I am also involved with Lori Marino of Emory University on a project using Computed Tomography to image the internal anatomy of fossil whale skulls. We have used the technology to measure the endocranial volume of fossil whales. Modern cetaceans have very large brains for their body size (not unlike we primates) and we are trying to figure out when that increase in brain size occurs in whale evolution to test hypotheses of the function of large brain size in cetaceans and primates. Below are some sample images of CT scans from a specimen of Zygorhiza kochii. The images go from left to right and from top to bottom. The upper left image is the very posterior of the skull.
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Zygorhiza kochii CT scan. Just the edges of the occipital condyle are visible. |
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Zygorhiza kochii CT scan. The occipital condyles, edges of the nuchal crest, and left exoccipital are visible. |
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Zygorhiza kochii CT scan. The foramen magnum is the light gray oval at the bottom center. |
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Zygorhiza kochii CT scan. The sides of the nuchal crest are projecting dorsally. |
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Zygorhiza kochii CT scan. The light gray area taking up most of the interior is the endocranial cavity. |
Click here to see a cool movie of CT scans of an Oligocene odontocete from Oregon.