Saturday, June 21, 2014

The Inside of the Skull Appears

I've been working on cleaning out the inside of the skull, starting from the rear end (posterior) and working forward. So far I've uncovered the pineal gland opening, the (probable) braincase and the insides of the three terminal projections. The quality of the bone is amazing! Everything is intact, the bone surface is clean and there is no apparent distortion. Here is the bottom overview. The teeth and exterior of the skull are at the bottom, the midline is along the top. The remnant of the last nautiloid is still in the middle of the skull, but it won't be there long.
Here is a closer view of the pineal foramen structure and the braincase. The pineal foramen are found in reptiles. It is the groove with a rounded edge descending from the top of the skull (top in this picture too) that is vaguely bullet-shaped. The pineal gland's full function is not well understood. They definitely were a significant part of the brain and required an opening without bone to let in ambient light through skin or a specialized lens. The brain case is immediately next to it to the right side (posterior). It is not real clear in this photograph but the furthest posterior part of the braincase is U shaped (since it's broken in half) for the brain stem to exit. It would be a round hole if whole. 

The U-shaped section might be a little clearer in this shot - at the top. The braincase is the upper projection. 
You can also see how much of the inside of the skull is showing. The skull varies very elegantly in thickness and strength. The thicker section diagonally across the middle is about 1 cm thick, while the part below it is only about 1-2mm thick. Very Fragile! The lower projection is actually the Quadrate where the jaw bone articulates. It had a very large cartilage pad on the inside of the  projection which appears blurry because it points right at the camera at this angle. 

This is a clearer shot of the Quadrate in better profile. You can also see the pineal gland hole in the top of the skull on the right side - it looks like a notch. 

Last of all here's a free-hand shot:

I suspect it might be very interesting to do a FEA (Finite Element Analysis) on this skull to determine things like biting force, etc. The bone thickness is easy to measure (not just estimate) and the angles and curves are beautiful and elegant too.

Sincerely, Greg Carr

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