrasts within a specimen, they can be segmented to digitally skeletonize preserved specimens and digitally prepare fossils. And because HRXCT data are digital, they can be made accessible to everyone via the Internet. The Digital Library of Morphology ( at UT Austin now serves HRXCT imagery for almost 200 Recent and extinct species, with taxa ranging from a grasshopper to the oldest known dinosaur to Homo. DigiMorph features QuickTime animations of HRXCT slices along orthogonal axes, rotations of 3D reconstructions, and cutaways showing progressive sections through 3D reconstructions. It also serves Java applets that feature dynamic scrolling through specimen volumes and a measurement tool, and files that can be downloaded to ‘print’ copies of specimens on a variety of rapid-prototyping machines. The combination of HRXCT and DigiMorph promises to transform morphological study for the worldwide scientific community.