Partial mosasaur skull? So many questions!

[Jimbone]

Hello all,  I have been working on this for sometime. All the fossils were found in the same place in a 2ft square spot in pierre shale in south central Nebraska. I have pieced what I was sure about (obviously keyed or "fit" together well). All were found randomly in the 2ft square location. Some of my questions are:

1- Is this a small Mosasaur or is it a similar reptile?

2- Can more of the pieces be IDed? I can take further pictures of any piece with a scale reference. Also, I will lay the pieces out and write a number next to it for clarity.

3- what is a good method of adding pieces to the skull that will be "floating" or missing surrounding pieces to attach to? 

[PaleoNoel]

That is a spectacular find, congratulations! Definitely a small mosasaur. Perhaps a young Tylosaurus based on the protruding snout, but I'll call upon some of the mosasaur guys!

@Praefectus @pachy-pleuro-whatnot-odon @Jared C

I believe the bone above the tape measure is a quadrate.

[Jared C]

Wow, beyond all doubt a mosasaur, and spectacular one at that. The pierre shale is often unkind to vertebrate fossils, so finding this skeleton with such excellent preservation is a real achievement. Furthermore, it's pretty rare to hear about mosasaurs coming out of Nebraska - while I reason they must be there since there is some cretaceous strata, I can't think of a single specimen I've read about from the state. 

 

That quadrate (ear bone) is very Clidastes like, and on it's own makes your specimen referrable to the genus. The particularly sharp, pointed premaxilla is also suggestive of Clidastes, and I think I see a coronoid in there, steeply upturned at the rear, which would support inclusion in subfamily Mosasaurinae (which Clidastes is in)

 

 

Compare your quadrate side by side with the holotype Clidastes specimen, which bears a quadrate in the lower right of the pic

 

 

Your frontal and parietal also compares well to the C. propython holotype above.

 

 

So, in conclusion, I'd label your find as Clidastes propython.

If you like erring on the side of caution, you can also go Clidastes cf. propython. The only reason for the "cf." precaution would be because depending on who you ask, there is one other Clidastes species swimming around during the Campanian (when the Pierre shale was deposited) called C. moorevillensis. I do not have pictures of that much rarer taxon handy unfortunately.

 

Edited August 8 by Jared C

[Praefectus]

Clidastes propython based on the presence of an infrastapedial process on the quadrate. Difficult to see in the pictures, but assuming it hasn't been damaged, the curved lateral margin of the frontal also excludes C. moorevillensis. 

[trilobites_are_awesome]

Wow that's crazy!

[Jimbone]

Thank you for the direction all. Given the smaller size of the Genus Clidastes averaging 2–4 meters (6.6–13.1 ft) in length is it safe to say this is an adult?

 

I have added images of the quadtate in the same orientations of the propython reference and also moorevillesis reference I found. Also added a closer image of infrastapedial process area. Hard for me to see a difference. Top of the skull is much closer to the propython.

 

 

Moorevillensis below:

 

And some additional areas mentioned:

 

Infrastapedial process area

 

 

 

 

[TriVeratops]

I love the armature you created. Gives an idea of life appearance while also being unobtrusive. 

[Jimbone]

Any ideas on these?

 

 

 

[Jaybot]

What. A. Find.  That is amazing!  Great work so far mounting the skeleton.  That is one aspect of fossil preparation that I have 0 experience in, as everything we find here is un-associated  random bones.

 

  As far as mounting the random bones, and possibly the verts, @Ptychodus04 can probably give some great advice.

[Ptychodus04]

I would suggest adding small steel rods with thin annealed steel brackets to your existing armature to hold the floating bones. This would allow you to get the bones in the right place without a ton of restoration to fill the gaps.

[jpc]

Excellent find.  As someone else mentioned, I don't think there are any mosasaurs known from south central Nebraska, maybe not anywhere in the state.  If you ever feel inclined, I am sure the museum in Lincoln would be happy to get this as a donation... maybe even put it on display. 

 

If you can find a copy of Dale Rssell's Systematics and Morphology of American Mosasaurs, it has really good illustrations of all the isolated skull bones.    

[Jaybot]

8 minutes ago, jpc said:

As someone else mentioned, I don't think there are any mosasaurs known from south central Nebraska, maybe not anywhere in the state.

Hmm I do recall reading somewhere about the mosasaurs of the pierre shale in Nebraska.  Can't remember where, I'll try to find it later if I have the time.

[Jimbone]

Thanks @jpc I found a PDF copy. Thats a lot of information. I think I will do myself a favor and find a hardcopy.

[Jimbone]

@Ptychodus04 That method crossed my mind, I could weld a stiffer support from the existing frame down the centerline to support the first several verts and smaller bendable supports from it for floating skull pieces. Looking for typical "best practices" before getting to deep.

[Ptychodus04]

5 hours ago, Jimbone said:

@Ptychodus04 That method crossed my mind, I could weld a stiffer support from the existing frame down the centerline to support the first several verts and smaller bendable supports from it for floating skull pieces. Looking for typical "best practices" before getting to deep.

That’s how I would go about it. A 1/16” or 3/32” steel rod would bend easily once annealed and would be more than enough to hold the small bones in place. 
 

Depending on how many vertical supports you want, you could go as small as 1/4” for the main support for the verts. If you wanted only a couple vertical pieces, you will want to go a little bigger for stability.

[Andúril Flame of the West]

Wow, what a breathtaking find! 

 

And a fantastic job on putting the pieces together so well. The preservation on this piece is wonderful and I look forward to seeing any future progress on this assembly. 

[Jimbone]

I need some help with C1 atlas vertebrae. I had thought that the single piece in the images below was the C1, mainly because of the odd shape and the single intervertebral disc. Maybe it is, but it doesnt make sense with the illustration in "Systematics and morphology of American mosasaurs". With its size and symmetry of my piece, C1 atlas vertebrae it would be a good fit.  Also, the two pieces hot glued down have some Symmetry and resemble two pieces of the illustration on the left. 

 

Thoughts, ideas, suggestions?

 

Thanks,

Jim