Large Cretaceous vert

[truceburner]

This was found in a Travis County TX creek. It's 9cm long and 9.5cm wide. I find mosasaur vertebrae from time to time, but rarely this massive, and never exhibiting biconvexity. Is it indeed mosasaur? Fused intercentrum? Time to turn to TFF for help on this one. Thanks in advance.

[Max-fossils]

It does indeed kinda look like a vert, but some photos taken from above will be useful.

Also, do you know the exact age of the fossils found in Travis County? I live nowhere near Texas (I'm in the Netherlands), so I have no clue about any geology there...

Looking around on the web, it seems like most fossils date from the Cretaceous period, and are from marine species, therefore making a mosasaur vert quite probable. But it could belong to any other aquatic reptile.

 

I'm not a pro on this, so let's wait for others to give their opinion.

 

Best regards,

 

Max

 

[truceburner]

Yes, upper Cretaceous, but I'm not sure which formation this comes from. Found in a stream environment where I've found various Mosasaur verts, jaw sections, ptychodus/squalicorax/scapanorhynchus shark teeth, etc. The preservation looks very much like the typical mosasaur material found around here. I'll try to add a few more pictures.

[truceburner]

[fifbrindacier]

I agree it is a vertebra.

[Max-fossils]

Yup, looks a lot like a mosasaur vert!

 

Great find

 

Best regards,

 

Max

[JohnJ]

Bruce, I think your original thoughts were correct.  Although highly eroded, it appears to be two fused mosasaur vertebrae with only a fragment left of one of them.  Cool find.

[truceburner]

Thanks, @JohnJ. I'm thinking this paper may be relevant, but, outside of the specimen's large size, I lack any clues about where this vertebra would have been in the spinal column. Any additional thoughts appreciated. 

[BobWill]

It's hard to say from the photos but can you tell us if there is a concave surface on one end with part of another vert covering some of it?  Until John noticed it could be two verts I thought it was convex on both ends.

[erose]

Hey, Glad to see you posted this on the FF. You brought that thing up to me at Fossil Fest this weekend. I was working the club's ID table. I think JohnJ has the right diagnosis. I was was also leaning that way as well but sent you over to the University of Texas table. Guess they didn't have any better idea as well. Paleontologists are just too darned specialized. If you don't get the expert on your fossil they may not know more than the average joe.

 

Have you ever seen the Onion Creek Mosasaur at the Texas Memorial Museum? There are easily vertebrae of that size if not bigger.  Worth a visit either way.

 

Cool fossil!

 

And thanks for visiting Fossil Fest Sunday.

 

Erich

[frankh8147]

The bone structure and overall shape screams out Mosasaur. I've never dug in Texas but if I found this in New Jersey, I would definitely label it as Mosasaur without too much debate.

[truceburner]

Thanks, @erose. Yes, this is one of the ones I brought to Fossil Fest - thanks to you and the crew for putting on a great show as always. The UT paleontologists weren't sure, but asked me to check against plesiosaur, which doesn't appear to be correct. I have seen the Onion Creek Mosasaur at TMM, but it's been a while. I may have to see if I can get back over there this week.

 

I'm attaching another pic (not this specimen, totally separate) that shows what I think is going on. If we assume my vertebra is like the one furthest left in the image below, I think it must have fused with the protuberance of the vert just in front of it, and all that remains of that vert on my specimen is the convexity shown in red. Easier to see in hand, as is always the case.

 

Appreciate all of your comments. 

[erose]

That is exactly what we are all thinking.

[JarrodB]

Nice mosasaur vert.

[minnbuckeye]

So would it be living mosasaur vertebral pathology... discspondylosis??? If so, very nice find.

[LSCHNELLE]

Nice find truceburner!  I am hunting Travis County creeks also.  But,  I have never seen anything that large. Blessings on your future pursuits. 

[LSCHNELLE]

Truceburner,  this must be out of the Austin Chalk Group formations.  That would be the only place to find both Ptychodus and large Mososaur verts - unless the large vert was washed downstream into an Eagle Ford area.  Do you have any pics of the Ptychodus teeth you are finding there?  Only three species of Ptychodus have been found in the Austin Group. 

[truceburner]

Thanks for your comment, @LSCHNELLE. A few of my 10 Ptychodus finds are here. I will make an effort to photograph some of the others I've found and post them. Which three Ptychodus species are in the Austin Group? I presume P. mortoni, P. martini, and P. rugosus. For what it's worth, I'd love to add to that list! 

[LSCHNELLE]

Didn't see Austin Chalk (Kau) Ptychodus - only Eagle Ford (Kef) .  You must have both Kef and Kau outcrops upstream of your collecting location. Kau teeth generally have a low crown height except P. Rugosus - it is very rare. Your teeth have moderately high crowns. Also, small and non-medial teeth can be difficult to ID.  The first one looked like P. Anonymous. Second might have been P. Occidentalis.  A top side pic might help to verify.  The third, I am not sure.

[truceburner]

Taylor group, Ozan formation, perhaps? Certainly other formations upstream.

[LSCHNELLE]

Truceburner:  The formations you mentioned are the youngest ones that could have Ptychodus fossils. But,  they should be only the three you mentioned. Yours do not appear to be any of those three.  A large Mosasaur vert would have probably come from the Austin Group formations you mentioned (Ozan or Taylor of Santonian) or from Navarro Clay (Campanian) . During the Turonian stage they were very small reptiles (3 to 5 feet long).   The Ptychodus teeth you posted look like Turonian age Upper Eagle Ford.  So, those teeth should be coming from older upstream or nearby upfaulted outcrops.  

[JohnJ]

29 minutes ago, LSCHNELLE said:

Truceburner:  The formations you mentioned are the youngest ones that could have Ptychodus fossils. But,  they should be only the three you mentioned. Yours do not appear to be any of those three.  A large Mosasaur vert would have probably come from the Austin Group formations you mentioned (Ozan or Taylor of Santonian) or from Navarro Clay (Campanian) . During the Turonian stage they were very small reptiles (3 to 5 feet long).   The Ptychodus teeth you posted look like Turonian age Upper Eagle Ford.  So, those teeth should be coming from older upstream or nearby upfaulted outcrops.  

 

Lee, are you suggesting that the Ozan formation and undivided Taylor formations are in the Austin Group?  If so, when did this change?  I understood that the Taylor Group and Navarro Group were separate geologic units from the Austin Group. 

[LSCHNELLE]

No. I got that wrong.  I temporarily confused the Austin Group members (Atco, Vinson, Jonah, Dessau, Burditt, Pflugerville, McCown, and others) with the Sprinkle Clay (also known as Lower Taylor Marl or Ozan Formation (USGS terminology).

[JohnJ]

3 minutes ago, LSCHNELLE said:

No. I got that wrong.  I temporarily confused the Austin Group members (Atco, Vinson, Jonah, Dessau, Burditt, Pflugerville, McCown, and others) with the Sprinkle Clay (also known as Lower Taylor Marl or Ozan Formation (USGS terminology).

 

Thanks; I wondered if I'd missed a new paper on the local geology.    It's confusing enough in the field when you are in the transitions between the two groups.