Frustrating Turonian vertebra

[Jared C]

This vert was found in 91 million year old Eagle Ford strata, and while I assume it can only be fish at this point, it doesn't match any of the fish verts I compared it to ( Enchodus, Xiphactinus, Protoshyraena and Pachyrhizodus (I'm not even sure Pachyrhizodus and Protosphyraena were around in the Turonian, were they?)

 

My thoughts below - please teach me otherwise if wrong:

 

I don't think shark due to the thick, bony processes

Not Mosasaur or Plesiosaur

The placement of the processes is similar to Ichthyosaur, but that would be extremely unlikely for this time period and this vert has concentric growth rings, which to my vague knowledge, ichthyosaurs don't have

 

So, that leaves fish - but which one?

Edited June 30, 2022 by Jared C

[jpc]

shark?

 

 

[Jared C]

13 minutes ago, jpc said:

shark?

 

 

those concentric rings make me want to say shark too, as well as how evenly disc like it is - but I don't think they have the possibility of bony processes like these unless it's severely pathological?

[JohnJ]

@LSCHNELLE

@Carl

@Ptychodus04

[jpc]

55 minutes ago, Jared C said:

those concentric rings make me want to say shark too, as well as how evenly disc like it is - but I don't think they have the possibility of bony processes like these unless it's severely pathological?

That's why I gave it a question mark.  I hope someone else can tell us more.

 

[Ptychodus04]

It looks a lot like the images I’ve seen of ptychodus verts. They are thick in cross section compared to other sharks.

 

It is possible to have preserved processes on shark verts but it’s uncommon.

[ThePhysicist]

My vote is lamniform shark - doesn't look like the vertebrae of other large bony fish of that time. I think the odd processes we are seeing may be squashed haemal arches (or pathological growth of the arches)? Are there two holes on the other side? If so, I'd be even more convinced - they would be foramina for the neural arch.

 

 

^https://www.fao.org/3/a0212e/A0212E10.htm

 

Cardabiodon centrum:

^ Newbrey et al. (2013)

 

[Carl]

19 hours ago, JohnJ said:

@LSCHNELLE

@Carl

@Ptychodus04

Can't add much to this argument. I agree that the centrum is very sharklike, so pathology is a possibility.

[Jared C]

13 hours ago, ThePhysicist said:

Are there two holes on the other side? If so, I'd be even more convinced - they would be foramina for the neural arch.

 

Thank you. Hard to say if there are holes, I need to prep it closer. Thanks for the explanation!

[LSCHNELLE]

Shawn Hamm says Pachyrhizodus caninus verts. 

 

@Jared C

[siteseer]

It wouldn't be shark anyway as the neural and hemal arches are cartilaginous and wouldn't fossilize in a recognizable form like that.  Shark centra are at least partially ossified so they can be preserved - still rather fragile/easily chipped or broken.

[Jared C]

13 hours ago, LSCHNELLE said:

Shawn Hamm says Pachyrhizodus caninus verts. 

 

Blown away! Thanks for taking the trouble to ask him

[LSCHNELLE]

Your welcome. I noticed that answers were not coming very easily for us amateurs or semi-professionals and I figured that Shawn might know.

[JohnJ]

On 6/30/2022 at 10:31 AM, Jared C said:

I'm not even sure Pachyrhizodus and Protosphyraena were around in the Turonian, were they?

 

LINK

[LSCHNELLE]

On 6/30/2022 at 10:31 AM, Jared C said:

I'm not even sure Pachyrhizodus and Protosphyraena were around in the Turonian, were they?

 

Yes they were. Per this scholarly article of one from the early Turonian. 

https://www.researchgate.net/figure/Disarticulated-skull-bones-of-Pachyrhizodus-caninus-COPE-1872-CPC-301-from-the-early_fig5_233565447