Need help with IDs for vertebrae from North Sulphur River, TX: Mosasaur or Turtle?

[bluefish1766]

Hi all

My son and I were going through our unsorted fossils, and we came upon two vertebrae from the North Sulphur River in Texas that appear similar in shape though differ in size.  Both have one vertebral face that is convex while the opposite side is concave.  I've read that this type of ball-and-socket joint can be found in both turtles and mosasaurs.  What do you all think?  Any help is greatly appreciated.

 

Bret 

[Jared C]

Unfortunately I can't give you a definitive answer based on shape alone. Others can, they just need to find their way here first. However, what I can say is that the odds favor Mosasaur greatly, as Mosasaur materiel around there is much more common than turtle material. That doesn't eliminate turtle yet though 

[Rockwood]

The numbers do add up. And I think most turtle vertebra are more complex.

[pachy-pleuro-whatnot-odon]

I know I'm late to the party, but thought I'd chip in anyway. For, while I have no experience with turtle vertebrae, what Jared says above is definitely true. Moreover, from a quick glance on Google, it would seem that the articular faces of turtle vertebrae are not always perfectly round, which supports my hunch that the second vertebra is indeed mosasaur. It's likely the first specimen is also a mosasaur, but I'm more hesitant to express an opinion about that one as its so fragmentary and worn.

 

May be @Harry Pristis, @digit or @jpc can exclude turtle, however, in which case both vertebrae can be confirmed as mosasaur. Nice finds either way!

[digit]

Keep in mind that when considering turtle verts that you only have compare to cervical (neck) and caudal (tail) verts as all of the thoracic verts are fused to the neural elements of the carapace. Too worn and much different looking from the limited scope of turtle verts that I'm familiar with (snappers, sliders and softshells from the Montbrook site).

 

 

Cheers.

 

-Ken

[val horn]

What of croc

[pachy-pleuro-whatnot-odon]

5 minutes ago, val horn said:

What of croc

 

I don't think I've ever heard of crocodile from the NSR...

[val horn]

there has been some croc found in nsr.  though not much,  when i look at his vertebrae and I look at a croc vertebrae that I found in florida they have very similar shapes.  I dont expect the same concave surfaces in mosassaur but I am no expert

[JohnJ]

I think both are heavily eroded mosasaur vertebrae.  The first one is a cervical (neck) vertebra. This is indicated by the remains of a small process on the ventral side.  The second is dorsal vertebra very close to the neck based on the sharp ridge opposite the neural channel.

 

From Russell's work:

 

[pachy-pleuro-whatnot-odon]

2 minutes ago, JohnJ said:

I think both are heavily eroded mosasaur vertebrae.  The first one is a cervical (neck) vertebra. This is indicated by the remains of a small process on the ventral side.  The second is dorsal vertebra very close to the neck based on the sharp ridge opposite the neural channel.

 

I agree, this is also what I'm thinking. As to comparison with crocodile, I think the sides around the ridge in the first vertebra are too rounded for the sharp process of a crocodilian...

[Harry Pristis]

6 hours ago, pachy-pleuro-whatnot-odon said:

 . . . 

May be @Harry Pristis, @digit or @jpc can exclude turtle, however, in which case both vertebrae can be confirmed as mosasaur. Nice finds either way!

I don't know much about reptile osteology, even less about their vertebrae.  I do have a large tortoise vert which may have some resemblance, though clearly not a match.

 

[jpc]

I agree with JohnJ... mosasaur.

[digit]

I think we have a consensus building.

 

 

Cheers.

 

-Ken

[pachy-pleuro-whatnot-odon]

4 minutes ago, digit said:

I think we have a consensus building.

 

Definitely, I think so too Thanks guys!