Real or fake mosasaur jaw

[pachy-pleuro-whatnot-odon]

7 hours ago, Praefectus said:

I'm pretty sure the bone is an upside down maxilla, so the nerve exits are part of the maxillary division, not mandibular.

 

I agree. The second jaw does look like a maxilla to me as well...

 

7 hours ago, Praefectus said:

This jaw looks much more reconstructed. I am suspicious of if the teeth are original and how well the piece has been put together.

 

I'd say the teeth and bone are real, although the jaw is much more damaged and I'm therefore suspicious it may have undergone more repair. It's also unclear to me whether the teeth are original or have been replaced as well. Generally, I find the tooth count rather high for a natural piece, as tooth positions often go missing in the process of fossilisation. However, better images would be needed to properly analyse which parts of this jaw are original and which have been reconstructed.

 

7 hours ago, Praefectus said:

Teeth look original to me. The morphology difference is the gradual increase in crown robusticity seen in prognathodontine mosasaurs. The back teeth had more crushing function.

 

While this is undeniably true and the right part of the jaw specimen certainly comes from the rear part of the lower jaw, what surprises me is that these teeth show so little posterior curvature and, even more surprising, that there are so many of these squat teeth. In most skulls I've seen there are at most two, with a more gradual transition between anterior and posterior tooth morphologies. That is, I find the transition in tooth shape between the left and right sections of the jaw quite marked and therefore remarkable. At the same time, the bone texture seems to continue quite well between the two sections of bone, and there seems to be a foramen on the break that runs across it. This suggests the two pieces do belong together - something that seems corroborated by the mode of preservation of the teeth...