BROCHU, C. A.: Beyond Mere Morphology: Reflections of a Computed Tomography Addict

Computed tomographic (CT) technology has become a standard method for nondestructively accessing the interior structures of irreplaceable fossils. This vastly increases the informative power of fossils and allows researchers a unique opportunity to visualize internal features in three dimensions, either through three-dimensional reconstruction or as animations of sequential slices. Either mode (2-D or 3-D) can bring new insight into the study of fossil organism morphology, whether the focus is phylogenetics, functional morphology, physiology, or any other research program. There are additional practical applications of CT imagery to fossil preparation and the tracing of post-collection human modification. CT imagery improves the researcher’s ability to illustrate complex internal structures, both to the research community and the general public. The data can be published in its native digital format, either over the World Wide Web or through media such as CD-ROM or DVD, effectively allowing the dissemination of “virtual specimens”. Simple software applications allow colleagues, teachers, and students to interact with the data. Digital anatomical atlases can be generated for a broad diversity of taxa, which gives instructors and students a larger sample of available study specimens. One such atlas has already been made available for Alligator mississippiensis. Application of CT imagery to popularly-known taxa, as was recently done with Tyrannosaurus rex, gives researchers a new means of making important morphological and evolutionary points to the general public. Nonavian dinosaurs are inherently interesting to people, and a host of evolutionary questions, from the anatomy of pneumatic structures in the skull to origin of birds, can be addressed through a combination of careful phylogenetic analysis and CT imagery. This lets scientists highlight principles common to all comparative biologists to the public.