The Cleveland tyrannosaur skull (Nanotyrannus or Tyrannosaurus): new findings based on ct scanning, with special reference to the braincase. Lawrence M. Witmer & Ryan C. Ridgely, Kirtlandia 37: 61-81.
We subjected the skull to computed x-ray tomography (CT scanning), followed by computer analysis and 3D visualization. The braincase and a number of other bones (e.g., vomer, quadrate, quadratojugal, palatine, mandible) were digitally "extracted" from the CT datasets. Although the new findings strongly confirm the long-held view that CMNH 7541 pertains to a tyrannosaurid, the mosaic of characters it presents makes finer taxonomic assignment difficult. For example, some characters support affinities with T. rex, yet other characters argue for a much more basal position.
The key question that awaits resolution is whether the differences observed can be attributed to juvenility, and such resolution will require information from new, as yet unpublished specimens. Nevertheless, some of the differences seen in CMNH 7541 (e.g., the pattern of pneumatic foramina in the basicranium) are highly divergent and are harder to attribute to ontogeny. Among other findings, we report here thin, laminar structures within the main nasal airway that are interpretable as being respiratory turbinates, which have potential implications for metabolic physiology.
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The key question that awaits resolution is whether the differences observed can be attributed to juvenility, and such resolution will require information from new, as yet unpublished specimens. Nevertheless, some of the differences seen in CMNH 7541 (e.g., the pattern of pneumatic foramina in the basicranium) are highly divergent and are harder to attribute to ontogeny. Among other findings, we report here thin, laminar structures within the main nasal airway that are interpretable as being respiratory turbinates, which have potential implications for metabolic physiology.
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