Identify these bones please

[santoury]

These are from a loggerhead sea turtle - I'm doing this in conjunction with a biologist studying these animals, and he gave me a "riddle" to solve.

What I have appears to be EITHER an upper OR a lower jaw bone, with the "beak part" which is separate, but fits perfectly over the bone.

I have posted each piece separately (bone, and beak) at different angles, "right side up" and "upside down" which ever is correct.

I'd appreciate any input in figuring out if it's the upper, or the lower jaw, so I can solve the riddle. He has the skull, but he did not let me see where this jaw was positioned.
Thanks!

 

[necrocanis]

it's the lower jaw or mandibles. It's quit nice.

 

[necrocanis]

oh yeah you are holding it the way it goes underneath the cranium in the very bottom picture.

 

[santoury]

So this goes directly beneath the skull, rather than an extension? In that case, where does the upper beak go? The skull did not seem to have a "pointy end" for that, it was pretty flat, like a human's in front.
This is very interesting, thank you!

 

[necrocanis]

Here's a pic of a loggerhead turtle skull side view to show you some comparison. The beak goes in the front and the back of the V when viewed from the front is where the hinge is. Hope this helps!

skull pictured courtesy of www.boneclones.com

 

[santoury]

Wow - very cool - thanks for sharing! Riddle solved! So there is only one beak - the "lower" ?

 

[necrocanis]

look at the skull, there is an upper and lower beak just like on a bird it grows forever, and is made of kerotine just like your nails. They self sharpen on each other. The lower beak if you look closer is made to fit inside the concave upper beak and rub together much like the edge of scissors for a superior cutting edge! This is how most if not all turtle beaks work.

 

[sncboom]

Cool pics