Mosasaurus Jaw, double-checking authenticity ;)

[LordTrilobite]

Mosasaurs replaced their teeth all the time during their life. At any time a mosasaur would likely have been missing a few teeth that would be later replaced. So it hasn't much to do with age.

 

Also, I don't think that last jaw is Halisaurus. The back edge of the teeth are too straight. Could possibly be a very young Prognathodon.

[FossilSniper]

7 minutes ago, LordTrilobite said:

Also, I don't think that last jaw is Halisaurus. The back edge of the teeth are too straight. Could possibly be a very young Prognathodon.

Well then, you have corrected two seller identifications in one forum! 
Alrighty, thank you again.

And, for future reference- is there a chart that I can use to distinguish types of mosasaur from their teeth?

[LordTrilobite]

Not really. Generally mosasaur teeth aren't very well identifiable. Eremiasaurus and Prognathodon for example have pretty similar teeth.

 

Your best bet is this thread:

 

[Aurelius]

1 hour ago, LordTrilobite said:

I'm sorry but I'm gonna have to strongly disagree. That jaw bone is absolutely definitely real.

 

I agree. Definitely no reason to think the jaw bone is fake.

[Auspex]

10 hours ago, LordTrilobite said:

The strange spacing is likely due to missing teeth

I had considered that, but the space is only a half space, compared to that between the second and third tooth.

If you fill that gap with a morphologically similar tooth, then #2 & #3 will be too far apart by comparison.

I remain uneasy about its authenticity.

[Aurelius]

I think the apparent issue could be explained by teeth that have slightly drifted from their sockets, giving a misleading appearance. I think someone capable of producing an otherwise-perfect fake would have placed the teeth properly.

 

Here's the closest parallel I have, also Halisaurus, and the same bone. Mine isn't quite as good, but they look pretty similar to me. 

 

[LordTrilobite]

Drifting is definitely a thing that happens, even if the teeth don't completely leave the jaw. They sometimes slightly move around.

[Aurelius]

I just wanted to add something to my advice about prepping these, that I'd forgotten to mention. If the fossil itself becomes wet, it becomes INCREDIBLY delicate. As in, may fall apart with only slight pressure. It seems to be fine to get them wet (and I've found that the very, very careful application of a moist brush is sometimes essential to get off the final bits of sand), but you MUST let them dry fully and completely before doing any further prep which goes near the fossil. Once fully dry again, they seem to regain their structural integrity. Once a fossil has gotten wet, I leave it out for a day to dry before I touch it again.

[FossilSniper]

6 hours ago, Aurelius said:

I just wanted to add something to my advice about prepping these, that I'd forgotten to mention. If the fossil itself becomes wet, it becomes INCREDIBLY delicate. As in, may fall apart with only slight pressure. It seems to be fine to get them wet (and I've found that the very, very careful application of a moist brush is sometimes essential to get off the final bits of sand), but you MUST let them dry fully and completely before doing any further prep which goes near the fossil. Once fully dry again, they seem to regain their structural integrity. Once a fossil has gotten wet, I leave it out for a day to dry before I touch it again.

Thank you.
I will not have to learn the hard way. 

[LordTrilobite]

Personally, with Moroccan mosasaur fossils I only apply water when it's absolutely necessary. Generaly I prep them dry by purely mechanical means and use cyanoacrylate to stabilise the clean areas.